PARELJA LOPEZ, JORGE, Yacimientos Petroliferos Fiscales Bolivianos (YPFB), Santa Cruz, Bolivia; * JAMES D. TUCKER, and DANIEL C. HITZMAN, Geo-Microbial Technologies, Ochelata, OK

ABSTRACT: Hydrocarbon Microseepage Signatures of Seismic Structures Identified byMicrobial Surveys, Sub-Andean Region, Bolivia

An extensive microbial survey compared the hydrocarbon microseepage signatures to newly identified seismic structures in YPFB's Ichoa-Chimore-Sajta block, Sub-Andean region, Bolivia. The microbial survey was completed in conjunction with a two-year seismic campaign throughout the region. Shallow soil samples were collected every 250 meters along existing seismic lines. Microbial samples were analyzed using the Microbial Oil Survey Technique (MOST) developed by Phillips Petroleum Company for a specific suite of microorganisms associated with light hydrocarbons. Regions of elevated microbial activity are indicative of hydrocarbon microseepage. Large clusters of elevated microbial activity were identified over several seismic structures indicating hydrocarbon microseepage related to thes structures. The structures were ranked according to the size and intensity of the elevated microbial activity. Two structures with anomalous microbial signatures have been drilled and found to be productive. The microbial data was used as an additional layer of information related to hydrocarbon microseepage and was merged with geological and geophysical data for subsequent exploration efforts.

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