Polymer Gel Water-Shutoff Applications Combined With Stimulation Increase Oil Production and Life of Wells in the Monterey Formation Offshore California

Abstract

Excessive water production from the Monterey Formation of the Sockeye Field offshore Santa Barbara, California led the operator to consider polymer gel water shutoff treatments. Field water rates were approaching the limit of the platform water handling capacity and threatened to curtail future development and/or require a multi-million dollar facility expansion. By utilizing chromium crosslinked polyacrylamide gel technology, the operator significantly reduced the water production. However, after gel treatments were injected and the wells were returned to service, both water and oil production were significantly lower. The operator subsequently stimulated the wells with acid and saw significant increases in oil rates while maintaining a reduction in water production.The result of combining the water shutoff treatments with the stimulation was a lowered water production rate and increased oil rate that neither technique would have yielded on its own. At this time, four wells have been treated with both gel and acid and one has been treated with gel alone. Of the four treated with gel and acid, three had reduced water rates and three had increased oil rates. Moreover, all gel treatments were pumped down production tubing without the need of a rig, using the vendor's self-contained trailer that included all mixing and pumping equipment. While not specifically designed for offshore use, this equipment greatly simplified logistics and the total cost was low enough that the economics could be based solely on savings in water handling costs.

Use of Hydrochloric Acid To Remove Filter-Cake Damage From Preformed Particle Gel During Conformance-Control Treatments

“…Some field applications reported promising results from combining water-shutoff and stimulation technologies to improve oil recovery. Zhao et al (2004) evaluated several acid systems, finding them to be compatible with three types of plugging agents that can be used in different reservoirs. Their results, obtained from the Weicheng and Mazhai oil fields, show an improved injection profile and greater oil increase in the responding wells.…”

The use of polymer-gel solutions for remediation of potential CO2 leakage from storage reservoirs

“…Crosslinked hydrolysed polymer-gel injection is used in petroleum industry to improve conformity of fluid flow in the reservoir, remediate leakage around wells and also used in conjunction with enhanced oil recovery at various temperature and pressure conditions [1,2,3,4,5] and to improve miscible CO 2 floods [6,7].…”