Rotary steerable systems: mathematical modeling and their case study

Caetano P. S. Andrade,Andrzej Tunkiel,Dan Sui,J. Luis Saavedra

doi:10.1007/s13202-021-01182-6

Caetano P. S. Andrade, Andrzej Tunkiel + Show 2 more

Open Access

https://doi.org/10.1007/s13202-021-01182-6

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Abstract

Directional drilling is a common and essential procedure of major extended reach drilling operations. With the development of directional drilling technologies, the percentage of recoverable oil production has increased. However, its challenges, like real-time bit steering, directional drilling tools selection and control, are main barriers leading to low drilling efficiency and high nonproductive time. The fact inspires this study. Our work aims to contribute to the better understanding of directional drilling, more specifically regarding rotary steerable system (RSS) technology. For instance, finding the solutions of the technological challenges involved in RSSs, such as bit steering control, bit position calculation and bit speed estimation, is the main considerations of our study. Classical definitions from fundamental physics including Newton’s third law, beam bending analysis, bit force analysis, rate of penetration (ROP) modeling are employed to estimate bit position and then conduct RSS control to steer the bit accordingly. The results are illustrated in case study with the consideration of the 2D and 3D wellbore scenarios.

Highlights

Directional drilling has been bringing a lot of innovations and increased the efficiency of hydrocarbons extraction, especially in these past decades
The offset is activated with 100% of its haul when there is necessity of increasing or decreasing the angle of the well, and it is deactivated or use 0% of its haul when the well needs to maintain its angle
Since our goal is to use a rate of penetration (ROP) model that represents the conditions of the formation, the bending resultant force on the bit and the effect of offset controller, so that the ROP approximations presented in this study achieve it, but validations are necessary in the further development

Summary

Introduction

Directional drilling has been bringing a lot of innovations and increased the efficiency of hydrocarbons extraction, especially in these past decades. Directional drilling is extremely useful when a wellbore needs to reach a target or a number of targets that are located at a horizontal distance of thousands meters from the well site, among other advantages Mitchell and Miska (2011). The directional drilling techniques can be summarized into two mains: point-the-bit (POB) and push-the-bit (PUB). The first one involves bending of the bottom hole assembly (BHA) into the direction of the desired curvature, while the second one pushes the bit in the directional perpendicular to the axis of the drill string, achieving a curved well.

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