Martin Thomas Bayliss

Rotary Steerable Directional Drilling Stick/Slip Mitigation Control

Abstract This paper details the online-identification-based adaptive design of a stick/slip minimization algorithm and top-drive servo control for Rotary Steerable System (RSS) directional drilling tools. Stick/slip in this context refers to the downhole angular velocity variation of the bit about a nominal value. The basic pole placement controller designs are SISO linear but recursively evaluated based on an online Recursive Least Squares (RLS) identification of the open-loop plant parameters. System architecture implications for the stated algorithm are discussed, and simulation results included with and without adaptive stick/slip mitigation.

Mixed Uncertainty Analysis of Pole Placement and H∞ Controllers for Directional Drilling Attitude Tracking

This paper describes the design of attitude-hold controllers and their subsequent stability and performance analysis for directional drilling tools as typically used in the oil industry. Based on an input transformation developed in earlier work that partially linearizes and decouples the plant dynamics of the drilling tool, the resulting plant model is used as the basis for both a pole placement (as detailed in previous work) and optimal H∞ controller designs. A structured uncertainty stability and performance analysis is then performed on each of the two controller designs. Results for a transient simulation of the proposed controller are also presented.

Vector Based Kinematic Closed-Loop Attitude Control-System for Directional Drilling

An attitude control system is presented here, where the attitude of a drilling tool is represented by a unit vector and hence non-linearities of Euler angles are avoided. It is shown in simulation that the control system has a stable orbit about the desired attitude in the presence of drop and turn rate biases, and with a spatial delay due to the sensors. The attitude controller is embedded into a way-point tracking control system where it is demonstrated that the controller tracks the position and attitude of each way-point and minimizes the strain energy along the path.

Structured uncertainty analysis of pole placement and H∞ controllers for directional drilling attitude tracking

Abstract This paper describes the design of attitude-hold controllers and their subsequent stability and performance analysis for directional drilling tools as typically used in the oil industry. Based on an input transformation developed in earlier work that partially linearizes and decouples the plant dynamics of the drilling tool, the resulting plant model is used as the basis for both a pole placement (as detailed in previous work) and optimal H ∞ controller designs. A structured uncertainty stability and performance analysis is then performed on each of the two controller designs. Results for a transient simulation of the proposed controller are also presented.

Recursive Variable Horizon Trajectory Control for Directional Drilling Using Elliptical Helixes

Abstract A modified Model Predictive Control (MPC) scheme is proposed, based on geometric construction, for the trajectory following of a directional drill used to produce well-bores in the oil and gas industry. Currently, trajectory control is done manually, but there is a drive to automate the process. The paper outlines the method and describes the construction of a helix that meets the boundary conditions as well as constraints on the curvature. The resulting curve provides a path that is followed to return the drill to the reference path. The path is periodically recalculated to provide the basis for an MPC-type scheme. The scheme is tested in simulation and results indicate a good response.

Robust Linear Feedback Control of Attitude for Directional Drilling Tools (13th IFAC Symposium on Automation in Mining, Mineral and Metal Processing)

Abstract This paper describes the design of an inclination- and azimuth-hold controller for directional drilling tools typically used in the oil industry. A control input transformation that partially linearizes and decouples the plant dynamics is proposed. A pole-placement method is used to design the controller and an analysis of the stability robustness is performed using the small gain theorem. Results for a transient simulation of the proposed controller are also presented.

Bilinear modelling and bilinear PI control of directional drilling

This paper presents the design of an inclination- and azimuth-hold controllers and their subsequent stability and performance analysis for directional drilling tools as typically used in the oil industry. Using an input transformation developed in earlier work that partially linearizes and decouples the plant dynamics of the directional drilling tool, a bilinear model of the directional drilling tool is developed and is used as the basis for Bilinear PI controller design. Results for a transient simulation of the proposed BPI controller are presented and compared with that of the PI controller of the earlier work. It is presented that BPI controller gives more consistent responses over a broader operating range compared to the PI controller. In addition, the effect of time delay on the feedback measurements with respect to the stability and performance is investigated in the simulations.