涠洲11-1油田调整井水基钻井液优选与应用

Optimization and Application of Water Based Drilling Fluid for Adjusting Well in Weizhou 11-1 Oilfield

涠洲11-1油田位于南海北部湾海域,钻井过程中遇到的中新统灯楼角组和角尾组是关键的地层。角尾组上部泥质含量较高,使用常规强包被型钻井液作业时,极易出现钻屑聚集形成泥球的现象,这不仅影响了钻井效率,还可能造成起下钻过程中的遇阻。为了解决这个问题,同时提高角尾组中下部砂岩层的储层保护效果,通过分析已钻井的相关资料,优选了海水聚合物钻井液和EZFLOW无固相钻井液。对比强包被型PDF-PLUS/KCl钻井液,海水聚合物钻井液更具分散性,可有效防止泥球形成;EZFLOW无固相钻井液剪切稀释性强,悬浮携带性能和储层保护性能更佳。在涠洲11-1油田A平台的两口调整井中的成功应用表明,所优选的钻井液有效改善了角尾组出泥球问题,同时提高了起下钻效率和储层保护效果。

Weizhou 11-1 oilf ield is located in the Beibu Gulf of the South China Sea.The Zhongxin Formation Dengloujiao Formation and Jiaowei Formation encountered during drilling are key formations.The upper part of the Jiaowei Formation has a high content of mud,and when using conventional strong coating drilling fluid operations,it is very easy for drill cuttings to accumulate and form mudballs,which not only affects drilling eff iciency,but also may cause resistance during tripping operations.In order to solve this problem and improve the reservoir protection effect of the middle and lower sandstone layers in the Jiaocaizhu Formation,through analyzing relevant data from previous drilling operations,we have optimized and selected sea water polymer drilling fluid and EZFLOW non-solid drilling fluid.Compared to the strong coating type PDF-PLUS/KCl drilling fluid,the sea water polymer drilling fluid has better dispersibility and can effectively prevent the formation of mud balls,while the EZFLOW non-solid drilling fluid has strong shear thinning properties,superior suspension and carrying performance,as well as better reservoir protection performance.Successful applications in two adjustment wells at the a platform of the Weizhou 11-1 oilf ield have demonstrated that the optimized drilling fluid effectively improves the problem of mud balls in the Jiaocaizhu Formation,while enhancing the eff iciency of drill string lowering and reservoir protection.