Integrated Geophysical and Geomicrobial Surveys, Chapare Region, Sub-Andean Bolivia

David Widdoes, Nicholas De Verteuil, James Tucker, and Daniel Hitzman

Approximately 4800 square kilometers of the Chapare region of Sub-Andean, Bolivia were surveyed in 1994 using combined 2-D seismic and geomicrobial surface geochemistry. The Microbial Oil Survey Technique, M.O.S.T., measures evidence of hydrocarbon microseepage by evaluating surface soils for butane associated microorganisms. Approximately 615 kilometers of seismic and over 2500 soil samples were collected for this integrated reconnaissance survey. Elevated microbial populations of these specific microorganisms indicate anomalous hydrocarbon microseepage is leaking from hydrocarbon accumulations. Integration of the geomicrobial data with geological and geophysical data was completed.

Parallel seismic and microbial traverses revealed significant areas of structural targets. A portion of the frontier study area demonstrates strong hydrocarbon microseepage which aligns with geophysical targets. A fault system identified from seismic interpretation was also mapped by distinct microbial anomalies at the surface. Comparative profiles and survey maps link microbial anomalies with geological and geophysical targets.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California