Study and Application of an InstantPolymer Fracturing Fluid

An instant polymer fracturing fluid has been developed to try to resolve the difficulties in disposing waste fracturing fluids and to minimize formation damage and pollution to the environment caused by fracturing fluids. Thickening agent, crosslinking agent, clay stabilizer and cleanup additive for the fracturing fluid were studied and optimized through laboratory experiment. The formula of the fracturing fluid suitable for use under formation temperature of 60-120℃ was prepared through laboratory evaluation of the fracturing as to its swelling ability, sand-carrying ability, gel-breaking ability, resistance to high temperature and shearing and its contribution to formation damage. Fracturing of 4 wells in Huabei Oilfield with this fracturing fluid was 100% successful. In fracturing operation, the low molecular weight polymer emulsion, multipurpose additives and ammonium persulfate are first pumped into a fracturing blender truck through metering pump, then mixed with water and proppants in the blender truck to start fracturing. The maximum sand ratio can be as high as 50%. This fracturing method, by combining the mixing of the fracturing fluid closely with operating, has the advantages as follows:1) there is no need for pre-mixing fracturing fluid, and the operation is thus simplified, and operation efficiency is enhanced. 2) the volume of the fracturing fluid can be prepared based on actual requirement, thereby minimizing residual fracturing fluid. The flowback fluid can be recovered for mixing new fracturing fluid, thereby minimizing the pollution to environment. 3) the fracturing fluid has a neutral pH value and is free of residue, and formation damage is thus minimized.