海上油气井套管拔桩工具能力分析及试验验证

Capacity Analysis and Experimental Verification of Casing Pulling Tools for Offshore Oil and Gas Wells

为实现海上油气井侧钻和弃置等作业中套管的经济、高效回收,突破平台修井设施拔桩载荷能力限制,研制了一种基于液压驱动的套管拔桩工具。通过理论分析与模拟试验对拔桩工具能力进行了研究,计算了工具的理论拔桩能力,建立了水泥胶结状态下可拔出套管长度与拔桩力、水泥胶结强度、待拔桩套管外径及套管自重等的关系模型,并开展了套管拔桩全尺寸模拟试验,验证了工具的拔桩能力。研究结果表明:在液压缸20 MPa额定工作压力下,工具可产生3025.5 kN的拔桩力;以常用的ø244.5 mm胶结套管为例,额定工作压力下的理论可拔出长度为2.772 m;室内全尺寸模拟试验条件下,拔出同样长度水泥胶结的同尺寸套管,理论计算结果与全尺寸拔桩模拟试验结果误差仅为7.13%,符合性良好。理论分析及全尺寸模拟试验验证了液压拔桩工具的可行性,所得结果可为工具现场应用提供理论及试验依据。

In order to realize economical and efficient recovery of casing during sidetracking and abandonment of offshore oil and gas wells and to break through the load limit of platform workover facilities,a hydraulic casing pulling tool was developed.The capacity of this hydraulic casing pulling tool was studied by means of theoretical analysis and simulation experiment.During theoretical analysis,the theoretical capacity of pile pulling tools was calculated and a model to study the relationship between the casing length to be pulled out and the pulling force,cementation strength,casing diameter and casing weight was established under cementation conditions.In addition,a full-scale casing pulling simulation experiment was carried out to verify the theoretical results.The results show that under the rated working pressure of 20 MPa of hydraulic cylinder,the pile pulling force was 3025.5 kN.Taking Φ244.5 mm cemented casing as an example,the theoretical pullout length under rated working pressure was 2.772 m.In the full-scale indoor simulation experiment,when pulling out the same length of cemented casing with the same size,the simulation results were in good agreement with the theoretical results,with an error of 7.13% only.In general,theoretical analysis and full-scale simulation experiment verified the feasibility of the hydraulic pile pulling tools and the results provide a theoretical and experimental basis for its field applications.