长庆低渗透油藏油层解堵技术综述

长庆油田三叠系延长组储层渗透率0.96×10-3μm2～6.43×10-3μm2,粘土矿物中酸敏、水敏性物质含量较高,地层水矿化度高达119g/L,部分油藏Ba2+含量1200～2400mg/L。因储层孔隙喉道细小,注水开发中因粘土颗粒运移,原油乳化液、结蜡、结垢所导致的油层堵塞十分严重。几十年来,油田不断深入研究并大规模实施了多种形式的油层酸处理、油层清防垢、油层压裂等解堵技术。在所统计的151口油井酸处理施工中,平均单井增油量由早期的142t上升到近期的391t,在所统计的48口油井清防垢施工中,低渗透层油井平均单井增油量由早期的321t上升到近期的338t,在所统计的92口油井压裂施工中,平均单井增油量由早期的112t上升到近期的161t。最近研制的油层综合解堵体系,又将单井增油量进一步提高到944t。相比之下,综合解堵、酸处理和清防垢的解堵效果优于油层压裂。将油层挤注防垢剂工艺与油层压裂工艺或油层酸处理工艺组合作业,可大幅度提高油层解堵效果。

Summary of blocking removal technology for low permeability reservoirs Changqing oilfield

The permeability of Triassic Yanchang formation in Changqing oilfield is 0.96×10-3μm2～6.43×10-3μm2.The formations have been choked by clay micrograins、wax、scales and emulsions. Three operation methods, such as the integration of operation by squeezing scale inhibitor and by squeezing scale remover, the operation by acidizing and the operation by fracturing, are used to formation choking solve.In the operation process of increasing the production for 151 producers by acidizing, the production increased to 391t/per producer. For 48 producers by squeezing scale inhibitor and by squeezing scale remover, the production increased to 338t/per producer. For 92 producers by fracturing, the production increased to 161t/per producer. The effect of acidizing and scale controlling is more obvious than that of fracturing. Recently,the choking solve tests are operated by squeezing the multifunction choking solve agent. It is shown that the production increased to 944t/per producer. Besides the integration of operation by fracturing and by squeezing scale inhibitor, the integration of operation by fracturing and by acidizing and the integration of operation by squeezing scale inhibitor and by squeezing scale remover are used to formation choking solve tests. The result showed that the effect of the integration of operation by fracturing and by squeezing scale inhibitor is more obvious than that of other two methods.