Research And Application Of Associated Fracturing Fluid In Low Permeability Reservoir Of Pear Depression

Fracturing fluid is a kind of working fluid during hydraulic fracturing treatment in reservoirs. Fracturing fluid properties play an important role in affecting the treatment success possibility and postfrac well performance.Based on the background of LiShu fault low permeability reservoir hydraulic fracturing treatment, for plant gum fracturing fluid applied in the region is large damage and clean fracturing fluid is poor heat-resisting property developed associative fracturing fluid system. It does not contain water-insoluble material,clean propped facture filling layer; it does not use cross-linking agent, avoiding the introduction of secondary damage; structure reversible, the viscosity can be quickly restored after the shear; it is a typical viscoelastic fluids, mainly flow through elastic carrying sand.By scanning electron microscopy, X-ray diffraction analysis pore throat characteristics and mineral composition of LiShu fault; analysis water> salt、alkali sensitivity, reservoir fluid; combined with field application requirements and system characteristics began the research about fracturing fluid formulations system. Adding thickening adjuvants B-55effectively enhance the ciscosity; adding the flow synergist FC-150reduce system initial viscosity, enhance system flexibility and pumping performance; then study on the breaking system, inhibitor for anti-welling, cleanup additive, demulsifier, chelating agent etc for the best formulation system.Indoor temperature, high temperature viscoelastic test, high temperature shear recovery, thixotropic experimental study showed that the system is typical of viscoelastic fluid, reversible structure, cut in all aspects of its performance impact is small, the temperature will decrease viscoelastic system but does not change the viscoelastic characteristics, excellent shear resistance, reduce the viscosity shear rate after recovery rate of86.3%; resist-bear shear thinning property, resist-temperature achieve140℃。 Other indoor performance evaluation showed that:the system absence contain residue, its damage ratio for matrix and proppant pack is low; the hydration property、demulsification capability and viscosity breaking is good and good compatibility with the formation; the broken fluid of surface and interfacial tension is low, has good flowback performance. Though coiled tubing friction study shows that the rate of system resistance reduction up to70%.Associating fracturing fluid system successfully applied in five wells, and the configuration is simple, easy to use, increase yield, indicating it can meet the LiShu fault low permeability reservoir development needs.