Ammonium Halide as Gelation Retarder for Crosslinkable Polymer Compositions

摘要

A method for blocking the permeability of a portion of a subterranean formation including the steps of: (a) selecting the portion of the subterranean formation to be treated, wherein the bottomhole temperature of the portion of the subterranean formation is equal to or greater than 250° F. (121° C.); (b) selecting estimated treatment conditions, wherein the estimated treatment conditions comprise temperature over a treatment time; (c) forming a treatment fluid that is a crosslinkable polymer composition comprising: (i) a water-soluble polymer, wherein the water-soluble polymer comprises a polymer of at least one non-acidic ethylenically unsaturated polar monomer; (ii) an organic crosslinker capable of crosslinking the water-soluble polymer; (iii) an ammonium halide; and (iv) water; (d) selecting the water-soluble polymer, the crosslinker, the ammonium halide, and the water, and the proportions thereof, such that the gelation time is at least 2 hours under the estimated treatment conditions; and (e) injecting the treatment fluid.

主权项

1. A method for blocking the permeability of a portion of a subterranean formation penetrated by a wellbore, the method comprising steps of:
(a) selecting the portion of the subterranean formation to be treated, wherein the bottomhole temperature of the portion of the subterranean formation is equal to or greater than 250° F. (121° C.); (b) selecting estimated treatment conditions, wherein the estimated treatment conditions comprise temperature over a treatment time; (c) forming a treatment fluid that is a crosslinkable polymer composition comprising:
(i) a water-soluble polymer, wherein the water-soluble polymer comprises a polymer of at least one non-acidic ethylenically unsaturated polar monomer;(ii) a polymeric organic crosslinker capable of crosslinking the water-soluble polymer;(iii) an ammonium halide, wherein the ammonium halide is present in a concentration of at least 100 lb/Mgal of the water; and(iv) water; (d) selecting the water-soluble polymer, the polymeric organic crosslinker, the ammonium halide, and the water, and the proportions thereof, such that a gelation time of the treatment fluid is at least 2 hours when tested under the estimated treatment conditions; and (e) injecting the treatment fluid through the wellbore into the portion of the subterranean formation.