Closed Loop Control of Drilling Toolface

摘要

A downhole closed loop method for controlling a drilling toolface includes measuring first and second attitudes of the subterranean borehole at corresponding first and second upper and lower survey stations. The first and second attitudes are processed downhole while drilling to compute an angle change of the subterranean borehole between the upper and lower survey stations. The computed angle change is compared with a predetermined threshold. This process may be continuously repeated while the angle change is less than the threshold. The first and second attitudes are further processed downhole to compute a toolface angle when the angle change of the subterranean borehole is greater than or equal to the threshold. The toolface angle may then be further processed to control a direction of drilling of the subterranean borehole.

主权项

1. A downhole closed loop method for controlling a drilling toolface when drilling a subterranean borehole, the method comprising:
(a) drilling the subterranean borehole; (b) receiving a reference attitude of the subterranean borehole, the reference attitude measured at an upper survey station; (c) receiving a measured attitude of the subterranean borehole; the measured attitude measured at a lower survey station; (d) processing downhole the reference attitude and the measured attitude to compute an angle change of the subterranean borehole between the upper and lower survey stations; (e) comparing the angle change of the subterranean borehole with a predetermined threshold; (f) repeating (c), (d), and (e) when the angle change of the subterranean borehole is less than the predetermined threshold; (g) processing downhole the reference attitude and the measured attitude to compute a toolface angle when the angle change of the subterranean borehole is greater than or equal to the predetermined threshold; and (h) processing downhole the toolface angle computed in (g) to control a direction of drilling of the subterranean borehole.