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 is necessary ranks among the top challenges within the oil industry. High-velocity gas flowing through the downhole hardware combined with the abrasive nature of finer formation solids dislodged and produced can significantly shorten the completion life and have strong financial implications for the operator. This paper describes the gravel-pack and filter-cake cleanup techniques applied to Mahogany MB-13, an offshore horizontal openhole completion and Trinidad's best producing well at the time of its production start-up. Optimizing these operations, along with correct well configuration and precise borehole placement in the reservoir structure, were fundamental to achieving high production rates. The gravel placement method and the uniform coverage of the gravel-pack screens helped to deter the creation of high- velocity spots. This result allowed the operator to use higher drawdown pressure differentials without damaging the completion. Aspects of the sand-control design, gravel-pack placement to ensure complete wellbore coverage, and the chemicals and procedures for filter-cake cleanup are analyzed in depth. The new-generation sand-control service tools that were developed to preserve the optimum wellbore conditions from the end of drilling through the completion are also discussed. Finally, production data from the MB-13 are presented to support the completion efficiency reported.