Mobil Oil Corporation

Robin B Montgomery

Eve S Sprunt

Duane C Uhri

David P Yale

A method and apparatus to determine in-situ 'creep' displacement in a cored or drilled borehole. A borehole creep displacement (BCD) tool is suspended into the borehole via a wireline logging cable. Gaging piston fluid forces gaging pistons in a mechanical/electrical assembly of said tool to extend and contact the borehole wall which causes gaging pressure to build. Upon reaching a predetermined pressure, excess fluid flows into a micro-motion fluid distribution body and into an actuator assembly causing an accumulator linear variable displacement transformer (ALVDT) to move thereby causing electrical signals to be transmitted to surface equipment. Once the LVDT has been displaced fully, a closed fluid system within the gaging pistons and a micro-motion assembly is created. Thereafter, any movement of the gaging pistons by the borehole wall will cause fluid motion of a micro-motion cylinder which is attached to a micro-motion LVDT. Movement of the micro-motion LVDT can be read as displacement in thousandths of an inch or as a direct mechanical gain for estimating electrical values.

Borehole 'creep' displacement tool

A sample of material is rotated within a pair of parallel, spaced-apart laser beams. Variations in the diameter of the sample are determined with azimuth from the amounts of the laser beams intercepted by the sample as it rotates about an axis perpendicular to the plane of the laser beams. The sample is translated along this axis within the path of the laser beams so that the diameter of the sample is determined for a plurality of spaced-apart planes through the sample perpendicular to the axis of rotation. The deformation of the material with stress is determined by measuring the variations in diameter of the sample as the stress on the sample is changed.

Growing community of inventors

Mesquite, TX, United States of America

Robin B Montgomery