The History of a New Play: Thunder Horse Discovery, Deepwater Gulf of Mexico
C. A. Yeilding, B. L. Yilmaz, D. I. Rainey, G. E. Pfau, R. L. Boyce, W. A. Wendt, M. H. Judson, A. K. Ray, R. Chen, S. G. Peacock, R. Hollingsworth, S. D. Duppenbecker, M. J. Bowman, 2005. "The History of a New Play: Thunder Horse Discovery, Deepwater Gulf of Mexico", Discoverers of the 20th Century: Perfecting the Search, Charles A. Sternbach, Marlan W. Downey, Gerald M. Friedman
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The Thunder Horse discovery is a significant accumulation of oil in the deepwater Gulf of Mexico (COM), offshore Louisiana. The exploration well test (1999) led to the discovery of a new play and challenged traditional exploration philosophies in the GOM deepwater. Successes in deepwater plays had been driven by seismic amplitudes, pool sizes had declined, as did BP’s discovery rate. Multiple exploration failures using the attribute-driven mindset caused us to reexamine our entire exploration philosophy. As a result, BP adopted a “back-to-basics and explore from the source rock up” approach that focused on the geologic elements of the basin, rather than seismic attributes. These shifts in philosophy changed the way we viewed prospectivity in the GOM, and targeted our exploration effort toward older stratigraphy in previously untested, deeper structues.
Regional work indicated that the Mississippi Canyon protraction area was a key area to focus our exploration efforts. Subsequent subregional analysis high-graded the most attractive prospects in the inventory and two turtle structures (inverted mini-basins) with primary targets in Miocene strata were prepared for initial play tests.
Before we could drill, we had to overcome major technical and non-technical hurdles such as securing an acreage position and obtaining access to rigs capable of drilling in 5000+ ft (1524+ m) water depths. Three-dimensional (3-D) seismic surveys and seismic depth-imaging breakthroughs were required to describe the prospect elements and position wells. When BP and partners tested the two top prospects in the play, one (MC 778-1, Thunder Horse) was successful. and one (MC 91 l-lst) was a failure. Post-appraisal of these wells helped us understand the potential and risks of this new play, and each additional well in the play continues to teach us new lessons.
Long range, unwavering focus has led us to success in discovering a new play. The regional framework created high value and impact in a short period of time. The subregional work was highly efficient in terms of cost and time. In contrast, prospect maturation and drilling were extremely labor-intensive, time-consuming and costly. This work flow forced us to make choices across our portfolio early in the exploration cycle to focus our energy and effort on the areas with the highest chance of success early on.