currently, the ute tribe, ute allottees, and the ute distri
TRANSCRIPT
UINTAH AND OURAY RESERVATION Currently, the Ute Tribe, Ute Allottees, and the Ute Distri-
Introduction bution Corporation in joint management hold 102,000 acres under lease, and more than 490 wells in production. The Utah Oil, Gas,
The Uintah and Ouray Indian Reservation is located in the Uinta Ba- and Mining Board conduct conservation spacing in cooperation
sin, in northeast Utah (FIGURES UO-1 and UO-2). The terrain is High with the Ute Tribe. Spacing rules for the Altamont-Bluebell field
Mountain desert in the central part of the basin, which is surrounded are set at a multi-well level allowing two wells per section, while
by mountain ranges on the edge of the basin. Elevation varies from undesignated field spacing is 40 acres for oil and 640 acres for gas.
approximately 5,600 feet to over 11,000 feet above sea level. The Some variations or exceptions exist by special ruling and order
area's main transportation conduit is U.S. Highway 40, which leads (Anderson, 1995).
east to Salt Lake City, Utah, and west to Denver, Colorado. The basin covers approximately 11,500 square miles, and Ute Indian Tribe jurisdiction comprises just over 4 million acres of this area, reaching from the Utah-Colorado border west to the Wasatch Mountain range.
Mineral Ownership
The Uintah and Ouray Indian Reservation is a checkerboard ownership reservation containing Ute Indian Tribe, Ute Indian Allotted, Ute Indian Tribe and Ute Distribution Corporation Jointly Managed Indian Trust minerals, along with fee (privately owned) and federal minerals. Indian properties cover approximately 1.2 million surface-owned acres, and 400,000 mineral-owned acres within the 4 million-acre jurisdictional boundary. Ute Indian Allottees, the Ute Indian Tribe, and the Ute Distribution Corporation own both surface and mineral properties in joint management.
112O 111O 110O 109OO 108O 107O
WA
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UINTA MOUNTAINS
WYOMING
UINTA BASIN
BO
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UTA
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Figure UO-2. Index map showing the Uintah and Ouray Indian Reservation in yellow (modified after Anonymous, 1995).
0 5 10 20 30
Scale, miles
N
L E G E N D
Oil Field
Gas Field
Reservation Boundary
COUNTY
CARBON
DUCHESNE COUNTY
COUNTY
Price
CARBON COUNTY COUNTY
MERY
PETERS POINT
COUNTY
UTAH
WASATCH
NUTTER CANYON
CHOKECHERRY CANYON
INDIAN RIDGE
FLAT ROCK
UINTAH COUNTY
COUNTYGRAND
MOON RIDGE
SEGUNDO CANYON
GR
EE
N
UINTAH
DUCHESNE
BLUE BENCH
FLAT MESA
WEST PLEASANT VALLEY
RIVER
PARIETTE BENCH
CASTLE PEAK
REFUGE
RANDLETT GYPSUM
HILLS
Fort Duchesne
Duchesne
MONUMENT BUTTE
WEST GUSHER
EAST GUSHER
Vernal
BITTER CREEK
SOUTH OURAY
UTE TRAIL
CHAPITA WELLS
Ouray
WONSITS VALLEY
BRENNER BOTTOM
HORSE SHOE BEND
BLUEBELL
ROOSEVELT
COTTONWOOD WASH
STARR FLATS
ALTAMONT TREND
CEDAR RIM
CEDAR STARVATION
ALTAMONT
DAGGET
UINTAH
DUCHESNE
COUNTY
COUNTYCOUNTY
COUNTY
COUNTY
SUM
MIT
WASATCH
RED WASH
Figure UO-1. Location of Uinta Basin and surrounding structural and physiographic features.Yellow area shows approximate boundary of Uintah and Ouray Indian Reservation (modified after Cashion, 1992).
UINTAH AND OURAY INDIAN RESERVATION Overview UTAH
39O
1
Uintah and Ouray Reservation Petroleum Exploration and Development
The Uinta Basin is a rich source of many energy-producing minerals. The greatest portion of the energy resources is hydrocarbons in the form of coal, oil, gas, oil shale, and bituminous sandstone and limestone.
Resources contained within the Uintah and Ouray Reservation include conventional and unconventional hydrocarbon deposits of oil and gas, oil shale, and tar sands in major quantity; coal, uranium, silver, copper, gold, gypsum, and phosphate are also present in minor to mid-economic quantities.
Cretaceous and older rocks contain many productive oil and gas zones. However, the major portion of the energy production from the Uinta Basin is from Tertiary rocks, and the distribution of the hydrocarbons and minerals is directly related to their depositional environment.
Uinta Basin production of oil and gas began in the late 1940's, with major development commencing in the late 1960's and expanding in the late 1970's and early 1980's. Over 300 million barrels of oil (MMBO) have been produced from the Greater Altamont-Blue-bell field alone. Conventional oil and gas deposits have been extensively explored and developed. The Green River and Wasatch Formations contain the bulk of the producing zones, with depth to these zones ranging from 6,000 to 18,000 feet. This has resulted in the development of the Greater Altamont-Bluebell oil field, and numerous undesignated smaller fields (FIGURES UO-2, UO-6).
The oil produced is high in paraffin content (pour point = 120 degrees F), making it an excellent gasoline refining feedstock. It is extremely rich with associated natural gas, with values falling between 900 and 1700 British thermal units (Btu). Only one natural gas field has been developed, and it is located east and south of the Green and White Rivers. It is bordered by the Natural Buttes Gas Field Unit, which covers 76,000 acres.
Total Ute Indian oil production approximates 1,250 barrels per day, a level that has held for the last 10 years. New well development and workover activity has been sufficient to offset the normal decline of the many oil and gas fields within the basin and the reservation area (Anderson, 1995).
Geology of the Uinta Basin
The Uinta Basin is a major sedimentary basin in the western-central Rocky Mountain province. It is bounded by the Uinta Mountain Uplift on the north and by the Wasatch Mountain Uplift and the eastern faulted margin of the Wasatch Plateau on the west. On the southwest and south, the San Rafael Swell and the Uncompahgre Uplift border the basin (FIGURES UO-2 and UO-3). The southern basin edge is generally considered to be the Book and Roan Cliffs, escarpments of Upper Cretaceous and Lower Tertiary formations which dip northwest,
north, and northeast into the basin. The northwest-southeast trending salt folds of the northern Paradox Basin plunge beneath the Book Cliffs in the southernmost part of the basin, and the two downwarps merge imperceptibly in this area. On the east, the Uinta Basin is separated from the Piceance Basin of northwest Colorado by the Douglas Creek Arch, which parallels the Utah-Colorado border (FIGURE
UO-3). The basin is quite asymmetric. Beds on the north flank dip 10 to
35 degrees south, whereas beds on the south flank dip only 4 to 6 degrees north (Chidsey, 1993). The north flank is highly complex, with
major faulting, steep to overturned beds, and multiple unconformities that allow youngest Eocene rocks to lie unconformably on top of Precambrian rocks. The basin axis is close to the mountain flank and moves northward with depth.
The Uinta Basin formed in Late Cretaceous and Paleocene time when, in response to rapid uplift and formation of the Uinta Mountains, the dominant north-south tectonic and sedimentation patterns of Cretaceous time shifted to west-east. The Uintas impose a dominant west-east trend through most of the basin; however, structures in the southeast portion have a strong northwest grain, reflecting the older buried Uncompahgre and Paradox trends.
Figure UO-3. Location and structural element map of the Uinta and Piceance Basin Provinces (modified after Gautier et al., 1995).
0
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25
KILOMETERS
SAN
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SWEL
L Green River
38o
40o
UT WY CO
AXIAL
UPLIFT Rangely
Springs
Grand Junction
CLIFFSBOOK
UINTA
BASIN
BOOK CLIFFS
PICEANCE CREEK
GUNNISON UPLIFT
WHITE RIVER
UPLIFT
UNCOMPAHGRE UPLIFT
SAWATC
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Craig
UPPER
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UINTA MTNS. UPLIFT
Price
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108 o106
UT CO
EXPLANATION
Upper Cretaceous rocks present
Thrust fault
25 50
50 MILES
SANDWASH BASIN
Vernal
Glenwood
BASIN EAGLE BASIN
CRETACEOUS
EROSION
PROVINCE BOUNDARY
Upper Cretaceous rocks absent
UINTAH AND OURAY INDIAN RESERVATION Geology UTAH
2
The Uinta Basin is filled with 30,000 to 32,000 feet of sediment in its northern and deepest portion (Figs. UO-4 and UO-5). Although the majority of the rocks exposed on the reservation are of Tertiary age, some pre-Tertiary age rocks are exposed on the northern and northwestern boundaries. Percentages of basin strata are subdivided as follows:
Tertiary (Eocene - Paleocene) 55% Upper Cretaceous - 25% Triassic - Lower Cretaceous 10% Paleozoic - 10%
GEOLOGIC TIME
GROUP AND FORMATION
CHARACTER OF BEDS THICKNESS (ft.)
EAST WEST
Quaternary Alluvium Alluvium, gravel surfaces, talus deposits, and other windblown deposits
Pleistocene Glacial Deposits Glacial drift, alluvium, and terrace deposits 0-70 0-70
Ter t
iary
Miocene Bishop Conglomerate Conglomerate, boulders 1 to 6 feet in diameter, sand and gravel
0-500 0-500
Oligocene Duchesne River Formation Varicolored shale, sandstone, and conglomerate 1370 1500
Eocene Uinta Formation Shale with sandstone interbeds 700-1650 1800-5400
Green River Formation Green to white shale, sandstone, oil shale in middle of formation
1800-2400 0-5000
Wasatch Formation Varicolored sandstone, shale, limestone 0-5000
Paleocene deposits absent due to unconformity
Cretaceous Currant Creek Formation Conglomerate, sandstone, and varicolored shale 0-4800
North Horn Formation Varicolored shale with sandstone interbeds 0-400 0-200
Upper Cretaceous
Mesaverde Group Upper section - Brackish-water sandstone, sandy shale, carbonaceous shale, and coal
0-3000 1000-2200
Lower section - Marine sandstone 0-500 300-1000
Mancos Shale (including Frontier Sandstone Member)
Black marine shale, thick massive sandstone, shaly sandstone
5000-6000 800-3500
Dakota Sandstone Cross-bedded tan sandstone 30-50 30-50
Jurassic Morrison Formation Varicolored shale with sandstone interbeds 780-800 780-800
Triassic Chinle Formation Shale with minor sandstone and conglomerate 230 300-380
Moenkopi Formation Shale, sandstone, siltstone, and limestone 2300 800
Permian Park City Formation Argillaceous, sandy limestone 80-500 80-500
Pennsylvanian Weber Sandstone Massive sandstone 1000-1500 1000-1500
Morgan Formation Varicolored shale and limestone with sandstone 300-800 300-800
Mississippian
Upp
er
Manning Canyon Shale Humbug Formation Great Blue Formation Interbedded shale, limestone, and sandstone 0-900 0-900 Molas Formation Doughnut Formation
Redwall Formation
Low
er
Leadville Formation Deseret Formation
Massive dolomite and limestone 0-1100 0-1100
Madison Formation
Devonian Sandstone, shale, carbonate 1000 2000
No identifiable Silurian or Ordovician deposits
Cambrian Tintic Quartzite or Lodore Formation
Sandstone, shale, and carbonate 0-2000 0-2000
Precambrian Uinta Mountain Group Quartzite with shale and conglomerate 12,000-20,000
Uncompahgre Suite Schist, gneiss, and granite
JUR
AS
SIC
TR
IAS
SIC
PE
RM
.P
EN
N.
p C
SIL.
UINTA BASIN PICEANCE BASIN AXIAL UPLIFTDOUGLAS CREEK ARCH
Browns Park Fm.
UTAH COLORADO
Duchesne River Fm. Uinta Fm. Green River Formation
Colton Fm. Wasatch
Fort Union FormationsFlagstaff Limestone
North Horn Formation
Wasatch Fm.
Lance Formation Lewis Shale
Mesaverde Gp.Price River Fm.
Sego Sandstone
Castlegate Sandstone Blackhawk Fm.
Mancos "B"
Mancos Shale
Ferron Sandstone Tununk Shale
Emery Sandstone
Frontier Formation
Mowry Shale
Dakota Sandstone
Entrada Sandstone
Navajo Sandstone
Cedar Mountain Formation
Morrison Formation
Stump Formation
Preuss Formation
Ankareh Fm.
Twin Creek–Carmel Formation
Curtis Formation
Chinle Formation Gartra Member Shinarump Conglomerate
Thaynes Limestone
Woodside Shale Moenkopi Formation State
Bridge Fm.Cutler Formation
Upper Weber SandstoneUpper Weber Sandstone
Lower Weber Sandstone Lower Weber Sandstone
Park City Fm. (Phosphoria)
Morgan Formation
Round Valley Limestone
Morgan Formation Minturn
Formation
MaroonFormation
Belden Shale Manning Canyon Shale
Humbug Fm. — Doughnut Sh.
Deseret Limestone
Madison Formation Madison Formation
Pinyon Peak Fm.
Leadville Limestone
Chaffee Fm.
Manitou Fm.
Dotsero Fm.
Sawatch Sandstone
Precambrian
Ophir Shale
Lodore Sandstone
Significant oil production
Significant gas production
Source rocksS
S
S
S
S
S
S S
S
S
S ?
S
S S
S
S
S
S
S
Currant C
reek
Conglom
erate
TE
RT
IAR
YC
RE
TAC
EO
US
MIS
S.
DE
V.C
AM
B.
ORD.
Figure UO-5. Diagram showing general correlation of rock units from the Uinta Basin, Utah, to the Axial Uplift, Colorado, and significant producing and source horizons (modified after Spencer and Wilson, 1988)
Figure UO-4. General stratigraphic column of the Uinta Basin (modified after Anonymous, 1995).
UINTAH AND OURAY INDIAN RESERVATION Geology Overview 3 UTAH
�During Eocene time (38-50 million years ago) lar ge amounts of sediment from adjacent higher areas were deposited in lacustrine and fluvial environments in the basin. These sediments, assigned to the Wasatch, Green River, and Uinta Formations, are perhaps more than 15,000 feet thick in the center of the basin, and contain important mineral resources (FIGURE UO-6). �Much of the area no w occupied by the Uinta Basin was covered by a large lake during Eocene time. Lacustrine marlstone, oil shale, limestone, siltstone, and sandstone of the Green River Formation were deposited in the lake. During the lake's expansionary periods, fluvial sediments were deposited which are now beneath and periph eral to the lacustrine sediments. These fluvial deposits form the shale, sandstone, and conglomerate of the Wasatch Formation. As the lake receded, fluvial sediments were deposited on its periphery, and eventually covered the entire area formerly occupied by the lake. These deposits comprise the Uinta Formation (Anderson,1995).�
Uinta Formation The Late Eocene Uinta Formation consists of fluvial deposits that overlie the Green River Formation from the last phase of Lake Uinta. Later, the lake filled up with volcaniclastic material, followed by abundant bedded evaporites. Depths to the top of the formation range from 2,566 feet to 3,678 feet, with the average being 3,554 feet. �Most of the production is from the Lo wer Uinta, which is a tran sitional unit between the Green River Formation and the fluvial Up per Uinta. The Lower Uinta is 350 to 450 feet thick in the Horse shoe Bend field, a reservoir that has produced over 15 BCF of non-associated gas and 5,000 barrels of condensate. This is the only res ervoir that has produced at least 5 BCFG from the Uinta Formation, although minor production exists elsewhere in the basin (FIGURES
UO-6 and UO-7). �The primary dri ve mechanism is gas expansion and gravity, and
0
0
1
1
2 3
2 3mi
4km
Horseshoe Bend
1600
D
U
1400
1800
2000
2200
R21E R22E
T 6 S
T 7 S
6 1 6
31 31
6
31 36 31
Producing gas well
Abandoned gas well
Field boundary
Federal no. 3
N
UINTA
COLORADO
0
0
10
10 20 30 40 20 30mi
50km
FERC
designated area
House 3
Buttes 2,3
2 2
Horseshoe Bend
1
2
Butte 2
Bluebell 2,3
Cedar Rim 2,3
2,3 Altamont
CO
LOR
AD
O
Duchesne
MOUNTAINS
WYOMING UTAH
UINT A
B ASIN
UTAH
Tight formation
Rock Natural
Powder Springs Walker
Hollow
Wonsits Valley
Vernal
Monument
Maximum extent of Uinta Basin plays
Rangeley
the trap is an updip stratigraphic pinch-out. The average monthly gas production has been increasing since 1981 due to development drilling and new wells that were drilled in the ear ly to mid-1980s. �The Uinta F ormation is rarely a primary drilling target, but it is a shal low, low cost target with potential for new discoveries (Morgan, 1993a).
�Green River Formation � The Eocene-Paleocene Green River Formation is 2,000 to over 8,000 feet thick. It accumulated in and around ancestral Lake Flagstaff and Lake Uinta, along with the alluvial-fluvial deposits of the Wasatch Formation.
Figure UO-7. Structure contour map of the Horseshoe Bend area. Datum is the top of Unit A,The Green River Formation was de average porosity of Green River reservoirs ranges from 5 to 20 per
posited as thick, regionally extensive cent, and the permeability ranges from 0.1 to 42 millidarcies (mD). Uinta Formation with a contour interval of 200 ft. stratigraphic sequences in marginal �The source rocks for oil and associated g as found in the Green Only wells that have produced from the Uinta
Formation are shown (modified after Morgan,and open lacustrine environments. River Formation are interbedded organic-rich carbonate mudstones 1993a).Depths to the top of the formation range from 2,315 to 7,456 feet, and
located at depths of 8,500 to 12,500 feet in the north-central part of the basin. Hydrocarbons, which were generated in deep overpres
most wells produce from zones 3 sured zones, migrated laterally along fracture systems to shallow 4,000 feet below the top. reservoirs located on the south and east flanks of the basin. �The majority of the producing �There are more than 60 kno wn reservoirs producing from the zones are channel sandstones about 10 Green River Formation, 9 of which have each produced more than 5 to 30 feet thick, but some reservoirs BCFG (FIGURE UO-6). The Roosevelt reservoir was the first to pro produce from carbonate grainstones duce gas from this formation in 1949. Monthly production peaked in
Figure UO-6. The Uinta Basin with the maximum extent of play areas based on production and hy 10 to 20 feet in thickness (FIGURE UO- the mid-1970s, and decreased to a low in 1982. It has been increasdrocarbon shows. Reservoirs are labeled: 1, Uinta Formation; 2, Green River Formation; and 3, Wa 8). The porosity and permeability of ing since then due to in-fill drilling programs in several reservoirs satch Formation. Note outline for Federal Energy Regulatory Commission (FERC) tight formation these zones can be either reduced or enhanced by diagenetic effects. The
designated area (Wasatch/Mesaverde) in the east part of the basin. Hachured line indicates approx imate limits of Tertiary units in the Uinta Basin (modified after Chidsey, 1993a).
(Chidsey, 1993b). �
UINTAH AND OURAY INDIAN RESERVATION Producing Formations UTAH
4
N
Figure UO-8.
Net sandstone isopachs (solid lines with contour in
Alluvial-fluvial
Alluvial-fluvial
N 0
0
10 20mi
10 20 30km
Carbon Co. Emery Co.
Uintah Co. Grand Co.
Duc
hesn
e C
o.
Gre
en
Rive
r
Approximate base of T
Colton Formation
Colton Formation
Colton Formation
Was
atch
Form
atio
n
Green River Formation Uta
h C
olor
ado
Figure UO-9. Note
4926'-6975'
IPF 1900 MCFGPD 3 BWPD
Green River Formation .
Natural Buttes Field Coastal Oil Gas Corp.
CIG 62D-36-9-22
'
4400
4600
4800
5000
5200
5400
5600
5800
6000
6200
6400
Figure UO-10.
T 9 S
R17E
+1000
+1200
+1400
+1600
+1800
Duc
hesn
e C
o.U
inta
h C
o.
+8000
0
0 1km
1mi
20
20
10
10
20
30
20
20 10
Depths to the top of the formation range from 3,147 to 10,754 feet (FIGURE UO-9).
Most of the production comes from lenticular fluvial-alluvial
sandstones are usually isolated and encased in siltstones, mudstones, and shales (Figure UO-10). Porosity and permeability are generally reduced by diagenesis, so production is enhanced near or along ma
north-central part of the basin. Source rocks for the non-associated
least 5 BCFG (Figure UO-6).
The total monthly gas production increased between 1973 and 1982, and
Structure contour map with isopach of single sandstone bed, Monument Butte reservoir, Duchesne and Uinta Counties, Utah. Structure contours (dashed lines with contour interval of 200 ft.) are based on a datum approximately 150 ft. below the middle marker of the Green River Formation and show no structural closure.terval of 10 ft.) are based on one of many individual productive sandstone units encased by shale or mudstone. Isopach geometry indicates deposition of sandstone by meandering streams. The trap is created by updip pinch-out of channel sandstone to south along regional strike (modified after Chidsey, 1993b).
Marginal lacustrine
Open lacustrine
Vernal
Was
atch
Co.
Price
ertiary rocks
Major depositional facies and distribution of formations at the Paleocene-Eocene boundary.widespread Wasatch-Colton deposition in the Uinta Basin (modified after Chidsey, 1993).
Mesaverde Group
Perf.
(gross)
Was
atch
For
mat
ion
T.D. 7000' Completed: 4-26-81
S.P Res.
nw sw sec. 36 T9S R22E Uintah County, Utah
K.B. 4949
Typical SP-resistivity log of the Natural Buttes Wasatch reservoir, Uintah County, Utah (modified after Chidsey, 1993c).
Wasatch Formation
The Eocene-Paleocene Wasatch Formation is up to 3,000 feet thick. It accumulated in and around ancestral Lake Flagstaff and Lake Uinta in an intertonguing relationship with the Green River Formation. It was deposited as thick, regionally extensive stratigraphic sequences primarily in an alluvial-fluvial environment peripheral to the ancestral lakes.
channel and alluvial overbank sandstone deposits. The productive
jor fault and fracture zones. The average porosity ranges from 5 to 20 percent, and the permeability is 0.1 mD or lower.
The source rocks for oil and associated gas found in the Wasatch Formation are organic-rich carbonate mudstones of the Green River Formation, and are located at a depth of 8,500 to 12,500 feet in the
gas are organic-rich siltstones and mudstones, carbonate shales, and coals of the Mesaverde Group, located at depths of 6,000 feet or greater.
There are more than 60 known reservoirs, 5 of which have produced at
The first reservoir to produce from the Wasatch Formation was Peters Point in 1953.
has been fairly constant since then (Chidsey, 1993c).
UINTAH AND OURAY INDIAN RESERVATION Producing Formations UTAH
5
30
25
20
15
10 9
8
7
6
5
4
3
2
1
25th to 75th PERCENTILES
0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.5 2.0 2.5 3.0
PO
RO
SIT
Y, I
N P
ER
CE
NT
10th percentile
VITRINITE REFECTANCE, IN PERCENT
Type curve
90th percentile
Mesaverde Group Figure UO-11. Plot of core-plug porosity vs. reflectance for 25th
Gas from Mesaverde Group reservoirs is found in both structural and 75th porosity percentiles (joined by vertical lines) of nonmarine sandstone intervals of the Mesaverde Group, Uinta and Piceance
and stratigraphic traps. Some reservoirs, like those in Natural Buttes Field, are part of larger, basin-centered gas traps where the gas collects downdip from more permeable water-filled reservoirs. Average depth to the top of productive reservoirs ranges from 1300 to >8500 feet.
Creek Basins. Mesaverde data are compared with type curve and to 10th and 90th porosity percentiles representing sandstones in general. Note that the porosity does not decrease within the window of hydrocarbon generation (Ro of 0.070-1.8%) (modified after Nuccio et al., 1992).
The terminology of the Mesaverde Group is complex, due to facies changes that occurred as the Cretaceous Interior Sea transgressed and regressed along its western margin in the Piceance-Uin-ta Basin area. The Mesaverde consists of three dominant reservoir facies: lenticular, fluvial sandstones of the Williams Fork Formation, coals that occur in the basal portion of the Williams Fork Formation, and extensive shoreline-marine sandstones of the Iles Formation.
The fluvial sandstones of the Williams Fork Formation are approximately 4000 feet thick in the eastern part of the Piceance Basin, thinning to <2000 feet on the Douglas Creek Arch and 2200
Figures UO-12A and 12B. Map showing the region (pink area) between Ro2900 feet in Natural Buttes Field in the Uinta Basin. These sand-0.70 and 1.8%, where porosity of sandstones at the base of the Mesaverde
stones are lithic arkoses and feldspathic arenites containing authi- Group does not decrease as a function of increasing Ro. This region defines genic quartz and carbonate cement. They have low porosities, rang- the area of optimum gas recovery for A, Upper Mesaverde; B, Lower Mesaing from 7-12%, and low matrix permeabilities (<0.1 mD) due to verde (modified after Nuccio et al., 1992).
the abundance of authigenic clays. The shoreline-marine sandstones of the lower Mesaverde Iles o o o o o o o o o o o o o o o o o o111 00' 110 45' 110 30' 110 15' 110 00' 109 45' 109 30' 109 15' 109 00' 111 00' 110 45' 110 30' 110 15' 110 00' 109 45' 109 30' 109 15' 109 00'
A
Duchesne
Altamont Jensen
Gre
en R
iver
MILES0
0
10 20 30
10 20 C
OL
OR
AD
O
2.00
1.10
0.75
0.60
0.50
Price
Vernal
30 KILOMETERS
UT
AH
B
Duchesne
Altamont Jensen
Gre
en R
iver
MILES0
0
10 20 30
10 20
1.50
1.10
0.75
0.65
CO
LO
RA
DO
Price
Vernal
30 KILOMETERS
UT
AH
Formation were deposited during transgressive and regressive cycles along northeast-southwest trending shorelines. These sandstones merge with fluvial facies to the northwest and the Mancos Shale to the southeast. The most productive members are the Cozzette, Corcoran, and Castlegate Sandstones.
The Castlegate Sandstone is a clean, fine-grained, subarkose to sublitharenite, with low porosity and permeability due to pore-filling authigenic clays. It was deposited along ancient shorelines or as offshore bars. In the southeastern part of the Uinta Basin, 50-70 feet thick Castlegate sandstones produce from structural traps at depths of 8000 feet. Permeabilities range from 0.5-0.9 mD. All fields that produce from the Castlegate involve some type of structural closure, and several close against faults. Production rates are enhanced by the associated tectonic fractures.
Source rocks for gas produced from the fluvial sandstones at
o40 30' o40 30'
oo 40 15'40 15'
oo 40 00'40 00'
o
Natural Buttes Field are coals and carbonaceous shales. The source 39 45'
for the shoreline-marine sandstones is probably the Mancos Shale. Porosities of the Mesaverde Group sandstones remain unusually stable over a large vitrinite reflectance interval (FIGURES UO-11 and UO-
o39 45'
o
12), implying that sparsely explored deep central basins may hold 39 30'
some promise (Tremain, 1993).
o39 30'
o39 15'
UINTAH AND OURAY INDIAN RESERVATION
o39 15'
Producing Formations UTAH
6
Mancos Shale
As of December 1990, almost 359.5 BCF of natural gas have been produced from Upper Cretaceous Mancos Shale reservoirs (FIGURE
UO-13). Most of the production comes from the silty, tight gas sandstone reservoirs of the Mancos B (also called the Emery Sandstone) in the middle of the Mancos Shale. Gas is also produced from the Mancos A/Morapos Sandstone, a conventional, clean sandstone found in the upper transition zone between the Mancos Shale and the overlying Mesaverde Group (FIGURE UO-14).
The Douglas Creek North Field has produced >5 BCFG from the Upper Mancos/Morapos Sandstone (figure 13). In this area, the Upper Mancos consists of up to 34 feet of mud to coarse-grained, well-sorted sandstone with 20% porosity and 100 mD permeability. It was deposited as shelf sands in a marginal-marine setting, and is probably time-equivalent to the Castlegate Sandstone.
The Mancos B consists of 500 to >1000 feet of finely interbedded and discontinuous claystone, siltstone, and very fine- to fine-grained sandstone, with an average net pay interval of 30-250 feet. It is characterized by low porosities and permeabilities, with porosities ranging from 10-11% on the Douglas Creek Arch, to <2% on the flanks. Permeabilities are <0.1 mD on the average. Mancos B sediments were deposited on a northerly prograding submarine slope or foreslope, approximately 100 miles to the east of the time-equivalent Emery shoreline in Utah (Noe, 1993a).
Utah Colorado
Gas fields <5BCF >5BCF
FERC tight sand areas
Approximate line of section
Mancos Marine Sandstone play
Grand Junction
0
0
10 20 30mi
50km40302010
Rangeley Douglas Cr. N.
Philadelphia Cr.
Cathedral
Douglas Cr. W.
Dragon Trail
Lower Horse Draw
UIN
TA
BA
SIN
UNCOMPAHGRE UPLIFT
PARADOX BASIN Mesa
Delta
DO
UG
LA
S C
RE
EK
AR
CH
CO
LO
RA
DO
UTA
H
PICEANCE BASIN
C
A
B
C'
A'B
'
Douglas Cr.
3000
0
0 20,000
6,000
40,000 ft
12,000 m
Vertical exaggeration 50:1
Douglas Creek fault
Datum 3000 ft above sea level
00
100
500
200 750
300 1000
m ft
Argo Unit 2-20
sec 20, T5S, R102W
Cities Service USA 1
sec 7, T4S, R102W
Nat. Assoc. Pet Govt. 1
sec 6 T3S, R102W Superior
Unit 3 sec 1 T3S, R102W
Texas Douglas Cr. 1
sec 9 T2S,R101W
Phillips Unit B-1
sec 18, T1S, R101W
G. E. Kadane Moran 1
sec 2, T1N, R101W
Mesaverde Group
Anchor Tongue
Mancos A
Mancos B(Emery)
Mancos B
(Morapos)
L. SegoU. Sego
Mancos A
U. Sego
L. Sego
Buck Tongue
(Morapos)
Silt Marker
S.P. R
S.P. RS.P. R
S.P. RS.P. RS.P. RSP RS.P. R
Man
cos
Sha
le
5000
40
00
3000
5000
40
00
1000
2000
1000
2000
1000
2000
1000
2000
1000
2000
S N
Figure UO-14. South to north structural cross section along the Douglas Creek Arch of the Mancos B interval and other sandstones in the transitional zone between the Mancos Shale and Mesaverde Group (modified after Noe, 1993a).
Figure UO-13. Gas fields of the Upper Cretaceous Mancos Shale (modified after Noe, 1993a)
UINTAH AND OURAY INDIAN RESERVATION Producing Formations UTAH
7
UINTAH AND OURAY INDIAN RESERVATIONUTAH
TYPE LOGS a n A r r o y o F i e l d
D A K O TA S I LT
D A K O TA
S A N D S T O N E
C E D A R M O U N TA I N
F O R M AT I O N
M O R R I S O NF O R M AT I O N
E N T R A D AS A N D S T O N E
B u c k h o r nM e m b e r
B r u s h y B a s i nM e m b e r
S a l t W a s hM e m b e r
48
00
50
00
52
00
54
00
Figure UO-15. Type log from the San Arroyo Field (modified after Hill and Bereskin, 1993).
Figure UO-16. Three dimensional model of Dakota Sandstone depositional environments at Hell's Hole Field (modified after Moretti et al., 1992).
ALLUVIAL
VALLEY
COASTAL
PLAIN
FORSHORE
SHOREFACE
M I L E S
FE
ET
00
25
50
1 2 3
Distributary Channel
Braided Stream
Coastal Plain with Marshes
Cross Bedding
Beach Ridges
Foreshore Sand
Shoreface Slope and Sand
Highlands
Marine Shale
Figure UO-17. Structure contour map of the top of the Entrada Sandstone, San Arroyo/Westwater area, Grand County, Utah. The area that is productive from the Entrada Sandstone is colored in pink. The Bar X Field has produced less than 5 BCF of gas from the Entrada Sandstone. Contour interval is 500 feet (modified after Morgan, 1993b).
R 24 E R 25 E R 26 E
T16S
T17S
R 23 E
1000
500
250020001500
1000
500
0
-500
500
500
0-500
DU
D DU U
DU D
U DU
0
0
1
1
2
2
3
3
4
4 5 6
mi
km
Westwater
San Arroyo
Bar X
Producing Formations 8
Dakota Sandstone, Cedar Mountain Formation,Morrison Formation
The Dakota Sandstone, Cedar Mountain Formation, and Morrison Formation are similar in lithologic succession. Each contains a bas-al, continuous, conglomeratic sandstone or conglomerate, like the Salt Wash Member of the Morrison Formation, the Buckhorn Con-glomerate of the Cedar Mountain Formation, and the lower part of the Dakota Sandstone. This is overlain by interbedded shales and lenticular sandstones, like the Brushy Basin Member of the Morrison and the upper units of the Cedar Mountain and Dakota (Figure UO-15). The basal conglomeratic units are braided stream deposits, while the upper units of the Morrison and Cedar Mountain Forma-tions are thought to be floodplain and meandering stream deposits. The Upper Dakota was deposited in a complex coastal setting con-
sisting of coastal plain, fluvial, swamp, marsh, tidal flat, delta, beach, and nearshore marine environments (Fig. UO-16).
The Morrison Formation is approximately 350-450 feet thick, the Cedar Mountain Formation is approximately 0-150 feet thick, and the Dakota Sandstone is approximately 40-250 feet thick (Noe, 1993b).
Entrada Sandstone
In northeastern Utah, the Entrada Sandstone consists of dune and in-terdune eolian deposits associated with the northerly retreat of a Ju-rassic sea. The sandstones are gray to orange, fine- to medium-grained, well-sorted and cross-bedded.
Gas and some oil are produced from traps formed by anticlinal closures on Laramide structures. Three Entrada reservoirs have pro-duced >44 BCF gas; most of this production comes from San Arroyo Field (FIGURE UO-17). Average depth to the top of the reservoir var-ies from 5250 feet at San Arroyo to 6700 feet at Wilson Creek Field in Colorado. Average net pay thickness in the Uinta Basin is 118 feet at Westwater Field. Average porosity ranges from 16% at San Ar-
royo to 24% at Westwater.Source rocks for San Arroyo and
Westwater Fields may have been or-ganic-rich marine deposits of the Per-mian Phosphoria and Pennsylvanian Paradox Formations (Morgan, 1993b).
UINTAH AND OURAY INDIAN RESERVATIONUTAH
Figure UO-18. Location map of Rangely Field and other major and minor Weber Sandstone reservoirs (modified after Hemborg, 1993).
0 150 30 10
Fluvial
Dune
Dune
Extra
Extra
Dune
FluvialDuneExtra
Dune
Extra
Extra
Dune
Dune
Dune
FluvialExtra
Fluvial
Extra
Fluvial
Extra
Extra
Fluvial
Fluvial
Fluvial
Dune
Extra
Fluvial
Flu
vial
Ext
raD
un
eD
un
e C
om
ple
x E
xtra
Du
ne
Ext
raD
un
eD
un
eD
un
e
Sedimentarystructure
Density porosity(%)
Gamma ray(API units)
Horizontallamination
Cross-lamination
Convolutelamination Burrows Root casts
Depth(ft)
5600
5700
5800
5900
6000
6100
6200
6300
- 5800
- 5820
- 5840
- 5860
- 5880
- 5900
Depth(ft)
Extra=Extradune
Figure UO-19. Wireline log and core description of the No. 139Y UPRR, Rangely Field. Core shows one cycle of Weber deposition (modified after Hemborg, 1993)
Weber Sandstone
The Weber Sandstone is a fine-grained, subarkosic to quartz arenite of eolian origin deposited during Desmoinesian, Missourian, and Wolfcampian time. In Rangely Field, productive eolian sands were deposited in dune, interdune, and extradune environments (FIGURE
UO-19). These sandstones are either cross-laminated or massively-bedded, the cross-laminated lithofacies being the major producer with an average porosity of 12%. Permeability along laminae averages 2 mD, while permeability across laminae averages 0.4 mD.
Cumulative production from the Weber Sandstone as of 1990 is
724.7 BCF of associated gas and 772 MMBO. The Rangely Weber reservoir contributed 98.9% of the total gas production (FIGURE UO-
18). Average depth to the top of the Weber is 6500 feet, and the trap-ping mechanism in all Weber reservoirs is anticlinal closure (Hem-borg, 1993).
N
GREEN RIVER BASIN
WYOMINGUTAH
WYOMING
UTA
H
COLORADO
CO
LO
RA
DO
UINTABASIN
PICEANCEBASIN
White Riveruplift
SAND WASHBASIN
Uncompahgreuplift
RIO BLANCO
GARFIELDMESA
Thornburg
MOFFAT ROUTT
DUCHESNE UINTAH
UTAH COLO
WASATCH
Weber Sandstone play
Precambrian outcrop
Major oil and gas fields without Weber production
<5BCF Weber associated gas fields
>5BCF Weber associated gas fields
Altamont - Bluebell WonsitsValley
Ashley Valley
Vernal
Uinta Basin boundary fault Split Mtnanticlines
Red Wash
Dou
glas
Cre
ek A
rch
Yampa fault
Skull Cr. anticline
Willow Creek faultRangely
WinterValley
ElkSprings
DanforthHills
Maudlin Gulch
Moffat
Craig
Grand hogback
Glenwood Springs
North Flank fault
Henry's Fork fault
Uinta fault
Wolf Creek fault
111o 110o 109o 108o
41o
40o
0
0
10 20 30 40 50
10 40 60 80
mi
km
Producing Formations 9
Play Summary The United States Geological Survey identifies several petroleum plays in the Uinta-Piceance Basin Province and classifies them as Conventional and Unconventional (Gautier et al., 1995). The discussions that follow are limited to those with direct significance for future petroleum development in the Uintah and Ouray Indian Reservation (TABLE 1).
Play Types Conventional Plays- Discrete deposits, usually bounded by a downdip water contact, from which oil, gas or NGL can be ex-
tracted using traditional development practices, including production at the surface from a well as a consequence of natural
pressure within the subsurface reservoir, artificial lifting of oil from the reservoir to the surface where applicable, and the main-
tenance of reservoir pressure by means of water or gas injection.
Unconventional Plays- A broad class of hydrocarbon deposits of a type (such as gas in tight sandstones, gas shales, and
coal-bed gas) that historically has not been produced using traditional development practices. Such accumulations include
most continuous-type deposits.
Reservation: Uintah and Ouray Total Production in Geologic Province: Uinta-Piceance Basin Province as of 1996 Uinta-Piceance Basin Undiscovered resources and numbers of fields are
Province Area: 40,000 sq. miles (25.6 million acres) Oil:Reservation Area: 6250 sq. miles (4 million acres) Gas:
NGL:
486,712 MBO for Province-wide plays. No attempt has been made 1,992,627 MMCFG to estimate number of undiscovered fields within the 40,262 MBNGL Uintah and Ouray Indian Reservation.
Undiscovered Accumulations > 1 MMBOE Play Probability Drilling depths Pay Thickness Porosity/PermeabilityPlay Type USGS Description of Play Oil or Gas Known Accumulations Field Size and Number (chance of success) (min., mean, max.)Designation
Field Size (median, mean)Uinta Tertiary Oil and Gas Gas (15 BCFG, 18.9 BCFG)Play Fluvial and lacustrine sandstones Gas
Gas (917,288 MMCFG) Oil (2 MMBO, 2.8 MMBO) (500, 3000, 6000)ft Variable 10-15%/v, low to 1000 md 2002 in the Wasatch and Green River Both
Oil (485,592 MBO) No. of Undiscovered Fields (min., median, max., mean) 1 Oil
1 Formations. Gas (2, 6, 15, 7.1) (1000, 5000, 14000)ftOil (4, 13, 30, 14.7)
Upper Cretaceous Field Size (median, mean)
Conventional Play Shallow sandstones of the Mostly Gas Gas (129,540 MMCFG) Gas (12 BCFG, 15.2 BCFG) Gas up to 80 feet 8-18%/<0.1md
2 2003 Mesaverde Group. No. of Undiscovered Fields (min., median, max., mean) 1 (500, 3500, 6000)ft
Gas (10, 23, 50, 25.9)
Cretaceous Dakotato Jurassic Play
Fluvial Dakota Sandstone,
3 discontinuous fluvial Morrison 90% Gas2004 Sandstone, blanket eolian 10% Oil
Field Size (median, mean)Gas (10 BCFG, 13.1 BCFG)Oil (1 MMBOE, 1.5 MMBOE)
Gas Dakota - 25 feet 10-25%/Gas (579,169 MMCFG)
No. of Undiscovered Fields (min., median, max., mean) 1 (500, 3500, 6000)ft Buckhorn - 26 feet Unknown PermeabilityOil
Entrada Sandstone. Gas (3, 15, 25, 14.6) (1000, 4000, 6500)ft Morrison - 11 feet
Oil (1, 2, 4, 2.2)
Permian-Pennsylvanian Field Size (median, mean)Very high risk Oil (9 MMBO, 25.0 MMBO) Oil 11-14%/ sandstones and carbonates. Mostly Oil Oil EUR (980.5 MMBO) No. of Undiscovered Fields (min., median, max., mean) 1 275 feet
Sandstones and 2005 Permian-PennsylvanianCarbonates Play
Gas EUR (>706 BCFG) Oil (1, 4, 15, 5.7) (6000, 10000, 12000)ft Unknown Permeability
4 Basin Margin Field Size (median, mean)
Subthrusts Play 2014 reservoirs range from Both N/A
Oil (2 MMBO, 5.3 MMBO) Oil Gas (15 BCFG, 25.0 BCFG) (5000, 12000, 18000)ft Unknown No. of Undiscovered Fields (min., median, max., mean) Gas
Closures beneath thrusts,
(hypothetical) Paleozoic to Tertiary in age. 0.18
Oil (1, 2, 7, .05) (5000, 14000, 25000)ft5 Gas (1, 3, 10, .07)
Cretaceous Self-Sourced Fractured Shales Play Upper Mancos fractured shale.
1 Oil/Gas 10->50 feet 10-20%/0.01-100md(hypothetical, continuous) 2009 Best fracturing occurs in brittle Both Oil EUR(14 MMBO) Per well EUR estimates vary (500, 2800, 6000)ft
6 siltstones, carbonates, and calcareous shales.
Tight Gas Uinta Tertiary East Play
Medium- to fine-grained fluvial2015 sandstones interbedded with
(3000, 6400, 10500)ft
7 (continuous) mudstones, siltstones, shales, Gas N/A N/A 1 Gas up to 80 feet <5-9%/<0.1md
and some coal of the Wasatch Fm.
Tight Gas Uinta Medium- to fine-grained fluvial
GasTertiary West Play sandstones interbedded with up to 80 feet 4-8%/<0.01md(hypothetical, continuous) 2016 mudstones, siltstones, shales, Gas N/A N/A 1 (4500, 7500, 11000)ft
8 and some coal of the Wasatch Fm.
9
Basin Flank UintaMesaverde Play Based on widespread occurrence Gas
(hypothetical, continuous) 2018 of tight, gas-saturated continental Gas N/A N/A 1 (8000, 9500, 15000)ft 4->12%/<0.1mdand marginal marine sandstone.
Deep Synclinal UintaMesaverde Play Based on expected occurrence of Gas 3-8%
10 (hypothetical, continuous) 2020 gas-saturated tight Mesaverde Gas N/A N/A 1 (15000, 20000, 25000)ft
N/A Unknown permeability
Sandstone at depths >15,000 feet.
Table 1. Play summary chart. Conventional play type Unconventional/Hypothetical play type
UINTAH AND OURAY INDIAN RESERVATION Play Summary Table 10 UTAH
UINTAH AND OURAY INDIAN RESERVATIONUTAH
Summary of Play Types
The United States Geological Survey has identified many petroleum plays in the Uinta-Piceance Basin Province, classifying them as Con-ventional and Unconventional. The discussions that follow are limit-ed to those plays with direct significance for future petroleum devel-opment on the Uintah and Ouray Indian Reservation. Most of the following is extracted from USGS CD-ROMs DDS-30 and 35 (Gaut-ier et al., 1995). Table 1 is a summary of applicable USGS plays of the Uinta-Piceance Basin Province pertaining to the Uintah and Our-ay Reservation.
Conventional PlaysDefinition - Discrete deposits, usually bounded by a downdip water contact, from which oil, gas, or NGL can be extracted using tradi-tional development practices, including production at the surface from a well as a consequence of natural pressure within the subsur-face reservoir, artificial lifting of oil from the reservoir to the surface where applicable, and the maintenance of reservoir pressure by means of water or gas injection.
PLAY 1 - UINTA TERTIARY OIL AND GAS PLAYThe Uinta Tertiary Oil and Gas Play is based on oil and gas accumu-lations primarily in stratigraphic traps in fluvial and lacustrine sand-stones in the Wasatch and Green River Formations. The play area is limited updip by the presence of brackish and fresh water in rocks near the outcrop.
Reservoirs: Reservoir sandstones of the Wa-satch and Green River Formations are Paleo-cene and Eocene in age and are predominant-ly litharenites and feldspathic litharenites over most of the basin. Some lacustrine limestones produce in the deeper part of the basin. Po-rosities range from <10 percent in the deep Altamont-Bluebell field area to >15 percent at shallower depths (<4,000 feet).
Source rocks: The source rocks for much of the non-associated Wasatch gas in the basin are the underlying Cretaceous Mesaverde gas-prone coals, shales, and mudstones, but some may have a Tertiary origin. In the northern part of the basin, oil is the predominant hy-drocarbon. This oil comes from lipid-rich la-custrine shales and marlstones in the Green River Formation. A complex mixing of oil and gas from different sources has resulted in more gas fields at shallower depths and pre-dominantly oil in deeper reservoirs. This is the opposite of what occurs in many other ba-sins.
Timing and migration: The Mesaverde Group began generating gas in the Early Terti-ary, and the Green River Formation began generating oil and gas in the Middle Tertiary to the present. The deep (>10,000 feet) Terti-ary oil fields are highly overpressured as a re-sult of present-day hydrocarbon generation.Traps: The traps are mostly stratigraphic, but some structural-stratigraphic traps occur, such as the Red Wash Field area (EUR 175 MMBO, 373 BCFG). The largest producing area is the greater Altamont-Bluebell area, which has an estimated ultimate recovery of
260 MMBO and 378 BCFG; however, the field is being actively downspaced from 640 acres per well to 320 acres per well. This ad-ditional drilling should significantly increase recovery.
Exploration status and resource potential: The conventional gas part of this play is fairly well explored, but a maximum of 15 conven-tional fields greater than 6 BCFG may be found, according to U.S.G.S. estimates (Table 1). Because of the very large volume of oil generated deep in the basin, a maximum of 30 oil fields greater than 1 MMBO may remain to be found.
Analog Example: Greater Altamont - BluebellFigures: UO-20 and UO-21
Location: T 1 N - 4 S, R 2 E - 7 W, on ReservationProducing formations: Wasatch and Green River FormationsOther significant shows: Mesaverde Sandstone, gas;
Uintah Formation, gas and oilLithology: Fluvial sandstone, lacustrine sandstones,
limestones, dolomitesType of drive: Solution gasNet pay thickness: Multiple zones with variable thicknessPorosity: 2-20%, average >10%Permeability: Variable in individual pay sections, ranges
from very low up to 1,000 mD inunconsolidated sands
Estimated primary 316 MMBO, 360.5 BCFG, 330.2 MMBWrecovery:Other major analog fields: Greater Natural Buttes
Monument ButtesRed WashWalker HollowWonsits Valley
GreenRiver
outcrop
NorthHorn
outcrop
Coltonoutcrop
Wasatchoutcrop
GreenRiver
outcrop
Uinta and DuchesneRiver outcrop
A
A'
Price
Duchesne
Vernal
Uinta uplift
WYOMING
UTAH
UTA
H
CO
LOR
AD
O
8000'
9000'
7000
'
6000
'
5000
'
4000
'
3000
'
39o
40o
41o
109
o
110
o
111
oN
30
50
0
0
10
10
20
20 30 40
mi
km
Figure UO-20. Combined thickness of the Green River, Wasatch/Colton, and North Horn Formations with outcrop areas indicated. Contour interval is 1000 feet. Cross section A-A' is shown in Figure UO-21 (modified after Chidsey, 1993a).
Figure UO-21. Generalized southwest to northeast cross section of Tertiary rocks in the Uinta Basin showing major facies, intertonguing relationships, and stratigraphic names. Area of fluid-pressure gradients >0.5 psi/ft indicated in red. Line of section is shown in Figure UO-11 (modified after Chidsey, 1993a).
CONVENTIONAL PLAY TYPE: Uinta Tertiary Oil and Gas Play 11
6000 2000
3000 1000
00
4 8 12 16 20 mi
5 10 15 20 km
ft m
Paleozoic-Mesozoic rock
Duchesne River Fm.
Uinta Fm.
Colton Fm.
Wasatch F
m.
North Horn Fm. (part)
Colton Fm.
Green River Fm.
9000
6000
3000
SL
-3000
-6000
-9000
Altamont - Bluebell fields
North Horn Fm. (part) & Mesaverde Group
ASW
A'NE
Area of fluid-pressuregradients >0.5 psi/ft
UPPER CRETACEOUS CONVENTIONAL PLAY
This is primarily a gas play in sandstones of the Mesaverde Group at shallow depths in both the Piceance and Uinta Basins; however, discovered fields are mostly in the Piceance Basin. Fields are localized by structure, but stratigraphic traps have also been found. The play is limited downdip where the reservoirs become unconventional (tight) and is limited updip by fresh-water flushing. The Mesaverde part of this play has some areal overlap with tight Mesaverde reservoirs. The tight rocks are generally beneath and/or downdip of conventional Mesaverde reservoirs.
Reservoirs: The reservoir rocks are Cretaceous Mesaverde Group sandstones deposited in marginal-marine, fluvio-deltaic, and fluvial environments. Some very fine-grained sandstone and siltstone reservoirs were deposited in a shallow-marine shelf environment seaward of, and in part beneath, the Mesaverde Group. These reservoirs include the Mancos Shale "B" and equivalents, but much of the Man-cos "B" fields are tight and developed by drilling, although there is some potential for field growth.
Source Rocks: The Mesaverde Group source beds are organic shales (including some coals) interbedded with sandstones.
Timing and Migration: Time of generation is Late Tertiary to present. Traps: Traps are predominantly structural-stratigraphic and stratigraphic. Accumulations are found at depths of <1,000 feet to 6,000 feet, with a median depth of 3,500 feet.
Exploration Status: The conventional part of the play is well explored in the Piceance Basin and only moderately explored in the Uinta Basin. Because of the large volume of gas generated by Mesaverde source beds, the U.S.G.S. estimates that a minimum of 10 and a maximum of 50 conventional fields may be discovered (Table 1).
Analog Field Greater Natural Buttes Figures: UO-22 to UO - 25
Location: T 8-10 S, R 19-23 E (SLB&M), T 36 S, R 25-26 E (SLPM), Uinta County, Utah, on Reservation
Producing formations: Green River Formation, Wasatch Formation Mesaverde Group
Other significant shows: None Lithology: Fluvial and lacustrine sandstones,
limestones, dolomites Type of drive: Pressure depletion Net pay thickness: Individual sands may be up to 80 feet in
thickness Porosity: 8-18%, average 12% (logs) Permeability: Generally less than 0.1 mD Estimated ultimate recovery: 0.5 BCFG Other major analog fields: Devil's Playground
Red Wash Wonsits Valley
0
0
6mi
10km NOutline of gas field
Outline of oil field
Line of cross section
Fault (E-W) dashed where uncertain
Gilsonite vein (NW-SE) dashed where uncertain
T
S11
T
S10
T
S9
R18E
R21E R22E R23E
White
River
Gre
en
River
A
A'
Figure UO-22. Map of the Greater Natural Buttes Gas Field (modified after Osmond, 1992).
A A'31 MILES
GREEN RIVER FM.
WASATCH FM.
2000 FT.
MESAVERDE GROUP
2500 FT.
CASTLEGATE SANDSTONE
MANCOS SHALE
NORTH HORN FM.
Figure UO-23. Diagrammatic west-east cross section showing stratigraphy of the Greater Natural Buttes Field and position of Wasatch producing sandstones that overlie the Mesaverde. Line of section is shown in Figure UO14 (modified after Osmond, 1992).
Figure UO-25. Stratigraphic column for Greater Natural Buttes (GNB) Field, showing formations which produce oil and gas in GNB and nearby fields (modified after Osmond, 1992).
Gray-Green Shale and Fluvial SandstoneUINTA
FM.
0-1700
Gilsonite Veins
GREEN
RIVER
FM.
3800'
MAHOGANY OIL SHALE BED
'H' MARKER
Lacustrine and Marginal Lacustrine Gray-Green Shale,
Marlstone and Sandstone
DOUGLAS CREEK MEMBER
PRODUCTION
Horseshoe Bend 12 Miles N of GNB
WASATCH
FM.
2000'
White River, 5 Miles North of GNB OIL with ASSOCIATED GAS
Red Wash/Wonsits to N and NE Monument Butte and Other Fields to W
GAS Greater Natural Buttes, SE Red Wash/Powder Springs 9 Miles NE of GNB
Greater Natural Buttes Peters Point, 20 Miles SW of GNB
Red Shale and Fluvial Sandstone
NORTH HORN - FLAGSTAFF Varicolored Shales, Fluvial Sandstone, Lacustrine Limestone and Coal 'OHIO CRK CGL' - BEDS AT DARL CYN' Sandstone with Dark Chert Pebbles
West
Farrer FM. Tight Sands and Siltstones, Gray Shale and Coal
NELSEN FM. - 700FT. COAL BEARING
IMMATURE FOR GAS
MATURE
East
MESAVERDE
GROUP
2200' - 2900'
MANCOS SHALE - 5000' (Marine)
Dakota Sandstone (Fluvial)
Upper Level for Gas Generation Cuts Down, Stratigraphically, Eastward Across GNB from 1000' Above Mesaverde to below the Base of Mesaverde; Based on Coal Rank High Volitile A Bituminous R 0.85%
(Nuccio and Johnson 1986)
+-
o
Greater Natural Buttes
Book Cliffs 30 Miles S of GNB
PAL
EO
C
EN
EC
RE
TA
CE
OU
S
EO
CE
NE
SURFA
CE
Figure UO-24. Structural contour map of Natural Buttes Field. Bold line depicts approximate Reservation boundary (modified after Hill and Bereskin, 1993).
+1000
+500
+500
+1000
- 500
+1000
- 500
_0+
_0+
Field Outline
Uintah Special Meridian
Salt Lake Meridian
R 20 E R 22 E R 23 ER 21 E
T 8 S
T 9 S
T 1 0 S
T 1 1 S
Datum: Top Wasatch Formation Contour Interval: 500 feet
UINTAH AND OURAY INDIAN RESERVATION CONVENTIONAL PLAY TYPE: Upper Cretaceous Conventional Play 12 UTAH
CRETACEOUS DAKOTA TO JURASSIC PLAY
This is primarily a conventional reservoir play, but tight reservoirs are mixed with the conventional rocks. The discovered fields are mostly structurally controlled. Based on known fields, it appears to be predominantly a gas play (90 percent gas, 10 percent oil). The Cretaceous Dakota Group (including the Cedar Mountain Formation) and the Jurassic rocks were combined into one play by the U.S.G.S. because many fields produce from rocks of both ages and any structure drilled has the potential for accumulations in both. The Wilson Creek Field is the southeasternmost structure along a series of producing structures that includes the Maudlin Gulch Field. The down-dip limits of the play are where the rocks become tight and reservoirs are unconventional (>6,000 feet).
Reservoirs: The Cretaceous Dakota reservoirs vary from lenticular to continuous, and are predominantly fluvial in the play area. The Jurassic reservoirs range from discontinuous fluvial sandstones of the Morrison Formation to blanket eolian sandstones of the Entrada Sandstone. Porosities range from <11 percent to about 25 percent.
Source rocks: Source rock data for this play are lacking in the public record, but some dark shales, mudstones, and thin coals are present in the Dakota Group. The overlying marine Cretaceous Mowry
R 22 E R 23 E R 24 E
from the Dakota Group (including the Cedar Mountain Formation) and the Jurassic Entrada Sandstone (FIG
URES 27 and 28). Many of the fields have significant amounts of nitrogen and CO2 (as much as 25 percent). T
Exploration status and resource 15
potential: The play is maturely de- S
veloped for large fields, but subtle structures and stratigraphic traps
T may contain as many as 25 signifi- 15.5 cant accumulations (TABLE 1). S
- 990
26 25
- 753
30
- 710
29
- 342
28
35
-1570 - 100
- 600 - 400
36
- 617
31
- 523
32 33
0
800 - 1200- 1400
- 1600
- 828
UINTAH CO
31 32 33 34 CARBON, CO 35
- 1121
3 FENCE
- 351
CANYON
6 5 4
- 13
3
91
2
SP IEL
TYPE LOG F i e l d
M O R R I S O N
B u c k h o r n M e m b e r
B r u s h y B a s i n M e m b e r
FENCE CANYON FIELD Uintah and Carbon Counties, Utah
T E X A C O 3 F E N C E C A N Y O N
S a n A r r o y o
D A K O TA S I L T
S A N D S T O N E
C E D A R M O U N TA I N
F O R M AT I O N
F O R M A T I O N
48
00
D A K O TA
50
00
5
20
0
54
00
OO
OO
OO
O
OO
OO
O
78
00 MANCOS
SHALE
MARKER
CGL.
MORRISON FM.
79
00
8
00
0
81
00
8
20
0
PERFS: 7978-8016 Ft.
DATUM
DA KOTA SILT
DAKOTA SS
CEDAR MTN. FM.
BUCKHORN
8079-8106 Ft.T IPF: 877 MCFGPD COMPLETED: 9-29-61 16
S G E O L O G Y B Y J O H N O S M O N D
S a l t W a s h M e m b e r
0 2000' 4000' 1 M I L ESTRUCTURE MAP DATUM: TOP OF DA KOTA SILT
and Mancos Shales are both known source beds (mostly oil prone). Figure UO-26. Structure map and typical electric log from Fence Canyon Field (modified after Hill and Bereskin, 1993).
Timing and migration: The hydrocarbons were probably generated in Late Cretaceous to Early Tertiary time, and some may have migrated into younger Tertiary structures.
Traps: The known traps are predominantly structural, and some have stratigraphically modified the accumulation. Many of the fields are situated on surface anticlines; they tend to be large and were dis-
Figure UO-28. Type log from the San Arroyo Field (modified after Hill
covered relatively early in the exploration cycle. San Arroyo-East
SAN FIELD R 2 5 E R 2 6 E
T
S 1 6
U N I T
CO
LO
RA
DO
1 2 0 0
1 3 0 0
1 4 0 0
1 5 0 0
1 6 0 0
1 7 0 0
1 8 0 0
1 9 0 0
2 0 0 0
1 7 0 0
S A N A R R OYO
A N T I C L I N E
B A R - X
A N T I C L I N E
ARROYO
S A N A R R O Y O
UT
AH
DATUM: TOP OF DAKOTA SILT CONTOUR INTERVAL: 100 FT.
and Bereskin, 1993). Canyon (EUR 174 BCFG) was discovered in 1955 and produces
Figure 26
Location:
Cretaceous Mancos Shale
Lithology:
10-16%
10 BCFG
Other major analog fields:
Analog Example: Fence Canyon
T 15-16 S, R 22-23 E, (SLB&M), Uinta and Grand Counties, Utah, on Reservation
Producing formations: Dakota Sandstone, Buckhorn Conglomerate, Morrison Formation
Other significant shows:
Sandstone, white, fine-medium grained, conglomeratic
Type of drive: Gas expansion
Net pay thickness: Dakota - 25 ft., Buckhorn - 26 ft., Morrison - 11ft.
Porosity:
Permeability: Unknown
Estimated ultimate recovery:
Evacuation Creek, Hell's Hole, Park Mountain, San Arroyo
Analog Example:Figures: UO-27, UO-28
Location:
None Lithology:
Member), shale with occasional sandstone beds
10-20%
NA
Not calculated
San Arroyo
T 16 S, R 25-26 E, (SLPM), Grand County, Utah, just east of Reservation
Producing formations: Dakota Sandstone
Other producing zones: Castlegate Sandstone, Cedar Mountain and Buckhorn Conglomerate Members of the Cedar Mountain Formation, Brushy Basin and Salt Wash Members of the Morrison Formation, Entrada Sandstone
Other significant shows: Interbedded sandstone and shale (Dakota), variegated mudstone with sandstone lenses (Cedar Mountain), sandstone to conglomerate (Buckhorn
(Morrison), sandstone (Entrada)
Type of drive: Gas expansion
Net pay thickness: 13-80 feet, variable
Porosity:
Permeability:
Estimated primary recovery:
E N T R A D A
S A N D S T O N E
Figure UO-27. Structural contour map of San Arroyo Field (modified after Hill and Bereskin, 1993).
UINTAH AND OURAY INDIAN RESERVATION CONVENTIONAL PLAY TYPE: Cretaceous Dakota to Jurassic Play 13 UTAH
UINTAH AND OURAY INDIAN RESERVATIONUTAH
Analog Field: Greater Hell's HoleFigures: UO-29 to UO-31
Location: T 10 S, R 25 E, (SLB&M), Uinta County, Utah; T 1-2 S, R 104 W, Rio Blanco County, Colorado,east of Reservation
Producing formations: Dakota GroupOther significant shows: Mesaverde shales and coals, Mancos Shale (B),
Weber Sandstone (Maroon), LeadvilleLithology: SandstoneType of drive: Gas depletionNet pay thickness: 25 ft. average, max 57 ft., min 5.5 ft.Porosity: 14-18%Permeability: 0.1-10 mDEstimated ultimate recovery: 26.2 BCFG, 65,000 BC
COMPOSITE TYPE LOGHELL'S HOLE FIELD
D a k o t a S i l t
U p p e r D a k o t a A
U p p e r D a k o t a B
M i d d l e D a k o t a C
L o w e r D a k o t a D
M o r r i s o n
M a r i n e S h a l e
S h o r e f a c e t o F o r e s h o r eM a r i n e S a n d s
S h o r e f a c e M a r i n e S a n d s
C o a s t a l P l a i n ,F l u v i a l C h a n n e l ,
O v e r b a n k
B r a i d e d A l l u v i a lC h a n n e l s
C o n t i n e n t a lM u d , S i l t , a n d S a n d
T D
70
00
69
00
68
00
67
00
66
00
0 100 200 30 20 10 0 -10
Figure UO-29. Composite type log for the Dakota section at Hell's Hole, Rio Blanco County, CO, and Uintah County, UT (modified after Moretti et al., 1992).
ALLUVIAL
VALLEY
COASTAL
PLAIN
FORESHORE
SHOREFACE
M I L E S
FE
ET
0
0
25
50
1 2 3
Distributary Channel
Braided Stream
Coastal Plain with Marshes
Cross Bedding
Beach Ridges
Foreshore Sand
Shoreface Slope and Sand
Highlands
Marine Shale
Figure UO-30. Three dimensional model of Dakota Sandstone depositional environments at Hell's Hole Field. (modified after Moretti et al., 1992).
UINTAMOUNTAINS
DAGGET
MOFFAT
UINTAH
DUCHESNE
RIO BLANCO
GARFIELD
MESAGRAND
CARBON
WYOMING
UTAH COLORADO0 10 20 50mi.
UTA
HC
OL
OR
AD
O
RangelyField
AXIAL ARCH
DOUGLAS
CREE
KA
RC
H
Hell's HoleArea
UINTA
BASIN
PICEANCE
BASIN
ALTAMONT
NATURAL BUTTES
N. DOUGLAS
RED WASH
PICEANCE CR.
SAND WASHBASIN
111O
110O
109O
108O
107O
107O
41O
40O
39O Figure UO-31. Map showing the Hell's Hole area (modified after Moretti et al., 1992).
CONVENTIONAL PLAY TYPE: Cretaceous Dakota to Jurassic Play 14
UINTAH AND OURAY INDIAN RESERVATIONUTAH
Analog Example: RangelyFigures: UO-18, 19, 32, 33
Location: Rio Blanco County, Colorado, east of ReservationProducing formations: Weber SandstoneOther significant shows: NoneLithology: SandstoneType of drive: CombinationNet pay thickness: 275 feetPorosity: 15%Permeability: 25 mDEstimated ultimate recovery: 904 MMBOOther major analog fields: Ashley Valley, Thornburg
Figure UO-32. Map showing the Early Wolfcampian paleogeography of the Uinta-Piceance Basin Region during maximum transgression (modified after Johnson et al., 1992).
Highland area of low to moderate relief
Alluvial fan, alluvial plain, delta plain
Eolian dune field
Sabkha, playa, restricted shallow-marine setting
Shallow- or nearshore-marinesand-rich environment
Offshore-marine sand-rich environment
Carbonate shelf, platform, or reef
ELEPHANTCANYON
FORMATION
CUTLERFORMATION
WEBERSANDSTONE
WEBERSANDSTONE
MAROONFORMATION MAROON
FORMATION
FRONT RANGEUPLIFT
SAWATCHUPLIFT
UNCOMPAHGRE
UPLIFT
OQUIRRHGROUP
FRYINGPANMEMBER
UTA
H
CO
LO
RA
DO
Vernal
fault zone
Grand Junction
Glenwood Springs
fault
zone
Gore
Green RiverSalina
Salt Lake City
Uncompahgre fault zone
Garmesa
Price
PAKOONDOLOMITE
Craig
loessite
112o 111o 110o 109o 108o 107o
41o
40o
39o
Highland area of high to moderate relief30 mi50 km
00 100 km
60 mi
PLAY TYPE 4
PERMIAN-PENNSYLVANIAN SANDSTONES AND CARBONATES PLAY
This is primarily a play for structural and stratigraphic traps in Per-mian and Pennsylvanian sandstones and carbonates. The objective reservoirs were deposited in predominantly marine and eolian envi-ronments. Some redbeds occur, but are not part of the prospective facies.
The eastern part of the play is bounded by the expected limit of porous sandstone. The southern boundary is limited by expected presence of structural and stratigraphic traps in the Uinta Basin; the northern limit is based on the expected limit of conventional reser-voirs. This play is thought by the U.S.G.S to be very high risk.
Reservoirs: The Permian-Pennsylvanian reservoirs are both sand-stone and carbonate. The sandstones have good reservoir quality at shallow depths (<8,000 feet). The carbonates are expected to be po-rous at least as deep as 12,000 feet. The shallow sandstones (Weber Sandstone) have about 11-14 percent porosity in the only two dis-covered fields in the play.
Source rocks: The source rocks for the discovered oil fields are not known, but the Park City (Phosphoria) Formation was probably the source, requiring long-range migration. Some local Pennsylvanian marine shales may also be a source.
Timing and migration: The hydrocarbons must have migrated pri-or to Tertiary tectonism, so generation was probably during the Up-per Cretaceous.
Exploration status and resource potential: Only two fields have been found in the province, both of which are related to anticlinal closures, and both of which produce oil. The play is for oil with as-sociated gas, but it is possible that some gas fields of less than mini-mum size (6 BCFG) may also be found. Several Pennsylvanian sandstone and carbonate reservoirs produce on closures just outside the province in the Maudlin Gulch Field area (Danforth Hills Anti-cline).
The two producing fields in the play are Ashley Valley Field in Utah (EUR 25.5 MMBO) and Rangely Field in Colorado (EUR 955 MMBO, 706 BCFG). Ashley Valley produces from about 4,000 feet and Rangely from 5,500 to more than 6,000 feet. The play depths for undiscovered accumulations range from 6,000 to 12,000 feet. The play below 8,000 feet is relatively unexplored by drilling, but is
CONVENTIONAL PLAY TYPE: Permian-Pennsylvanian Sandstones and Carbonates Play 15
?
?
Maroon FmSs
Fm
Ss
Morgan Fm
Ss
Mor
gan
Fm
Maroon Fm
Belden Sh M
intu
mF
m
Ss
Mar
oon
Fm
Round
Ls
Schoolhouse
Leonardian
Virgilian
Desmoinesian
Atokan
SeriesSystemEra Eastern Uinta Basin Piceance Basin
PE
RM
IAN
Weber
Park City Fm Park City
Weber Web
erW
eber
Mor
rison
Fm
Valley
Tongue
Wolfcampian
Missourian
Morrowan
PE
NN
SY
LVA
NIA
N
PAL
EO
ZO
IC
PLAY TYPE 5 BASIN MARGIN SUBTHRUSTS PLAY (HYPOTHETICAL)
This play is primarily for closures beneath high- to low-angle thrusts. Figure UO-3 shows some of the flanking thrusts present along the northern to eastern part of the province. The play is hypothetical, and both oil and gas should be present. The only nearby analog is the Tepee Flats Field in the eastern Wind River Basin-Casper Arch area. Here, thick, unfractured Cretaceous marine shale provides a seal for an oil and gas accumulation in the Upper Cretaceous Frontier Formation.
Reservoirs: The reservoirs for this play range in age from Paleozoic to Tertiary. Reservoir quality may be poor, especially for prospects deeper than 12,000 feet. The Mississippian carbonates are expected to be porous in most parts of the play.
Source rocks: The source rocks are within the subthrust section. Possible source
rocks containing more than 1 percent total organic carbon (TOC) are found in the Lower Tertiary, Upper Cretaceous, and Pennsylvanian Belden Shale (FIGURE UO-33). The Jurassic Curtis Formation may be a local source bed.
Timing and migration: The timing is uncertain, but most of the thrusting took place during the Laramide Orogeny.
Traps: Traps are most likely structural and structural-stratigraphic (FIGURES UO-34
and UO-35). Play depths should range from 5,000 feet to as much as 25,000 feet.
Exploration status and resource potential: The play is almost unexplored by drilling and only moderately explored by seismic mapping. Based on the abundant fields near the thrusts in the Uinta Basin, a median field size of 2 MMBO and 15 BCF of non-associated gas, and a maximum field size of approximately 50 MMBO and 150 BCFG are estimated for this play.
Figure UO-33. Nomenclature and correlation for the Weber Sandstone in the East Uinta and Piceance Basins. Unconformities indicated by white patches (modified after Hemborg, 1993).
N
32 35
R 7 E
T 3 N
A A'
T 2 N
Nugget completion
5
8 contact
(-3415')
-3800 -3600
-3400-3200
-3000 -2800
-2600
-2400
-2800-3000-3200-3400-3600-3800
-3000
-320
0-3
400
-3800-3600
Oil-Water contact (-3415')
Dry Hole
Twin Creek completion
Twin Creek and Nugget completion
11
Oil-Water
4-10S 3-2 UPRR
3-3 UPRR 2-1 Bingham
2-5 Bingham,
Frontier Fm (Kf)
Aspen Sh (Ka)
Kelvin Fm (Kk)
Stump/Preuss Ss (Jsp)
Twin Creek Ls (Jtc)
Nugget Ss (Jn)
Ankareh Fm (TR a)
Thaynes Ls (TR t)
R w)
Bear Rive
r Fm
(Kbr
) Ka
Absaroka
thrust Hilliard Sh (Kh)
0
0 1km
1 mi
Oil
Jsp
Jsp
Jsp
Kk
Kk Kk
Kk
KeKe
Te
Te
Tw-TfWasatchFowkes?
+8000'
+6000'
+4000'
+2000'
-2000'
-4000'
-6000'
-8000'
-10000'
A'A WEST EAST
B
Pineview Field Evanston Fm (Te)
Wasatch Fm (Tw) 1 Pineview
1 Newton Sheep
3-9 UPRR 2-1 A
Evanston Fm (Ke)
Woodside Sh (T
Frontier Fm (Kf)
Water
Sea level
Figure UO-34. Typical geometry of a shallow east-trending structure, Pineview Nugget Reservoir, Summit County, Utah (not on reservation). Gas is trapped in an asymmetrical thrusted anticline in the hanging wall of the Absaroka Thrust system. Structure contour map of the top of the Nugget Sandstone (modified after Hjellming, 1993). Figure UO-35. Cross section through the reservoir. Line of section shown in Figure UO-34 (modified after Hjellming, 1993).
UINTAH AND OURAY INDIAN RESERVATION CONVENTIONAL PLAY: Basin Margin Subthrusts Play (Hypothetical) 16 UTAH
DEFINITION: Unconventional Plays Unconventional Play- A broad class of hydrocarbon deposits of a type (such as gas in "tight" sandstones, gas shales, and coal-bed gas) that historically has not been produced using traditional development practices. Such accumulations include most continuous-type deposits.
Cretaceous Self-Sourced Fractured Shales Play (Hypothetical)
Oil is produced from fractured Upper Cretaceous Mancos Shale and its equivalents. The best fracturing occurs in brittle siltstones, carbonates, and calcareous shales.
The play outline is based by the U.S.G.S. on the known occurrence of production and the tectonic features associated with known and suspected potential. In the play, the best open fractures occur at the maximum flexure on anticlines or monoclines. Fractures also produce well where shear zones or faults occur. The play boundary is fairly easy to define except in the area between Rangely and the Axial Uplift, where proprietary seismic data indicate the presence of several subsurface thrusts, including thrusts associated with the White River Field structure.
Reservoirs: The reservoirs are open fractures in brittle siltstones, carbonates, and calcareous and siliceous shales. The producing intervals vary from 10 feet to more than 50 feet thick. The fracturing is highly variable, and one well in the play has produced over 1 MMBO.
Source rocks: The enclosing marine shales are the source rocks. The richness varies from about one percent to more than four percent TOC, based on unpublished information.
Timing and migration: The oil was probably generated in the Late Tertiary during maximum burial.
Traps: The traps are formed by the enclosing unfractured, more plastic shale, which contains less silt and carbonate than the brittle facies. The largest accumulation in the play is found in Rangely Field (EUR 14 MMBO). The highest concentration of oil wells producing from the Mancos Shale at Rangely is along the south flank of the structure at the point of maximum flexure.
Exploration Status and Resource Potential: The play is moderately well explored by vertical wells but nearly unexplored by slant- and horizontal-hole drilling. The U.S.G.S. assumed a low success ratio for the overall play area. Although this play is classified as a contin-uous-type play (e.g., tight gas), production should be localized by individual fractured structures and fracture trends.
EUR estimates per well are extremely variable and, although the play is treated as a continuous-type occurrence, the U.S.G.S also simulated individual undiscovered fields or "sweet spots" within it to assist in assessment. On this basis, the success ratio in well-mapped struc
tural flexures is considered quite high, perhaps more than 50 percent; also, there is high potential for finding many areas of small production, and perhaps as many as 10 larger fields (Table 1).
Analog Example: Greater Douglas Creek FIGURES UO-13, UO-14
Location: Rio Blanco County, Colorado west of Reservation
Producing formations: Mancos, Mancos (B) Shale Other significant shows: Morapos Formation Lithology: Sandstone Type of drive: Pressure depletion and water drive Net pay thickness: 30-250 feet Porosity: 2-20% Permeability: 0.01-100 mD
TIGHT GAS UINTA TERTIARY EAST PLAY
This play is based on well-established gas production from the Ute-land Butte, Chapita, and Buck Canyon zones of the Tertiary Wasatch Formation. Updip to the south and east, the play limit is based on an increase in reservoir quality and a change to mostly conventional reservoirs that have gas-water contacts, which are included in the Uinta Tertiary Oil and Gas Play. Downdip to the north, the play boundary is defined as the point where it becomes predominantly an oil play and is included in Play Type 1. The western limit is along the Green River drainage, where the play becomes higher risk and has been assessed separately by the U.S.G.S. as Tight Gas Uinta Tertiary West Play (Play Type 8). The overall Wasatch tight gas plays (7 and 8) are based on vitrinite reflectance (Ro) levels in the underlying Cretaceous Mesaverde Group. Rice and others (1992) and Fouch and others (1992) showed that Wasatch gas has migrated upward from the Mesaverde Group and that the play occurs between the basal Mesa-verde Ro limits at 1.1-1.5 percent.
Reservoirs: Reservoir rocks are generally medium- to fine-grained feldspathic litharenites and litharenites deposited primarily in fluvial environments. They are interbedded with mudstones, siltstones, shales, and some coal. Porosity ranges from less than 5 percent to more than 9 percent. The reservoirs range in depth from about 3,000 feet to about 10,500 feet, having a median depth of 6,400 feet.
Source rocks: The predominant source of the gas is in the underlying Mesaverde Group (Fouch and others, 1992; Nuccio and others, 1992; Rice and others, 1992).
112 o 111o 110o 109o 108o
41o
40o
39o
38o
Contact
core samples:
CIRCLE
CLIFFS
UPLIFT
SAN RAFA
EL
SWELL
SE
VIE
R
WA
SAT
CH
P
LAT
EA
U
BO
OK
CO
LO
RA
DO
UPLIFT
UNCOMPAHGRE
CLIFFS
CREEK
PICEANCE
BASIN
NB SC
BELT
UINTA UPLIFT BASIN
Riv
er
Gre
en
30 mi 50 km
0 0 100 km
60 mi
EXPLANATION
Fault
Thrust fault
Gas well that provided
NB, Natural Buttes field SC, Southman Canyon field
Tertiary volcanic and intrusive rocks
Tertiary sedimentary rocks
Precambrian sedimentary rocks
Precambrian metamorphic rocks
Precambrian intrusive rocks
HENRY MOUNTAINS
UTA
H
WYOMING
OR
OG
EN
IC
SAND WASH
UINTA BASIN
Figure UO-36. Generalized geologic map of the Uinta Basin Province showing location of cored wells (modified after Pitman et al., 1986)
UNITAH AND OURAY INDIAN RESERVATION UNCONVENTIONAL PLAY TYPE: Cretaceous Self-Sourced Fractured Shales Play (Hypothetical) 17 UTAH
Play 8: TIGHT GAS UINTA TERTIARY WEST PLAY Play 9: BASIN FLANK UINTA MESAVERDE PLAY (HYPOTHETICAL) (HYPOTHETICAL)
This play is the western extension of Tight Gas Uinta Tertiary East Play (Play Type 7) and is separated from Play 7 along the Green River drainage. Although the river is a surface feature, it more or less coincides with a westward decrease in drilling activity and reservoir quality. It is higher risk than Play 7 and, on this basis, it was decided by the U.S.G.S to use separate assessment parameters.
Reservoirs: This play draws on the same reservoirs as Play 7, yet porosities are somewhat lower here, ranging from less than 4 percent to about 8 percent in reservoir sandstones. The play depths range from about 4,500 feet to 11,000 feet, with a median depth of 7,500 feet.
Source rocks: The underlying Mesaverde Group is the gas source. The play limits approximately coincide with maturation levels of Ro 1.1-1.5 percent in gas-prone source beds in the basal part of the Mesaverde Group.
Timing and migration: Gas generation began in the Late Tertiary and may be continuing presently in the Mesaverde in the deeper parts of the basin; however, it is possible that vertical gas migration from the Mesaverde may not be as effective as it is in Play 7.
Traps: Traps are both stratigraphic and diagenetic.
Exploration status: There is considerably less drilling activity in this play relative to Play 7. The play is only sparsely to moderately explored by drilling.
1890
1910
1930
1950
1970
1990
A B
Cor
ed
l
Cor
ed
l
1 10 100 1 10 100
Carbonate
1280
1300
1320
1340
1360
1380
OHM-M /M2
DE
PT
H
IN
ME
TE
RS
inte
rva
inte
rva
marker
RESISTIVITY,
Tusc
her
form
atio
n
Was
atch
form
atio
n (u
pper
par
t)
This play is based on the widespread occurrence of tight, gas-saturated continental and marginal marine sandstone. The south, east, and west limits of the play are based on thermal maturation levels in the basal part of the Mesaverde Group. The reservoirs grade updip into more conventional Mesaverde reservoirs having gas-water contacts (see Upper Cretaceous Conventional Play Type 2). Mesaverde burial depths greater than 15,000 feet designate the downdip (north) play boundary (Fouch and others, 1994).
Reservoirs: The reservoirs are fine- to medium-grained litharenites to feldspathic litharenites, becoming coarser to the west. Most reservoir permeabilities are <0.1 md. Porosities range from <4 percent to >12 percent, averaging about 8 percent (FIGURES UO-11 and UO-12) (Nuccio and others, 1992). Play depth varies from 8,000 feet to 15,000 feet, having a median of 9,500 feet.
Source rocks: Source rocks are gas-prone, thermally mature coals, carbonaceous shales, and mudstones of the Mesaverde Group (FIG
URES UO-11 and UO-12).
Timing and migration: Gas generation began in the Tertiary and may be continuing to the present in the deeper parts of the play. The basal Mesaverde has a thermal maturity greater than Ro 1.1 percent.
Traps: Traps are both stratigraphic and diagenetic.
Exploration status: The play is essentially unexplored due to depth, economics, poor reservoir quality, and the fact that it is mostly overlain by oil- and gas-producing rocks of the Tertiary Green River Formation.
Figure UO-37. Electric log profile of cored wells (modified after Pitman et al., 1986).
UINTAH AND OURAY INDIAN RESERVATION Unconventional Play 8: Tight Gas Uinta Tertiary East and West Plays 18 UTAH
DEEP SYNCLINAL UINTA MESAVERDE PLAY (HYPOTHETICAL)
This play is based on the expected occurrence of gas-saturated, tight Mesaverde sandstones at depths greater than 15,000 feet. The limits of the play are based on depth and reservoir quality. This play borders Play 9 and involves the same suite of rocks.
Reservoirs: Reservoir rocks are sandstones interbedded with mudstones, siltstones, shales, and some coals. Porosity is generally lower than in Play 9, and although there is almost no drilling, the U.S.G.S. expects porosity to be <8 percent to about 3 percent, having a median of 5-6 percent (Table 1). Reservoir depths are >15,000 feet, as deep as 25,000 ft, and have a median of 20,000 feet (FIGURES UO-42 through
UO-44).
Source rocks: Gas-prone organic material interbedded with sandstone has generated large volumes of gas.
Timing and migration: Gas generation commenced in the Tertiary, and may be continuing at the present time. The thermal maturity of the Mesaverde is in excess of Ro 1.5 percent, and the deeper rocks exhibit >Ro 2.0 percent.
Traps: Traps are both stratigraphic and diagenetic.
Exploration status: The play is not well explored, due to the fact that primary interest in the area is in the overlying Tertiary reservoirs.
PRICE
WA
SA
TC
H
PLA
TEA
U
SAN
RA
FAEL
UPL
IFT
Price
BOOK CLIFFS
B
Utah Lake
Green River
0
0
25 50
4020 Miles
BOOK
CLIFFS
BOOK CLIFFS
Colora
do Rive
r
CO
LO
RA
DO
Grand
UNCOMPAHGRE
UPLIFT
Natural Buttes field
PICEANCE CREEK
PCreekD
ougl
as C
reek
A
rch
Gre
en
Riv
er
Island field
field
B'
A
A'
Greater Altamont-Bluebell field
WA
SATCH
MTN
S
Lak
eM
tns
Salt Lake City
field
Oil field
Gas field
Rifle Springs
WH
ITE
RIV
ER
UPLIFT
ELKMOUNTAINS
Uinta and Piceance Creek Basins
111o 110o 109o 108o
40o
39o
CANYON
Kilometers
Sunny-side Tar Sand
UINTA
BASIN
UTA
H
Junction
BASIN
arachute
Pariette Bench
Roosevelt
Duchesne
UINTA MOUNTAINS
Vernal
Greater Red Wash
Glenwood
Rangely
Approximate outline of
Green River Fm.
Green River Fm.
Alluvial and minor lake
Upper Cretaceous Nonmarine
Neslen Fm.
Marine
Sego Sandstone
Mancos Shale
Mancos Shale
Castlegate SS and
Littoral and shelf
0.50% Rm
0.75% Rm
1.10% Rm
2.0% Rm
Eocene
16 mi 0
650 ft
A
Altamont-Bluebell Bench Island
A'
1 2 3 4 5 6 7 8
Tertiary
Open Lake; Type I
Marginal Lacustrine Mixed Lake and Fluvial Type I, II, and III Colton and Wasatch Fms. Alluvial; Type III
Tertiary and U. Cretaceous North Horn Fm.
Type I, II, and III
Tuscher and Farrer Fms. Braided and meandering fluvial; Type III
Coastal Plain; Type III
Shore, nearshore
Open marine; Type II and III
Buck Tongue of
Blackhawk Fm.; Type III;
Mes
aver
de G
roup
Paleocene
Gas Well
Oil Well
Dry Hole
Oil producing zone
Gas producing zone
Pariette
Figure UO-38. Index map of the Uinta and Piceance Creek Basins area showing location of cross-sections A-A' (Figure UO-43) and B-B' (Figure UO-44) (modified after Nuccio et al., 1992).
Figure UO-40. Cross section B-B', which ex- B tends from outcrops on the southwest flank of the Uinta Basin through the Altamont-Bluebell Field. Producing intervals for some of the basin's fields are projected into the line of section. See Figure UO-42 for line of section (modified after Nuccio et al., 1992).
6000 2000
3000 1000
0 0
4 8 12 16 20 mi
5 10 15 20 km
ft m
Uinta Fm.
Colton Fm.
Wasatch F
m.
North Horn Fm. (part)
Colton Fm.
9000
6000
3000
SL
-3000
-6000
-9000
Altamont - Bluebell fields (A-B)
North Horn Fm. (part) & Mesaverde Group
B'
BW
AB
GAS
OIL & GAS
Island
Horseshoe Bend Tertiary
Cretaceous
Paleozoic-Mesozoic rock
Duchesne River Fm.
Green River Fm.
Redwash Field (RW)
Sunnyside Tar Sand
Natural Buttes Pariette Bench
Duchesne, Monument
Figure UO-39. Cross section A-A' through the Uinta Basin, Utah, showing types of kerogen found at various stratigraphic intervals, levels of thermal maturity (Rm lines), and associated hydrocarbon producing zones. See Figure UO42 for line of section (modified after Nuccio et al., 1992).
UINTAH AND OURAY INDIAN RESERVATION UNCONVENTIONAL PLAY: Deep Synclinal Uinta Mesaverde Play (Hypothetical) 19 UTAH
REFERENCES
Anderson, R. C., 1995, ed., The Oil and Gas Opportunity on Indian Lands: Exploration Policies and Procedures, Bureau of Indian Affairs.
Anonymous, 1995, Uintah and Ouray Reservation, in Anderson, Robert C., ed., The Oil and Gas Opportunity on Indian Lands: Exploration Policies and Procedures, 1995 Edition, Bureau of Indian Affairs, p.93-106.
Cashion, W.B., 1992, Oil-Shale resources of the Uintah and Ouray Indian Reservation, Uinta Basin, Utah, in Fouch, T.D., Nuccio, V.F., and Chidsey, T.C., Jr., ed., Hydrocarbon and Mineral Resources of the Uinta Basin, Utah and Colorado: Utah Geological Association Guidebook 20, Salt Lake City, Utah U.S.A., Utah Geological Association.
Chidsey, Thomas C. Jr., 1993a, Uinta Basin [UN] Plays-Overview, in Hjellming, Carol A., ed., Atlas of Major Rocky Mountain Gas Reservoirs: New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico, p. 83.
Chidsey, Thomas C. Jr., 1993b, Green River Formation, in Hjellming, Carol A., ed., Atlas of Major Rocky Mountain Gas Reservoirs: New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico, p. 85-86.
Chidsey, Thomas C. Jr., 1993c, Wasatch Formation, in Hjellming, Carol A., ed., Atlas of Major Rocky Mountain Gas Reservoirs: New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico, p. 87.
Fouch, Thomas D., Nuccio, Vito F., Osmond, John C., Macmillan, Logan, Cashion, William B., and Wandrey, Craig J., 1992, Oil and gas in uppermost Cretaceous and Tertiary rock, Uinta Basin, Utah, in Fouch, T.D., Nuccio, V.F., and Chidsey, T.D. Jr.ed., Hydrocarbon and Mineral Resources of the Uinta Basin, Utah and Colorado: U.S. Geological Association Guidebook 20, Salt Lake City, Utah U.S.A.
Fouch, T.D., Schmoker, J.W., Boone, L.E., Wandrey, C.J., Crovelli, R.A., and Butler, W.C., 1994, Nonassociated gas resources in low-permeability sandstone reservoirs, lower Tertiary Wasatch Formation, and Upper Cretaceous Mesaverde Group, Uinta Basin, Utah: U.S. Geological Survey Open-File Report (in press).
Gautier, Donald L., Dolton, Gordon L., Takahashi, Kenneth I., and Varnes, Katherine L., eds., 1995 National Assessment of United States Oil and Gas resources- Results, Methodology, and Supporting Data: U.S. Geological Survey Digital Data Series DDS30 1995.
Hemborg, H. Thomas, 1993, Weber Sandstone, in Hjellming, Carol A., ed., Atlas of Major Rocky Mountain Gas Reservoirs: New Mexi
co Bureau of Mines and Mineral Resources, Socorro, New Mexico, p. 104.
Hill, Bradley G., and Bereskin, S. Robert, eds., 1993, Oil and Gas Fields of Utah: Utah Geological Association Publication 22, Salt Lake City, Utah, U.S.A.
Hjellming, Carol A., ed., 1993, Atlas of Major Rocky Mountain Gas Reservoirs: New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico.
Johnson, Samuel Y., Chan, Marjorie A., and Konopka, Edith A.,1992, Pennsylvanian and Early Permian Paleogeography of the Uinta-Piceance Basin Region, Northwestern Colorado and Northeastern Utah: U.S. Geological Survey Bulletin 1787-CC.
Moretti, George, Jr., Lipinski, Paul, Gustafson and Slaughter, Arville, 1992, Dakota Sandstone deposition and trap door structure of Hells Hole Field , eastern Uinta basin, Utah and Colorado, in Fouch, T.D., Nuccio, V.F., and Chidsey, T.C., Jr., eds., Hydrocarbon and Mineral Resources of the Uinta Basin, Utah and Colorado: Utah Geological Association Guidebook 20, Salt Lake City, Utah U.S.A.
Morgan, Craig D., 1993a, Uinta Formation, in Hjellming, Carol A., ed., Atlas of Major Rocky Mountain Gas Reservoirs: New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico, p. 84.
Morgan, Craig D., 1993b, Entrada Sandstone, in Hjellming, Carol A., ed., Atlas of Major Rocky Mountain Gas Reservoirs: New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico, p. 104.
Noe, David C., 1993a, Mancos Marine Sandstones, in Hjellming, Carol A., ed., Atlas of Major Rocky Mountain Gas Reservoirs: New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico, p. 99-100.
Noe, David C., 1993b, Dakota Sandstone, Cedar Mountain Formation, and Morrison Formation, in Hjellming, Carol A., ed., Atlas of Major Rocky Mountain Gas Reservoirs: New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico, p. 101102.
Nuccio, V.F., J.W. Schmoker, and T.D. Fouch, 1992, Thermal maturity, porosity, and lithofacies relationships applied to gas generation and production in Cretaceous and Tertiary low permeability (tight) sandstones, Uinta Basin, Utah, in Fouch, T.D., Nuccio, V.F., and Chidsey,T.C., Jr., eds., Hydrocarbon and mineral resources of the Uinta Basin, Utah and Colorado: Utah Geological Association Field Symposium, 1992, Guidebook 20, p. 7793.
Osmond, John C., 1992, Greater Natural Buttes gas field, Uintah
County, Utah, in Fouch, T.D., Nuccio, V.F., and Chidsey, T.C., Jr., eds., Hydrocarbon and Mineral Resources of the Uinta Basin, Utah and Colorado: Utah Geological Association Guidebook 20, Salt Lake City, Utah U.S.A.
Pitman, J.K., Anders, D.E., Fouch, T.D., and Nichols, D.J., 1986, Hydrocarbon Potential of Nonmarine Upper Cretaceous and Lower Tertiary Rocks, Eastern Uinta Basin, Utah, in Spencer, Charles W., and Mast, Richard F., eds., Geology of Tight Gas Reservoirs, AAPG Studies in Geology #24.
Rice, D.D., Fouch, T.D., and Johnson, R.C., 1992, Influence of source rock type, thermal maturity and migration on composition and distribution of natural gases, Uinta Basin, Utah, in Fouch, T.D., Nuccio, V.F., and Chidsey, T.C., Jr., eds., Hydrocarbon and mineral resources of the Uinta Basin, Utah and Colorado: Utah Geological Association Field Symposium, 1992, Guidebook 20, p. 95-109.
Spencer, Charles W., and Wilson, Robert J., 1988, Petroleum Geology and Principal Exploration Plays in the Uinta-Piceance-Eagle Basins Province, Utah and Colorado: U.S. Geological Survey Open-File Report 88-450-G.
Tremain, Carol M., 1993, Mesaverde Group, in Hjellming, Carol A., ed., Atlas of Major Rocky Mountain Gas Reservoirs: New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico, p. 97-98.
UINTAH AND OURAY INDIAN RESERVATION References 20 UTAH