Open Access

ARTICLE

On Appropriately Matching the Bottomhole Pendulum Assembly with the Anisotropic Drill Bit, to Control the Hole-Deviation

Deli Gao¹, Zhen Dong¹, Hui Zhang¹

1 Key Laboratory Of Petroleum Engineering in the Ministry of Education, China University of Petroleum, Beijing 102249, China. E-Mail: gaodeli@cupedu.cn and dz19880317@126.com

Computer Modeling in Engineering & Sciences 2012, 89(2), 111-122. https://doi.org/10.3970/cmes.2012.089.111

Abstract

The bottom hole pendulum assembly is a type of bottom hole assembly (BHA) for controlling the hole deviation, and has been widely used in drilling engineering. Generally, the ability of the drill bit to penetrate laterally, is different from its ability to penetrate axially, so that the drill bit has an anisotropy which affects the hole-deviation-control characteristics of the BHA. The tilt angle and the side force of the drill bit are obtained by a BHA analysis based on the method of weighted residuals. Thus, the effective drilling force can be determined using the rock-bit interaction model. On this basis, the effects of the drill bit anisotropy on the hole-deviation-control characteristics of the bottom hole pendulum assembly are illustrated by a case study, which shows that the bottom hole pendulum assembly should be appropriately matched with the drill bit of the "side-aggressive" and "short gauge protection" type. The critical drill bit anisotropy index is defined and the factors which influence it are discussed. The bottom hole pendulum assembly would make the hole-deviation dropping or building when the drill bit anisotropy index may be greater or less than the critical drill bit anisotropy index, respectively. In summary, matching the drill bit anisotropy appropriately with the bottom hole pendulum assembly is critical to effectively control the hole deviation and improve the drilling efficiency.

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Keywords

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