两种主要高强度套管的耐磨性能试验

套管磨损是深井、超深气井钻井过程中困扰作业人员的突出问题,摸清P110和V140这两种主要钢级的高强度套管的耐磨性能对于钻井设计选用套管具有重要意义。为此,采用美国摩尔技术公司的全尺寸套管磨损试验机,模拟油气田现场的钻井作业参数以及钻井液配方,开展了钻杆接头与套管内壁间低、中、高3种典型的侧向力对P110和V140钢级套管的全尺寸实物磨损试验研究,检测并对比分析了磨损套管试样在不同磨损时间段的磨损沟槽深度、沟槽宽度、磨损系数、摩擦系数以及磨损体积等参数,并对套管摩擦表面进行了扫描电镜分析,进而探讨了不同工况条件下的套管摩擦机理。结果认为:在低侧向力的情况下,两种套管的磨损情况基本相当;在中等侧向力的情况下,V140套管的磨损比P110套管严重;在高侧向力的情况下,P110套管的磨损明显要大于V140套管;随着钻杆接头与套管内壁之间接触侧向力的增加,摩擦副之间的摩擦系数增大且处于黏着磨损状态。该研究成果对于在套管柱设计中根据不同井眼曲率考虑套管的耐磨性能选用套管具有参考价值。

Wear resistance of two kinds of high-strength casings: An experimental study

Casing wear is a noticeable issue in the drilling operations of deep and ultra-deep gas wells, so it is remarkably important to investigate the wear resistance of P110 and V140 steel for the casing selection in drilling design. In this paper, the full-scale casing wear tester produced by Moore Industries International, Inc. was used to simulate the actual drilling parameters and drilling fluid formula used in oil and gas fields. Sequentially, full-scale physical wear tests on P110 and V140 steel casings were conducted under three typical low, medium and high lateral contact forces between tool joints and the casing interior wall. Afterwards, associated inspections and a comparative analysis were performed for the depth and width of casing wear groove, wear coefficient, friction coefficient, wear volume, and other parameters which were obtained at different wear stages of casing samples. Finally, the casing friction surface was examined by a scanning electron microscope to further discuss the casing wear mechanism under different working conditions. The study showed that under a low lateral contact force, the wear degrees of two kinds of casings were similar; but under a medium lateral contact force, V140 steel casing was worn more seriously than P110 steel casing, and under a high lateral contact force, P110 steel casing was worn obviously more serious. With the increase in the lateral contact force between tool joints and the casing interior wall, the friction coefficient in a frictional pair increased accordingly, which was in an adhesive wear state. This study will provide valuable reference for the casing selection in the casing string design based on the casing wear resistance considered according to different wellbore curvatures.