Patent ID: 7347003
Filing Date: 2008-03-25
Classification: E21B,G01B

Abstract:
1. A device capable of measuring minute axial displacement of rock structures in a borehole, comprising: a releasable-deployable axial frame, wherein said releasable-deployable axial frame supports and positions a proximal anchor unit and a distil anchor unit in a borehole until each of said proximal anchor unit and said distil anchor unit is securely attached by fixed anchor points to the wall of said borehole and said releasable-deployable axial frame is released; said proximal anchor unit and said distil anchor unit each comprises a fixed anchor point, a reversible anchor actuator, and a deployable anchor face capable of being deployed with a force of up to 2,000 pounds, whereby said anchor points secure said anchor unit to said borehole wall opposite the point of contact of said anchor face with said borehole wall; means to measure axial displacement of rock structure in a borehole comprising: a pair of reference rods, temperature compensating means, a displacement transducer, a proximal and a distil axial frame release, and a reference rod registration element, wherein, wherein the proximal end of said releasable axial frame is releasably connected to said proximal anchor unit and the distil end of said releasable axial frame is releasably connected to said distil anchor unit; and further wherein the first member of said pair of reference rods is securely attached to said proximal anchor unit, extending vertically towards said distil anchor unit, and the second member of said pair of reference rods is securely attached to said distil anchor unit, extending vertically towards said proximal anchor unit; and further, wherein said proximal anchor unit and said distil anchor unit each comprise said fixed anchor point structurally opposite said deployable anchor face, and said anchor actuator capable of causing the deployment said deployable anchor face with up to 2000 pounds force whereby said anchor unit moves forcefully in a direction opposite the direction of deployment and contact of said anchor face with the wall of said borehole and further whereby said anchor point securely connects said anchor unit to said borehole wall; a deployable reference pin, part of the reference rod registration element, positions and aligns said first reference rod and said second reference rod thereby establishing a baseline distance from which axial displacement of rock structures in said borehole between said proximal anchor unit and said distil anchor unit are measured; said first member of said pair of pair of reference rods moves freely in relation to said second member of said pair of reference rods when said releasable axial frame is disengaged from said proximal anchor unit and from said distil anchor unit and when said deployable reference pin is also disengaged from said first member of said pair of reference rods and from said second member of said pair of reference rods; a plunger piece is attached to the upper surface of said distil anchor unit and said displacement transducer is linked to said proximal anchor unit; said plunger piece is functionally connected to said displacement transducer such that movement of said plunger piece caused by relative movement of said proximal anchor unit and said distil anchor unit is measured as movement of the rock surfaces on which said anchor units are secured by said anchor points; a temperature compensating means is connected to said proximal anchor unit and provides connection by a metal expansion element to support said displacement transducer and adjust movement to account for effects of temperature variations.