TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractA Gulf of Mexico deepwater subsea development project required seawater injection for pressure maintenance of the producing reservoir. Typical water injector performance in the Gulf of Mexico has been characterized by rapidly declining injectivities that could be partially restored by frequent acid treatments. This type of performance was unacceptable for this field development plan, which required one subsea water injector capable of injecting up to 25,000 BWPD continuously for up to five years.Two changes to typical Gulf of Mexico water injector completion design were incorporated: 1) an openhole frac pack completion, and 2) a unique downhole filter system. These changes resulted in improved water injector performance compared with that typically experienced in the Gulf of Mexico. Initial injectivity was excellent and remained so over the entire injection period. No acid stimulations were required to either initiate or maintain injection. This paper presents the design and installation aspects as well as the actual performance results for this water injector.

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.