Instant non-residue cellulose fracturing fluid

The traditional cellulose fracturing fluid is very difficult to blend,with poor temperature resistance performance,gel breaking is not completely,serious damage to the stratum,and has many other problems.Instant non-residue cellulose fracturing fluid is composed of 0.4% Hydroxyethyl carboxymethyl cellulose,FAG-500,0.2% tackifier FAZ-1,0.5% modifier FAJ-305.

The base solution of traditional cellulose fracturing fluid,under medium degree of mineralization,is 67.5mPa.s.In PH 4.5-5.0,mixing the crosslinking agent FAC-201 in the base solution could get gel.Under the conditions of 120℃, 170s-1,the viscosity of fracturing fluid is around 150mPa.s after 70 minutes of gel shear,it will be suitable for the fracturing of reservoir stratum which is lower than 130℃.Add 0.002% gel breaker ammonium persulfate,after 1.5 hours of gel shear under the conditions of 100℃ and 170s-1,the gel breaker will not destroy the rheological property of the construction system.There will be not residue after gel breaking,the surface tension of the gel breaker fluid is 24.44mN/m,the interfacial tension is 3.20mN/m.

The storage modulus G’and loss modulus G’’ of 0.3% FAG-500 fracturing fluid gel respectively are 7.2Pa and 1.6Pa.The cross-linked gel sand-carrying fluid of 40% sand ratio is heated by water bath of 90℃ for 6 hours, there is no desilting phenomenon,the sand-carrying performance is very good.The damage rate caused by the fracturing fluid to core permeability is 24.75%.

This instant non-residue cellulose fracturing fluid has many advantages,such as,being instant and easy to blend,acid cross-linked,could be used without proof of agent. According to the result of on-site application in two dense oil wells and dense gas well in changqing oilfield,the success rate of construction is more than 95% and the effective rate is 100%.