Two record wells were recently drilled in the ultra-deepwaterEastern Gulf of Mexico. The wells were the fastest two wellsdrilled in water depths greater than 7,000 ft in the GoM. Ahigh-performance water-based mud (WBM) was used to drillthe intermediate sections. The fluid had comparableperformance to a synthetic-based mud (SBM), with theadvantage of cuttings disposal permission in thisenvironmentally sensitive offshore area. Significant savingswere realized by not carrying the cuttings to shore fordisposal. Other advantages included (a) no losses whilerunning and cementing casing and (b) easier displacements.The fluid was re-used on two consecutive wells and thenstored for further applications.The authors will detail the careful planning that coupledwith fit-for-purpose solutions allowed setting these recordswhile reducing the overall well cost. The wells were drilled inthe Lloyd Ridge area of the Eastern Gulf of Mexico,categorized as "zero-discharge" for SBM cuttings. The use ofthe high-performance WBM saved the hauling and disposingof approximately 2,000 bbl of cuttings on each well. Costsavings were also accomplished by avoiding fluid losses whenrunning and cementing the casing. On a similar project drilledcompletely with SBM, 2,156 bbl of mud were lost whilerunning and cementing the 13?-in. casing.Comparison of drilling and economic performance of thenew water-based mud and the synthetic-based mud areincluded in this paper to offer a comprehensive analysis. Alsopresented are innovative solutions introduced to optimize holecleaning and shale inhibition.
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