低渗油田储层酸化解堵技术应用

Application of Acidification Blocking Removal Technology in Low Permeability Oilfields

低渗油田在开发过程中储层容易产生各类污染伤害,导致储层渗流能力下降,从而影响开发效果。对已产生伤害的储层,需要进行有效的解堵来提高储层渗流能力。经过岩心分析,研究区延长组储层内粘土矿物含量较高,在酸化作业时,由于注酸体系及规模控制不当,容易造成二次污染,使得酸化作业失败。通过室内实验研究分析延长组储层岩心与常用低渗储层酸液体系酸蚀作用效果,从而判断出不同酸液作用于岩心的最佳酸液反应浓度,以及酸岩反应速率。通过实验研究,优选出最佳的酸化液体系及酸化工艺流程,并给出了酸液用量的计算方法。研究成果可有效的指导现场酸化工艺的实施,也为同类低渗油田酸化工艺酸液体系优选提供参考。

All kinds of pollution damages of low permeability oil reservoir in the development process easy happen, making reservoir seepage capacity decrease to affect the development effect. For the reservoirs which has been damaged, it is necessary to solve the problem effectively to improve the seepage capacity. Through the core analysis, it＇s pointed out that the content of clay minerals in the reservoir of Yanchang formation in the study area is high, which is easy to cause secondary pollution due to improper control of the acid injection system and scale. Through indoor experiments, the acid etching effect of low permeability reservoir acid system to Yanchang Formation reservoir cores was analyzed, so as to determine the best acid concentration and the acid rock reaction rate. Through the experimental study, the optimum acidizing fluid system and acidizing process flow were selected, and the calculation method of acid dosage was given. The research results can be used to guide the implementation of acidizing technology in the field, and to provide reference for acidizing fluid system optimization of similar low permeability oilfields.