川西致密砂岩气藏井筒积液储层损害机理研究

川西致密砂岩气藏储量丰富，但存在井筒积液现象，储层损害严重，从而影响开发效率。深入认识井筒积液储层损害机理是从根本上解决积液储层伤害的前提和基础。针对气井井筒积液储层损害问题，开展井筒积液储层损害定量化评价实验，分析其损伤机理。结果表明，储层含水敏性矿物，易与液体产生反应；且中小孔隙多，造成毛管压力高，导致井筒积液损害严重。井筒压力每增加1 MPa，储层损害程度增加约6%；泡排剂对储层的损害程度随浓度的增加而增大，泡排剂与凝析油作用后对地层造成的损害更大，泡排剂浓度大于0.5%时，对储层的损害程度可达90%以上。研究结果为揭示川西致密砂岩气藏井筒积液储层损害机理提供了科学依据。

Study on Damage Mechanism of Wellbore Fluid Accumulation Reservoir in Tight Sandstone Gas Reservoirs in Western Sichuan

The tight sandstone gas reservoir in western Sichuan is rich in reserves, but there is a phenomenon of wellbore effusion and serious reservoir damage, which affects the development efficiency. Understanding the damage mechanism of wellbore effusion reservoir is the premise and foundation to fundamentally solve the damage of effusion reservoir. In this paper, aiming at the damage problem of wellbore liquid accumulation reservoir in gas wells, quantitative evaluation experiments of wellbore liquid accumulation reservoir damage are carried out to analyze its damage mechanism. The results show that the reservoir water-sensitive minerals are easy to react with liquid; and small and medium pores, resulting in high capillary pressure, and in serious wellbore effusion damage. When the wellbore pressure increases 1 MPa, the reservoir damage increases about 6%. The damage degree of foaming agent to the reservoir increases with the increase of concentration, and the damage to the formation caused by foaming agent and condensate oil is greater. When the concentration of foaming agent is greater than 0.5%, the damage degree to the reservoir can reach more than 90%. The results provide a scientific basis for revealing the damage mechanism of wellbore effusion reservoir in tight sandstone gas reservoir in western Sichuan.