HETEROGENEOUS SHALLOW-SHELF CARBONATE BUILDUPS IN THE PARADOX BASIN, UTAH AND COLORADO: TARGETS FOR INCREASED OIL PRODUCTION AND RESERVES USING HORIZONTAL DRILLING TECHNIQUES
The Paradox Basin of Utah, Colorado, Arizona, and New Mexico contains nearly 100 small oil fields producing from carbonate buildups within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to 10 wells with primary production ranging from 700,000 to 2,000,000 barrels (111,300-318,000 m{sup 3}) of oil per field and a 15 to 20 percent recovery rate. At least 200 million barrels (31.8 million m{sup 3}) of oil will not be recovered from these small fields because of inefficient recovery practices and undrained heterogeneous reservoirs. Several fields in southeastern Utah and southwestern Colorado are being evaluated as candidates for horizontal drilling and enhanced oil recovery from existing, vertical, field wells based upon geological characterization and reservoir modeling case studies. Geological characterization on a local scale is focused on reservoir heterogeneity, quality, and lateral continuity, as well as possible reservoir compartmentalization, within these fields. This study utilizes representative cores, geophysical logs, and thin sections to characterize and grade each field's potential for drilling horizontal laterals from existing development wells. The results of these studies can be applied to similar fields elsewhere in the Paradox Basin and the Rocky Mountain region, the Michigan and Illinois Basins, and the Midcontinent region. This report covers research activities for the first half of the third project year (April 6 through October 5, 2002). This work included capillary pressure/mercury injection analysis, scanning electron microscopy, and pore casting on selected samples from Cherokee and Bug fields, Utah. The diagenetic fabrics and porosity types found at these fields are indicators of reservoir flow capacity, storage capacity, and potential for enhanced oil recovery via horizontal drilling. The reservoir quality of Cherokee and Bug fields has been affected by multiple generations of dissolution, anhydrite plugging, and various types of cementation which act as barriers or baffles to fluid flow. The most significant diagenetic characteristics are microporosity (Cherokee field) and micro-boxwork porosity (Bug field), as shown from porethroat radii histograms, and saturation profiles generated from the capillary pressure/mercury injection analysis, and identified by scanning electron microscopy and pore casting. These porosity types represent important sites for untapped hydrocarbons and primary targets for horizontal drilling. Technology transfer activities consisted of exhibiting a booth display of project materials at the Rocky Mountain Section meeting of the American Association of Petroleum Geologists, a technical presentation, and publications. The project home page was updated for the Utah Geological Survey Internet web site.
- Research Organization:
- Utah Geological Survey (US)
- Sponsoring Organization:
- (US)
- DOE Contract Number:
- FC26-00BC15128
- OSTI ID:
- 816086
- Resource Relation:
- Other Information: PBD: 1 Dec 2002
- Country of Publication:
- United States
- Language:
- English
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HETEROGENEOUS SHALLOW-SHELF CARBONATE BUILDUPS IN THE PARADOX BASIN, UTAH AND COLORADO: TARGETS FOR INCREASED OIL PRODUCTION AND RESERVES USING HORIZONTAL DRILLING TECHNIQUES
Increased oil production and reserves utilizing secondary/tertiary recovery techniques on small reservoirs in the Paradox Basin, Utah. Annual report, February 9, 1997--February 8, 1998