Patent ID: 6581701
Filing Date: 2003-06-24
Classification: C09K,E21B

Abstract:
A method for reducing the loss of circulation fluids into flow passages of a subterranean formation during well drilling, completion or workover operations, such circulation fluids being selected from the group consisting of drilling fluids, completion fluids and workover fluids said with method comprising:(a) directly introducing at the well-head into a circulation fluid selected from a group consisting of drilling fluids, completion fluids and workover fluids an effective amount of a dry, solid, water insoluble but gel-forming and water swellable polyacrylamide polymer which has a particle size distribution in the range of about 0.50 millimeters to about 2.5 millimeters and which swells from about 25 to 300 times its weight of tap water when placed therein, and (b) allowing the gel-forming polymer to enter the lost circulation zone and allowing the gel forming polymer to remain in said zone to absorb the aforesaid weight of waxer and swell to the appropriate volume thereby sealing fissures and reducing the loss of said circulation fluid upon resuming well drilling, completion or work-over operations.