1. vb. [Drilling]

To control the direction of a well based on the results of downhole geological logging measurements rather than three-dimensional targets in space, usually to keep a directional wellbore within a pay zone. In mature areas, geosteering may be used to keep a wellbore in a particular section of a reservoir to minimize gas or water breakthrough and maximize economic production from the well.

See related terms: directional drilling,  geosteering