• To demonstrate reservoir properties in a plan view projection with objectives to promote optimal field development.

• The maps will be used for well placement, reserves calculation, reservoir performance monitoring.

• Mapping is part of reservoir characterization, therefore the results of which very depend on the expert’s working knowledge in applied geologic models

WELL PLACEMENT

• TOP/SURFACE MAPS :– Structure Map– Fault Map– Unconformity Map

• THICKNESS MAPS :– Isopachous Map Gross & Net

• OTHERS & COMBINED MAPS :– Isoporosity Map - Isopermeability Map– Pressure Map - Saturation Map– Productivity Map - Shale Map– Net to Gross Sand Map - Etc.

Carried out by DG

MAPPINGMAPPING CONCEPTUAL WORKFLOWCONCEPTUAL WORKFLOW

1. GEOLOGIC MODEL1. FACIES2. STRATIFICATION3. CONTINUITY4. TRENDS5. TECTONIC

2. GEOLOGICAL MAP1. STRUCTURE2. ISOPACH3. FAULTS/BARIER4. UNCONFORMITY

3. RESERVOIR MAP1. NET PAY2. POROSITY3. PERMEABILITY4. PRESSURE5. PRODUCTIVITY

SEISMIC

WELL LOGS

CORE & CUTTINGANALYSIS

WELL TESTS &PRESSURE

FLUID ANALYSIS

PRODUCTIONDATA

INTERPRETATION,ZONATION,

INTEGRATION,CORRELATION,

ANALYSIS&

DEFINE VALUES

D A T A PROCESINGPROCESSING PRODUCTS

REGIONALGEOLOGY

BASIC KNOWLEDGEBASIC KNOWLEDGE FOR RESERVOIR CORRELATION & MAPPINGFOR RESERVOIR CORRELATION & MAPPING

• LOG ANALYSIS (electro-facies, reservoir parameters, stratigraphy, structure, etc.)

• SEISMIC INTERPRETATION (structure, reservoir continuity, hydrocarbon indications)

• SEDIMENTARY FACIES, DEPOSITIONAL ENVIRONMENTS & SEQUENCE STRATIGRAPHY

• MODELS OF BASINS & RESERVOIRS, AND ALSO REGIONAL GEOLOGY OF THE MAPPED FIELD trends of sedimentation & major tectonic and it’s ramifications

• BASIC RESERVOIR ENGINEERING pressure regime, models, fluid propertie and production performance.

• BASIC COORDINATE SYSTEMS/GEOMETRY & STEREOMETRY base map, well trajectory, lease boundary etc.

LOG ANALYSIS FOR RESERVOIR CORRELATION & MAPPING

• LITHOLOGY / FACIES IDENTIFICATIONS & MARKERS DETERMINATION continuity, consistency, missing sections & repetition sections (faults or overturn)

• DEPOSITIONAL ENVIRONMENT

• VERTICAL ZONATIONS– TOP & BOTTOM– FLOW UNIT

• FLUID CONTACTS OWC, GOC & GWC

• RESERVOIR PARAMETERS Por, Perm, Sw etc

• NET PAY THICKNESS DETERMINATIONS

BASIC CURVE SHAPE OF SP & GRfor facies & sedimentary environment determinations

DIP METER dip patterns and it’s geologic association

DIPMETER USES :•Structural dip & fault determinations.•Facies, type of sands & it’s trends interpretations (micro resistivity•Fracture identification•Sedimentary structure can be identified with processed Dipmeter or FMI (formation imaging)

FMI fulbore formation micro imagerRAB resistivity at the bit

SEISMIC FOR RESERVOIR GEOLOGY

• Aid in :– Reservoir facies mapping reservoir distribution : lithology,

isopach etc 3D– Reservoir properties mapping porosity– Locating / define fluid contacts– Monitoring fluid fronts 4D– Sructure & stratigraphic interpretations

• Seismic methods :– 2D Seismic– 3D seismic– VSP– Well to well seismic– Time-lapse seismic monitoring etc.

EXPLOSIVE

LAPISAN BATUAN

EXAMPLE

VSP

SLB, OFR, 2007 Autumn

V S P(Vertical Seismic Profiling)

Example : Comparison of VSP & Seismic Results

SLB, OFR, 2007 Autumn

SURFACE SEISMIC IMAGESURFACE SEISMIC IMAGE

TIES WITH VSP

3D Seismic

Basic of 4D Seismic

Example : 4D Seismic uses

DEPOSITIONAL ENVIRONMENTSDEPOSITIONAL ENVIRONMENTS AND SEDIMENTARY FACIESAND SEDIMENTARY FACIES

Distinctive and Common Sedimentary Distinctive and Common Sedimentary Facies Associations Facies Associations

Vertical successions principally identified by lithology, associations and vertical arrangement of sedimentary structures indicative of particular sedimentary depositional environments

CARBONATE DEPOSITIONAL ENVIRONMENTS(DIAGRAM BY R.G. LOUCKS AND C.R. HANDFORD, UNPUBLISHED)

SEQUENCE STRATIGRAPHY CONCEPTSSEQUENCE STRATIGRAPHY CONCEPTS• Sequence stratigraphy highlights the role of allogenic controls on

patterns of deposition, as opposed to autogenic controls that operate within depositional environments

– Eustasy (sea level)– Subsidence (basin tectonics)– Sediment supply (climate and hinterland tectonics)

COMPONENTS OF SEQUENCES

SLB, OFR, JAN93

GROSS NET NET PAY

• A MAPABLE PORTION OF THE TOTAL RESERVOIR WITHIN WHICH GEOLOGICAL AND PETROPHYSICAL PROPERTIES THAT AFFECT THE FLOW OF FLUIDS ARE CONSISTENT AND PREDICTABLY DIFFERENT FROM THE PROPERTIES OF OTHER RESERVOIR ROCK VOLUME ( mod. EBANK, 1987)– A specific volume of reservoir, may be composed of

one or more lithologies and any nonreservoir rock types

– Correlative and mappable at the interwell scale– Zonation is recognizable on wireline logs– May be in communication with other flow unit

LEVELS OF RESERVOIR

HETEROGENETY (fluviatil rock)

FlowUnits

Gamma RayLog

PetrophysicalData

PoreTypesLithofaciesCore

1

2

3

4

5

CorePlugs

CapillaryPressureφ vs k

GEOLOGICAL AND PETROPHYSICAL DATA USED TO DEFINE FLOW UNITS

Schematic Reservoir Layering Profilein a Carbonate Reservoir

Baffles/barriers

3150

SA -97A SA -251 SA -356 SA -71 SA -344 SA -371 SA -348 SA -346 SA -37

3200

3250

3300

3350

3100

3150

3250

3300

3250

3150

3200

3100

3150

3200

3250

3200

32503250

3350

3300

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3300

3100

3200

3250

3300

3350

3150

3200

3250

Flow unit

From Bastian and others

E

• BASED ON :– PRODUCTION TESTINGS the most

reliable methods

– LOGS (electrical logs combined with FDC & CNL)

– PRESSURE SURVEY pressure gradient from RFT

– SEISMIC hydrocarbon indications

Fluid Contact Determination with fluid gradient from RFT

oilwater

RFT depth

Water Gradient 0.433 psi/ft

pressure

dept

h

Oil G

radient 0.367 psi/ft

OWC

CORRELATIONSCORRELATIONS• “Reservoir Correlation” is part of pre-mapping works

of reservoir to locate and trace the lateral distribution, continuity, geometry of reservoirs and it’s flow unit.

• Correlation should be carried out based all the available data, a sedimentological and stratigraphic model of the reservoirs.

• Some pre-correlation works notes:– Wireline log will be the basic data and will be calibrated and

integrated with other data analysis results such as core analysis especially.

– Vertical profile analysis of well data should be carried out previously to establish the facies, sequences and sedimentary environment.

– Zonation of lithology and flow unit, and also marker inentifications should be geologically sound.

– Define the zone top & bottom, zone thickness (gross & net) etc.

Tips for Correlation

• Stratigraphic Cross Section is the best demonstration of a correlation results.

• The section should show reservoir lateral and vertical facies changes, markers continuity, missing & repetition sections, completion & prod. testing notes, etc.

• Good markers can be organic shale, coal/lignite, limestone beds, glauconite, siderite etc. which has good continuity and correspond to the geologic events such as maximum flooding, emmergence etc.

• Start the correlation with the whole log section of individual well, make zonation based on electro facies then define all markers and zones of interest. Indicates any missing and repetition section. Then carry out a detail correlation of objective reservoirs.

• For reservoir connectivity indication use also fluid contents and contacts, pressure data and production performance data

• Prepare a good tabulation (database) of geologic data such as depth of top & bottom of reservoir, net & gross thickness, fault’s depth etc.

CORRELATION PROBABILISTIC to DETERMINISTIC

After EA Arief S, IPA, 2001

A

B

C

D

LATIHAN

LATIHAN

OIL

OIL OWCA

C

B

D

WELL #123

WELL #456

LATIHAN

OIL

OIL OWCA

C

B

D

WELL #123

WELL #456

LATIHAN

OIL

OIL OWCA

C

B

D

WELL #123

WELL #456

Tip for Reservoir Mapping• Prepare a good base-map based on coordinates of

wells and seismic shot points (line & BM).• Plot the data accurately then start contouring from

the highest positions for structure and refer to seismic maps.

• Stucture contour should be stop whenever cross/meet the fault plane. Consider the fault throws and missing/repetition sections for the next blocks contouring.

• For isopach maps initiate with facies map construction then followed with isopach contouring.

• Understand the contouring principles such as no crossing contour etc.

-1000

’

-1100’

-1200

’ -130

0’ -120

0’ -1100

’-1

000’

-1000’

-1100’

-1200’

-1100’

-100

0’

-120

0’

-120

0’

-1000’

-1100’

-1200’

-1100’

-1000

’

0’

10’20’

20’10’0’

0’10’

20’

10’

0’20’

30’

30’

20’

-1000’

-1100’

-1200’

-1300’

-1400’

-1500’

-1600’

-1700’

-1700’-1600’

-1500’

-1400’

-1300’

-170

0’-1

600’

-150

0’-1

400’

-130

0’-1

200’

-110

0’-1

000’

PLAN VIEW

SECTION VIEW

10001010

10201030

1040

1050

NET PAY MAP CONSTRUCTION

STRUCTURE MAP

Contour unit in meter sub-seaContour interval 10 m

OWC @ 1050 mss

0 m

5 m

10 m

15 m

10 m

5 m

0 m

NET PAY MAP CONSTRUCTION

ISOPACHOUS MAP

Contour unit in meterContour interval 5 m

15 m

0 m

5 m

10 m

15 m

10 m

5 m

0 m

NET PAY MAP CONSTRUCTION

NET PAY MAP

1510

50 Contour unit in meter

Contour interval 5 m

10101020

10301040

1050

SURFACES OF FAULTS X AND Y

down

FAULT MAP

WEST-EAST CROSS SECTION

A SandA Sand

B Sand

B Sand

B

UNCONFORMITY

STRUCTURE MAP OF A SAND

ISOPACHOUS MAP OF A SAND

NET PAY MAP OF A SAND

STRUCTURE MAP OF B SAND

ISOPACHOUS MAP of B SAND

NET PAY MAP OF B SAND

NET GAS

NET OIL

FAULT ANALYSIS SEALING OR NON SEALING

• Can be based on :– Log analysis– Well test data– Pressure build-up analysis– Interference test– Production data– Using radioactive tracer– Core & Rock Cutting– Correlation & Sratigraphic analysis

Disagregated & cemented

Phillosillicate- smear

framework

clay-smear fault rocks

ALLAN DIAGRAM

A

B

A

B

C

C

D

D

E

E

F

Allan Diagram for non-sealing fault

DOWN BLOCK

UP BLOCK

DOWN BLOCK

UP BLOCK

Common Oil Water Contacts

OIL

OIL OIL

OIL

WATER

WATER

0 m

5 m

10 m

15 m

10 m

5 m

0 m

NET PAY MAP CONSTRUCTION

NET PAY MAP

1510

50 Contour unit in meter

Contour interval 5 m

10101020

10301040

1050