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Reservoir Simulation

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Reservoir Simulation
Chapter-one
Introduction
Sadam .H
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THE CHALLENGE OF RESERVOIR SIMULATION …
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Incentives for running a flow simulation
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Computer Modeling
The reservoir model
Fluid flow Equation within the reservoir
The reservoir is modeled by subdividing the reservoir
volume into an array, or grid, of smaller volume
elements, which called: gridblock, cell, or node.
The well model
Fluid flow that represents the extraction of fluids from
the reservoir or the injection of fluids into the reservoir
The well bore mode
Fluid flow from the sand face to the surface
The surface model
constraints associated with surface facilities, such
as platform and separator limitations
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Reservoir simulator
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Reservoir simulation model
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Reservoir simulation model
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Main modeled phenomena
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Definitions
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Types of models
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Types of simulators
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Types of simulators
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Black Oil model
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NUMERICAL MODELS: DISCRETIZATION
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Reservoir Simulation PLANNING
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A question of Scale
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Prediction Future performance
Reservoir Simulation Model
Geological Model
Reduce Operation Expenses
Increase Recovery
History Matching
Prediction
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Problem definition
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Data review
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Main Types of Data
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Study approach
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Study approach
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GRID TYPES
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GRID TYPES
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Sugar box geometry
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Sugar box geometry
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Corner point geometry
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Reservoir description : PROPERTIES
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Reservoir description : PROPERTIES
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Reservoir Discritization
Defination: the reservoir is described by a set of gridblocks (or
gridpoints) whose properties, dimensions, boundaries, and locations in the
reservoir are well defined.
Block centered grid
Point distributed grid
i-1
i
i+1
ΔY
ΔX
ΔX
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Block Identification and Ordering
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Block Identification and Ordering
• Natural ordering
• Zebra ordering
• Diagonal D2 ordering
• Alternating diagonal
D4 ordering
• Cycle ordering
• Cycle-2 ordering
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GRID SIZE SELECTION
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ACTIVE and DEAD CELLS
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GEOLOGICAL CONSTRAINTS
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CHOICE OF VERTICAL DISCRETIZATION
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Using LGR to model gas coning
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Block-centered grid
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Block-centered grid
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Block-centered grid
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Dip or fault ?
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CPG grid intercell flow
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Fault description in CPG grid
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Example of CPG reservoir model
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Fault description in CPG grid
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Reservoir layering: Use of log Correlation
K.FEKI
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Upscaling
• Optimum level of
and techniques
for upscaling to
minimize errors
Gurpinar, 2001
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Rock properties: Main parameters
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Rock properties: Net thickness and porosity
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Rock properties: Compressibility
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Rock properties: Compressibility
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Horizontal & Vertical Permeability
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Horizontal Permeability
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Vertical Permeability
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History Matching
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History Matching
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History Matching
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FIRST STEP - GENERAL FIELD MATCH - RUN 1
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FINAL STEP - GENERAL FIELD MATCH - RUN 3
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Predictions
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Predictions
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Predictions
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Fluid flow equations
Conservation laws
–
Conservation in mass
Assume:
–
–
Isothermal condition
complete and instantaneous phase equilibration in each cell
Conservation in energy
Conservation in momentum
Additional constraints
Wells and facilities
Large number of non-linear equations
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Fluid flow equations
Type of fluid in the reservoir
Flow regimes
Reservoir geometry
Number of flowing fluids in the reservoir
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Type of fluid in the reservoir
Incompressible
Slightly compressible
Compressible
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Flow regimes
Steady State flow
Unsteady State flow
Pseudo Steady State flow
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Reservoir geometry
Radial flow
Linear flow
Spherical and Hemispherical flow
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Number of flowing fluids in the
reservoir
Single Phase flow
Two phase flow
Three phase flow
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IN OUT
Reservoir Simulator
Pressure
Saturation
Newton-Raphson (IMPLICIT)
all primary variables are calculated at the same time.
IMplicit Pressure Explicit Saturation (IMPES)
The IMPES procedure solves for pressure at the new time level using
saturations at the old time level, and then uses the pressures at the
new time level to explicitly calculate saturations at the new time level
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Numerical Models
Black oil model
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Depletion
Water Injection
Component: oil water gas
Phase: Oil water gas
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Compositional model
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Gas injection to increase or maintain reservoir pressure
Miscible flooding as the injection gas goes into solution with oil
Carbon dioxide flooding, with the gas soluble in both oil and water
Thick reservoirs with a compositional gradient caused by gravity
Reservoirs with fluid compositions near the bubblepoint
High-pressure, high temperature reservoirs
Natural-fracture reservoir modeling.
Component: C1,C2, ….So2,H2S,N2,..
Phase: Oil water gas
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Chemical model
o
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Polymer and surfactant injection
Component: Water oil surfactant alcohol
Phase: Agues oleic microemulsion
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Reservoir simulators
ECLIPSE
GPRS
SENSOR
NEXUS
UTCHEM
Boast 3
COMET3
…
Objective
Accuracy
Time
Limitations
User friendly
Easy to integrate
…
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Eclipse reservoir simulator
• Commercial reservoir simulator for over 25 years
• Black-oil
• Compositional
• Thermal
• Streamline
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Eclipse reservoir simulator
Local Grid Refinement
Gas Lift Optimization
Gas Field Operations
Gas Calorific Value-Based
Control
Geomechanics
Coalbed Methane
Networks
Reservoir Coupling
Flux Boundary
Environmental Traces
Open-ECLIPSE Developer's Kit
Pseudo-Compositional
EOR Foam
EOR Polymer
EOR Solvent
EOR Surfactant
Wellbore Friction
Multisegmented Wells
Unencoded Gradients
Parallel ECLIPSE
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