Fracture Modelling
In fractured reservoirs across China, South-East Asia, the Middle
East, South America, Canada, Russia and Europe, fields are being
poorly swept, wells are encountering early water breakthrough
and oil is being lost. Two-thirds of the world’s proven reserves lie
in areas with acknowledged fracture-affected recovery and in a
large number of cases the issue is not being addressed. Fractured
reservoir fields are often unique, there is no off-the-shelf solution.
But you can still model your reservoir and find a good solution.
Roxar’s RMSFracture software, a fully integrated module of RMS TM,
will help both general and specialist users gain insight into their
reservoir behaviour. RMSFracture is both fast and easy enough for
fracture model creation and updating to become as routine as
updating the facies model.
IN SUMMARY
• Tempest
MORE
wasinteractive.
first commercialized in 1999 and
• Flexible,
fast and
is used on some of the world’s largest fields.
• Multiple scenarios and uncertainty assessment based on
fracture model inputs.
• Create your fracture model on large geological grids for
more accuracy.
• Condition permeabilities to real well data.
• Benefits from the full integration with the best
geomodelling and upscaling tools and direct links to
simulation packages.
• Can generate data for single-porosity or dual porosity
models.
Integrated Fracture Modelling Solution
Fractures play an important role in understanding the flow
behaviour of many reservoirs. In order to appreciate the role of
fractures we must be able to:
• Predict the fracture density away from the well.
• Predict which fractures are likely to contribute to flow.
• Model dynamic properties of the fractures in a way that is
consistent with observation.
Roxar is focused on efficiently building effective fracture
models based on:
• Conditioning models to well fracture data.
• Providing geologically reasonable extrapolation trends
for well data.
• Using dynamic information to constrain the model based
on interpreted well test permeability.
Roxar’s fully integrated RMSFracture module offers a four-step, no
fuss modelling solution.
Fast and Robust Permeability Mapping
This modelling technique is based on direct inversion and produces
effective permeability maps. Where well permeability data is
available this provides the rapid achievement of a fracture
permeability model, calibrated to real well permeability information.
When there is a clear, confident understanding of the fracture
distribution and reliable extrapolation trends, this is an extremely
fast and smooth route to a robust fracture permeability model. The
straight-to-grid modelling functionality generates effective
permeability maps.
• Based on the distribution of fractures in the reservoir.
• Direct export to single porosity reservoir simulators.
• Fast and directly calibrated to dynamic well data.
• Excellent performance times for large numbers of wells.
• The more wells, the better the results!
Fracture Modelling
Discrete Fracture Networks - Detailed Modelling
While it is possible to go directly from trend modelling to
matching effective permeability, it is often insightful to use discrete
fracture networks (DFNs) to build a fracture model that is valid from
a structural geological perspective. Lack of reliable well data may
mean that a model must be constructed from core geological
concepts, using aspects of the 3D model to constrain the input. For
this, greater control over the details of the fracture model is
necessary. RMSFracture can handle very large numbers of fractures
with such speed that it can truly be said to model the field at the well
scale.
DFNs model fractures explicitly. The distribution of fractures may be
described by fracture density 3D parameters. These maps may be
determined by a number of different methods including:
• Proximity to fault
• Curvature
• Stress models
Fracture permability realisations
Integral Stress Calculator
RMSFracture contains its own stress modeller, taking an applied
stress field and using elastic dislocation modelling to map the stress
distribution in the reservoir volume. This gives a snapshot of the
stress field which created the fracturing. Parameters derived from
the stress tensor are returned to RMS as a series of grid properties
which are immediately available for use in controlling the local
variations in orientation and distribution of fractures in the model.
The stress modelling interface has been streamlined for ease of use.
Geomechanical constants can be adjusted where necessary to
accommodate the impact of significant changes in rock behaviour.
RMSFracture can thereby model fracture networks developed
from a causal approach or from a descriptive approach,
allowing maximum flexibility in data utilisation.
For more information please go to www.roxarsoftware.com
or email us on [email protected].
Stress field modelling output, showing on left, likelihood of failure and on the right, the
orientation of the fractures formed during failure.
Different models are possible depending on fracture type or
orientation, stress boundary conditions etc. It is also possible to
generate density and orientation constraints based and conditioned
to wells or any outcrops observations.
RMS can thus be used to generate models of areas where data are
very limited or poorly interpretable.
The DFN is constructed to:
• Strickly follow the trends dictated by the indicator maps (stress,
curvature etc).
• Allow for individual modelling of specific fracture types and
their truncation rules.
• Respects well observations, to azimuth data, and to rock
parameters or layering.
Roxar 2013
The model can be interactively modified to provide maximum
quality control on the final product.
ROXAR AS, GAMLE FORUSVEI 17, PO BOX 112, 4065 STAVANGER, NORWAY TELEPHONE +47 51 81 8800 FAX +47 51 81 8801 WWW.ROXAR.COM