数值模拟法在膨胀套管修复套损井技术中的应用

为了分析膨胀套管在套损井修复过程中的应力、应变及残余应力情况,剖析膨胀过程中管材内部变化规律,利用ANSYS软件建立了膨胀套管在套损井修复应用中的有限元模型,优选模型的边界条件,进行模型的数值模拟分析.数值模拟结果直观地反映了管材膨胀过程中的应力一应变情况,结合实验室台架试验及现场施工,总结出可在制管、套管膨胀和后处理3个阶段采取有效措施消减残余应力;膨胀套管在高压液体作用下发生二次形变后.内径尺寸比膨胀锥的外径单边增加0.9～1.3 mm,据此修正了膨胀锥、膨胀套管和原套管尺寸间的经验公式.在华北油田京708井采用膨胀套管技术修复套损井,施工完成后,产油量增加,含水率降低,达到施工要求,表明膨胀套管补贴套损井技术的有限元数值模拟分析符合油田现场施工的需求.

Application of numerical simulation in the SET(Solid Expandable Tubular) repair for casing damage wells

In order to analyze the stress, strain and residual stress of the SET applied in repairing casing damage wells and to analyze the internal tube changes, the SET finite element model is established by ANSYS, the boundary condition of the model is optimized and numerical simulation is carried out. The numerical simulation results directly reflect the stress-strain in the expansion process. With the laboratory and field tests,it is concluded that effective measures could be taken to reduce the residual stress in pipe manufacturing, casing expanding and post-processing stages. The secondary deformation of the SET occurres under high-pressure liquid, and compared with the expansion cone, the radius size unilaterally increases 0.9-1.3 mm. This is used to amend the empirical size formula of the expansion cone, SET and original casing. After the application of the SET repair technology in Well Jing 708 in Huabei Oilfield, oil production increased and water cut decreased, showing that the finite element analysis of the SET meets the oilfield needs.