The Application of Self-assembled Compound Fracturing Fluid in Horizontal Fracturing

To satisfy the needs for low permeability horizontal well fracturing, a compound fracturing fluid has been developed through self-assembly of a comb polymer and surfactant micelles. This fracturing fluid contains no cross-linkers and water insoluble matter. At 80℃, the self-assemble fracturing fluid containing 0.3% co 0 mb polymer CD-1 and 0.2% surfactant has storage modulus of 290 Pa, far greater than the loss modulus, showing an obvious viscous-elasticity. At flow rate of 5 m³/min, the percent reduction in friction achieved with the fracturing fluid is 74.05%, showing an obvious low friction nature. Different self-assembled fracturing fluids all have surface tensions less than 27 mN/m, and interface tensions less than 0.8 mN/m, satisfying the needs for the flow-back of fracturing fluids. Average permeability impairment by these self-assembled fracturing fluids is 18.04%, far less than that of the guar gum fracturing fluids, which is 78.75%. Laboratory evaluation and field application have all indicated that the self-assembled fracturing fluids have high efficiency of friction reduction and low damage to reservoir formation, and higher production rates have been gained using these fracturing fluids. It has also demonstrated the soundness of the theory, which states that through self-assembly of polymers and surfactant micelle, a structure can be developed in the fluid to carry sands. The self-assembled fracturing fluid has satisfied the needs for fracturing wells with special holeprofiles, and provided a new way of developing low permeability reservoirs.