射孔套管抗挤强度综合因素有限元分析

射孔完井是国内外使用最广泛的完井方法,但是大量的现场实践表明,射孔对套管强度有较严重的影响,所以确定套管射孔后的抗挤强度的变化趋势是合理选择套管的重要依据。利用非线性弹塑性有限元法建立了螺旋布孔的射孔套管强度分析的空间有限元力学模型,该模型可以通过任意改变射孔孔径、孔密、相位角、壁厚、套管尺寸以及不同钢级套管的材料力学特性参数等,对射孔套管抗挤强度进行各种综合因素的有限元力学分析。经分析认为:高钢级或高强度套管能有效提高射孔套管抗挤强度;随着孔径、孔密的增加,套管的抗挤强度降低;相位角在180°时,套管的抗挤强度最低。研究结果为合理地选择套管、延长其使用寿命提供了一定的理论依据。

FINITE ELEMENT ANALYSES ON SYNTHETIC FACTORS OF PERFORATING CASING''''S COLLAPSE STRENGTH

The perforated completion is by far the most popular method of completing a well at home and abroad.But lots of field applications indicate that perforation has serious effect on the casing safety,how to guarantee the collapse strength of perforating casing is still a difficult subject to the development of the petroleum industry.In this paper,the spacial finite element mechanics model of the strength analysis of perforating casing with screw holding was established by using non-linear elasticity-plasticity finite element method.In the model the parameters including perforation diameter,perforation density,perforation phase angle,wall thickness,casing dimension and material mechanics property of casing with different steel rating can be changed discretionarily,so the finite element analyses on synthetic factors of perforating casing's collapse strength can be carried through conveniently.Detailed analyzing the change of collapse strength and remaining strength on the casing with different steel rating,wall thickness,and dimension under outer loading,the result of the investigation provides a theoretical basis for rational choosing casing and prolonging their life.