深水弃井作业套管切断的判断方法

摘要

在进行海洋石油弃井作业后，必须把水下井口系统从泥线以下切割回收到地面。目前主要采用水力机械内切割技术进行套管拆除。在深水弃井作业中，判断套管是否被切断是提高弃井作业效率的关键。如果套管未被切断，将造成取不出套管甚至出现打捞工具被拉断等井下事故。针对这个问题，提出了一种通过冲次和立管压力现场数据来判定套管是否被切断的方法，并通过现场试验验证此方法的可靠性。%In the offshore oil operations,the subsea wellhead system must be cut and sent to the ground in the abandoned wells.The cutting technology mainly is used in hydraulic machinery in the abandoned wells casing demolition technology at present.And in the deep water abandonment operations,judging whether the casing is cut off is the key to improve the working efficiency of the abandoned wells.If the casing has not been cut off,the casing can’t be pulled out and even the casing salvage is pulled off.Aiming at this problem,it establishes cutting tools casing cutting sim-ulation model using the Bernoulli equation in combination with hydraulic experiment,and judge whether the casing was cut off according to the flow and riser of wellhead pressure numerical val-ue.The field test proves to be valid,it can be used to guide the work.