理论研究和现场应用表明，对地层压力系数小于１的低渗透、低压力、强水敏性油层，若使用水基压裂液，由于其静水压力大于地层压力，再加上截面压差作用和毛细管作用，使压后压裂液返排困难，油井迟迟不能投产，并有把油井压死的危险；若使用泡沫压裂液，因使用的液氮较多，现 Theoretical research and field application show that if the water pressure fracturing fluid with low permeability, low pressure and strong water sensitivity is used, the hydrostatic pressure is greater than the formation pressure and the cross-sectional pressure difference Capillary action, so that after the pressure fracturing fluid back row difficulties, the delay in production wells, and the danger of crushing oil wells; if the use of foam fracturing fluid, due to the use of liquid nitrogen is more, now