深井裸眼封隔器分段酸压管柱打捞实践

Practices of Fishing Packer Strings for Open Hole Multi Stage Acid Fracturing in Deep Wells

安岳气田灯影组气藏广泛采用大斜度井/水平井裸眼封隔器分段酸压工艺试油完井,悬挂封隔器及下部管柱被“永久性”留在井下。如果利用原裸眼侧钻,则需要打捞分段酸压管柱至套管鞋以下30 m左右。MX126井和GS121井前期打捞作业历时均超过50 d,打捞效率非常低,主要原因为:悬挂封隔器双向锚定,裸眼封隔器和连接油管埋卡严重且位于大斜度井段,压井后长时间静止埋卡越来越严重;钻井液压井后切割油管受阻,没有完成落鱼切割分段;套磨铣导致封隔器解体,倒扣时落鱼出现多处退扣,倒扣打捞效率低。针对上述问题,优化了打捞技术措施:钻井液压井前,采用泵送径向切割工艺在清水中切割油管,确保切割成功率;采用带压拔出插管循环压井,缩短钻井液浸泡时间,降低次生卡钻风险;优选磨铣工具和打捞工具,优化磨铣工艺和震击解卡打捞工艺,维持落鱼完整性、力求捞出整段被切割落鱼。该技术成功应用于MX146井和GS127井后期的打捞作业,分别用时12 d和5 d。该技术可以显著提高裸眼封隔器分段酸压管柱的打捞效率,具有推广应用价值。

Open hole multi stage acid fracturing technology for highly deviated well and horizontal well has been widely applied to the exploration and development of Dengying Gas Reservoir in Anyue Gas Field.The liner hanger packer and the string below has been “permanently” retained downhole.However,if sidetracking is to be made below the casing shoe,part of the string must be retrieved till the top of fish is about 30 m below the casing shoe.Early,each fishing job carried out in Well MX146 and Well GS121 almost lasted more than 50 days.The fishing efficiency was pretty low.The main reasons are as follows:Located in highly deviated section,with bidirectional anchored liner hanger packer and sticking open hole packers and sticking connecting tubing,the multi stage acid fracturing string is stuck tightly,and even getting worse for being stationary after well killing;Tubing cutting failed due to tight point and the string had not been parted in Well GS121 after the well was killed by drilling fluid;Packer broke up during milling or washing over,and the efficiency of backoff is quite low because of threaded joints of the string unscrewing unexpectedly.And then technologies are optimized:In order to part the string successfully,cut tubing in clear water before killing the well with drilling fluid by wireline conveyed radial cutting torch(RCT) which can be pumped downhole in place;To avoid secondary hazards,kill the well using “strip-make circulation-and kill” method,and then shorten the duration of the string being engulfed in drilling fluid;In order to maintain the integrity of downhole fish and fish out the whole cut section,mills tools and fishing tools are optimized,milling and jarring process are improved.The optimized technologies have been successfully applied in fishing operations in Well MX 146 and Well GS127,which consumed 12 days and 5 days respectively.The fishing efficiency has been significantly improved.