TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractSeveral sand control completions in the initial development of a Gulf of Mexico deepwater turbidite field failed prematurely when placed on production. After an extensive multi-discipline review of completion designs and procedures, the cause of these completion failures was determined to be an inverted sand-shale stress contrast, that is, shales were at lower minimum horizontal stress than adjoining sand layers. Direct evidence of this sand/shale stress reversal was obtained from mechanical strength property data derived from dipole sonic logs in two wells in this field.Frac pack completion design was modified to account for this sand/shale stress reversal by incorporating perforation standoff from adjacent shales and by using smaller pad volumes. The modified design was successful in achieving excellent frac packs in seven subsequent completions in this field. Long-term performance of these modified frac pack completions has been excellent.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractSeveral sand control completions in the initial development of a Gulf of Mexico deepwater turbidite field failed prematurely when placed on production. After an extensive multi-discipline review of completion designs and procedures, the cause of these completion failures was determined to be an inverted sand-shale stress contrast, that is, shales were at lower minimum horizontal stress than adjoining sand layers. Direct evidence of this sand/shale stress reversal was obtained from mechanical strength property data derived from dipole sonic logs in two wells in this field.Frac pack completion design was modified to account for this sand/shale stress reversal by incorporating perforation standoff from adjacent shales and by using smaller pad volumes. The modified design was successful in achieving excellent frac packs in seven subsequent completions in this field. Long-term performance of these modified frac pack completions has been excellent.