Fault modelling software from Badleys: TrapTester

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Fault modelling software from Badleys
TrapTester TransGen
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What is TrapTester?
the software formerly known as FAPS

• TrapTester is a structural analysis toolkit
• Suite of advanced functionality in one
  environment for fault trap integrity analysis
  risking
• Tools for
• Visualizing, interpreting and analyzing fault
  horizon data
• Building faulted framework models with
  stratigraphic property infill
• Predicting fault trap integrity with pressure,
  stress mechanical data (fault seal analysis,
  column height prediction, fracture stability )

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Interpretation Data Direct links
OpenWorks R2003, 1998.8

• Horizon Fault interpretation
• Well data (paths, curves, well-based picks)
• Seismic data (SeisWorks, IESX, Charisma)
• ( import only)

IESX Charisma GF3.8, 4.0

• Also extensive ascii I/O e.g.
• Fault horizon surfaces as tri-mesh / grids,
  inc. RMS, Petrel formats
• Faults and horizons on vertical horizontal
  sections
• Fault surfaces framework polygons as XYZ data
• Wells, well picks, attribute logs

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Framework model using intersecting faults
Create intersecting faults (with automatic
functions) and analyse all faults at same
time Result 3D geometric tie of horizons
fault polygons across all faults and modelling of
displacement across branchlines Displacement
is partitioned across branchlines
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Fault-displacement mapping to quality-check
interpretation
Problem Discrepancy in fault polygon due to
anomaly in horizon interpretation that may be due
to mis-picks, absence of other faults,
etc Solution Interpret new structure or edit
horizons on sections or in 3D Edit fault
polygons directly on fault surface
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Allan fault-plane diagrams
Problems Seismic horizons too widely spaced to
depict detailed reservoir stratigraphy required
for fault-seal analysis.
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Stratigraphic in-fill
Reservoir intervals and horizon surfaces are then
populated with Vshale from wells for use in the
SGR algorithm
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Allan diagram shows areas of juxtaposition seal
and areas of potential cross-fault leakage
Downthrown Red juxtaposed against Upthrown Yellow
Yellow reservoir zones self-juxtaposed across
fault
up
down
Downthrown Yellow juxtaposed against Upthrown
Green
Areas of reservoir non-overlap juxtaposition
seal at fault. Grey non-reservoir sealing
lithology on both sides of fault plane.
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Determination of potential leak points in the
trap complex
Fault zone composition (SGR) calculated using
well model (or acoustic impedance volume)
Shale Gouge Ratio painted onto reservoir
juxtaposition areas (leak points on Allan
diagram) Green low SGR high risk of
cross-fault leakage Red high SGR low risk of
cross-fault leakage
Faults with only the potential leak points
highlighted
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Seismic fault slicing
Footwall (upthrown) seismic
Hangingwall (downthrown) seismic

• Seismic slices are extracted from the 3D volume,
  on either side of the fault
• Up to 5 slices from each side (e.g. 25m, 50m,
  75m, etc)
• Displayed on the fault plane
• Excellent for visualisation of reflection
  pattern on each side of the fault, for QC of
  modelled juxtaposition relationships

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Fault seal analysis using fault slices from
inverted seismic volumes
Seismic volume inverted to Vshale
Problem Very difficult to predict
reservoir-scale layering and variation in
interval properties in areas of complex
stratigraphy, such as channel systems
etc. Solution Use inverted seismic data
(calibrated to lithology, e.g. Vshale) and
integrate volume property with displacement
fields on faults
Result Seal potential for all faults derived
directly from volume properties (green low, red
high seal potential)
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Fault statistics and analysis based on sampling
the faulted horizon framework
Length vs Throw Lateral extent of fault traces in
areas of poor or sparse data quality and can be
used as an aid to correlating fault segments in
2D data sets
Frequency Plots Predict the number of faults with
throws of a certain value less then the limit of
seismic resolution
Array summation fault related strain Examine
partitioning of displacement between different
elements of a fault array and calculate the
fault-related strain in a particular area
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Likelihood of fault reactivation
Methodology developed in collaboration with
National Centre for Petroleum Geology
Geophysics (NCPGG), University of
Adelaide. Assessment of fault reactivation
likelihood by looking at how far the stresses
acting on a fault plane are from tensile and/or
shear failure. Leakage of hydrocarbons along the
fault zone is more likely when the slip
tendency is high (i.e. the elevation in pore
pressure required to induce failure is low).

• Input data
• Pore pressure data points (gradients, depths,
  pressures)
• In situ stress data points (gradients, depths,
  magnitudes)
• Mechanical properties (coefficient of friction,
  cohesive strength)

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FaultED - A new add-on module for TrapTester-5
Algorithms for Elastic Dislocation (E-D)
modelling have been implemented within TrapTester
to predict the 3D strain and stress tensors in
the rock volume surrounding seismically-mapped
faults. This allows us to predict small-scale
fracture patterns.
Fracture planes predicted from calculated stress
tensor
red normal faulting, cyan/magenta strike-slip
Horizon colour-coded by calculated shear stress
fracture intensity
E-D model of seismically-mapped fault
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TrapTester - Summary

• TrapTester bridges the gap between geometric
  framework models and geological analysis
  prediction
• During interpretation, fault plane analysis can
  help to identify problems with the data, to
  determine fault linkage and to derive more
  complete analysis of juxtaposed reservoir
  intervals
• Having built a framework model, predictors for
  column height and fault reactivation can be
  derived to quantify fault trap integrity and
  assess risk
• Provides all the tools for trap integrity risking
  and analysis in one seamless environment for
  exploration and appraisal

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after TrapTester. .TransGen getting fault
properties into reservoir simulators
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TransGen A tool for generating geologically
meaningful fault transmissibility multipliers
for ECLIPSE simulation models, and for examining
the influence of faults on flow
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Summary of TransGen methodology Geologically
derived transmissibility multipliers
SGR
Displacement
Thickness
Permeability
Transmissibility multiplier
Fault-rock permeability is a user-defined
function of SGR, displacement, depth
After Manzocchi et al. 1999
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Scott Field TransGen analysis
The Scott Field ECLIPSE model achieved a close
history match when the SGR methodology was used
to calculate transmissibility multipliers for
faults.
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Future developments (funded by Shell UK, Statoil
Petrobras)
1 Additional fault-rock properties (SSF, CSP,
etc) via a macro language
2 Routine inclusion of sub-resolution fault-zone
structure (relays, normal drag, damage zones)
3 Routine inclusion of two-phase fault-rock
properties (Manzocchi et al, 2002) to acknowledge
the changing relative permeabilities as oil
saturation in the fault zone changes through time
during production
With the relay incorporated using the proposed
methodology
Pressure distribution in a layer
4 Further refinement and calibration of
algorithms against reservoir production data
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TransGen summary Calculate transmissibility
multipliers at all faulted cellular connections
in an ECLIPSE model. Visualise and QC ECLIPSE
faulted reservoir connections and compare with
seismically-mapped fault juxtaposition
relationships. A visualisation environment for
engineers and geologists to help understand and
discuss faulted reservoir models. Import ECLIPSE
re-start file to visualise the impact of fault
properties on flow simulations.
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TrapTester testing faulted trap integrity in
exploration and appraisalTransGen
transmissibility multipliers for production
simulation