Large diameter borehole apparatus

摘要

Apparatus for positioning a detector at a plurality of depth locations within a large diameter borehole includes an elongated body member having a pair of diametrically opposed hydraulic pad displacement members mounted thereon. A pad mounting member is pivotally attached to each pad displacement member and a pair of borehole wall contacting members are pivotally attached to each pad mounting member. A signal detector is mounted behind one or more of the pad members. At each test depth a hydraulic power system deploys the pad displacement members from the body member to an extended position and extends the wall engaging pad members into contact with the borehole wall.