Design and Long-Term Production Performance of Frac Pack Completions in a Gulf of Mexico Deepwater Turbidite Field Having Inverted Sand-Shale Stress Contrasts: Case History

摘要

Several sand control completions in the initialdevelopment of a Gulf of Mexico deepwater turbidite fieldfailed prematurely when placed on production. After anextensive multi-discipline review of completion designs andprocedures, the cause of these completion failures wasdetermined to be an inverted sand-shale stress contrast, that is,shales were at lower minimum horizontal stress than adjoiningsand layers. Direct evidence of this sand/shale stress reversalwas obtained from mechanical strength property data derivedfrom dipole sonic logs in two wells in this field.Frac pack completion design was modified to account forthis sand/shale stress reversal by incorporating perforationstandoff from adjacent shales and by using smaller padvolumes. The modified design was successful in achievingexcellent frac packs in seven subsequent completions in thisfield. Long-term performance of these modified frac packcompletions has been excellent.