射孔套管抗内压强度计算与拟合

Calculation and Fitting of the Burst Strength of Perforation Casing

现有研究对影响射孔套管剩余强度因素的分析通常是单独将其关于螺旋角、孔径和孔密的关系分别拟合成曲线,没有将影响射孔套管剩余强度降低系数几个因素联合起来。为此,通过有限元方法计算了不同相位角、不同射孔密度和不同射孔孔径的破裂压力和相应的射孔套管剩余强度系数,并将这些数据按不同相位角拟合成射孔孔密和射孔孔径的函数。对拟合结果的验证表明,原始计算数据与拟合计算数据之间的差异小于1%,拟合函数能精确地表示有限元模拟结果,可以方便地用于射孔套管的破裂强度计算。

Current research usually conducts a separate fitting of the relationships between helix angle, aperture and perforation density into the curves with respect to the analysis of the relationships influencing perforated casing＇ s residual strength. The factors influencing the dropping-coefficient of perforated casing＇ s residual strength are not connected. Therefore, the finite element method was used to calculate the bursting pressure of different phase angles, perforation densities and perforation diameters as well as the corresponding residual strength coefficient of casing. These data were fitted into the functions of perforation densities and perforation diameters according to different phase angles. The verification of the fitting result shows that the error between the original calculation data and the fitting calculation data is less than 1%. The fitting function can precisely express the finite element simulation result and it can be used conveniently to calculate the bursting strength of perforated casing.