Abstract

Polymeric damage is due to inconsistent or incomplete breaks of stimulation fluids as well as dynamically formed filtercakes produced by drill-in fluids or drilling muds. Several methods have been employed with limited success to remove polymeric damage in an effort to increase well productivity.

Prior treatments to remove this type of damage consist either of bleach (sodium hypochlorite) or acids. In case of horizontal wells with slotted liners or screens bleach or acids are not preferred. Additional expensive trips have become mandatory when coiled tubing or drill-pipe are utilized for spotting the treatment. Additionally, the mineralogy of some formations precludes the use of acids.

Recent extensive research was conducted to develop a treatment which could effectively reduce this type of polymeric damage in either horizontal or fracture stimulated wells. Core flow evaluations and regained conductivity testing have shown that multi-fold improvements can be achieved even at elevated temperatures exceeding 250 F and over a wide pH range.

A case study of several low productivity wells suffering from polymeric damage was conducted. Post-frac production histories and return flow analysis were evaluated to characterize the damage and guide the remedial treatment design. A detailed study of field case histories including 11 fracture stimulated wells, which were suffering from polymeric damage, are presented and demonstrate how multifold improvements in well productivity could be achieved.

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