塔里木盆地某井堵漏技术分析

Technical analysis plugging a well in Tarim Basin

井漏不仅是钻井过程中的普遍现象,且是制约安全、快速钻井的重要因素之一。某井钻进至5700m在奥陶系蓬莱坝组发生漏失,通过一系列措施钻进至6640m寒武系阿瓦提格组中部漏失结束,漏失井段达940m;漏失地层岩性主要为粉晶白云岩、云质灰岩、灰质云岩、白云岩为主;75%的漏失发生在钻进过程中,最小漏速为1.8m3/h,最大漏速56m3/h,漏速多数在10~20m3/h。自发生井漏开始,该井采取了降密度、降排量、随钻堵漏、边漏边钻、静止堵漏以及桥塞堵漏等方法成功钻进至漏失结束,共采取了8次桥接堵漏和11次随钻堵漏。从这口井的堵漏经过和成果来看,本井漏失为裂缝型漏失,采用桥接堵漏技术堵漏成功与堵漏配方中架桥颗粒大小、堵漏材料浓度等息息相关。

Lost circulation is not only a common phenomenon in the process of drilling,it is also one of the most important factors to restrict safe and fast drilling.A well is drilled to 5700 m,and lost circulation is presented in the Penglaiba formation of Ordovician system,eventually it disappears in the 6640 mthat is located in the middle of Awatige formation of Cambrian system.The powder crystal dolomite,cloud mass limestone,calcareous dolomite and dolomite are the main lithology for leakage formation.Also,75% of the leakage occurs in the process of drilling,and leakage rate is mainly between 10m3/h and 20m3/h,meanwhile minimum and maximum leakage rates are 1.8m3/h and 56m3/h,respectively.Since lost circulation occurs,reduction in density and flow rate,plugging while drilling,static plugging,plugging using bridging agent,and other measures are taken to successfully drill through leakage formation,and eight plugging using bridging agents and eleven plugging while drilling are conducted.The operational results show plugging using bridging agent for the fractured leakage is related to bridging particle size,plugging material concentration,etc.