3.0 Correlations

8/12/2019 3.0 Correlations

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Logs and Correlations

E & P CORE PROGRAMME

Techniques

3


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isochore = isopach

isochore thickness

isopach

Isopach - Isochore Thickness


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Net to Gross Ratio

Top of Reservoir

Bottom of Reservoir

5'Net

10'Net 20'

Gross

LegendProductive

Non ProductiveN/G = 15/20 = 0.75


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The Gamma Ray Log

inc GR

GR Log

Legend

Sand Shale Bore Hole

GR Sonde


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The Gamma Ray Log Interpretation

Legend

Sand

API Units0 GR 100

Depth Interpretation

Non Reservoir

Non Reservoir

Non Reservoir

Reservoir

Reservoir

100

200

Sand Line 0% ShaleNet Sand Cut-off Line 50% ShaleShale Line 100% Shale


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Correlation: Why??

To understand the lateral continuity and variation ofthe reservoir sands in the field so that the field can bedeveloped optimally

To develop depositional model of the reservoir sandsand bounding shales in order to understand the facies

distribution within the reservoir interval


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Correlation: Tools

Electric Logs :GR (Gamma Ray)Resistivity Log (ILD or MSFL)SP (Spontaneous Potential)SonicDensity LogNeutron Porosity + etcs.

OthersMicrofossils dataCore description dataSeismic picks (Converted from TWT to Depths)


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Correlation: Methods

Electric Logs :Identify a common surface to be used as datum (i.e coal)Positions and 'hangs' all wells on this surface according to its

sequence from the mapIdentify 'sand unit' and try to correlate them laterallyCorrelate 'minor' events to complete the correlation for detail

facies interpretation

Datum :Surface that represent the same 'time-line' during deposition

Faults :If correlation is 'lost' or similar event do not exist betweenwells - A break in the sedimentary layersMissing layer - Normal faultCreated duplicate layer - Reverse fault


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DATUM PLANE CORRELATION

2500

2600

2500

2600

Datum

C-Marker

D Sand

E Sand

2500

2600

Fault

Well 1 Well 2 Well 3

Base sand

Missing in well 2


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STRUCTURAL CORRELATION

Datum : on the same depths (usually TVD) for all wellsTo represent the GOC /GWC or OWC contacts on its truestructural position

For field development, the correlation is to display otherapplicable well information that needs true structural positions


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2500

2600

2500

2600

2500

2600


Fault


Datum on sameTVDSS


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2500

2600

2500

2600

C-Marker

D Sand

E Sand

2500

2600


Fault


Base sand


15/20

Correlations

Well: A Well: B Well: C Well: D

l


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1

4

1

2

4

1

2

4

1

2

33

BIOSTRATIGRAPHIC CORRELATION


1

4

1

2

4

1

2

4

1

2

33

LITHOSTRATIGRAPHIC CORRELATION

Van Wagoner et al. 1990

Correlations
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NO. 3 NO. 27 NO. 15 NO. 10 NO. 2SP Amplified

Short Normal

E1 MARKER = DATUM

CORRELATION EXCERCISE


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NO. 3 NO. 27 NO. 15 NO. 10 NO. 2SP Amplified

Short Normal

CORRELATION EXCERCISE = SOLUTION

E1 MARKER = DATUM


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CORRELATION EXCERCISE

GR GR GR GR GR

Structures

RIP-UP CLASTS, PEBBLESWAVE RIPPLE

HUMMOCKY X-BEDS

CURRENT RIPPLE

PLANAR BEDS

THROUGH X-BEDS

0 140 0 140 0 140 0 140 0 140


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CORRELATION EXCERCISE = SOLUTION

FS/SB

SB

C1

C2

C3

C4

C5

Truncated stacked sands

GR GR GR GR GR

Fluvial Channel

Shoreface

Tidal Delta

Shelf Mudstone(Marine)

Swamp Mudstone-TerrestrialFS

Documents

3.0 Correlations