Final Presentation for subsurface evaluation of blue peral field

8/13/2019 Final Presentation for subsurface evaluation of blue peral field

http://slidepdf.com/reader/full/final-presentation-for-subsurface-evaluation-of-blue-peral-field 1/22

A Case Study on

Sub-Surface Evaluation of Blue

Pearl Field

TEAM NAME: EAGLES ( ISM DHANBAD)ABHISHEK SRIVASTAVA ( Final Year, 5 Yr M.Sc.Tech Integrated Applied Geology)

JIGYASU AGRAWAL (Third Year, 5 Yr M.Sc.Tech Integrated Applied Geology)

ANJU KUMARI(Third Year, 5 Yr M.Sc.Tech Integrated Applied Geology)



• Workflow

• Geological Introduction.

• Reservoir Seismic interpretation and identification of

main reservoir field.

• Interpretations from the depth contour map.

• Petrophysical analysis.• Core and Thin section analysis.

• Formation pressure data against depth (TVDSS) plotting

and interpretation.

•

Reserve calculation and result.• Field Development Plan



Geological Introduction

It is an offshore field that sits in a passive margin setting. Alternative sand and

shale sequences with two erosional unconformities during Late Miocene and

the Pliocene are present. Reservoir rocks are clastic rocks of Miocene.Trapping mechanism is structural i.e. hydrocarbons are accumulated in the

structurally high areas.

There are two sequences of major events – 2 sea-level fall and 2 sea-level

rise, which deposited thick piles of sand and shale in the Blue Pearl Field.

Tectonic setting is a Passive margin where deposition occurred in NE-SW

direction. Several stages of growth faulting occurred due to massive influx of

sediments in the basin.

Workflow

Starting from Structural Analysis, Seismic Interpretation, Well Correlation

& Petrophysics, we have identified the most probable prospects for

estimating the reserves and develop the field.



• SYN SEDIMENTARY FAULTS AND ANTIFORMAL DOME STRUCTURES PRESENT FOR

TRAPPING MECHANISM IN THE BASIN.

• BEDS ARE FLAT AND SLIGHTLY TILTED DUE TO FAULTS.

• CHANNEL FILLS ARE PROMINENTLY OBSERVED.

• SYN SEDIMENTARY FAULTS, ANTIFORMAL DOME STRUCTURES PRESENT FOR

TRAPPING MECHANISM IN THE BASIN.

• TRUNCATION SURFACE AND COASTAL ONLAP VISIBLE.

• BEDS ARE FLAT AND TILTED DUE TO FAULTS.

•

SEQUENCE FOR MARINE TRANSGRESSION AND PROGRADATION ARE VISIBLE.

For C-C’ and A-A’:

For B-B’ and A-A’

Seismic Interpretation

There are three depth seismic sections and the seismic section CC’ is along NW-SE

which is oblique to shoreline thus helpful in interpreting lateral facies variation. Two

unconformities are observed in which, Miocene one is the top of Reservoir Rock and

the Pliocene one can be easily identified by the presence of erosional truncations.BB’ is perpendicular to shorelines and AA’ is oblique to both shoreline and delta and

hence helps in determining the lateral continuity.

Reservoirs are marked with pink.



OWC



OWC



GOC

OWC









Structural Contour Maps of Blue Pearl field

Structural Analysis

There are three stages of deformation in the area. Dome

and Basin structures were generated during these stages.

Six structural highs are present with general trend of

ENE-SSW. These are present in North and SE parts of the

field.Olique 3D representation of field



Structural Contour Maps with Gas-Oil contact and oil-Water Contacts

Oil Water Contact Gas Oil Contact

Total Area: 22500000 m2

Area inside oil water contact (including gas oil contact): 10950296.90 m2

Area inside gas oil contact: 3435357.22 m2



WellsGross

ThicknessNet Thickness Net to Gross Avg Porosity Avg Water Saturation RHOB

A1 75.0 65.2 0.869 0.247 0.661 2.20

C4 118.0 101.0 0.855 0.210 0.677 2.32

C5 69.0 58.5 0.847 0.165 0.565 2.23

D2 88.0 62.0 0.704 0.186 0.637 2.23

D3 90.0 71.4 0.793 0.220 0.706 2.25

D7 76.0 62.6 0.823 0.206 0.677 2.28

Avg 86.0 69.8 0.811 0.2056 0.653 2.24

Petrophysical Analysis





Combined analysis of Logs and Thin section

• Towards the top we have coarse grained sands which have high porosity for gas

and have high water saturation with higher density and low visual porosity

(nearly 10%).These grains are highly reworked as the grains are well rounded.

• As we move downward the amount of sand increases decreases as sand packets

are present inside mudstone. Here ill sorting of rocks and presence of pointed

rocks is noted. Also visual porosity increased to 25%. Oil content is visible in thin

section and is confirmed from the logs. Inverse grading of sand and mud

sequence is noted. As we move down we encounter mudstone redded with

haematite.



This is a period of progradation. The sequence

is coarsening upward with mudstone

lithologically dominating the bottom part of

the sequence.

This is the second period of

progradation. Initially we have gently

dipping coarse sandstone beds. The dips

get steeper as we move downwards. Flat

beds and then landward dipping beds

characterize the sequence at the deeper

part of the sequence. The bottom part is

characterized by siltstone and also

contains bioturbudations.

Analysis of Sedimentary Logs



FORM. PRESSURE (PSI) DEPTH (FT) GRADIENT

DEPTH (M

TVDSS) O/W/G

2577.2 5396.25984 1644.8

2582 5413.32 0.281357267 1650 O

2586 5427.09936 0.290289244 1654.2 O

2600 5472.3744 0.309221151 1668 O

2604.7 5481.56064 0.511634793 1670.8 W

2614 5511.744 0.30811679 1680 O

2620 5531.4288 0.304803706 1686 O

2654 5606.8872 0.450579392 1709 W

2630 5552.754 0.443350846 1692.5 W

2640 5577.36 0.406404942 1700 W

2652.4 5606.8872 0.419951773 1709 W

Formation pressure data against depth (TVDSS) for A1

Here the oil water contact is measured at 1686 m.




DEPTH (M

TVDSS) O/W/G

2525.4 5251.57656 1600.7

2522.9 5288.32152 -0.068036542 1611.9 G

2525.3 5314.56792 0.091441112 1619.9 G

2525.9 5334.90888 0.029497133 1626.1 G

2525.7 5343.11088 -0.024384297 1628.6 G

2527 5347.704 0.283032013 1630 O

2531.6 5362.4676 0.311577122 1634.5 O

2533 5369.35728 0.203202471 1636.6 O

2538 5380.18392 0.461823798 1639.9 W

2541.5 5389.69824 0.367866542 1642.8 O

2553.8 5419.8816 0.407509303 1652 W

2564.7 5456.29848 0.299311748 1663.1 O

2602.5 5550.45744 0.401448784 1691.8 W

2602.2 5550.45744 #DIV/0! 1691.8 W

2611 5572.76688 0.394451855 1698.6 O

2615.7 5582.2812 0.493992214 1701.5 W

2619.7 5593.43592 0.358592596 1704.9 O

2698.2 5733.52608 0.560353418 1747.6 W

2711.4 5764.3656 0.428022226 1757 W

2621 5600.3256 0.551085101 1707 W

Formation pressure data against depth (TVDSS) for D 2

Here the oil water contact is measured at 1663 m and gas oilcontact at 1628.6 m .



Formation pressure data against depth (TVDSS) for D 3


DEPTH (M

TVDSS) O/W/G

2536.85 5423.851368 1653.21

2542 5440.189752 0.315208652 1658.19 O

2547.9 5466.075264 0.227926726 1666.08 O

2552.68 5480.117088 0.340411616 1670.36 O

2563.4 5512.498584 0.331053266 1680.23 O

2567.4 5530.018056 0.228317383 1685.57 O

2580 5559.64368 0.425307497 1694.6 W

2584.7 5574.341664 0.319771746 1699.08 O

2587.2 5590.81128 0.151794675 1704.1 G

2592.3 5603.27832 0.409078659 1707.9 W

2594.7 5608.068288 0.501047189 1709.36 W

2605.3 5630.705808 0.468249172 1716.26 W

2606.8 5635.692624 0.300793131 1717.78 O

2618.2 5658.691032 0.495686484 1724.79 W

2618.4 5664.005928 0.037630087 1726.41 O

Here the oil water contact is measured at 1704 m.



RESERVE CALCULATIONS

• Gas-Oil Contacts and Oil-Water Contacts are determined using pressure data and well

log data and using software we have extrapolated these GOCs and OWCs to get the

gross rock volume for reserve estimation.• We have used extrapolated oil-water and oil-gas contacts for the entire field including

areas where no wells are drilled so far. This way we calculated total reserve of 5.282

BCF gas and 43.72 Mbbl oil, out of which 0.7 BCF gas and 19.67 Mbbl oil would be

recovered, for which 26 wells should be drilled for full exploitation in 15 years at a

rate of 5000 bbl/day.

GRVEff

PorosityHC Sat NTG FVF Volume (m^3) Volume (Bbl) Volume (SCF)

Recovery

Factor

Recovery(BBL and

SCF)Recovery(BBL)

Gas 15367065.1000 0.2056 0.3460 0.8210 0.0060 149582933.8236 940742029.1100 5282471496.8636 0.7500 3961853622.6477 705556521.8325

Oil 152358468.2000 0.2056 0.3460 0.8210 1.2800 6951827.6133 43720739.0430 0.4500 19674332.5693 19674332.5693

Total 167725533.3000 3981527955.2170 725230854.4019



Field Development Plan

We recommend drilling initial wells at site W1, W2, W3 and W4 which are prospective

zones for hydrocarbon accumulation in the northern and western side of the Blue Pearl

field.



THANK YOU

Documents

Final Presentation for subsurface evaluation of blue peral field