Increased Scale and Combined Microbial and Sorbed Soil Gas Techniques Advance Hydrocarbon Microseepage Strategies for Both Exploration and Development Programs

Daniel C. Hitzman and Brooks Rountree
Geo-Microbial Technologies, Ochelata, OK

Recent light hydrocarbon microseepage surveys for oil and gas benefit from advanced scale parameters - increased pattern size and tighter sample densities - as well as integrating two seepage signature methodologies. Current extensive surface geochemical surveys utilize large grid patterns in frontier regions and/or tighter sample spacing in mature production areas. Initial microbial (M.O.S.T -- Microbial Oil Survey Technique) signatures of light hydrocarbon anomalies are further tested with sorbed soil gas (SSG) analyses in order to determine reservoir source preference. This two-technique approach concentrates collection efficiencies, provides maximum laboratory results, and offers increased integration with geological and geophysical data sets.

Large hydrocarbon microseepage surveys are being completed both onshore and offshore in frontier areas before, during, and after seismic campaigns. Likewise, detailed microbial and sorbed soil gas are used to evaluate mature basins and fields for possible new reservoirs and heterogeneities leading to new production zones, compartments, and offset targets. Microbial MOST surveys indentify preferred microseepage locations while the subsequent sorbed soil gas analyses examines C1 - C4 ratios to determine the oil, condensate, or gas reservoir source. Multiple case studies from several continents, including international frontier regions, multi-phase prospect delineations, and development evaluations in mature basin plays, will be presented. The increased size and scope of these recent surveys provide a renewed geochemical strategy for oil and gas exploration.

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas