Western Atlas International, Inc.

Derryl G Schroeder

Jacques Maissa

Marcelo F Civarolo

A method and apparatus for acquiring a plurality of sidewall cores from an earth formation intersected by a wellbore while a coring tool is located downhole. A sidewall coring tool is provided having an internal core receptacle for receiving and storing sidewall cores in serial orientation. The coring tool incorporates a movable bit box providing rotary support and linear coring and retracting movement of a rotary coring bit. A bit box tilting and rotation actuator is incorporated within the coring tool for achieving breaking at the core sample from the formation and for selectively positioning of the bit box and rotary coring bit at a coring position where the bit is oriented in normal relation with the axis of the wellbore and a core ejecting position where the rotary coring bit is positioned in registry with the internal core receptacle for deposit of cores in serially oriented relation therein. Another actuator is provided for accomplishing lateral coring and retracting movement of the rotary coring bit for acquiring a core and for retracting the bit and core within the coring tool. A third actuator is provided within the coring tool for displacing cores from the rotary coring bit into the core receptacle after the rotary coring bit has been positioned in registry with the core receptacle. A mechanism is also provided for locking the coring bit against inadvertent extension during bit box rotation. The sidewall coring mechanism further incorporates a reduction gear transmission permitting slow speed, high torque rotation of the coring bit, which transmission is automatically disengaged when the bit box is rotated from the coring position.

Method and apparatus for acquiring and identifying multiple sidewall

A carrier apparatus for a radioactive well logging instrument is disclosed that includes an elongated generally cylindrical tool body adapted for wireline suspension within a well borehole and mounting an elongated sensor pad assembly carrying a radioactive source and at least one detector and adapted for a nesting fit with the tool body. Knuckle joint links mounted on the tool body engage opposite ends of the sensor pad for laterally extending the pad assembly from the tool body into contact with the borehole wall. The knuckle joint links provide independent preselected force loading to each end of the pad assembly and permit articulation of the pad assembly with respect to the tool body axis for maintaining the sensor pad assembly in contact with the borehole wall under rugose conditions. In addition, a pair of decentralizing arms are mounted on the tool body on the side opposite the side carrying the sensor pad assembly for contacting the borehole wall and decentering the longitudinal axis of the tool body in the borehole in the direction of extension of the sensor pad assembly. A pair of spring assemblies are disposed in the tool body and cooperate with each of the decentralizing arms for providing independent preselected force loading to each of the arms and applying a predetermined decentralizing force load to the borehole wall. The knuckle joint links, the decentralizing arms and the spring asemblies are actuated by motors mounted on the carrier and applying loading forces to the decentralizing arms.

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Houston, TX, United States of America

Derryl G Schroeder