Patent ID: 9394476
Filing Date: 2016-07-19
CPC Classification: C09K,E21B

Claim Text:
1. A well treatment method comprising: forming a well treatment fluid by combining ingredients including an aqueous fluid, a viscosifying agent, a crosslinker, and a rheology modifier containing glyoxal; crosslinking the viscosifying agent in the aqueous fluid using the crosslinker, the glyoxal not delaying the crosslinking and the crosslinking increasing viscosity of the well treatment fluid to a first viscosity; treating a well with the well treatment fluid exhibiting the first viscosity; chemically changing the glyoxal after the crosslinking and thereby forming oxalic acid, the glyoxal not being substantially chemically changed before the crosslinking; and after treating the well, decreasing viscosity of the crosslinked well treatment fluid to a second viscosity less than the first viscosity as a result of forming the oxalic acid.