镇北油田注水井欠注原因分析及治理对策

Analysis of Under-injection in Injection Wells of Zhenbei Oilfield and the Countermeasures

为了解决镇北油田长8储层注水井高压欠注的问题,对该油田长8储层的储层特征、储层敏感性、注入水水质、岩石表面润湿性等因素进行了研究和分析,确定了镇北油田长8储层欠注的主要原因。研究表明:储层原始物性差(平均渗透率0.69mD),酸敏性强(58.14%),注入水与地层水配伍性差(产生CaSO4沉淀),岩石界面水润湿性差(弱亲油)是镇北油田欠注的主要原因。针对这些原因拟解决的对策是:研发并优化适合该油藏的酸液体系,开发出能防止该油藏水化膨胀的高效缩(防)膨剂,研发出性能较好的缓蚀阻垢剂,筛选出适合该油藏的表面活性剂增注体系。

In order to solve the problem of high-pressure and under-injection in injection wells of Chang 8reservoir in Zhenbei Oilfield,the reservoir characteristics,reservoir sensitivity,injection water quality and wettability on rock surface of Chang 8reservoir were studied and analyzed,the major reasons of under-injection were determined.The study result shows that the poor original reservoir physical property(0.69mD),strong acid sensitivity(58.14%),poor compatibility between injection water and formation water(producing CaSO4deposition)and poor water wettability on rock interface(weak oil-wet)were the main causes of under-injection in Zhenbei Oilfield.For these problems,the countermeasures are to develop and optimize the suitable acid system for the reservoir,develop a high efficient clay stabilizer to prevent hydration and expansion,develop a high efficient corrosion/scale inhibitor,select the most suitable surfactant of injectionaugmenting system for Chang 8reservoir.