水下井口弃井作业除垢技术及应用

Application of heavy oil cleaning agent in east South China Sea oil field

南海东部油田拥有近百口水下井口采油树,随着投产时间增加,油井出现特高含水、低油速度、低采出的“一高二低”状态,为改善其开发效果,提高储量动用程度,采收率,需回收老井生产管柱并侧钻新井眼进而动用剩余油富集区,进一步提高采出程度。然而随着采油树下入时间的增长,水下井口结垢严重,清理工作困难,水下井口的清洁度成为油管挂对接及回收关键,成为制约回收老井管柱并侧钻新井眼的主要困难[1],采用高效除垢技术,可以显著提高水下井口弃井作业时效。对水下井口结垢物的无伤软化处理程序,提高水下弃井及再次完井成功率,为后续作业提供宝贵的经验。

The eastern South China Sea oilfield has nearly 100 subsea wellhead trees.With the increase of production time,the oil wells appear the“one high and two low”state of extra high water cut,low oil velocity and low production.In order to improve its development effect,improve the degree of reserve utilization and recovery rate,it is necessary to recover the production pipe of the old well and sidetrack a new well to use the remaining oil enrichment area and further improve the recovery degree.However,with the increase of the time of planting the tree,the scaling of the subsea wellhead is serious,and the cleaning work is difficult.The cleanliness of the subsea wellhead becomes the key to the docking and recovery of the tubing,and becomes the main difficulty to recycle the pipe of the old well and sidetrack a new well.The use of efficient scaling technology can significantly improve the efficiency of the abandonment operation of the subsea wellhead.The non-invasive softening treatment procedure of the scaling of the subsea wellhead can improve the success rate of the subsea abandonment and re-completion,and provide valuable experience for the subsequent operation.