Fracturing or gravel-packing fluid with CMHEC in brine

A method of treating a treatment zone of a subterranean formation penetrated by a wellbore of an injection well, the method comprising:

• introducing a treatment fluid into the treatment zone, wherein the treatment fluid comprises:
• (i) an aqueous phase comprising water having a concentration of total dissolved inorganic salts in the range of about 1000 ppm to about 500,000 ppm, wherein the aqueous phase comprises at least one of:
• a sulfate concentration of about 4,000 ppm or greater, a phosphate concentration of about 100 ppm or greater, a carbonate concentration of about 100 ppm or greater, or a barium concentration of about 37,000 ppm or greater;
• (ii) a carboxymethyl hydroxyethyl cellulose, wherein:
• (a) the carboxymethyl hydroxyethyl cellulose has a carboxymethyl degree of substitution is in the range of about 0.3 to about 0.45 per glucopyranose unit in the polymer;
• and
• (b) the carboxymethyl hydroxyethyl cellulose has a hydroxyethyl molecular substitution is in the range of about 2.1 to about 2.9 per glucopyranose unit in the polymer;
• (iii) a breaker;
• and
• (iv) a crosslinker.

A system comprising:

• a pump fluidly coupled to a tubular extending into a wellbore penetrating a subterranean formation;
• and
• the tubular containing a treatment fluid that comprises:
• (i) an aqueous phase comprising water having a concentration of total dissolved inorganic salts in the range of about 1000 ppm to about 500,000 ppm, wherein the aqueous phase comprises at least one of:
• a sulfate concentration of about 4,000 ppm or greater, a phosphate concentration of about 100 ppm or greater, a carbonate concentration of about 100 ppm or greater, or a barium concentration of about 37,000 ppm or greater;
• (ii) a carboxymethyl hydroxyethyl cellulose, wherein:
• (a) the carboxymethyl hydroxyethyl cellulose has a carboxymethyl degree of substitution is in the range of about 0.3 to about 0.45 per glucopyranose unit in the polymer;
• and
• (b) the carboxymethyl hydroxyethyl cellulose has a hydroxyethyl molecular substitution is in the range of about 2.1 to about 2.9 per glucopyranose unit in the polymer;
• and
• (c) the treatment fluid is substantially free of any crosslinker;
• and
• (iii) a breaker.