摘要
汶川地震断裂带科学钻探工程钻遇地层非常复杂,地层破碎、膨胀缩径,坍塌、掉块严重,多次出现卡埋钻等事故,同时复杂地层取心率偏低。WFSD-2孔在取心率很低井段,为补取岩心运用套管开窗侧钻技术;而在WFSD-4孔施工中,套管内出现卡钻事故,为绕障采用套管开窗侧钻技术。介绍了复杂事故井套管开窗侧钻从准备到实施的工艺流程和技术措施。套管开窗侧钻的成功应用为后续工程实施节约了时间和成本,对今后类似作业具有很好的指导和借鉴作用。
During the drilling operation of Wenchuan earthquake fault science drilling project( WFSD),due to stratum breaking,borehole shrinkage and borehole walls' collapse,drilling accidents occurred frequently and core recovery has been low. In the borehole section of WFSD-2,where the core recovery was poor,sidetracking technology was used to get better core recovery and core quality. During the drilling of WFSD-4 hole,pipe stuck accidents occurred within the casing,casing sidetracking technology was used to by pass the obstacle in the hole. This article describes the casing sidetracking technology used in complex formations,referring to the technical measures adopted from preparation to implementation period.The successful application of sidetracking save project implementation time and cost,this will be good guidance and reference for future similar operations.