Directional Drilling: Trajectory Design and Position Uncertainty Study for a Laboratory Drilling Rig.

Abstract

This thesis investigates how trajectory optimisation and position uncertainty calcu- lations can be performed on a laboratory drilling rig.

The improvements made are to be used on the drilling rig designed and manufactured by UiS Drillbotics team, for the international Drillbotics competition. This year's competition presented a new set of challenges, including a pre-planned trajectory, hitting target points before exiting the well and an integrated error model. The requirements are presented in detail in the guidelines provided by Drilling Systems Automation Technical Section (DSATS) committee.

The models presented in this thesis are intended to advance the current system, where automated optimisation of trajectories and position uncertainty calculations can easily be performed and visualised. Using Bezier curves for trajectory optimisa- tion and the ISCWSA error model, these calculations are presented and tested for both fi eld cases, and generated trajectories with the dimensions of the laboratory drilling rig.

The solutions presented offers a possibility to intuitively visualise the results to the driller and observers. The trajectory optimisation is a process conducted before any drilling is initiated, and imported to the main GUI for comparison between planned trajectory and drilled trajectory. The position uncertainty calculations are exible, and can be speci cally con gured for different sensor packages and con dence lev- els. The uncertainty calculations are plotted together with the trajectory, which enables the driller and system to identify deviations and reconsider the trajectory if necessary.