Closed-Loop Geosteering Device and Method

摘要

A closed-loop method for geosteering a subterranean borehole includes rotating a roll-stabilized control unit in the borehole, obtaining formation evaluation sensor measurements via sensors located in the control unit, and processing downhole the sensor measurements to obtain a corrective steering tool setting that may be applied to a steering tool to control a direction of drilling. A logging while drilling method includes obtaining sensor measurements via sensors located on a rotating roll-stabilized control unit and processing the sensor measurements to obtain an LWD image. A downhole tool includes a downhole tool body and a roll-stabilized control unit. The roll-stabilized control unit is deployed in a through bore of the tool body such that it is free to rotate with respect to the tool body. A tool face sensor and a partially shielded gamma ray sensor are deployed in the roll-stabilized control unit.

主权项

1. A closed-loop method for geosteering a subterranean borehole, the method comprising:
(a) causing a bottom hole assembly to drill a subterranean borehole, the bottom hole assembly including a steering tool having a roll-stabilized control unit, the roll stabilized control unit including at least one formation evaluation sensor and a tool face sensor deployed therein; (b) causing the roll-stabilized unit to rotate with respect to the borehole while drilling in (a); (c) causing the formation evaluation sensor and the tool face sensor to obtain corresponding sensor measurements while rotating in (b); (d) processing the sensor measurements obtained in (c) to compute a borehole image parameter; (e) processing the borehole image parameter to obtain a corrective steering tool setting; and (f) applying the corrective steering tool setting to the steering tool to change a direction of drilling.