Energy Policy Act of 2005 (Ultra-deepwater and Unconventional Resources Program)
Paleozoic Shale-Gas Resources of the Colorado Plateau and Eastern Great Basin, Utah: Multiple Frontier Exploration Opportunities
The overall goal of this project is to develop the data and techniques needed to spur exploration and development in frontier shale-gas basins in Utah. Specifically, the project team plans to map shale-gas reservoir intervals with significant gas potential; characterize the geologic, geochemical, and petrophysical properties of these reservoirs; formulate strategies to reduce exploration costs and drilling risk in environmentally sensitive areas; and recommend best practices to complete and stimulate shale-gas wells while minimizing costs and maximizing gas recovery.
Utah Geological Survey (UGS), Salt Lake City, UT 84114
Halliburton Energy Services, Vernal, UT 84078
Bereskin and Associates, Salt Lake City, UT 84109
GeoX Consulting, Inc., Salt Lake City, UT 84105
Shale-gas reservoirs in Utah have tremendous untapped potential. Paleozoic shales in the Colorado Plateau and eastern Basin and Range provinces have long been known for their potential as source rocks for hydrocarbons that have migrated into other formations but, until recently, they have not been considered as in-situ gas reservoirs.
Shale-gas reservoirs in Utah include the Mississippian Manning Canyon shale of north-central Utah; the Delle Phosphatic Shale Member of the Mississippian Deseret Limestone of western Utah; and the Pennsylvanian Paradox Formation of southeastern Utah. Shale horizons within these formations are widespread, thick, organic-rich, thermally mature for gas generation, and contain natural fractures for secondary permeability. These horizons have recently begun to be targeted for gas exploration, in some cases, in environmentally sensitive areas.
Although the organic content of some of these shales is known, detailed information on their distribution, thickness, reservoir quality, and basic rock mechanic properties is virtually nonexistent. In addition, completion and stimulation practices tailored to these formations have not been established or published.
This project aims to fill these knowledge gaps by pulling together existing well data on these shale formations; conducting detailed petrophysical, geochemical, and rock mechanical analyses of available cores and cuttings; collecting outcrop data where available; performing regional mapping of structure, thickness, thermal maturity, and depositional facies for key shale gas reservoirs; and completing a set of recommendations for best completion practices for these frontier shale gas reservoirs based on the reservoir properties defined in this study.
If successful, this project could spur new exploration and development of multiple emerging frontier shale-gas reservoirs, which could lead to trillions of cubic feet of gas added to our nation’s gas supply. The intention is to focus industry attention on the extensive Paleozoic shale-gas resource potential in the Colorado Plateau and eastern Basin and Range Province and to provide the information needed to promote aggressive exploration and development programs in the targeted reservoirs. Targeted reservoir units include the Mississippian Manning Canyon shale of north-central Utah; the Delle Phosphatic Shale of western Utah; and the Pennsylvanian Paradox Formation of southeastern Utah.
Specific products resulting from this project will include recommended completion and stimulation practices for each of the targeted reservoir units, maps and cross-sections identifying shale-gas play areas, and resource potential estimates. These products should provide a starting point for formal resource assessments of the targeted reservoir units – to-date, no formal assessment of these plays has been completed.
Work on this project began in August 2008. Work has been completed on two initial tasks and one additional task: 1) the development of a Project Management Plan with a work breakdown structure that concisely addresses the objectives and approach for each task, with major milestones and decision points, 2) the development of a Technology Status Assessment that describes the current state of knowledge of the shale-gas potential in the targeted reservoir units, and 3) Data Compilation.
This task was aimed at compiling all published information on stratigraphy, petrology, rock mechanics, geochemistry, and geochronology for the targeted reservoirs. A well database was developed that included stratigraphic tops, formation tests, completion and production information, and other relevant reservoir data. An assessment was conducted of the Pennsylvanian Paradox Formation and Mississippian Manning Canyon Shale cores and well cuttings that are included in the UGS’s Core Research Center (UCRC) collection. In addition, available geochemical analyses were compiled (in the UCRC files), and well logs tiff images pertinent to the Manning Canyon shale, Delle Phosphatic Member, Gothic shale, Hovenweep shale, and Chimney Rock shale were downloaded.
The team submitted Deliverable # 5: Bibliography of Published Stratigraphic Definition, Petrographic, Rock Mechanics, Geochemistry, and Geochronology Analysis, and Deliverable #6. Well Database (Significant Penetrations, Tops, Formations Tests, Completion Information, Production, and Other Reservoir Data).
Core and Cuttings Examination and Sample Analysis
The team completed describing core (seven wells) of Gothic, Chimney Rock, and Hovenweep shales from the Paradox Formation of the Paradox Basin, which are housed at the UCRC. The entire core was digitally photographed, and stratigraphic columns were prepared for each core. Thin sections from the described core were prepared, described, and photographed. Samples were selected and collected for laboratory analysis. The following analyses have been completed: geochemical (total organic carbon/RockEval), tight rock analysis (porosity, permeability, grain density, fluid saturation, etc.), x-ray fluorescence, and triaxial compression testing.
The UGS acquired two Manning Canyon Shale cores and evaluated cuttings from numerous wells in central and western Utah. These cores were also described and digitally photographed. Thin sections from the described core were prepared, described, and photographed placing special emphasis on depositional environments. Samples were selected and collected for analysis. The following analyses have been completed: geochemical (total organic carbon/RockEval) and x-ray fluorescence. Logs and well cuttings were examined, and stratigraphic logs were constructed from Manning Canyon Shale wells. The character of individual lithotype cycles and facies were described, and the lithotypes that were represented in well logs and outcrop sections were inventoried.
The team collected radiation measurements using a gamma-ray spectrometer from Manning Canyon in the North Springs #1 well and constructed sets of Strater log plots for the newly available LAS files for the Manning Canyon from Carbon Canal 5-12 and State 15-32-15-12 wells. Spreadsheets for gamma-ray spectrometry log values for these wells were used to construct cross plots delineating relationships between U, Th, K contributions to the gamma-ray log profile and their mineralogic interpretations.
Task 6. Outcrop Examination & Sampling
Geochem data on Delle Member were compiled. The team sent samples for age dating, updated the correlation chart, and developed base maps for Manning Canyon and Delle. Reports were reviewed by Waanders, for age and thermal maturity on Manning Canyon samples collected in the field and from well cuttings. They then reviewed maps and papers, began collecting samples from northern Utah; reviewed logs and sample descriptions from Steam Ventures well in northern Utah which penetrated Manning Canyon; and developed a base map of sample locations, outcrops, and penetrations of Mississippian Manning Canyon and Delle. Samples were sent to Wagner Petrographic to be made into thin sections. From here, the team scouted and collected samples of Mississippian Manning Canyon in the Provo Canyon, Mt. Nebo area, and Daggett and Uintah Counties (flanks of Uinta Mountains). Samples were correlated from northern Utah for age and thermal indexing.
The team began measuring and describing Manning Canyon Shale section in Soldier Canyon, Oquirrh Range, northern Utah, and also collected representative samples and gamma-ray measurements along the section; 2/3 of the section was completed before winter set in.
The Utah Geological Survey created and is maintaining a Web site (http://geology.utah.gov/emp/shalegas/index.htm [external site]) dedicated to displaying project news, results, and reports.
The UGS had an exhibit booth displaying project materials, objectives, etc. during the American Association of Petroleum Geologists (AAPG) 2009 Annual Convention in Denver, Colorado, June 7-10. Project team members presented two papers, based on project work at the AAPG convention: (1) “Shale Gas and Shale Oil Resources of the Paradox Basin, Colorado and Utah,” by Steve Schamel; and (2) “Gas Shale Characteristics from the Pennsylvanian of Southeastern Utah, USA,” by Robert Bereskin, John McLennan, Tom Chidsey, and Tarn Bereskin; AAPG posted the latter on the Search and Discovery website and on the UGS project Website. Researchers submitted two abstracts for the 2010 American Association of Petroleum Geologists Annual Convention - 1) “Palynomorph Age and Thermal Alteration of the Mississippian Manning Canyon Shale and Doughnut Formation - Implications for Paleozoic Shale Gas Potential of Western and Central Utah,” and 2) “Manning Canyon Shale: Utah's Newest Shale Gas Resource;” the latter was accepted for presentation. Submitted abstracts titled 1) "Pennsylvanian Organic Mudstone Reservoir Characteristics from the Paradox Basin, Southeastern Utah," 2) "Burial Histories of Mississippian Potential Source and Shale-Gas Reservoir Rocks, Central and Western Utah,” and 3) “Manning Canyon Shale: An Emerging Shale Gas Resource" for the 2010 Rocky Mountain Section Meeting of AAPG to be held in Durango, CO, June 13-15. A technical session was organized featuring these and other shale gas talks for the AAPG Rocky Mountain Section Meeting.
The UGS Industry Outreach Geologist setup a Technical Advisory Board meeting hosted by Bill Barrett Corp. in Denver, CO, April 5.
The Utah portion of "Unconventional Energy Resources: 2008-2009 Review" for the Energy Minerals division of the AAPG was completed and submitted, and the Energy Mineral Division of the AAPG provided a report on shale gas activity in Utah to be included in the Shale Gas Committee Report for their Annual Leadership Meeting November 12, 2009.
The UGS Industry Outreach geologist created a contact list of people and companies (31 as of October 2009) interested in the project to provide them with technical progress reports, the UGS newsmagazine, "Survey Notes," and press releases.
The major remaining effort includes the following tasks.
Although completed in terms of required deliverables, we continue efforts to acquire additional critical cores needed for study that are stored at other facilities. Downloading of well logs tiff images pertinent to the Manning Canyon shale, Gothic shale, and Delle Phosphatic Member is ongoing.
Core and Cuttings Examination and Sample Analysis
This task focuses on developing detailed descriptions of existing slabbed core; analysis of thin section, scanning electron microscopy (SEM), and X-ray diffraction (XRD) samples; plug analysis for porosity and permeability;; geochemical analysis including total organic carbon and vitrinite reflectance; and rock mechanic analysis including triaxial tests, and tight rock analysis. Ongoing work includes completion of SEM and XRD analysis.
We are currently evaluating all laboratory, thin sections, core descriptions for Paradox and Mississippian shales in order to prepare various project deliverables.
Outcrop Examination and Sample Analyses
This task involves gathering outcrop samples for analysis and comparison with cored intervals from wells, detailed measurement and description of key outcrops, and detailed analyses of selected samples using the techniques applied to core and cuttings (as above). Samples were collected and examined from outcrops of the Gothic shale of the Paradox Formation in San Juan Canyon, southeastern, Utah, and the Manning Canyon Shale at Soldier and Provo Canyons, the Lake Mountains, and Mount Nebo, north-central Utah. UGS has begun preparing samples for analysis. In addition, we began digitizing geophysical well logs for comparison to outcrop localities.
The team will continue measuring and describing Manning Canyon Shale section in Soldier Canyon, Oquirrh Range, northern Utah. They also collected representative samples and gamma-ray measurements along the section. Other outcrop localities will possibly be described, sampled, and gamma-ray profiled.
Determination of Best Completion Practices
In this task Halliburton will develop best practices and recommendations for shale-gas well completion in the targeted reservoir intervals. The following issues will be addressed: horizontal versus vertical wells, fracturing techniques, acidization, and perforation method. These recommendations will be based on the data compiled by UGS for this study and on Halliburton’s shale-gas experience in other U.S. basins.
The UGS project team met with Halliburton team members in Vernal, Utah, to review project progress, status, and turnover all laboratory analysis completed to date. Halliburton began to compile and analyze completion data for Gothic and Hovenweep wells and assemble a database for best completion practices.
Regional Correlation, Mapping, and Depositional History Analysis
The project team is preparing structure, stratigraphic thickness, thermal maturity, and depositional facies maps of key shale-gas units to illustrate the location and distribution of the reservoirs. In addition, regional cross-sections and burial history plots are being constructed for the gas-shale reservoirs. UGS continues construction of regional structural contour and isopach maps of the Gothic, Chimney Rock, and Hovenweep shales of the Paradox Formation from the UGS dataset. Also, burial history plots for the Manning Canyon Shale in central Utah have been produced.
The team is compiling and drafting regional data maps of TOC, Tmax, vitrinite reflectance, and production index for Mississippian and Pennsylvanian shale gas units. They are preparing graphs of hydrogen index vs. oxygen index and hydrogen index vs. TOC for Mississippian and Pennsylvanian shale gas units.
In the final synthesis, the project team will identify significant shale-gas sweet spots for each of the targeted shale-gas reservoirs and document all the project results in a final report.
The Utah Geological Survey created and is maintaining a Web site (http://geology.utah.gov/emp/shalegas/index.htm [external site]) dedicated to displaying project news, results, and reports. In addition, the project will be publicized at industry conferences and technical meetings.
The UGS will have an exhibit booth displaying project materials, objectives, etc. during the AAPG 2010 Annual Convention in New Orleans, Louisiana, April 11-14, and the 2010 Rocky Mountain Section Meeting in Durango, Colorado, June 13-15. Project team members will present a paper, based on project work at the AAPG convention: 1) “Manning Canyon Shale: Utah's Newest Shale Gas Resource,” on April 14. Project team members will also present the following papers, based on project work the AAPG convention: 1) "Pennsylvanian Organic Mudstone Reservoir Characteristics from the Paradox Basin, Southeastern Utah," 2) "Burial Histories of Mississippian Potential Source and Shale-Gas Reservoir Rocks, Central and Western Utah,” and 3) “Manning Canyon Shale: An Emerging Shale Gas Resource" for the 2010 Rocky Mountain Section Meeting of AAPG in June in Durango, CO.
The UGS will hold a Technical Advisory Board meeting hosted by Bill Barrett Corp. in Denver, CO, April 5, 2010, to review project progress and results with companies exploring or producing Paleozoic shale gas in Utah.
The UGS will prepare and submit the Utah portion of "Unconventional Energy Resources: 2009-2010 Review" for the Energy Minerals division of the AAPG.
Project Start: August 9, 2008
Project End: August 5, 2011
DOE Contribution: $428,491
Performer Contribution: $212,122
RPSEA – Charlotte Schroeder (email@example.com or 281-690-5506)
NETL – Virginia Weyland (Virginia.Weyland@netl.doe.gov or 281-494-2517)
Utah Geological Survey – Thomas Chidsey, Jr. (firstname.lastname@example.org or 801-537-3364)
Well Database [xls]