Methods for Controlling Lost Circulation in A Subterranean Well and Materials Therefor

摘要

Method for controlling lost circulation in a subterranean well using oil-dispersible lost-circulation materials which comprise fibers that are coated (or sized) with a lipophilic coupling agent, a lipophilic film-forming polymer or both. The fibers are preferably between about 6 mm and about 25 mm long, and between about 10 μm and about 200 μm in diameter. The fibers may be added to carrier fluids comprising oil-base fluids, synthetic-base fluids, invert-emulsion-base fluids and combinations thereof. The preferred fiber concentration in the carrier fluid is between about 0.55 g/L and about 28.5 g/L. The carrier fluid may be a drilling fluid, a spacer fluid or a lost-circulation pill.

主权项

1. A method for controlling lost circulation in a subterranean well, comprising:
(i) selecting one or more fibers that are sized with a nonpolymeric lipophilic coupling agent; (ii) mixing the selected fibers with a carrier fluid comprising one or more members selected from the group consisting of an oil-base fluid, a synthetic-base fluid and an invert-emulsion-base fluid; and (iii) pumping the carrier fluid into the lost-circulation zone, wherein the fibers are polyamide fibers or polypropylene fibers or both.