Drilling: Implementation of Novel Tar Casing Drilling Tool in Deepwater Gulf of Mexico
Unexpected tar encounters have derailed many drilling programs in the deepwater Gulf of Mexico. In late 2007, while drilling Chevron's Big Foot #3 appraisal well, an extremely mobile tar formation was encountered below salt. Numerous unsuccessful attempts were made to drill through the tar before determining that it would need to be cased off for drilling to continue.
Due to extreme tar mobility, and because of high torque seen during conventional drilling, a novel approach to liner drilling was pursued. This presentation, based on SPE 118901, details how Chevron worked in conjunction with its partner and service providers to implement the new casing drilling tool in order to resume drilling operations and get the Big Foot well back on track. Details on the tool's application, lessons learned and future tar casing drilling tool enhancements will also be presented.
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