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Transcript of Numerical Well Testing A Method for 3D Model Validation ... · PDF file3D Model Validation...
DELIVERING KNOWLEDGE. DEVELOPING COMPETENCE.
Numerical Well Testing A Method for 3D Model Validation using Pressure
Transient Tests
USE OF THE INTEGRATED SOFTWARE SYSTEMS FOR MODELING HYDROCARBON RESERVOIRS
Authors: Vasile Badiu and Florin Vasile Badiu - I.C.P.T. Câmpina Presented at PETROM Symposium, 24-26 may 1999, Câmpina Published in Revista Românå de Petrol, Nr. 2, April - June 2002
Translated from Romanian by Florin Vasile Badiu, GTA at UTA, Texas, February 2005
© 2008 PetroSkills, LLC. All rights reserved.
Static and Dynamic Models
– Principles: • We need to build Static and Dynamic Models in an appropriate
Integrated Reservoir Modeling (IRM)Procedure
• The model is never better than the data, the people, the tools and the techniques used (to obtain it)
• At all times, the model is NON-PERFECT
• The model is good, as long as we “believe” in it
• History matching is finished only when you run out of time, money or both
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Integration - Concept
Data
Tools Technology
People
Integration
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Static and Dynamic Models in the past In The Industry
– Analog and Physical Modeling - until 1972
– 2D Numerical Reservoir Simulation - from 1970 until 2001
– 2D Streamline Simulation - from 1972 until 2001
– 3D&3P Numerical Reservoir Simulation - from 1985 until 2001
– Integrated Reservoir Modeling using Integrated Software System - from 1993
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Integrated Reservoir Modeling
RESERVOIR SIMULATION 3D FLUID DISTRIBUTION
GEOLOGICAL MODELLING 3D FRAMEWORK MODEL
SEISMIC INTERPRETATION BASE MAP
GEOLOGICAL MODELLING 3D BLOCK DIAGRAM
STREAMLINE SIMULATION 2D STREMLINE DISTRIBUTION
WELL LOG ANALYSIS SYNTETIC LOG
PROJECT DATABASE
MANAGEMENT
MAPPING BASE MAP
SEISMIC INTERPRETATION SECTION FROM A 3D SURVEY
WELL TEST ANALYSIS LOG-LOG PLOTS
UPSCALING 3D SIMULATION MODEL
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Multidisciplinary Team
The key is to find the way for an Integrated
Reservoir Modeling with multidisciplinary team
and 3D model validation using additional well test
data and System Procedures.
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An Integrated Reservoir Modeling Validation Procedure
Data Acquisition and Analysis
Static Model Building
Dynamic Model Building
Reservoir Simulation
Prediction Evaluations
Integrated Reservoir Modeling Study Report
Validation Well Tests
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Reservoir Simulation today and tomorrow
Analysis Floviz, Office
Grid building Flogrid
PVT-data PVTi
Well data preparation Schedule
Rock data SCAL
Wellbore hydraulics
VFPi
Well Testing Weltest
Geological model GEOFRAME OpenWorks
Irap RMS Petrel
Processing Eclipse 100-500, Frontsim
History Matching (SimOpt, Weltest)
Well events Production data
Well test data Well logs
Interactiv Pet. Saphir, Topaze Mbal, Fieldpro
Economic Evaluation Peep, Merak
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What is Validation Procedure Time?
History Match 60%
Prediction 15% Model Construction
20%
Presentation & Documentation 5%
History Match Is the Longest
Portion of Validation
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Objectives and deliverables
! Objectives: – to validate and correct the near wellbore regions (3D model)
from the simulation models when well test data are available.
! Deliverables – to create an easy to follow workflow for matching numerical
well test with field data. For this workflow are used the applications: Flogrid, ECLIPSE 100, Weltest, SimOpt (Schlumberger Products)
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The Method
It consists of four steps: 1. Analysis of test data using state-of-the-art analytical methods. 2. Extracting the area of influence of the well test from the
available numerical simulation model and modifying the grid to allow for transient-level analysis.
3. Modifying the properties in the extracted area until measured pressure and derivative are matched with model response.
4. Verify the production history of all wells using the new full-field model. Repeat step 3 if necessary to obtain consistent results.
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From SPE 95905
The Method
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Test model
! A single vertical well was considered with the perforations from 994 m to 1024 m.
The field data were simulated using a very
fine model with 1.2 million cells.
A cell has 2mx2mx1m.
The numerical well test was simulated using a
726 cells model.
A cell has 36mx36mx5m.
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Static properties
Variogram:
Horizontal Range = 100 m
Vertical Range = 2 m
Sill = 500
+
Porosity = 0.2, Permeability populated using well data.
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Static properties
Permeability Mean ≈ 30 mD Permeability Mean ≈ 43 mD
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Oil Production
Pressure Coarse Model
Fine Model
Simulation procedure
3d Model
+
Well target: Oil Rate 50 m3/day
FVF & Viscosity
Dynamic properties
Relative permeability curves
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Weltest comparison
Reservoir Datum Depth (TVD): 994 m
Top of Reservoir Depth (TVD): 994 m
Initial Reservoir Pressure: 200 bar
Fine Model Analysis
Av. Permeability: 30.9 mD
Total Skin: -0.1
Average Well Pressure: 171.4 bar
Initial Res Pressure: 200 bar
Well perf length: 30.0 m
Coarse Model
Fine Model – Field Data
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Matching kh vs. kv
History match the pressure data by changing the vertical and horizontal permeability of the coarse model.
Real Data (Fine Model) Coarse Model Data
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Results
Coarse Model
Fine Model
Oil Production
Pressure Coarse Model
Fine Model
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Case Study – Horizontal Well
► Type of Well: Horizontal
► Type of Test: Drawdown (22 days )
► Initial Pressure: 235 bar
► Bubble Point Pressure: 149 bar
► Number of Cells: 9568 (23x13x32)
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The Well Test Data
Drawdown Test
Oil Production
Pressure
Drawdown pressure & Oil Flow Rate
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Horizontal Well Model
The Volume of influence of the horizontal well extracted from the available numerical
simulation model Horizontal well
Permeability Log
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Permeability Mean ≈ 4.26 mD
The model in
► The numerical well test was simulated using a
9568 cells model (23x13x32).
► The model cells has: ► DX= 16 m ► DY = 14 m ► DZ = 5 m.
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History matching
Simulated Data
Observed Data
Bottom Hole Pressure
► Average permeability before history matching: 4.26 mD ► Average permeability after history matching: ≈ 2.1 mD
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Weltest Results Log-Log Drawdowns
Field Data Analysis
Simulation Data Analysis
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Measured Data – Reservoir Answer
Simulation Model
Welltest comparison Log-Log Drawdown
Measured Data – Reservoir Answer
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Unit Scale Simulation Model
The Simulation Model has 25000
cells: ► NX = 25 ► NY = 25 ► NZ = 40
3D Reservoir Unit Fluid Distributions
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Conclusion of Example of IRM► The traditional history matching for a full field model can
take months. A quick validation of the model with Numerical Well Test (NWT) will take days allowing changes in the model before going into a full field study.
► NWT is a useful and practical method for 3D Model Validation and near wellbore modeling for mature fields.
► NWT enables the use of the additional information obtained from well tests in reservoir description & performance predictions.