TUCKER, JAMES D., DANIEL C. HITZMAN, and DONALD O. HITZMAN, Geo-Microbial Technologies, Ochelata, OK

ABSTRACT: Productive Thrust Sheets and the Surface Fault Traces Identified by Microbial Survey, Arkoma Basin, Oklahoma

A large microbial survey was conducted over a portion of the Arkoma basin, Oklahoma, to identify microbial trends related to recently discovered productive areas. The microbial survey analyzed shallow soil samples for a specific suite of microorganisms associated with light hydrocarbons using the Microbial Oil Survey Technique (MOST) developed by Phillips Petroleum Company. Regions of high microbial activity indicate the presence of elevated hydrocarbon gases in the soils related to microseepage. The microbial samples were collected from the shallow soil environment every 0.1 mile along existing roads and right of ways. The Arkoma basin presents a particular problem for any surface geochemical technique due to the depth of the reservoirs and the highly faulted and thrusted nature of t e region. Despite these obstacles, large clusters of elevated microbial activity were identified over specific thrust sheets where successful deep gas wells have recently been drilled. Likewise, several dry holes were accurately predicted in thrust sheets having only background values indicating little hydrocarbon microseepage present. Often measured microbial activity changed rapidly after crossing into different thrust sheets, thus indicating a microbial signature able to identify sheet boundaries. In some areas, clusters of elevated microbial activity dropped rapidly with no mapped fault boundary, possibly indicating the presence of unmapped fault blocks. Mapped surface faults were identified by isolated microbial highs wherever the surface trace was crossed. In these deep, highly fau ted environments, microbial surveys appear to be a powerful exploration tool for identification of productive thrust sheets and surface fault traces.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.