Patent RU-2701675-C2 (RU)
Title: Cross-linked gel based on acrylamide polymer or copolymer and breaker composition, as well as methods for use thereof
Inventor: LI TSZYAN
IPC: C09K8/68
Filed: 2014-12-30
Granted: 2019-09-30
Abstract: FIELD: soil or rock drilling; mining. 
     SUBSTANCE: invention relates to well treatment fluids for use in underground formation hydraulic fracturing systems. Well treatment fluid containing monomers of acrylamide-AA polymer or copolymer, one or more cross-linking agents - CA and one or more iron-containing compounds or breaker composition consisting essentially of one or more iron-containing compounds - ICC, water and/or one or more compound-enhancers selected from urea, ethylene diamine tetraacetic acid - EDTA, EDTA salts, citric acid, aminotricarbonate - ATC acid and salts thereof, polyphosphonate and polyphosphate compounds, boric acid and its salts, carbonate salts of alkali metals - CSAM, diethylenetriaminepentaacetic acid - DTPA, humic acids - HA and lignosulphates - LS. Well treatment fluid containing an aqueous dispersion or emulsion of AA polymer or copolymer, one or more CA and one or more ICC or thinner composition, consisting essentially of one or more ICC, water and/or one or more compound-enhancers selected from urea, EDTA, EDTA salts, citric acid, ATC acid and salts thereof, polyphosphonate and polyphosphate compounds, boric acid and salts thereof, CSAM, HA and LS. Well treatment fluid containing a gel containing an AA polymer or a copolymer crosslinked by one or more CAs, and one or more ICC or a breakthrough composition consisting essentially of one or more ICC, water and/or one or more compound-enhancers selected from urea, EDTA, EDTA salts, citric acid, ATC acid and salts thereof, polyphosphonate and polyphosphate compounds, boric acid and salts thereof, CSAM, DTPA, HA and LS. Method of treating a wellbore, comprising introducing into a wellbore of monomers of an AA polymer or copolymer, one or more CA and one or more ICC or a breakthrough composition, consisting essentially of one or more ICC, water and one or more compound-enhancers selected from urea, EDTA, EDTA salts, citric acid, ATC acid and salts thereof, polyphosphonate and polyphosphate compounds, boric acid and salts thereof, CSAM, EDTA, HA and LS. Well bore treatment method involves introduction of an aqueous dispersion or emulsion of an AA polymer or copolymer, other said liquid components into the well shaft. Well bore treatment method involves introduction of a gel containing an AA polymer or a copolymer cross-linked with one or more CAs, and the rest of the above components into the well shaft. Method of hydraulic fracturing of a subterranean formation - HFSF, involves obtaining: monomers of AA polymer or a copolymer and other said components and their pumping with the possibility of creation or expansion of a crack in a subterranean formation and leaving the components in the fracture. HFSF method, which involves preparing an aqueous dispersion or emulsion of an AA polymer or copolymer and the other said components and the ICC or thinner composition, consisting essentially of one or more ICC, water and/or one or more compound-enhancers selected from urea, EDTA, EDTA salts, citric acid, ATC acid and salts thereof, polyphosphonate and polyphosphate compounds, boric acid and salts thereof, DTPA, EDTA, HA and LS, and pumping them with possibility of creation or expansion of crack in underground formation and leaving them in crack. Method of HFSF, including obtaining of gel containing AA polymer or copolymer cross-linked with one or more CA, and ICC or thinner composition consisting essentially of ICC, water and/or one or more compounds-amplifiers selected from urea, EDTA, EDTA salts, citric acid, ATC acid and salts thereof, polyphosphonate and polyphosphate compounds, boric acid and its salts, DTPA, EDTA, HA and LS, and pumping with the possibility of creation or expansion of a fracture in a subterranean formation and left in the fracture. Proposed method comprises the following: production of any of said liquids and its pumping with the possibility of creation or expansion of crack in underground reservoir and its remaining in fracture. Invention is developed in dependent items of the formula. 
     EFFECT: technical result is the increase in the treatment efficiency. 
     23 cl, 3 ex, 1 tbl, 3 dwg