permeability porosity packing

15
1 These powerpoint files were produced for the Earth History class at the Free University Berlin, Department of Geological Sciences The copyright for texts, graphical elements, and images lies with C. Heubeck, unless otherwise specified. Download, reproduction and redistribution of theses pages in any form is hereby permitted for private, personal, non-commercial, and class-related purposes use as long as the source is identified. Despite of my efforts, I cannot guarantee the completeness, correctness and actuality of the material. Prof. Christoph Heubeck Institut für Geologische Wissenschaften Freie Universität Berlin Malteserstr. 74-100 12249 Berlin GERMANY ph: ++49-(0)30-83870695 fax: ++49-(0)30-83870734 [email protected] http://userpage.fu-berlin.de/~cheubeck/ Packing, Porosity, and Permeability Today‘s Lecture Why is this important ? Links und Literatur Porosity and scale Porosity Development with depth as a function of … Permeability Definition Relationship to porosity Porosity Definition Types Sandstones and Carbonates Packing

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Page 1: Permeability Porosity Packing

1

These powerpoint files were produced for the Earth History class at the Free University Berlin, Department of Geological Sciences

The copyright for texts, graphical elements, and images lies with C. Heubeck, unless otherwise specified.

Download, reproduction and redistribution of theses pages in any form is hereby permitted for private, personal, non-commercial, and class-related purposes use as long as the source is identified.

Despite of my efforts, I cannot guarantee the completeness, correctness and actuality of the material.

Prof. Christoph HeubeckInstitut für Geologische WissenschaftenFreie Universität BerlinMalteserstr. 74-10012249 BerlinGERMANY

ph: ++49-(0)30-83870695 fax: ++49-(0)[email protected] http://userpage.fu-berlin.de/~cheubeck/

Packing, Porosity, and Permeability

Today‘s LectureWhy is this important ?

Links und Literatur

Porosity and scale

Porosity Development with depth as a function of …

PermeabilityDefinitionRelationship to porosity

PorosityDefinitionTypesSandstones and Carbonates

Packing

Page 2: Permeability Porosity Packing

2

Why do we need a porous system ?

Fundamentals of civilisation• water• Heat, convection and conduction• Mineralizing solutions

Permits storage (porosity) and transmission (permeability) of liquids and gases

Packing in loose sand

(Simplification: spheres, loose)

• Porosity is independent of grain size• Porosity is dependent of packing• Packing is dependent on depositional and diagenetic

history

Cubic packingCoordination number = 6; φ = 0.42)

Rhombic packing(coordination number = 8: φ = 0.26)

Differences in packing in recent dunes(fine-grained quartz sand)

Saltation

Avalanches Grain fall

39 %

47 %

43 %Schenk (1981)

Packing in loose sand

Φ =

Packing: Approximating Reality

grain sizes due to to sorting (eolian vs. alluvial fan)

grain shapes and orientations

Lithologies / solubility

Degree of cementation

Page 3: Permeability Porosity Packing

3

Packing (and Porosity) in sandstones is therefore dependent on

• Lithology (resistance against compaction)•Grain size•Grain orientation•Grain sorting•Degree of cementation

Fundamental Reservoir Properties

Porosity (φ; to store) Permeability (k; to flow)

high φ; high k

low φ; high k

low φ; low k

high φ; low k

The plumbing of a reservoir ?

http://www.micromeritics.com/pore_cor.htmlWhy is this important ?

Links und Literatur

Porosity and scale

Porosity Development with depth as a function of …

PermeabilityDefinitionRelationship to porosity

PorosityDefinitionTypesSandstones and Carbonates

Packing

Page 4: Permeability Porosity Packing

4

What is pore space ?

Cement: Chemically precipitated minerals connecting grains

Matrix: Mechanically or chemically instable particles (mostly of clay minerals, fine-grained quartz, and calcite).

Pores: A network, mostly filled with gas or liquid, of open space

Framework:mechanically stable; Sedimentedparticles

How is pore space quantified ?

Fundamental: Concentration of solids, C

C = VSolids / VTotal(%)

Porosity is therefore the ratio of pore volume to total volume.

Porosity φ is that part of the sedimentary rock notoccupied by solids.

φ = 1 - C (%)

thereforeφ = 1 - (VSolids / VTotal)

or

φ = (VTotal - VSolids ) / VTotal

Porosity Ranges

Sand and gravel 20-50 % Till 10-20 % Silt 35-50 % Clay 33-60 % Clastic sediments typically 3-30 % Limestone <1 to 30 %

Basalt 1-12 % Tuff 14-40 % Pumice - 87 %

Fractured crystalline rock 1-5 % Unfractured crystalline rock ~0.1 %

http://geodynamics.wustl.edu/classes/hydrology/lectures/ch_02/ch_02.html

What porosity types exist ?

1. DescriptiveIn sandstones: Intergranular, Intragranular, Fracture, Dissolution, .In carbonates: Many

3. Geneticprimary / secondary

2. Engineering / Technicaleffective / ineffective

Page 5: Permeability Porosity Packing

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Descriptive porosity (in a sandstone)

Intragranular

Dissolution porosity

Intergranular

Fracture porosity

Engineering Porosity

Total Porosityφt = φeff + φineff

Effective Porosity φeff

• contributes to fluid flow• connected porosity• intergranular or fracture

Ineffective Porosity φineff

• is in sandstones mostly intragranular porosity

Primary porosity:

Pore space remaining after deposition

Secondary porosity:

Results of • Dissolution of existing

minerals (grains / cement) • Sediment shrinkage• Fracturing

Genetische Porosität Genetic Porosity: Primary

Primary porosity in sandstones is mostly intergranular

Rotliegend Sandstone, Northern Germany

Page 6: Permeability Porosity Packing

6

Genetic Porosity: Secondary

• Secondary “oversized pores”: Dissolution of instable volcanic or metamorphic grains

Carboniferous Escarpment Fm., fluvio-eolian, Bolivia

Secondary porosity

Dissolved VRF, Feldspar

Secondary, intergranular, probably ineffective porosity

Rotliegend Sandstone, Northern Germany

Secondary porosity

http://www.creationresearch.org/vacrc/sem04.html

Etched Feldspar

Secondary, intragranular, probably ineffective porosity

Carbonates

Mineralogy: Calcite / Aragonite / Dolomite

Particle size

Sequence stratigraphy:Upbuilding, outbuilding, onlap, offlap …

Facies: Platform, Reef, Ramp, Slope

http://mgg.rsmas.miami.edu/groups/csl/trips/bahamas.htm

Page 7: Permeability Porosity Packing

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Why the distinction ?

varied or independentconsistentφ-k correlation

commonly inadequaterepresentativeCore plugs

feasible to impossiblefeasible or easyVisual estimate

majorminor – moderateImportance of fracturing

major!minor – moderateInfluence of diagenesis

greatly varied„negative“ of particlesPore shape

f (diagenetic and biologic processes)f (particle size, sorting)Pores sizes

Interparticle and intraparticleinterparticleTypes of primaryporosity

40-70%25-40%Amount of primaryporosity

CarbonatesSandstones

Choquette and Pray, 1970

Types of porosity in carbonates

Fabric-Selective Not Fabric-SelectiveFractureChannelVugCavern

Fabric-Selective or Not

Breccia Boring Burrows Shrinkage

Choquette and Pray, 1970

InterparticleIntraparticleFenestralShelterGrowth-Framework

Prim

ary

IntercrystalMoldic

Sec

onda

ry

Why is this important ?

Links und Literatur

Porosity and scale

Porosity Development with depth as a function of …

PermeabilityDefinitionRelationship to porosity

PorosityDefinitionTypesSandstones and Carbonates

Packing

Permeability: Definition

… is a measure of the ability of a fluid or a gas to cross a network of pores

• measured in Darcy (D, oder mD)• a measure of the degree of interconnectedness of pores• Critical neumber and size of pore throats

Page 8: Permeability Porosity Packing

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How is permeability measured ?

What influences the throughput of a fluid (Q) through a porous solid ?

Length l

Fluid viscosity µ

Cross-sectional area A

Pressure difference ∆p

l

µ

∆p

A

Q ~ A

µ∆p

l

therefore

(-)

(+)

(+)

(-)

Permeability - Darcy’s Law

Q ~ A

µ∆p

l

l

µ

∆p

A

kProportionality constant

Q = k Aµ∆p

l

What influences the throughput of a fluid (Q) through a porous solid ?

Permeability - Darcy’s Law

How is permeability measured ?Q = k A

µ∆p

l

Fluid reservoir, known volume, graded scale

Standardized geometry (A, l)Rate Q = V / t

keep ∆pund T constant

Permeability - Porosity

How are permeability and porosity related ? (in a sandstone)

0.01

0.10

1.00

10.00

100.00

1000.00

10000.00

0.00 0.05 0.10 0.15 0.20 0.25 0.30porosity (v/v)

perm

(mD

)

RT 1 > 3500 k/phiRT 2 450 - 3500RT 3 150 - 450RT 4 6.32 - 150RT 5 > 6.32

0.1µ

0.25µ

0.5µ

5 µ

2 µ

1 µ

20 µ

10 µ

Page 9: Permeability Porosity Packing

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Permeability - Porosity

How are permeability and porosity related ?

Porosity (%)

Per

mea

bilit

y(m

D)

How are phi and k related ?

0.01

0.10

1.00

10.00

100.00

1000.00

10000.00

0.00 0.05 0.10 0.15 0.20 0.25 0.30porosity (v/v)

perm

(mD

)

RT 1 > 3500 k/phiRT 2 450 - 3500RT 3 150 - 450RT 4 6.32 - 150RT 5 > 6.32

0.1µ

0.25µ

0.5µ

5 µ

2 µ

1 µ

20 µ

10 µ

• Important for permeability prediction

• Empirical equations based on calibrated samples

• z.B. Carman-Kozeny equationK ~

Pe

Sv

• Pe = effective Porosity• Sv = surface (specific per unit volume of solid) ( in turn dependent on

grain size)

K = Pe

3

5 Sv (1-Pe)2

Permeability - Porosity

Why is this important ?

Links und Literatur

Porosity and scale

Porosity Development with depth as a function of …

PermeabilityDefinitionRelationship to porosity

PorosityDefinitionTypesSandstones and Carbonates

Packing 1

3

2

4

5

6

7

8

0 5 10 15 20 25 30 35 40

Depth dependence

Factors of porosity with depth:• Maximum depth• Mean grain size • Composition• Temperature gradient• Age• Pressure• Hydrocarbon fill

Page 10: Permeability Porosity Packing

10

1

3

2

4

5

6

7

8

0 5 10 15 20 25 30 35 40

Depth dependence

Factors of porosity with depth:• Maximum depth• Mean grain size • Composition• Temperature gradient• Age• Pressure• Hydrocarbon fill

1

3

2

4

5

6

7

8

0 5 10 15 20 25 30 35 40

Depth dependence

mechanicalshaking, -1000m

grain fracturingand bending,

-1000mchemical compaction: CaCO3, SiO2-cement,

>500m

cement and mineral dissolution: carbonate, anhydrite, feldspars

through CO2 ^

dehydration of smectite to illite (2000-3000m): -15% Vol. !

completely cemented

Mechanical compaction

Rotliegender Sandstein, Norddeutschland

Grain bending

Pressure effects

Mechanical breakage of plagioclase

Page 11: Permeability Porosity Packing

11

Leaching and Dissolution

Leached tuffaceous(fine-grained volcanic) fragment

1

3

2

4

5

6

7

8

0 5 10 15 20 25 30 35 40

Depth dependence

Coase-grained

Fine-grained

Factors of porosity with depth:• Maximum depth• Mean grain size• Composition• Temperature gradient• Age• Pressure• Hydrocarbon fill

1

3

2

4

5

6

7

8

0 5 10 15 20 25 30 35 40

Depth dependence

Quartzarenite

LithareniteRFs clay minerals

Factors of porosity with depth:• Maximum depth• Mean grain size • Mineralogical composition• Temperature gradient• Age• Pressure• Hydrocarbon fill

1

3

2

4

5

6

7

8

9

10

0 10 20 30 40

Lithic ss (>>5% / km)

Arkosic

ss(~5

% / km)

Quartz

ose ss

(< 5%

/ km)

Dickinson and Suczek (1979)

Page 12: Permeability Porosity Packing

12

1

3

2

4

5

6

7

8

0 5 10 15 20 25 30 35 40

Depth dependence and mineralogical composition

Quarzarenite

LithareniteRFs clay minerals

0 10 20 30 40 50 60 70 80 90 100

Qm

0

10

20

30

40

50

60

70

80

90

100

F

0

10

20

30

40

50

60

70

80

90

100

Dissected Arc

R e c y c l e d

Transitional Arc

Undissected Arc

Basement Uplift

Transitional Continental

CratonInterior

quartzose rec.

transitional rec.

lithic rec.

L0 10 20 30 40 50 60 70 80 90 100

Q

0

10

20

30

40

50

60

70

80

90

100

F

0

10

20

30

40

50

60

70

80

90

100

Dissected Arc

Recycled Orogen

Transitional Arc Undissected

Arc

Basement Uplift

Transitional Continental

CratonInterior

Composition and provenance

1

3

2

4

5

6

7

8

0 5 10 15 20 25 30 35 40

Depth dependence and mineralogical composition

LithareniteRFs clay minerals

Folk; 1951, nach Blatt, 1980

0 Low Moderate High Extreme

Removal of Clay

MatureSubmature SupermatureImmature

Much Clay Little or no clay

Grains not well sorted Grains well sorted

Grains not rounded Grains rounded

Sorting of nonclayfraction Rounding of grains

Total input of modifying kinetic energy

Quarzarenite

Mechanical compaction and porosity

Devonian greywacke, Taunus, Germany

1

3

2

4

5

6

7

8

0 5 10 15 20 25 30 35 40

Depth dependence

High: 4°C / 100m

Low: 1.3°C / 100 m

Factors of porosity with depth:• Maximum depth• Mean grain size • Mineralogical composition• Temperature gradient• Age• Pressure• Hydrocarbon fill

Page 13: Permeability Porosity Packing

13

1

3

2

4

5

6

7

8

0 5 10 15 20 25 30 35 40

Depth dependence

Carboniferous

Jurassic-CretaceousPermo-

Triassic

Paleocene

Selley, 1978

Factors of porosity with depth:• Maximum depth• Mean grain size • Mineralogical composition• Temperature gradient• Age• Pressure• Hydrocarbon fill

1

3

2

4

5

6

7

8

0 5 10 15 20 25 30 35 40

Depth dependence

Overpressurecompartments due to high

pore pressure

Factors of porosity with depth:• Maximum depth• Mean grain size • Mineralogical composition• Temperature gradient• Age• Pressure• Hydrocarbon fill

1

3

2

4

5

6

7

8

0 5 10 15 20 25 30 35 40

Depth dependence

Oil fill preventscementation

Factors of porosity with depth:• Maximum depth• Mean grain size • Mineralogical composition• Temperature gradient• Age• Pressure• Hydrocarbon fill

Why is this important ?

Links und Literatur

Porosity and scale

Porosity Development with depth as a function of …

PermeabilityDefinitionRelationship to porosity

PorosityDefinitionTypesSandstones and Carbonates

Packing

Page 14: Permeability Porosity Packing

14

How is permeability (k) and porosity (φ) related ?

• (sub-) microscopic pore scale (µm - mm)• hand sample (mm - dm)• outcrop (m - 100 m)• reservoir (100 m - x km)• basinal scale (xx km - xxxx km)

How is permeability (k) and porosity (φ) related ?

Grain and Pore Scale

Coarse Medium Fine Very Fine Silt

Very Poor

Poor

Moderate

Well

Very Well

Extremely well

0.125 0.0625 0.251.0 0.5 0.044

Grain Size

Sorti

ng

26

28

30

34

38

40

42

32

36

400

200

100

50 25 10 5

2.5

1.0

0.5

0.2

After Beard and Weyl, 1973

1-100µ

0.1-10 mm

1-10 cm

0.1-1m

φmin

φmax

Kmin ?Kmax ?

Levels of Reservoir Heterogeneity

0.1-10 km

1- 100 m

How is permeability (k) and porosity (φ) related ?

Grain and Pore Scale

Kaolinite

Hairy IlliteRotliegendes-Problem

http://www.creationresearch.org/vacrc/sem02.html

Page 15: Permeability Porosity Packing

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How is permeability (k) and porosity (φ) related ?

Reservoir or outcrop scale

Simple Tank

Layered Tank

NaturalReservoir

Permeability - Porosity

Literature

• Moore, Clyde H., 2001, Carbonate Reservoirs: Developmetns in Sedimentology, 55; Elsevier.

• Füchtbauer, Sedimente und Sedimentgesteine, p. 150-161.

• Blatt, H., 1990, Sedimentary Petrology (for diagenesis)

• Hutcheon, I., 1990, Aspects of diagenesis in coarse-grained silicilcastic rocks: in McIlreath, I., and D.W. Morrow, eds., Diagenesis: Geoscince Canada Reprint Series 4, p. 165-176.

• Allen, J.R.L., 1985, Principles of Physical Sedimentology (Chapter on Packing, p. 21-38)

• Barwis, McPherson, J.G., and Studlick, J.R.J., eds., Sandstone Petroleum Reservoirs: Springer (New York), 583 p.

• Wilson, M.D., 1994, Reservoir Quality Assessment and Prediction in Clastic Rocks: SEPM Short Course Notes 30, 432 p.

Permeabilität - Porosität

Links

• Eine virtuelle Tour durch die Porenräume eines Ölreservoirs (Pilotstudie des US DOE) http://greenwood.cr.usgs.gov/pub/dds/dds-033/USGS_3D/ssx_txt/all.htm

• Porosität und Permeabilität, angewandt auf die Erdölgeologie eines ganzen sedimentärenBeckens: http://www.ags.gov.ab.ca/AGS_PUB/ATLAS_WWW/ATLAS.HTM

• AAPG webseite: http://www.aapg.org

• Handout for the Geol 463 class at the University of Saskatoon (where is that ? Ask your Instructor); a few pages of good text; some figures : http://www.usask.ca/geology/classes/geol463/46306b.pdf

• Debra K. Higley, Michael P. Pantea, and Roger M. Slatt, 1997, 3-D Reservoir Characterization of the House Creek Oil Field, Powder River Basin, Wyoming: U.S. GEOLOGICAL SURVEY DIGITAL DATA SERIES DDS-33; Website, http://pubs.usgs.gov/dds/1997/dds-033/USGS_3D/ssx_txt/all.htm, V1.00 (access Dec. 11, 2002)