Mad Dog is a giant, subsalt, deep-water oil field that will be producing hydrocarbons for the co-owners BP, BHP Billiton Petroleum, and Chevron in the Gulf of Mexico for many years to come. The field was discovered in 1998 by the GC0826#1 well and sidetracks. Four appraisal wells proved up a material resource but also showed evidence of compartmentalization and imperfect subsalt seismic imaging. A spar development was selected and first oil was achieved in 2005. Further appraisal drilling continued from the spar rig and mobile offshore drilling units, ending with the Mad Dog North appraisal program in December...