三元洗井液预处理技术室内实验研究

Laboratory Experimental Study on Pretreatment Technology of Ternary Well-flushing Fluid

随着油田开发的不断深化,三元注入井大量增加,洗井作业是保障生产的有效措施,其施工后将产生大量的三元返排液。由于三元洗井液成分复杂、碱性高、黏度大,不能直接进入污水系统进行处理,因此需采取预处理措施降低洗井液黏度、含油量及悬浮物含量,减轻下游处理压力。通过对三元洗井液、压裂返排液及酸化返排液进行组分分析,并对混配机理进行研究,制定出三元洗井液—压裂返排液、三元洗井液—酸化返排液室内混配实验方案。通过处理水质对比,初步确定了采用酸化返排液处理三元洗井液具有较好的降黏和破乳效果,并且在三元洗井液与酸化返排液以1∶2体积比混合时,可将三元洗井液中含油质量浓度降至172.0 mg/L,悬浮物质量浓度降至13.3 mg/L,混合体系黏度降至2.2 mPa·s,有效降低了三元洗井液下游污水处理环节的难度。

With the continuous deepening of oilfield development,the number of ternary injection wells is increasing significantly.Well flushing operation is an effective measure to ensure production,and it will produce a large amount of ternary backflow fluid after construction.Due to the complex composition,high alkalinity,and high viscosity of ternary well flushing fluid,it cannot directly enter the sewage system for treatment.Therefore,pretreatment measures are needed to be taken to reduce the viscosity,oil content,and suspended solids content of well flushing fluid,so as to reduce the downstream treatment pressure.Through the component analysis of ternary well flushing fluid,fracturing backflow fluid,and acidified backflow fluid,and the research on the mixing mechanism,the laboratory mixing experimental schemes of ternary well flushing fluid-fracturing backflow fluid and ternary well flushing fluid-acidizing backflow fluid are developed.Through the comparison of the treated water quality,it is preliminarily determined that the treatment of ternary well flushing fluid with acidizing backflow fluid has better viscosity reduction and demulsification effect.And when the ternary well flushing fluid and acidizing backflow fluid are mixed with 1:2(volume ratio),the oil mass concentration in the ternary well flushing can be reduced to 172.0 mg/L,the suspended solids mass concentration can be reduced to 13.3 mg/L,and the viscosity of the mixed system can be reduced to 2.2 mPa·s,which effectively reduce the difficulty of the downstream sewage treatment of the ternary well flushing fluid.