Cairn case study

Spotlight

Akhil Prabhakar (Int. Mtech 4th yr GPT)Swapnil Pal (Int. Mtech 4th yr GT)Ojaswita Singh (Mtech 1st yr GPT)

IIT Roorkee

Base map

A B

C

D

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Cross-section across A-B

Dep

th (m

)

A B

S N

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500

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Cross-section across C-D

C

D

SE NW

0 20 40 60 80 100 120 140 160 180 2000

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Cross-section across C-D

Distance

Depth

SE NW

Traps

Anticlinal trap Fault trap

Following conclusions can be drawn from the base map:

Primary structural element: antiformal fold and fault

Trap: anticlinal trap

Area of Hydrocarbon accumulation: 53.15 Km2

Well log templates (GR)Well 1 Well 2 Well 3

Well no. Top reservoir

Base reservoir

mTVD mTVD

Well 1 765 859

Well 2 909 960

Well 3 878 956

Marker Data

Well log templates (GR)Well 1

Average gross reservoir thickness = 94m Net-sand thickness = 27.5mNet to gross (NTG) = 0.293Average porosity = 27%Average water saturation = 0.1

Well log templates (GR)Well 2

Average gross reservoir thickness = 51m Net-sand thickness = 21mNet to gross (NTG) = 0.411Average porosity = 27.17%Average water saturation = 0.08

Well log templates (GR)Well 3

Average gross reservoir thickness = 78m Net-sand thickness = 19mNet to gross (NTG) = 0.244Average porosity = 25.7%Average water saturation = 0.09

Comparison of different wells

Well 1 Well 2 Well 3 Field

Average gross reservoir thickness

94m 51m 78m 74.3m

Net sand thickness 27.5m 21m 19m 22.5m

Net to Gross 0.293 0.411 0.244 0.316

Average porosity 27% 27.17% 25.7% 26.6

Average water saturation 0.1 0.08 0.09 0.09

Depositional environment

Fluvial/detaic environment.• Alternating sand and shale.• Clastic sediments deposition in passive margin. Recovery factor: Primary 40% EOR 50-60%

Formation Pressure Data (Well 2)

Depth (mTVD) Formation pressure (psi)

946 1614

952 1619

956 1622

969.5 1639

977 1650

980.5 1655

Formation Pressure Data (Well 2)

Formation pressure

944 946 948 950 952 954 956 958 960 962 964 966 968 970 972 974 976 978 9801590

1600

1610

1620

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1660

Fluid contact depth

formation pressure

Depth (mTVDSS)

For

mat

ion

pres

sure

(ps

i)

Slope = 0.45 psi/feet

Slope = 0.25 psi/feetSlope = 0.22 psi/feet

Slope = 0.38 psi/feet

Slope = 0.44 psi/feet

Oil filled reservoir

Water filled reservoir

Oil-water contact

Calculations:

Total in-place hydrocarbon = 516.3319986 million hydrocarbon volumes

Recoverable reserves = 206.5327994 million hydrocarbon volumes

Volume produced per day by a well = 5000 hydrocarbon volumes

Production at this rate from 1 well for 15 yrs. = 27.375 million hydrocarbon volumes

Number of wells needed = 18 or 19 wells

Thank you