Patent ID: 9377556
Filing Date: 2016-06-28
CPC Classification: E21B,G01V

Claim Text:
1. A while-drilling method, comprising: a) providing an electromagnetic (EM) field source at an Earth surface location; b) providing a near-bit electromagnetic (EM) field receiver on a drill string in a borehole at a location proximate a drill bit; c) generating an electromagnetic (EM) field at the source; d) during drilling of the borehole, measuring a plurality of components of the EM field at the near-bit receiver; e) during drilling of the borehole, analyzing in real-time the measured components of the EM field as representative of a distance between the drill bit and a formation anomaly located ahead of the drill bit, the formation anomaly comprising a salt entrance; and f) adjusting at least one drilling parameter based on the measured components of the EM field prior to the drill bit reaching the formation anomaly.