Experimental Study on Damage Evaluation of Fracturing Fluid in Shale Oil Reservoir

As a reservoir reconstruction, fracturing fluid plays the role of transmitting pressure and carrying proppant, but it is also the main source of reservoir damage, which brings different degree of damage to the reservoir, and even causes production reduction or no production of oil well. How to correctly evaluate and analyze the damage degree of fracturing fluid in shale oil reservoirs plays an important guiding role in the effective development of low permeability reservoirs. The experimental study of fracturing fluid damage evaluation based on pressure oscillation method is established by using the self-developed fracturing fluid damage evaluation instrument. The damage of common fracturing fluid system on Jimsar shale oil reservoir core was systematically studied. The results show that compared with the conventional steady-state method, the pressure oscillation method is suitable for cores with permeability less than 0.01 mD. The experimental method is fast, simple and reproducible. It is clear that confining pressure, injection pressure and temperature have obvious influence on permeability. It is verified that the pressure oscillation method can effectively evaluate the damage degree of guanidine gum system and polymer system to the core of Jimsar shale oil reservoir.