MAJOR OIL PLAYS IN UTAH AND VICINITY

Utah oil fields have produced over 1.2 billion barrels (191 million m{sup 3}). However, the 13.7 million barrels (2.2 million m{sup 3}) of production in 2002 was the lowest level in over 40 years and continued the steady decline that began in the mid-1980s. The Utah Geological Survey believes this trend can be reversed by providing play portfolios for the major oil producing provinces (Paradox Basin, Uinta Basin, and thrust belt) in Utah and adjacent areas in Colorado and Wyoming. Oil plays are geographic areas with petroleum potential caused by favorable combinations of source rock, migration paths, reservoir rock characteristics, and other factors. The play portfolios will include: descriptions and maps of the major oil plays by reservoir; production and reservoir data; case-study field evaluations; summaries of the state-of-the-art drilling, completion, and secondary/tertiary techniques for each play; locations of major oil pipelines; descriptions of reservoir outcrop analogs; and identification and discussion of land use constraints. All play maps, reports, databases, and so forth, produced for the project will be published in interactive, menu-driven digital (web-based and compact disc) and hard-copy formats. This report covers research activities for the third quarter of the first project year (January 1 through March 31, 2003). This work included gathering field data and analyzing best practices in the eastern Uinta Basin, Utah, and the Colorado portion of the Paradox Basin. Best practices used in oil fields of the eastern Uinta Basin consist of conversion of all geophysical well logs into digital form, running small fracture treatments, fingerprinting oil samples from each producing zone, running spinner surveys biannually, mapping each producing zone, and drilling on 80-acre (32 ha) spacing. These practices ensure that induced fractures do not extend vertically out of the intended zone, determine the percentage each zone contributes to the overall production of the well, identify areas that may be by-passed by a waterflood, and prevent rapid water breakthrough. In the eastern Paradox Basin, Colorado, optimal drilling, development, and production practices consist of increasing the mud weight during drilling operations before penetrating the overpressured Desert Creek zone; centralizing treatment facilities; and mixing produced water from pumping oil wells with non-reservoir water and injecting the mixture into the reservoir downdip to reduce salt precipitation, dispose of produced water, and maintain reservoir pressure to create a low-cost waterflood. During this quarter, technology transfer activities consisted of technical presentations to members of the Technical Advisory Board in Colorado and the Colorado Geological Survey. The project home page was updated on the Utah Geological Survey Internet web site