Completion of High-Rate Gas Wells, Horizontal Gravel Pack and Filter-Cake Cleanup:A Case History From the Mahogany Field, Trinidad

摘要

Completing high-rate gas wells in areas where sand control isnecessary ranks among the top challenges within the oilindustry. High-velocity gas flowing through the downholehardware combined with the abrasive nature of finer formationsolids dislodged and produced can significantly shorten thecompletion life and have strong financial implications forthe operator.This paper describes the gravel-pack and filter-cake cleanuptechniques applied to Mahogany MB-13, an offshorehorizontal openhole completion and Trinidad’s best producingwell at the time of its production start-up. Optimizing theseoperations, along with correct well configuration and preciseborehole placement in the reservoir structure, werefundamental to achieving high production rates.The gravel placement method and the uniform coverage of thegravel-pack screens helped to deter the creation of highvelocityspots. This result allowed the operator to use higherdrawdown pressure differentials without damaging thecompletion.Aspects of the sand-control design, gravel-pack placement toensure complete wellbore coverage, and the chemicals andprocedures for filter-cake cleanup are analyzed in depth.The new-generation sand-control service tools that weredeveloped to preserve the optimum wellbore conditions fromthe end of drilling through the completion are also discussed.Finally, production data from the MB-13 are presented tosupport the completion efficiency reported.