摘要
在重新考察垂直井射孔完井条件下孔眼的应力状态后,利用替代方法给出了某一射孔深度处的孔眼壁面出现破裂所需要注入压力的计算公式.但分析公式,发现人工裂缝将会在射孔根部位置出现,于是给出了相应的地层破裂压力计算修正公式.研究结果表明,计算修正公式与原公式对比,更能反映射孔完井条件下地层的应力状态和实际情况,可供油田的钻井和压裂设计作参考.
The stress state of perforation holes was re-inspected in this paper,and it is found that the horizontal principal stresses should be substituted by the vertical and radial normal stresses. Utilizing the substituting method, the breakdown pressure for one certain position of perforation depth was derived. According to it, the artificial vertical fracture will appear at the base of the perforation, and the corresponding modified formula of formation breakdown pressure for arbitrary perforation completions was given. Comparing the formula with the original formula, we find that the original one can be seen as an approximation of formation breakdown pressure. The results show that the stress condition and actual situation of the perforated formation can be better reflected in the modified formula, which is applicable to guide drilling and fracturing designs of oilfields.
出处
《上海工程技术大学学报》
CAS
2009年第2期157-160,共4页
Journal of Shanghai University of Engineering Science
基金
上海市高校选拔培养优秀青年教师科研专项基金资助项目(shu06047)
关键词
垂直井
射孔孔眼应力
地层破裂压力
vertical wells
stress state of perforation holes
formation breakdown pressure
