华北油田地层水与注入水结垢趋势预测及影响因素

摘要

在注水开发过程中,油层或采出系统结垢会大大影响生产效率.开展地层水与注入水结垢规律和机理研究,可对现场除垢技术提供理论指导.采用Davis-Stiff饱和指数法和Ryznar稳定指数法,对华北油田京11区块地层水和注入水在不同温度、pH和成垢离子质量浓度等影响因素下的结垢趋势进行了预测,同时开展静态结垢实验研究了模拟水样的结垢规律.结果表明:华北油田京11区块地层水和注入水的离子组成和质量浓度非常接近且均具有严重的结垢趋势,且地层水的结垢趋势略高于注入水,垢样主要为碳酸钙;模拟水样的实际结垢率可达61％;温度、pH以及成垢离子质量浓度的升高均能大幅提高模拟水样的结垢率,结垢率的增长幅度随温度和pH的升高逐渐增大,而随成垢离子质量浓度的升高逐渐减小.%During water flooding development,scaling of oil layer or production system would greatly affect the production efficiency.Studying the scaling rule and mechanism of formation and injected water could provide theoretical guidance for field descaling technology.Davis-Stiff saturation index method and Ryznar stability index method were used to predict the scaling tendency of the formation and injected water of Jing-11 block in Huabei Oilfield under different temperatures,pH values and concentrations of scaling ions,and the scale rules were investigated by the static scaling test.The results show that the components and concentration of the formation and injected water samples are quite close to each other,both water samples have serious scaling tendency,and the scaling tendency of formation water is slightly higher than that of injected water.In addition,the scale sample of Jing-11 block is mainly composed of calcium carbonate.The scale formation ratio of simulated water sampie is 61％ under normal conditions,and it can be highly increased by raising temperature,pH and concentration of scaling ions.The increase rate of the scale formation ratio increases by the temperature and pH,but decreases by the concentration of the scaling ions in the solution.