Use of APSDM and EM_press inversion to impact evaluation of a west africa deepwater discovery
SEG Technical Program Expanded Abstracts
ExxonMobil Exploration Company, Houston, United States; ExxonMobil Production Deutschland GmbH, United States; ExxonMobil Development Company, United States; Esso Exploration and Production Nigeria Deepwater West Limited, Nigeria
Summary: In this paper we discuss the impact of APSDM and EM_PreSS inversion technology on the evaluation of a West Africa deepwater field. The field is located in an ExxonMobil operated block. The trap was defined as a distributary channel complex (DCC) on the flank of a faulted anticline. The hydrocarbon bearing sands have a class III AVO response for gas and a class III or II AVO response for oil. An exploration well and its side track discovered multiple oil reservoirs in Miocene sands. Using pre-stack time migrated (PSTM) data, dual fluid contacts were observed and interpreted for multiple reservoirs in several fault blocks. In general, oil-water-contacts (OWC's) observed on the PSTM data conform better to the depth structure maps than the gas-oil-contacts (GOC's). The GOC's are inconsistent across the fault blocks. The imaging of the GOC's was improved by anisotropic pre-stack depth migration (APSDM) and further sharpened by additional EM_PreSS inversion processing. An appraisal well and its side track confirmed the GOC determined from seismic interpretation. Use of the APSDM and EM_PreSS inversion favorably impacted business decisions during field appraisal and development planning, increasing our confidence to pursue development without drilling more appraisal wells.