Mechanism for Effect of Down Hole Differential Pressure on Rock Failure
详细信息
- 责任者：Zheng Deshuai (Key Lab. of Petroleum Engineering ; MOE ; China University of Petroleum ; Beijing 102249 ; China) ; Gao Deli
- 刊名：Journal of China University of Petroleum
- 出版年：2011
- 卷期：35(2)
- 关键词：地层压力 ; formation pressure ; 岩石破碎机理 ; rock fragmentation mechanism
- 页码：p.69-73
- 图表：4 illus., 11 refs.
- 分类号：2000
- issnNo：ISSN1673-5005
- isbnNo：CN37-1441/TE
摘要
In this paper, the expression of teeth invasion depth was developed, and rock failure model for teeth invasion was established according to Morh-Coulomb principle. Using the ratio of error function and depth x as the reference parameters for underbalanced drilling application, invasion depths under all kinds of differential pressures and β/x were calculated, and the variation law was analyzed. The results show that the expression of teeth invasion depth can clearly demonstrate respective effect of pressures and fluid on rock failure. This model can explain the mechanism of enhanced rate of penetration in underbalanced drilling, and it can depict the scope of application for dc index method correctly.