Exploring for New Opportunities in “Maturing” Deepwater Basins: Contrasting the Deepwater Gulf of Mexico and the Niger Delta
Richard Eisenberg1, Sankar Muhuri2, Carlos Rivero2, and Michael Roberts2
1Nigeria Mid-Africa, Chevron International Exploration, Houston, TX
2Chevron Energy Technology Company, Houston, TX
Deepwater basins have historically been explored from the top down, relying on the use of DHI’s to identify the “low hanging fruit”. Using this approach, high initial success rates are often followed by dry holes and smaller discoveries. Creaming curves for the Gulf of Mexico (GOM) and Niger Delta deepwater basins clearly illustrate these patterns. Discovered resource data in a maturing deepwater basin like the Gulf of Mexico, with over 700 exploratory wild cats, show the effects of increased drilling capability, rapidly developing geophysical technologies and the evolution of exploration play concepts. Rich petroliferous basins like the GOM are often “rediscovered”.
By comparison to the GOM, the challenges of developing new plays in the Niger Delta deepwater have proven to depend less on geophysical innovation and more on integrating a more limited knowledgebase, developing an improved understanding of the regional structural and stratigraphic framework, and comprehensive trend/play assessments of charge, seal and reservoir. Data mining of the extensive shelf area and a focused effort to obtain and integrate key deepwater and shelf well control has changed our understanding of the basin fill history. Interpretation of the extensive regional seismic network has modified the structural and stratigraphic framework and progressed our understanding of trapping mechanisms, major detachments and hydrocarbon charge. Regional velocity analysis has been used to assess the transient state of over-pressure, which controls porosity preservation, fluid flow, and top seal capacity. Integration of the framework interpretation with improved regional characterization of the key components of the petroleum system is the basis for a systematic approach to new opportunity assessment. Although economic hurdles remain, the Niger Delta is potentially poised for rediscovery.
AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery