Graft copolymers of dextran and polyacrylamide and methods of making and using same

A well treatment composition comprising:

• a graft copolymer of dextran and polyacrylamide, wherein the dextran is a backbone polymer comprising about 10 wt % to about 50 wt % of the graft copolymer, based on the total weight of the graft copolymer;
• and polyacrylamide, wherein the polyacrylamide is a side chain polymer comprising about 50 wt % to about 90 wt % of the graft copolymer, based on the total weight of the graft copolymer, wherein the graft copolymer has a weight-average molecular weight from about 1,000,000 g/mol to about 1,500,000 g/mol;
• an additive, wherein the additive is selected from a list comprising:
• one or more friction reducers, one or more viscosifiers, one or more breakers, one or more acids, one or more base, one or more salts, one or more biocides, one or more scale inhibitors, one or more deflocculants, one or more proppants, one or more surfactants, one or more chelating agents, one or more alcohols, one or more emulsifiers, one or more non-emulsifiers, one or more mineral control agents, one or more silt suspenders, one or more corrosion inhibitors, one or more foaming agents, one or more antifoam agents, one or more H2S scavengers, one or more O2 scavengers, one or more crosslinking agents, one or more surface tension reducers, one or more buffers, one or more clay stabilizers, one or more fluid loss additives, one or more temperature stabilizers, one or more diverting agents, one or more paraffin inhibitors, and one or more asphaltene inhibitors;
• and
• water, wherein the well treatment composition has a weight percent of the graft copolymer of dextran and polyacrylamide from about 0.12 to about 0.32.

A method of fracturing a subterranean formation, the method comprising:

• injecting a well treatment composition into a wellbore, wherein the well treatment composition comprises:
• dextran, wherein the dextran is a backbone polymer comprising about 10 wt % to about 50 wt % of the graft copolymer, based on the total weight of the graft copolymer;
• and
• polyacrylamide, wherein the polyacrylamide is a side chain polymer comprising about 50 wt % to about 90 wt % of the graft copolymer, based on the total weight of the graft copolymer, wherein the graft copolymer has a weight-average molecular weight from about 1,000,000 g/mol to about 1,500,000 g/mol;
• an additive, wherein the additive is selected from a list comprising:
• one or more friction reducers, one or more viscosifiers, one or more breakers, one or more acids, one or more base, one or more salts, one or more biocides, one or more scale inhibitors, one or more deflocculants, one or more proppants, one or more surfactants, one or more chelating agents, one or more alcohols, one or more emulsifiers, one or more non-emulsifiers, one or more mineral control agents, one or more silt suspenders, one or more corrosion inhibitors, one or more foaming agents, one or more antifoam agents, one or more H2S scavengers, one or more O2 scavengers, one or more crosslinking agents, one or more surface tension reducers, one or more buffers, one or more clay stabilizers, one or more fluid loss additives, one or more temperature stabilizers, one or more diverting agents, one or more paraffin inhibitors, and one or more asphaltene inhibitors;
• and
• water, wherein the well treatment composition has a weight percent of the graft copolymer of dextran and polyacrylamide from about 0.12 to about 0.36.