Patent ID: 7669668
Filing Date: 2010-03-02
Classification: E21B

Abstract:
1. A method of conducting measurements of a borehole while drilling the borehole in a geological formation, the method comprising the steps of: providing a rotatable drilling assembly having thereon, at a forward end, a drill bit and a borehole measurement tool connected rearward of the drill bit, the measurement tool including a pair of accelerometers mounted in a generally perpendicular relation on a plane of the measurement tool that is generally perpendicular to a longitudinal axis of the measurement tool; a pair of magnetometers positioned in a generally perpendicular relation on a plane of the measurement tool that is generally perpendicular to the longitudinal axis of the measurement tool; a caliper arm having a leading edge and a trailing edge, the leading edge pivotally connected with the measurement tool; and a linear actuator preloaded to engage the trailing edge of the caliper arm urging it outward from the measurement tool, the linear actuator comprising a spring-driven push rod oriented perpendicular to the longitudinal axis of the measurement tool; drilling the borehole by operating the rotatable drilling assembly; while drilling, contacting the wall of the borehole with the caliper arm; measuring the extension of the caliper arm contacting the borehole wall, thereby determining a distance between the measurement tool and the borehole wall; and repeating the contacting and measuring steps at multiple positions of the drilling assembly during drilling.