Water based fluids comprising multivalent salts and low molecular weight, low charge cationic polyacrylamide copolymers

摘要

A drilling system fluid and method of using same. The drilling system fluid comprises water as a continuous phase, an amount of a multivalent metal, and a quantity of a water soluble polyacrylamide copolymer having a charge density of at least about 1%. In a preferred embodiment, the fluid also comprises a second amount of a monovalent salt effective to increase gas hydrate suppression and decrease density when compared to a fluid consisting essentially of only a divalent salt in the absence of the monovalent salt.