大港油田南部页岩油勘探开发钻井液技术

为了解决大港油田南部沧东区块页岩油水平井井眼失稳的问题，分析了沧东区块地质特征、施工难点和井眼失稳机理，优选了抑制剂、封堵剂和润滑剂等3类关键处理剂，形成了BH-KSMShale页岩油勘探开发钻井液，并对其性能进行了室内评价。实验结果表明，该钻井液具有良好的性能，抗温达150℃，高温高压滤失量小于10 mL。该钻井液技术在大港油田南部的**701H、**702H、**1-2H和**2H井等4口井进行了现场试验，使用该钻井液后施工顺利，无井下复杂事故发生，井眼扩大率最大仅为8.67%。形成的BH-KSMShale钻井液非常适合大港油田南部油区页岩油水平井，能够解决长水平段井眼失稳问题，在大港油田页岩油勘探开发中具有广阔的应用前景。 

Drilling Fluid Technology for Exploration and Development of Shale Oil in South of Dagang Oilfield

Wellbore instability is a problem encountered in shale oil horizontal drilling in Cangdong block in the south of Dagang oilfield. To address this problem, the geological features of the Cangdong block, the operation difficulties and the mechanisms of borehole wall collapse were analyzed, and three key drilling fluid additives (shale inhibitor, plugging agent and lubricant) were selected to formulate a BH-KSMShale drilling fluid for shale oil development. Laboratory evaluation of this drilling fluid showed that the drilling fluid had good properties; it functioned properly 150℃, and the HTHP filtration rate was less than 10 mL. Four wells, well **701H, well **702H, well **1-2H and well **2H, in the south of Dagang oilfield were drilled using the BH-KSMShale drilling fluid. The drilling operation was performed smoothly, and there was no downhole trouble occurred during drilling. The maximum percent hole enlargement was only 8.67%. The BH-KSMShale drilling fluid is very suitable for the shale oil drilling in the south of Dagang oilfield; with this drilling fluid, the borehole wall collapse in horizontal drilling is avoided and it will find wide application in the future in shale oil development in Dagang.