大港油田长新5磨铣套管救援井设计与实践

Design and Application of Changxin 5 Milled Casing Relief Well in Dagang Oilfield

大港油田长5井因井口爆炸,造成浅层套管发生错断移位,井口处于高危失控状态。为此,设计长新5救援井,计划在垂深3 600 m钻穿油层套管及内部的油管,注水泥返至井口封堵消除隐患。针对救援井眼与事故井套管交汇控制、磨铣开窗等技术难题,首先钻试碰井眼探测事故井的套管位置采用随钻磁引导定位技术获取有效的磁干扰参数再优化救援井的井眼轨迹,实现两井对接交汇。最终救援井钻至3 587.6 m时,成功钻穿了Φ139.7 mm油层套管及内部的Φ73 mm油管循环钻井液使两井完全连通,注水泥封堵,彻底消除了事故井隐患。该井应用磁感应精准穿针技术钻穿事故井套管,进行注水泥封堵救援,创造了国内外首个成功案例。

Due to wellhead explosion in Well Chang5 in Dagang Oilfield,the shallow casing has been staggered and shifted,and the wellhead is at high risk of losing control. To this end,the Changxin5 relief well was designed,and it was planned to drill through the casing and internal tubing in the oil reservoir at the vertical depth of 3600 m,and return to the wellhead with cementing to eliminate hidden dangers. In view of the technical difficulties such as the control of the intersection of the casings of the relief well and the accident well,milling and window opening,the casing position of the accident well is detected by drilling a test hole,effective magnetic interference parameters are obtained by using the magnetic guidance while drilling positioning technology,and then the well trajectory of the rescue well is optimized to realize the docking and intersection of the two wells. The relief well was ultimately drilled to 3587. 6 m,successfully drill through the 139. 7 mm casing in reservoir and the73 mm internal tubing. The two wells were then to be connected by circulating drilling fluid,and to be plugged by pumping cement,which eliminating the hidden trouble of the accident well.This relief well successfully drilled through the casing of the accident well by using magnetic induction precise needle penetration technology,plugging with cement to perform rescuing operation,which creating the first successful case at home and abroad.