DOE's Unconventional Gas Research Programs 1976-1995
SOURCE: U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico OCS Region

3.2.4. Highlights of Important Results

The Western Gas Sands Program was designed to accelerate the production of domestic gas resources. It was directed specifically at the development of new and improved techniques for recovering gas from low-permeability gas reservoirs in western basins that at the time of initiation of the program could not be economically produced. The purpose of the program was to encourage and supplement industry efforts to develop technology and demonstrate the feasibility of producing from tight reservoirs.

The key contributions resulting from the WGS Program include:

  • Collection and analysis of core material from a variety of location to provide data on the fundamental reservoir properties of tight sandstones that had previously been lacking,
  • Development of new equipment and procedures for measuring tight sandstone rock properties,
  • Detailed characterization of the geology and tight sand gas resource potential of five Rocky Mountain basins, that provided a basis for subsequent decision-making related to both R&D and resource development investments,
  • Creation of an extremely well-characterized reservoir laboratory at the MWX site, that allowed for experiments that contributed critical insights towards answering questions related to the continuity of tight sands, the importance of natural fracture systems, the importance of in situ stress to hydraulic fracture design, and the size and shape of created hydraulic fractures compared to their design dimensions, and
  • Development of geologic and production predictive models that enhanced efforts to find and economically produce natural gas from tight gas sands.

Specific products related to particular projects are listed below.

The Multiwell Experiment (MWX)
  • Advanced Tight Gas Core Analysis Technology. Specialized equipment and techniques were developed at IGT, Core Labs, and New Mexico Tech to fully characterize the reservoir properties of very low permeability rocks. Of particular importance were methods that were developed to test rocks under both in situ stress and water saturation conditions and capillary pressure measurements to aid in the understanding of the important two-phase flow mechanisms (water and gas). These techniques are now routinely used for low-permeability core testing and are available commercially.

  • Reservoir Characterization Methodology. The core samples in the three closely spaced wells, along with the careful assessment of numerous surface outcrops of these same reservoir rocks, provided the information necessary to develop methods for quantifying the size of sandstone lenses in various depositional environments. This methodology, which is now used by numerous companies working in the tightsand basins, provides critical information needed for resource assessment, reserves calculations, fracture design, and well spacing in these fields.

  • Naturally Fractured Core Analysis. A process for analyzing fractured core has been transferred to numerous companies and is routinely used by industry and techniques for identification of coring induced fractures is widely used. Information from stress sensitivity testing of naturally fractured cores is now used in many reservoir and fracture models.

  • Stress Testing and Applications. MWX was the site where a methodology for microfracture stress testing through perforations using down-hole shut-in was fully developed and where anelastic strain recovery and circumferential velocity anisotropy were validated. Micro-fracture stress testing is a testing procedure now used routinely by companies throughout the world and anelastic strain recovery is a commercial service available through Halliburton. Altered stress fields due to fractures and other down-hole processes are now calculated and considered in many applications such as re-fracturing and in-fill drilling. The mechanism defined for the formation of regional fractures is being applied towards exploration strategies in many basins.

  • Advanced Tight Gas Log Analysis. By running multiple logging suites (including experimental logs such as Mobil’s televiewer, Amoco’s and Schlumberger’s longspaced sonic logs, and Schlumberger’s dipmeter), and coupling the results with the results of core analysis, new correlations were developed that more accurately predicted reservoir properties. The data was made available to all of the commercial logging companies.

  • Extreme Overbalanced Perforating. While attempting to develop methods for effectively connecting to and testing the reservoir, the first extreme overbalanced perforation operations were conceived and performed at MWX. Extreme Overbalanced Perforating is a service performed by Halliburton and used routinely.

  • Deviated or Horizontal Drilling in Fractured Reservoirs. The Slant Hole Completion Test resulted in a number of recommendations for using deviated well bores to exploit fractured reservoirs. This approach is now widely applied throughout the U.S.

While not strictly part of the 1977-1992 WGS Program, the Multi-Site Experiment (MSite) that followed on the heels of the MWX work resulted in a number of important contributions:
  • The first successful micro-seismic monitoring tests in tight gas reservoirs were conducted at MWX and showed that fractures grew out of zone proportional to the stress contrasts and that fracture lengths were considerably shorter than designed. The M-Site testing validated the accuracy of down-hole micro-seismic monitoring for real-time mapping of hydraulic fracture growth and established the accuracy of the technique, the interpretation of the data, and the technology needed to acquire and process the data. Micro-seismic monitoring is now considered the most accurate method of imaging fracture growth and is now a globally-available commercial service.
  • Downhole tiltmeters were first used for fracture monitoring during these tests and this technology is now a commercial service (Pinnacle Technologies) available to map fracture height and length.
  • Important insights into the mechanisms of fracturing were developed at M-Site and are now being used in fracture models. Some of these are the development of multistranded fracture systems as a routine part of fracturing, the identification of additional fracture height containment in highly layered reservoir systems, the measurement of a large fluid lag region around the fracture tip, the formation of secondary and T-shaped fractures, and the variability in fracture development with different fluid systems.

Mineback Stimulation Experiments
  • The Mineback Experiments at the Nevada Test Site provided the first observational evidence of fracture behavior in situ. These tests showed that in situ stress contrasts were the primary feature controlling fracture height growth, that modulus contrasts had little effect on height growth, that natural fractures caused considerable offsetting and branching of fractures, and that stress changes across faults and interfaces could stop fractures.
Western Gas Sands Associated R&D
  • Significant effort expended in developing hydraulic fracture diagnostic technology that could map the created fractures helped to advance surface tiltmeter technology for fracture mapping. Surface tiltmeters are currently used for monitoring fractures as part of a successful commercial service (Pinnacle Technologies).
  • Drilling technology was advanced by breakthroughs in PDC bits through work done at Sandia National Labs. This bit has proven to be fast and rugged in many of the rock types in western gas sands basins and PDC bits are commonly used throughout the industry.

Resource Assessment Projects
  • The program in resource assessment provided the first comprehensive scientific quantification and characterization of a vast new resource, removing any question that pursuing the difficult technical challenges of enabling large-scale tight gas production was clearly worthwhile, both for industry and government. Second, in tandem with the other efforts in the WGS Program, it highlighted the concept and importance of basin-center gas formations, providing a rationale for the unique off-structure exploration and development techniques that would enable production from overpressured, low-permeability reservoirs.

    As a result of this work, industry began not only to appreciate the volumes of gas present, but could also begin to see a way in which it could be produced. As a result, tight gas began to be widely recognized as a key part of the nation’s resource base. Most notably, the USGS, which had previously excluded tight gas in their national resource assessment, included the category for the first time in 1995. Key outcomes of the effort include:
    • Industry now knows how the resource is distributed in each basin, and which plays hold the most potential.
    • Industry has more information on the typical porosities, water saturations, temperatures, and pressures of the rocks containing the resources.
    • Industry now understands the unique qualities of basin-centered, or “continuous” deposits, and recognizes the need for new perspectives on appraisal methods tailored for conventional resources.
DOE expenditures in the Western Tight Gas Sands program from 1978 through 1992 amounted to about $95 million. From 1983 to 1988, most of the budget was used to fund basic research and sample analysis through the national laboratories. When the project emphasis changed from basic research to applied research in 1989, more funds were directed to actual procurements with private research companies and industry.

By the late 1980s, most of the research money was being spent in actual field demonstration projects. After 1992, research focused on tight gas sands became more product-oriented and a larger percentage of funding came from industry. In the basic and applied stages of the program, DOE expenditures led industry by 2 to l; in the demonstration stage, industry led DOE by nearly 3 to l.

According to the National Academy of Sciences report, “Energy Research at DOE: Was It Worth It? Energy Efficiency and Fossil Energy Research 1978 to 2000” published in 2001, the Western Gas Sands program was successful in its goal of increasing the supply of natural gas at lower cost. Tight gas production from the Rocky Mountain gas basins was only 162 Bcf in 1978 at the start of the program; 10 years later it stood at 224 Bcf and in 2000 (when the NAS report was written) production was estimated at 700 Bcf, a fourfold increase. Since the report was written, Rocky Mountain tight sand gas production has grown even more; 2004 production from the five targeted basins was 1433 Bcf, nearly nine times the rate at the start of the WGS Program.

The NAS report determined that the WGS Program “has significantly advanced understanding of complex, lenticular reservoirs and how fracturing is deployed in them.

A much larger part of the vast in-place resource in the basin-centered gas formations of the Rocky Mountain basins is now considered economically accessible.” In relating the costs and benefits of the WGS Program, the NAS credited the Program with developing technology and stimulating 35 percent of the tight gas produced from the Rockies from 1978 to 2005. The remaining 65 percent was assigned to industry’s activity, GRI’s R&D program (partially supported by DOE), and the influence of Section 29 tax credits for unconventional gas production. In calculating the benefits, the NAS included DOE R&D expenditures post-1992 (after the WGS Program had evolved into a more product-oriented R&D program) and estimated 2005 production from western tight gas sands at 800 Bcf (less than half of what was achieved). Even still, the NAS calculated a benefit to cost ratio of 8.9, and a contribution of $591 million (1999 dollars) from royalties on federal lands and from increased state severance taxes due to displacement of imports.

Further, the NAS report states that “Future application of tight gas sand technology in emerging plays and basins will substantially enlarge this part of the resource base … providing an environmentally clean fuel and greater domestic supply. The application of resource assessments, natural fracture detection and prediction technology, and advanced drilling and stimulation, means that less than half as many wells will need to be drilled to yield the same volume of reserves.”

A significant part of the success of the WGS program was its successful transition from a basic research program supported entirely by government to an applied research and demonstration program in which industry took over increasing support of the program. Coupled with governmental tax credit incentives under Section 29 of the Natural Gas Policy Act, this targeted research program brought an important source of natural gas into the national supply stream earlier and cheaper than it would otherwise have been made available.

Because of the substantial base of knowledge and technologies developed under the WGS Program, the Energy Information Administration (EIA) has been able to make predictions of strong future tight gas production. The EIA calls for tight gas production from the Rocky Mountain basins to reach nearly 2,300 Bcf and overall tight gas production in the U.S. to reach nearly 5,500 Bcf in 2020.

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Cover Page

Executive Summary

1. Background

2. GRI Research into Unconventional Gas Resources

3. Structure of the Enhanced Gas Recovery Program (EGR)

  • 3.1. Eastern Gas Shales Program (1976-1992)

  • 3.1.1. Key Questions and Related R&D Goals
  • 3.1.2. Program Design and Overview of Major Projects
  • 3.1.3. Key Eastern Gas Shales Projects
  • 3.1.4. Highlights of Important Results
  • 3.1.5. Subsequent Developments in DOE and Other Research Related to Eastern Gas Shales

  • 3.2. Western Gas Sands Program (1978-1992)

  • 3.2.1. Key Questions and Related R&D Goals
  • 3.2.2. Program Design and Overview of Major Projects
  • 3.2.3. Key Western Gas Sands Projects
  • 3.2.4. Highlights of Important Results
  • 3.2.5. Subsequent Developments in DOE Research Related to Tight Gas Sands

  • 3.3. Methane Recovery from Coalbeds Program (1978-1982)

  • 3.3.1. Key Questions Related to Coal Seam Methane
  • 3.3.2. MRCP Program Design and Overview
  • 3.3.3. Key Methane Recovery from Coalbeds Projects
  • 3.3.4. Highlights of Important Results
  • 3.3.5. Subsequent Research Related to Methane Recovery from Coalbeds

  • 3.4. Deep Source Gas Project (1982-1992)

  • 3.4.1. Key Deep Source Gas Projects
  • 3.4.2. Highlights of Important Results

  • 3.5. Methane Hydrates Program (1982-1992)

  • 3.5.1. Methane Hydrates Workshop (March 1982)
  • 3.5.2. Key Questions and Related R&D Goals
  • 3.5.3. Program Design
  • 3.5.4. Major Contracted Gas Hydrates Projects
  • 3.5.5. Methane Hydrate Research Efforts of METC's In-House Organization
  • 3.5.6. Highlights of Important Results
  • 3.5.7. Subsequent Developments in Methane Hydrate Research

  • 3.6. Secondary Gas Recovery (1987-1995)

  • 3.6.1. Key Objectives and Program Design
  • 3.6.2. Major Projects
  • 3.6.3. Major Results

    4. Elements of Spreadsheet Bibliographies (by Program)

    Appendix A: Details of Major 1970-1980 Unconventional Gas Resource Assessments

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