低渗油田储层堵塞机理及泡沫酸化学解堵

Mechanism of Reservoir Plugging and Foam Acid Chemical Deplugging in low permeability oilfield

低渗储层多次酸化解堵后酸化效果变差,为实现深度酸化提高储层酸化作用效果,通过岩心薄片及扫描电镜分析了储层微观孔隙结构特征,通过实验研究了储层岩心水敏、速敏和酸敏性。结果表明:研究区储层黏土矿物中伊利石含量较高,岩样孔喉半径小,渗透性较差,存在中等偏强水敏、中等偏弱速敏、酸敏性损害的情况。利用岩心酸蚀实验配比出缓速酸1.5%+氟化铵0.5%+盐酸15%作为泡沫酸主体酸液,酸蚀率达到15.6%,并优选出非离子起泡剂作为表面活性剂,并验证了其具有较好的抗盐和抗油性能。

In order to achieve deep acidification and improve the effect of reservoir acidification,the micro pore structure characteristics of the reservoir were analyzed by core slice and SEM.The water sensitivity,velocity sensitivity and acid sensitivity of the reservoir core were studied by experiments.The results showed that the illite content in the clay minerals of the reservoir was high,the pore throat radius of the rock sample was small,and the permeability was poor.There were moderate to strong water sensitivity,moderate to weak speed sensitivity and acid sensitivity damages.Through the core acid etching experiment,the retarded acid 1.5%+ammonium fluoride 0.5%+hydrochloric acid 15%was determined as the main acid of the foam acid,the etching rate reached 15.6%,and the nonionic foaming agent was selected as the surfactant.