成6井二开长裸眼井段防塌钻井液技术

Anti Collapse Drilling Fluid Technology for the Second Open Hole Section of Cheng-6 Well

成6井设计井深5950 m,二开井眼尺寸大,裸眼段长达3100 m,裸眼段上部地层和下部地层岩性差别大;钻进过程会穿过侏罗系发育硬脆性泥岩和煤层,钻进过程中井壁稳定和井眼净化难度大。为此,分析钻井液技术难点,确定钻井液技术措施,并开展钻井液体系研究,最终通过采用复合胺盐润滑防塌钻井液体系,辅助现场钻井液施工工艺,二开长裸眼井段施工中井壁稳定、井身质量好,平均井径扩大率为1.97%,取得了优快钻井的良好效果。

The design depth of Cheng-6 well is 5950 meters,and the size of the second open hole is large.The open hole section is as long as 3100 meters,and there is a significant difference in lithology between the upper and lower formations of the open hole section;The drilling process will pass through hard and brittle mudstone and coal seams developed in the Jurassic,making it difficult to stabilize the wellbore and purify the wellbore during the drilling process.To this end,the technical difficulties of drilling fluid were analyzed,drilling fluid technical measures were determined,and drilling fluid system research was carried out.Finally,by using a composite amine salt lubrication anti collapse drilling fluid system to assist in on-site drilling fluid construction technology,the wellbore wall was stable and the quality of the wellbore was good during the construction of the second open hole section.The average wellbore enlargement rate was 1.97%,achieving good results in fast and optimal drilling.