垂直射孔井地应力及破裂压力研究

STUDY ON EARCH STRESS AND FRACTURING PRESSURE IN VERTICAL PERFORATED WELLS

一般水力压裂井施工前都进行了射孔作业,不同的射孔参数可能会对压裂施工和压后产能产生不同程度的影响。应力分析是进行这类研究的基础,文章在国内外相关应力分析研究的基础上,运用解析方法研究了射孔后孔眼围岩的地应力分布,通过应力分布计算,结合抗拉破坏准则,对垂直射孔井水力压裂破裂压力进行了分析,得到了孔眼围岩应力分布和垂直射孔井水力压裂破裂压力的定性认识,可以为压裂井射孔工艺技术优化设计提供一定的指导。

Usually the oil wells are perforated before hydraulic fracturing,so different perforation parameters have different degree influence on the hydraulic fracturing treatment and the productivity of hydraulic fractured oil wells.Based on the studies of correlative stress both in China and abroad,this paper has deduced the earth stress distribution around the vertical wellbore wall after perforations.By calculating the earth stress distribution and in combination with tensile failure criterion of rock,the hydraulic fracturing pressure of vertical perforated wells has been investigated.Several qualitative conclusions about the stress distribution and the hydraulic fracturing pressure of vertical perforated wells have been gained.