胜利油田博24区块水平井筛管外泥饼酸洗工艺应用

Application of Acid Pickling Process for Mud Cake outside of the Screen in the Horizontal Well of Shengli Bo24 block

胜利油区博24区块水平井采用常规酸洗工艺时,存在成功率低、酸洗效果差的问题,主要表现为:①未考虑酸液与混油聚合物钻井液、污水以及地层的配伍性,酸洗效果差;②酸洗工艺中,未能对酸液使用量、注入与替出排量、反应时间等进行优化设计,致使酸液对近井地带的清洗效果欠佳;③酸洗泥饼时,一处的污染解除,酸液由此渗入地层,导致其余井段无法有效清除污染物。为此,开展酸液与聚合物钻井液、与过滤污水、与地层的配伍性室内实验,最终确定了酸液配方,完善了酸洗工艺,实施了多级控压泥饼清洗工艺,对酸洗程序与解堵液用量进行优化。对该区块6口水平井的现场应用表明,改进后的二次酸洗工艺可减小泥浆污染,恢复或提升油层渗流能力;多级控压、段塞顶替,增加下铣锥及通井刮管作业程序,可以提高水平井筛管外泥饼酸洗工艺成功率与应用效果。6口水平井平均日产油7.82t/d,平均日产液15.9t/d,改进后的酸洗施工成功率高达100%。

The application of problems of low success ratio acidizing fluid and oil emulsion general acid pickling in and poor acid cleaning drilling the horizontal wells of effect.The reasons were Shengli Bo24 block has the analyzed.The compatibility of fluid of polymer,waste water and formation was not considered.In the acid pickling process,the cleaning of the acidizing fluid at immediate vicinity of wellbore was not complete for non-optimization of acidizing fluid amount to be used,input and output discharge,reaction time and so on.When the mud cake was in acid pickling process,the pollution of certain position was removed,and the acidizing fluid was entered to the formations resulted in ineffective removal at other intervals.So,the compatibility experiment of the polymer drilling fluid,waste water,formation sand sample with the acidizing fluid was implemented.Formula of the acidizing fluid was determined and the technology of the acid pickling was improved.The technology of mud cake cleaning by multilevel pressure control was applied.The program of the acid pickling and the amount of water block remover to be used were optimized.Field application in six horizontal wells of this block shows that the improved secondary acid pickling technology can not only bring fewer mud pollutions,but make percolation capacity of reservoirs as before or enhanced.Multilevel pressure control,slug displacement and program of running cone and scraper for drifting can enhance the success ratio and effect.Daily oil productions of six horizontal wells were 7.82t/d and fluid productions were 15.9t/d equally.The improved acid pickling process was successful completely