Post on 23-Aug-2020
Integrating Sedimentology and Quantitative Rock Physics For Reservoir Characterization and Modeling in Field Development:
A Case Study of an Onshore Field in Niger Delta.
Presenter: Ebere BenardContributors: Taju Gbadamosi, Christian Ihwiwhu, Obiageli Chuka-Umeh,
Sotonye Okujagu, Maduabuchi Ndubueze, Kingsley Akpara, Collins Onyeukwu, Samuel Anikoh.
Seplat Petroleum Development Company Plc 27th July, 2016
Motivation For The Study
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Operating Risk
Drilling Risk
Geologic Uncertainty
Business Risk
Development Risk
$50 - $65 Bbl
@
Onshore fields do have attractive opportunities
Field development to improve proven and recoverable reserves
Operators do face challenges in developing these fields
Inherent geologic risk & uncertainty may lead to negative cash flow
Case Study and Development Challenge
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Case Study and Development Challenge Cont’d
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< 8% of Ultimate recoverable produced
Reserve
Profit
Ultimate Recoverable
Total STOIIP Estimation
Cumulative Production
Case Study and Development Challenge Cont’d
Outline
Introduction
Aim and Objectives of Study
Study Area and Niger Delta Geology
Integrated Workflow and Methodology
Conventional Methods and Development Challenges
Sedimentology of Fluvio-Deltaic Reservoirs
Quantitative Seismic/Rock Physics and Reservoir Characterization
Reservoir Sand Geometry and Well-to-Well Correlation
Integrated Reservoir Model and History Match
Prediction and Field Development Cases
Conclusion
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Introduction
Introduction
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Onshore fields have inherent development challenges Spatial & temporal variation in reservoir fluid Complex reservoir geometry Sand connectivity issues
Conventional 2D & 3D seismic interpretation Defined structural closure Unable to illuminate the internal architecture and lithofacies trapping style
Unconventional study technique was critical in resolving the key development challenges
Aim and Objectives of Study
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The aim is to improve on the geological understanding of the reservoir systems using quantitative rock physics and sedimentology
Objectives Reconstruct the depositional environments
Establish sand geometry and correlation techniques
Investigate stratigraphic barrier to flow
Construct a predictive geological model for optimal field development
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Study Area and Niger Delta Geology
Study Area and Niger Delta Geology
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Study Area
Niger Delta Map Niger Delta Stratigraphic Column
Geology of Deltas and Classification
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Modified Cuspate Delta (River Niger)Classification of Deltas
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Please Be Patient !!!
GEOLOGIST IN THE HOUSE
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Conventional Methods and Development Challenges
Horizon Interpretation and Structural Mapping
15Vertical Seismic Section
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Horizon Interpretation and Structural Mapping Cont’d
16Vertical Seismic Section
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Horizon Interpretation and Structural Mapping
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Structural Map
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18Layer Cake Sand Correlation
Well-To-Well Correlation and Fluid Interpretation
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19Layer Cake Sand Correlation
Well-To-Well Correlation and Fluid Interpretation Cont’d
?
??
P-1P-2
Layer Cake Reservoir Model and Initial History Match
History Match of Oil Rate History Match of Water Cut
Oil Rate SimulationOil Rate HistoryOil Rate Well Test
Water Cut SimulationWater Cut HistoryWater Cut Well Test
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Integrated Workflow and Methodology
Integrated Workflow and Methodology
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• Core & cuttings• Logs• Analogs• Sequence stratigraphy• Subsurface data integration
• Seismic sequence stratigraphy
• AVO inversion• Classification• Pattern
• Production• Simulation• History matching• Prediction• Economics
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Sedimentology of Fluvio-Deltaic Reservoirs
Sedimentology of Fluvio-Deltaic Reservoirs
Log analysis
Biostratigraphy/sequence stratigraphy and depositional environments
Core description/fossils identification and interpretation
Sedimentary analogs and depositional environments
Log Facies and Depositional Energy
25Log Facies and Depositional Energy Trend
Gamma Ray Log MotifsW-1
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Coarsening upward & increasing energy of deposition
Prograding deltaic sand deposits
Log Facies and Depositional Energy Cont’d
26Gamma Ray Log Motif Depositional Energy Trend
Biostratigraphy and Depositional Environments
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Fauna Population
Pollen Population
Candidate Maximum Flooding Surface
Fauna/Pollen Depth Plot Paleobathymetric (Water Depth) Plot
Benthic Foraminifera and Depositional Environments
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Depth Range(ft)
Indicator Fauna Age (ma) Paleobathy-metry
Depositional Environment
240 -3220Barren Eocene/Mio
ceneContinental
3640 - 5830
• Alabamina Spp
• Quinqueloculina
Eocene/Miocene
• Coastal deltaic
• Inner Neritic
• Inner-Middle Neritic
Coastal-deltaic/Marginal marine• Deltas/mouth bars• Tidal flats• Estuaries• Bay/Lagoons• Barrier islands• Littoral beach
Table Showing Paleobathymetry and Depositional Environments
Ichnofacies Identification and Depositional Environments
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Backshore-foreshore-nearshore Intertidal zone environments Fluvial/lacustrine environments Bay/lagoon Estuaries Tidally influenced tidal channels
Trace Fossils
• Core sedimentological description• Fine-medium-coarse grain sizes• Sedimentary structures (cross beddings)• Coal & rootlets• Heavy mineral inclusions• Iron stains & nodules (Siderite)
Core Description and Interpretation
Iron stain Coal
Sedimentary Analogs and Depositional Environments
Continental to Marine Depositional Environments
Bay/lagoon marginal marine environment
Sedimentary Analogs and Depositional Environments Cont’d
Barrier Bar with Occasional Channel Cut River Mouth Bar
River Mouth Bar
Barrier Mouth Bar
Delta Front EnvironmentDelta Front Environment
Sedimentary Analogs and Depositional Environments Cont’d
Braided Channel Systems
Single Meandering Channel
Upper Delta Plain
Delta Front
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Quantitative Seismic/Rock Physics and Reservoir Characterization
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illusion
Or
reality?
Quantitative Seismic/Rock Physics & Reservoir Characterization
Seismic Attribute and Sequence Stacking Pattern
36Vertical Seismic Section Showing Channel Scours
W-8 W-9
Seismic Attribute and Sequence Stacking Pattern Cont’d
37Vertical Seismic Section Showing Channel Scours
W-8 W-9
AVO Inversion Attribute & Reservoir Characterization
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Lambda-rho
Mu-rho
Shear Impedance
AVO Inversion Attribute Stratal Slices
Rock Physics and Seismic Attribute Calibration
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Correlation coefficient: 0.7
Seismic Attribute Segmentation & Discretization
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AVO Inversion Attribute
S-impedance
Mu-rho
Lambda-rho
3D Attribute Matrix Volume
Seismic Attribute Segmentation & Discretization Cont’d
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Elastic Property
Correlation CoefficientsPC1 PC2 PC3 PC4 PC5 PC6 PC7 PC8
4 ms 0.94 0.32 0.1 0.02 0.03 0.01 0.01 0.004
6 ms 0.96 0.27 0.03 -0.02 -0.04 0.01 -0.02 5E-04
8 ms 0.98 0.19 -0.03 0.03 0.01 -0.03 -0.01 -0.015
10 ms 0.99 0.11 -0.06 -0.05 -0.02 -0.004 0.02 -3E-04
12 ms 0.99 -0.01 -0.09 0.03 0.01 -0.002 -0.004 0.02
16 ms 0.97 -0.22 -0.04 0.02 0.003 0.031 0.003 -0.015
18 ms 0.95 -0.3 0.02 -0.05 0.04 -0.003 -0.02 3E-04
20 ms 0.92 -0.36 0.08 0.02 -0.03 0.01 0.01 0.004
Eigen Value 7.4 0.5 0.04 0.009 0.005 0.002 0.001 0.001
Table of Principal Component Analysis
Seismic Attribute Segmentation & Discretization Cont’d
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Seismic Geomorphology & Macro Sedimentary Features
43Discrete Facies and Depositional Facies Architecture
X
XXXXX
Elongate lobate pattern
Broad linear pattern
Seismic Geomorphology & Macro Sedimentary Features Cont’d
44Discrete Facies and Depositional Facies Architecture
X
XXXXX
Elongate lobate pattern
Broad linear pattern
Discrete Facies and Depositional Facies Architecture
Seismic Geomorphology & Macro Sedimentary Features Cont’d
Sinuous linear pattern
Flood Plain
Geomorphological Patterns and Sedimentary Analog
Meandering Channel
Braided Channels
XXX
XXXBarrier bar
Flood Plain
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Reservoir Sand Geometry and Well-To-Well Correlation
Sand Geometry and Well-To-Well Correlation
Labyrinth Sand Geometry
Layer-Cake Geometry
Jig-Saw Puzzle Sand Geometry
Beach Sand
Mouth Bar Sand Bar Sands
49Labyrinth Sand Correlation
Labyrinthine Well-To-Well Sand Correlation
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Integrated Reservoir Model and History Match
Geological Map
51Reservoir Depth Map
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Integrated Geological Model
52Fluid Saturation Interpretation
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Static Model
53Integrated Geological Model
Depositional Facies
End of History: Jan. 2016
Start of Simulation: September 1992
Reservoir Simulation
Oil Rate and Water Cut Simulation
Oil Rate and Water Cut History Match
Final 6 months Oil Rate & BSW matched satisfactorily Cum Oil matched with +/-10%
History Match of graph for oil rate and water cut
Pressure Match and Aquifer Sensitivity
History Match of graph of pressure
Prediction and Field Development Cases
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Vertical and horizontal well cases
Gas lift, ESP, PCP & Tubing sizes
Water injection option
Well count & development options
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Conclusion
Conclusion
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• The customized workflow with post-stack/prestack 3D seismic has reduced subsurface geological uncertainty in the field
• A predictive reservoir model have been constructed to test field development scenarios and optimize recovery
• Data integration and scenario testing is very important in resolving complex geological and field development challenges
• The customized workflow (AVO inversion & matrix algebra) will be used as analog in solving complex geological problems and development challenges in other fields.
For a billion years the patient earth amassed documents and inscribed them with signs and pictures which lay unnoticed and unused.
Stones have begun to speak, because an ear is there to hear them.
Layers become history and, released from the enchanted sleep of eternity, life's motley, never-ending dance rises out of the black depths of the past into the light of the present.
— Hans Cloos 1954
Quotes
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Thank You For Listening