液压加固补贴对破漏套管的仿真研究

针对胜利油田长距离套管损坏井连续破漏及管体刺漏等套管失效工况,以?139.7 mm×7.72 mm的N80套管为例,借助于ABAQUS有限元软件建立了破漏套管经液压加固补贴后的有限元模型,并对套管组合体模型的承载极限进行了定量分析。研究结果表明:破漏套管表面裂缝的存在对套管组合体承受外挤工况的影响较大,而对组合体承受轴向拉力、轴向压力以及内压等工况的影响甚微;当破漏套管最小裂缝宽度小于2.5 mm时,经液压加固补贴后的组合体在轴向拉力、轴向压力、内压以及外挤等4种载荷工况下的承载极限均高于无损套管的承载极限,满足现场工况要求;而当最小裂缝宽度大于6.5 mm时,补贴后的套管组合体承受的极限外挤载荷小于63.4 MPa,抵抗极限外挤的能力有所降低;通过更改补贴管材质,可明显提高补贴组合体在内压及外挤工况下的极限承载能力。研究结果对现场施工作业具有一定的指导作用。

Simulation on Hydraulic Reinforcing and Patching Technology for Damaged Casing

To solve the problems of casing failure,such as uninterrupted leaking and piercing in long intervals of wells in Shengli Oilfield,by taking the ?139.7 mm×7.72 mm N80 casing as a case,a finite element model of failed casing after hydraulic reinforcing and patching has been built using the ABAQUS software,and then the load limit of the patched casing string model has been quantitatively analyzed.The results show that fractures have a great influence on the casing string subjected to external extrusion,but have a little effect on the casing string subjected to axial tension,axial pressure and internal pressure.When the minimum fracture on the failed casing is less than 2.5 mm,the load limit of the casing string after hydraulic reinforcing and patching is higher than that of the casing string not damaged,under the same axial tension,axial pressure,internal pressure and external extrusion.The load limit of the casing string meets the requirements of field working conditions.When the minimum fracture is larger than 6.5 mm,the limit of the external extrusion load that can be borne by the casing string is less than 63.4 MPa after hydraulic reinforcing and patching,and the ability to resist extreme extrusion declines.The study result plays a certain guiding role for field operation.