漂浮接箍球壳式堵盖强度计算和试验研究

STRENGTH CALCULATION AND EXPERIMENTAL STUDY OF SPHERICAL COVER FOR FLOATING COUPLING

球壳式堵盖作为漂浮接箍的承压部件,在下套管过程中其强度直接影响漂浮接箍的承压密封作用。首先对球壳式堵盖的应力进行理论解析和仿真,综合考虑材料和压缩破坏失效形式,基于三向应力下的球壳模型建立了球壳式堵盖的强度计算公式。选用硼硅玻璃作为材料,通过压缩试验得到其抗压强度;采用仿真计算获得球壳式堵盖的应力状态并确定危险部位。然后通过压力试验获得球壳式堵盖的打开压力,将试验与计算结果进行对比。结果表明,球壳式堵盖的爆破压力为46.2 MPa±3.8 MPa,且破碎后漂浮接箍内部无残留玻璃,最大破碎颗粒小于10 mm×9 mm×3 mm,满足球壳式堵盖的强度要求。研究结果对水平井下套管中漂浮接箍的应用具有重要的意义。

As the pressure-bearing part of the floating coupler,the strength of the spherical cover directly affects the pressure-bearing and sealing function of the floating coupler in the process of lowering the casing.Firstly,the theoretical analysis and simulation of the stress of the spherical cover were carried out,and the strength calculation formula of the spherical cover was established based on the spherical shell model under three-way stresses,taking into account the material and compression the damage failure form.Borosilicate glass was selected as the material and its compressive strength was obtained by the compression test.The stress state of the spherical cover was obtained by simulation calculation and the dangerous area was determined.Then the burst pressure of the spherical cover was obtained by the pressure test,and the test and calculation results were compared.The results show that the opening pressure of the spherical cover was 46.2 MPa±3.8 MPa,and no residual glass was inside the floating joint after breaking.The maximum broken particles are less than 10 mm×9 mm×3 mm,which meets the strength requirement of the spherical cover.The results of the study are of great significance to the application of floating coupling in horizontal wells under casing.