Oil & Natural Gas Projects
Exploration and Production Technologies
Online, Optimization-Based Simulation of Fractured and Nonfractured Reservoirs
This project was selected in response to DOE's Oil Exploration and Production
solicitation DE-PS26-01NT41048, focus area Critical Upstream Advanced Diagnostics
and Imaging Technology. The goal of the solicitation was to continue critical
upstream cross-cutting, interdisciplinary research for the development of advanced
and innovative technologies for imaging and quantifying reservoir rock and fluid
properties for improved oil recovery
The goals of this project were to:
- Complete the development of the University of Utah discrete-fracture model
so that an alternative production-level fractured reservoir model is available.
- Incorporate the most modern numerical schemes in reservoir simulation algorithms
and implement the simulator on large PC clusters to demonstrate affordable parallel
- Develop optimization-based reservoir simulators so that exploitation of oil
reservoirs is planned in an economically optimal fashion and oilfields are operated
optimally over their lifetime.
- Implement the entire package on the internet so that the technology is available
and accessible to a wide group of independents.
University of Utah
Salt Lake City, UT
A three-dimensional, three-phase reservoir simulation of complex faulted/fractured
reservoirs using the modern linear and nonlinear solvers is now possible.
A client-server protocol will make it possible for interested engineers and
scientists to create two-dimensional fractured domains and run data files
remotely on the University of Utah servers.
If detailed fault/fracture characterization is available, it would now be
possible to incorporate this explicitly into three-dimensional, three-phase
reservoir simulators. An interactive tool developed as part of this project
will help geoscientists experiment with the placement and properties of faults.
A new set of tools to deal with complex faulted/fractured systems is now available
to the industry.
Most oil reservoirs are fractured to a certain degree. The models currently
used for fractured reservoir simulation do not explicitly consider the spatial
fracture characterization. Instead, the fracture presence is smeared out in
a dual continuum model. Better reservoir characterization methods are making
fracture mappings available. When the spatial characteristics of fractures
are considered, the resulting discrete fractur" models are also highly
computation intensive. The purpose of this project was to create finite-element
models that would be able to incorporate this characterization of faults/fractures
The original reservoir simulators were developed using numerical methods
and algorithms that were more suitable for the prevalent computational environments.
The more advanced, faster conjugate gradient-like methods for the solution
of linear equations, for example, have not been widely implemented. Parallelization
also has been beyond the reach of the independent producers because the multiprocessor
machines are very expensive.
There has been a great emphasis on the effect of reservoir geologic and petrophysical
properties on reservoir performance; however, little research effort has been
expended on understanding the effect of control variables on reservoir operation.
This is a difficult constrained-optimization problem. When resolved, this
will lead to optimum reservoir operation, continuous performance monitoring,
and possibly automatic model updating based on reservoir history. The Internet
is changing the way business is conducted, and it affords significant opportunities
to make the oil business more efficient. Making simulators available on the
Internet with online computing modules will open up the technology to independent
producers. This project was performed to address some of these issues.
Among the project highlights:
A three-dimensional, three-phase reservoir simulator based on the Control
Volume Finite-Element (CVFE) architecture was developed. Results from this
simulator were compared to output from Eclipse. Faults in Eclipse were modeled
using a fine-mesh representation.
A new numerical model, based on the mixed finite-element method was developed
Several two- and three-dimensional simulations of two- and three-phase flow
in faulted/fractured porous media were performed to demonstrate the applicability
of the methods developed.
It was shown that incorporation of hydraulic fractures was straightforward
using the approach described.
Most modern conjugate gradient numerical solvers were used. The simulators
were linked to Portable Extensible Scientific Computation toolkit.
Parallel computation schemes using MPI were employed, and scalability was
demonstrated on a 18-processor Linux cluster.
The feasibility of being able to embed optimization routines was demonstrated
by linking with the Toolkit for Advanced Optimization.
An interactive module based on the client-server protocol was created. This
module will let users run the simulators remotely on the University of Utah
servers or any other servers where the programs would be installed. This provides
affordable parallel computing access to independent producers.
Current Status (August 2005)
The project is in the no-cost extension period. It was to conclude on August
Primary production and waterflood in a complicated domain containing sloping,
intersecting fractures. A three-dimensional view, along with a section in
each of the three dimensions, is shown.
Mesh of intersecting sets of fractures (from Golder, Inc.) is shown in the
upper left. Gas saturations after 150 days of primary production with gas
accumulation at the top is at the upper right. Water saturation after 700
days is shown at lower left (water injection started at 150 days).
First Annual Report, September 2002; Second Annual Report, September 2003;
Interim Progress Report.
Project Start: September 1, 2001
Project End: August 31, 2005
Anticipated DOE Contribution: $680,000
Performer Contribution: $170,000 (21% of total)
NETL - Daiel Ferguson (firstname.lastname@example.org or 918-699-2047)
U. of Utah- Milind Deo (email@example.com 801-581-7629)