GEODYN2: A Bottomhole Assembly/Geological Formation Dynamic Interaction Computer Program

Abstract

pnt#nted at SPE meetings are subject to publicatan revlew by Editorial Committees of the Society of Petroleum Engineers Permission to copy IS rostmed to M abstract of not more than 300 words lllustratmns may not be copied The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented Write Publicatmns Manager, SPE. P 0 Box 833836. The basic drill string mechanics implemented within the program, the overall algorithm, and the more pertinent modeling features which permit this level of analysis are briefly outlined. The implementation of these features and how they allow calculation of the response behavior of a bottom hole assembly are demonstrated.Although the development and enhancement of modeling capabilities within GEODYNZ is ongoing, it is anticipated that the preliminary verification results thus far generated will further the understanding of the response behavior of BHAs. INTRODUCTION

Directional Drilling System Response and Stability

“…The direction of borehole-propagation in the plane is determined by a first-order differential equation (10).…”

“…Much has been published on the steady-state curvature tendencies of drilling assemblies and the complexities of their contact with the rock [1][2][3][4][5][6][7][8]. A considerable body of work has also been published on the dynamic vibration response of the drillstring as a mechanical structure [9][10][11][12][13][14][15][16]. Herein it is revealed that the space-curve of the centerline of the hole can be approximated by the response of a quasi-polynomial transfer function to steering actuator stimuli.…”

Systems Modeling and Design of Automated Directional Drilling Systems

“…The study of how drilling assemblies propagate the borehole migrated from the analytical approaches of Lubinksi and Woods (1955), Jiazhi (1982), Ho (1986Ho ( , 1987, and Miska (1987) to ever more sophisticated computer simulation approaches initiated by the early works of Millheim et al (1978), Millheim and Apostal (1981), Baird et al (1985), Jogi et al (1986), andBirades (1986). This paper returns to the crossroads of these approaches and takes the subject a little further down the analytical path similar to that of Neubert and Heisig (1996) and Pastusek and Brackin (2003).…”