Fundamental Research On Development And Application Of Fracturing-Oil Displacement Integrated Working Fluid

In this paper,cetyltrimethylammonium chloride,salicylic acid and oleic acid amide methylhydroxypropylammonium chloride were used as main agents,and DAA-6 used as a quaternary ammonium salt adsorption inhibitor,the mass fraction of HT was compounded to obtain a FDHT series fracturing-oil displacement integrated working fluid.Taking the general technical index of the viscoelastic surfactant fracturing fluid as the evaluation standard,the fracturing performance of the FDHT series fracturing-oil displacement integrated working fluid was comprehensively evaluated;the technical requirements of the composite flooding surfactant were used as the evaluation standard.The oil displacement performance of different dilutions of FDHT-6 fracturing-oil displacement integrated working fluid was break from crude oil ing liquid and FDHT-6 fracturing-oil displacement integrated working fluid was comprehensively evaluated.（1）Taking the general technical index of the viscoelastic surfactant fracturing fluid as the evaluation standard,the temperature resistance,salt tolerance,sand carrying performance and core damage rate of the FDHT fracturing-oil displacement integrated working fluid system were fracturing.The temperature resistance of FDHT-6 system was better than that of other systems.The viscosity of FDHT-6 system was 65.4 mPa·s with 90°C.Experiments showed that the FDHT system had a good ability to transport proppant at a shear rate of 170 s^-1 at a viscosity of 30 mPa·s,while the FDHT system had a viscosity of more than 30 m Pa·s at80°C,indicating the FDHT system.It had effective sand-carrying capacity with 80°C;FDHT-6 system and FDHT-4 system maintained stable viscosity at 65.4 mPa·s and 45.3 mPa·s during constant temperature 90°C and 170 s^-1 shearing for 1 h.The FDHT-2 system maintained a stable viscosity of 35.1 mPa·s during constant temperature 90°C and 170 s^-1shearing for 1 h;the FDHT system did not decrease the viscosity of the FDHT system with high temperature and constant shear rate,indicating FDHT series fracturing-oil displacement integrated working fluid system had good shearing performance;at the same temperature,as the sand content increases,the sedimentation speed increases;and with the same sand content,the sedimentation speed increases with the increase of temperature;The fracturing fluid of FDHT series fracturing-oil displacement integrated working fluid system had no residue,the damage rate to the artificial core was between 11.7%and 16.1%,which is the goal of“clean,no pollution”compared with the conventional silicone fracturing fluid system.Less damaged to the formation and good reservoir protection.（2）The technical requirements of the composite flooding surfactant were the evaluation criteria.The experimental results showed that the surface tension of the 2.0%FDHT-6fracturing-oil displacement integrated working fluid system of crude oil gel breaking were28.5.mN/m and 8.19×10^-3 mN/m,the surface tension of the surface（boundary）increased with the decrease of the concentration of the FDHT-6 fracturing-oil displacement integrated working fluid;The emulsification effect of FDHT-6 fracturing-oil displacement integrated working fluid system was the best.The emulsification effect of the FDHT-6 fracture-oil displacement integrated working fluid system was 22.0%of 2h with 80°C.With the decrease of the concentration of the FDHT-6 fracturing-oil displacement integrated working fluid,the emulsifying ability was weakened;the FDHT-6 fracturing-oil displacement integrated working fluid can transform the rock into a weak hydrophilic surface.The contact angles were contact angles of 69.7°,65.3°and 62.8°with 60°C,70°C and 80°C,respectively,which is beneficial to improve oil recovery;The static oil displacement effect of the crude oil breaker FDHT-6fracturing-oil displacement integrated working fluid system is the best.The static oil displacement rates reached 21.5%,26.0%and 36.5%with 60°C,70°C and 80°C,respectively.With the decrease of the concentration of FDHT-6 fracturing-oil displacement integrated working fluid,the static oil displacement effect With the decrease,the chemical flooding rate of 2.0%FDHT-6 and 0.67%fracturing-oil displacement working fluid of crude oil gel breaking reached 16.35%and 15.27%,respectively.