摘要
在非均匀地应力作用下,井眼钻成后在井周发生应力重分布,井壁容易在最小主应力方位发生井壁垮塌,最大主应力方位发生破裂以达到自然释放井周应力集中的目的。文章结合这种井筒自然的合理破损的工程现象,考虑工程允许的井筒破损时的应力环境,基于井径特征分析、测井资料分析及力学稳定性理论,发展了一种任意井斜条件下的考虑合理井壁破损的气体钻井井壁力学稳定性分析模型。分析结果表明,这种方法力学原理明确,建立的模型准确可靠,应用简单,且与实际情况更为吻合,克服了传统完整井筒极限平衡条件下的井壁力学稳定性分析的建议井段远低于气体钻井实际实施井段的问题,为气体钻井的井壁力学稳定性分析提供有效的基础参考。
Mechanical borehole stability is a prerequisite for gas drilling. In the non-uniform in-situ stress cases,reasonable and engineering allowable wellbore damage naturally occurs to release the borehole circumferential stress redistribution.Wellbore collapse always occurres in the direction of the minimum principal stress,and drilling induced cracks appear in the direction of the maximum principal stress. Considering this kind of reasonable wellbore damage,based on the analysis of borehole diameter characteristics,logging data and mechanical stability theory,a mechanical stability analysis mode for gas drilling of arbitrary inclination wells is developed,which has considered reasonable wellbore damage. The analysis results show that the method has an exact mechanical principle. The model is accurate and reliable,and more consistent with the actual situation.It overcomes the problem that the mechanical borehole stability analysis result is much lower than the actual gas drilling can apply under equilibrium limit condition.
出处
《钻采工艺》
CAS
北大核心
2018年第3期18-20,共3页
Drilling & Production Technology
基金
国家科技重大专项"涪陵页岩气水平井钻井技术示范"(课题编号:2016ZX05060-12)
关键词
气体钻井
井壁力学稳定
井筒破损
预测方法
gas drilling
wellbore mechanic stability
wellbore damage
prediction method
