C01 Intro Fracture Modeling 2010
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Transcript of C01 Intro Fracture Modeling 2010
QC and use Fracture
Attribute Data
Fracture Modeling – Petrel 2010
Initial Data
Analysis
Modeling Fracture
Parameters
Building Fracture
Model
Upscaling Fracture model with
Multiple Fracture Drivers
Import/Display
Simulation
Fracture Modeling
Intro
Theorethical
Background
Fracture Modeling Course Course Content
Day 1 Day 2
Introduction
Optional: Background theory
Import & display fracture data
QC and use fracture attributes
Initial data analysis
Modeling fracture parameters
Building a Fracture model
Upscaling fracture attributes
Fracture drivers
Dual porosity simulation setup
Fracture Modeling Course
Introduction Overview
What is Fracture Modeling?
Naturally Fractured Reservoirs
Fluid Flow Simulation Models
Fracture Modeling approaches
Fracture Modeling Workflow
Data Set - Location
Data Set - Geological description – Stratigraphy/Mechanical zones
– Fractures
Data Set - Comparative Outcrop studies
What is Fracture Modeling? Purpose and Process
Purpose Create simulation properties for matrix and fractures to
be able to predict reservoir behavior
Why? Many reservoirs are dual porosity/dual permeability
(Naturally fractured); leading to high flow zones not representative of the matrix flow capacity
Flow simulators have problems simulating these kind of reservoirs.
Process Multi-disciplinary approach;
Use analyzed fracture data from wells
Building a Fracture model (DFN+IFM)
Upscale fracture permeability, porosity and connection factor between matrix and fractures from the Fracture model
These data can subsequently be simulated
Naturally Fractured Reservoirs Simple Classification of Reservoir types
I. Fractures provide essential Porosity and Permeability – Requires large reservoir tank or thick pay zones to be economical (no matrix porosity)
II. Fractures provide essential reservoir Permeability – Most reservoirs with storage in matrix but low matrix permeability
III. Fractures assist Permeability in already producible reservoir – Higher porosity lithologies
IV. Fractures provide no additional Porosity/Permeability – Fractures act as Flow Barriers
% o
f To
tal P
erm
.
% of Total Poro.
I II
III
IV
100% ΦF
100% KF
Naturally Fractured Reservoirs Example of Reservoir types
I. Fractures provide essential Porosity and
Permeability
II. Fractures provide essential reservoir
Permeability
– Fluid communication from Matrix to
Fractures is important
– Fracture Morphology essential !
III. Fracture assist Permeability in already
producible reservoir
IV. Fractures provide no additional
Porosity/Permeablity
• Morphology
M to F communication
• Good Recovery Factor
• Good waterflood
sweep efficiency
• Morphology
Restricted communication
• Poor Recovery Factor in
tight Matrix
• Poor waterflood sweep
efficiency
MATRIX
DISCHARGE
M
F
Crossflow No Crossflow
M
Fluid Flow Simulation Models How to approximate nature?
Reality Approximation
In Place Reserves
Recovery
Well Productivity
Field Connectivity
Reality captured in 3D Models
Ideally hydrocarbon flow takes place in a Single Porosity / Permeability system
However in Dual Porosity reservoirs, fluids exist in two interconnected systems (matrix and fractures). This must be accounted for in Simulation models.
Fra
ctu
re
Mat
rix
Fluid Flow Simulation Models Dual Porosity (DP) models
Real Reservoir
Match Stick Model Layered Model Sugar Cube Model
Dual Porosity idealization A simplification of the real reservoir is done when creating a dual porosity model
Fluid flow and transport exist in both the connected fractures and matrix blocks
Two overlapping continua, where both are treated as porous media
Dual Porosity model types Simple layer model (sheet of parallel fracture sets)
Matchsticks model (2 orthogonal fracture sets)
Sugarcube model (3 orthogonal fracture sets)
Fluid Flow Simulation Models DFN vs. Dual Porosity models
DFN Model – Non Uniform Geometry – Variable Fracture Orientation – Variable Fracture Length – Variable Aperture - -> Variable Intensity and Interconnectivity
Dual Porosity Model – Fixed Geometry – Continuous Fractures – Equal spacing – Constant Aperture
DFN Model
Layered Model
Real Fractured
Medium
Fluid Flow Simulation Models Standard approaches to fracture modeling
Equivalent Continuum – Bulk response for equivalent porous media
Dual Porosity (DP) – Separate Matrix and Fracture blocks
Discrete Fracture Network (DFN) – Physical fracture representation – Upscaled to Dual porosity properties
Real Fractured
Medium
Equivalent Non-Fractured
Medium
Layered Model
DFN Model
Fluid Flow Simulation Models Petrel 2010 approach to fracture modeling
Implicit Fracture Model (IFM) – Yields directly fracture porosity and permeability as properties – Upscaled to Dual porosity properties
Discrete Fracture Network (DFN) – Physical fracture representation – Upscaled to Dual porosity properties
Real Fractured
Medium
Property Model
DFN Model
Combined Model
Fracture Modeling Workflow Petrel – Overall Fracture modeling workflow
Well data Data
Analysis
Model
Parameters
Create
Fracture model
Upscale
& Simulate
Fracture Modeling Workflow Petrel – Specific Fracture modeling processes
DFN
IFM
Fracture intensity
Hybrid
IFM / DFN
model
Data Set Teapot Dome – Wyoming (USA)
USA
Achnowledgements:
Thanks to Rocky Mountain Oilfield Testing Center and
U.S. Department of Energy for using Teapot data
Teapot Dome is located in central Wyoming. A comprehensive Data Management
project has been conducted to digitize and compile all available data. Data is
available e.g. for research and software testing/training.
0 1 km
N
Quaternary
Alluvium
Mesaverde Fm
Undifferentiated
NPR3 Boundary
1
2
3
4
51 Section
Location,Number
Unit 5: Fluvial Ss
Unit 4: Non-Marine Carb.
Sh with localized
coal
Unit 3: White Beach
Ss
Unit 2: Shoreface/Beach
Ss
Unit 1: Shallow Marine
Interbedded Ss
and Sh 10m
0
Data Set – Stratigraphy (Outcrops @ Alcova anticline)
Reworked from:
S.Raeuchle et al, 2006 and Cooper, S. 2000
East West
Cretaceous
Measverde Fm
Teapot Sandstone
Parkman Sandstone
Carboniferous
Tensleep Fm
0 1 km
N
Quaternary
Alluvium
Mesaverde Fm
Undifferentiated
NPR3 Boundary
1
2
3
4
51 Section
Location,Number
Unit 5: Fluvial Ss
Unit 4: Non-Marine Carb.
Sh with localized
coal
Unit 3: White Beach
Ss
Unit 2: Shoreface/Beach
Ss
Unit 1: Shallow Marine
Interbedded Ss
and Sh 10m
0
Data Set – Mechanical Zones (Mesaverde Fm. Outcrops)
Generalized Stratigraphic column
– Parkman Sandstone Mb. (Mesaverde Fm.)
Mechanical zones
Separating units according to mechanical properties is important due
to mechanical influences on fracture characteristics.
Compiled from Mallory et al., 1972; Spearing, 1976, and
Rocky Mountain Oilfield Testing Center field data.
From: Cooper, 2000; Cooper et al., 2001, 2003.
Data Set – Mechanical Zones (Tensleep Sst. Outcrops)
Stratigraphic systems
Separating units according to stratigraphic architecture is also important for
prediction of complex fracture development in low-complex reservoir facies.
Compiled from Zahm & Hennings, 2009 (AAPG Bulletin)
Data Set – Fracture Intensity (Tensleep Sst. Outcrops)
Fracture intensity at multiple scales
High variability in fracture intensity was demonstrated, caused by original depositional
architecture, overall structural deformation and diagenetic alteration of the host rock.
Fracture intensity depends on stratigraphic scale.
1. Throughgoing fractures
2. Sequence Bound fractures
3. Facies Bound fractures
4. Lamina Bound fractures
Compiled from Zahm & Hennings, 2009 (AAPG Bulletin)
Data Set – Faults at Teapot Dome (Outcrops)
Map of faults and representative
hinge-perpendicular fractures
Map of faults and representative
hinge-parallel fractures
Modified from: Cooper et al., 2006
Data Set – Fractures at Teapot Dome (Outcrops)
N
covered
0 1 m
Throughgoing fractures Cross fractures
Illustrations from: Cooper, 2000
Fracture map of a pavement surface Illustrating
the nature of throughgoing fractures and cross
fractures at the top of a single sandstone bed at
Teapot Dome Conceptual 3D model of fracture outcrop patterns
developed at Teapot dome.
Data Set – Fractures related to Lithology (Outcrops)
Unit 5: Fluvial SsUnit 4: Non-Marine Carb.
Shwith localized
coalUnit 3: White Beach
Ss
Unit 2: Shoreface/BeachSs
Unit 1: Shallow MarineInterbedded Ssand Sh 10m
0
0 1 km
N
QuaternaryAlluvium
Mesaverde Fm
Undifferentiated
NPR3 Boundary
n = 24
N
n = 23
Charted Locality
Illustrations from: Cooper, 2000
A
B
Throughgoing
fractures
Rotation to
Fold Hinge
Surface outline
(boundary) of
subsurface 3D grid
Overthrust
Tensleep Fm top
Data Set – Infer Outcrop observations to subsurface 3D models?
EXERCISES Module 1
P.42 - 49