Abstract: An apparatus for logging a formation traversed by a borehole includes a tool adapted for conveyance inside the borehole, a tool bias mechanism comprising a flexible member coupled to a first side of the tool body and adapted to urge a second side of the tool body into contact with a side of the borehole, a sensing pad responsive to a property of the formation, and a pad bias mechanism independent of the tool bias mechanism coupling the sensing pad to the second side of the tool body and adapted to urge the sensing pad into contact with the side of the borehole.

Abstract: An apparatus for logging a formation traversed by a borehole includes a plurality of logging tools adapted for conveyance inside the borehole. The plurality of logging tools includes a tool body, a sensing pad responsive to a density property of the formation coupled to the tool body, a current emitting measure electrode responsive to a lateral resistivity property of the formation incorporated on the sensing pad, a mechanism for urging the sensing pad in contact with a side of the borehole coupled to the tool body, and a pair of mass isolation bands disposed about the tool body to isolate a mass of the tool body adjacent the measure electrode.

Abstract: A borehole caliper tool includes a tool body and an arm coupled to the tool body. The arm is deflectable relative to the tool body. The caliper tool further includes a cam coupled to the arm such that a position of the cam changes as the arm deflects. The caliper tool further includes a proximity sensor for sensing the position of the cam, wherein the position of the cam provides an indication of the deflection of the arm relative to the tool body.

Abstract: A borehole caliper tool includes a tool body, a bow spring flexibly coupled to the tool body, a target coupled to the bow spring, and an ultrasonic transducer coupled to the tool body, wherein in operation the ultrasonic transducer transmits an acoustic pulse to the target and receives an echo of the acoustic pulse from the target.

Abstract: A borehole caliper tool includes a tool body, a bow spring flexibly coupled to the tool body, a target coupled to the bow spring, and an ultrasonic transducer coupled to the tool body, wherein in operation the ultrasonic transducer transmits an acoustic pulse to the target and receives an echo of the acoustic pulse from the target.

Abstract: A borehole caliper tool includes a tool body and an arm coupled to the tool body. The arm is deflectable relative to the tool body. The caliper tool further includes a cam coupled to the arm such that a position of the cam changes as the arm deflects. The caliper tool further includes a proximity sensor for sensing the position of the cam, wherein the position of the cam provides an indication of the deflection of the arm relative to the tool body.

Abstract: A combined resistivity tool incorporating both induction/propagation antennas and lateral resistivity antennas disposed in recesses of downhole tubulars, in which a lateral resistivity antenna includes an insulating base layer disposed in the recess; a toroidal antenna disposed over the insulating base layer; and a shield disposed over the recess.

Abstract: A method is disclosed for compressing a frame of data representing parameter values, a time at which each parameter value was recorded, and an orientation of a sensor at the time each parameter value was recorded. Generally the method includes performing a two-dimensional transform on the data in the orientation domain and in a domain related to the recording time. In one embodiment, the method includes calculating a logarithm of each parameter value. In one embodiment, the 2-D transform includes generating a Fourier transform of the logarithm of the parameter values in the azimuthal domain, generating a discrete cosine transform of the transform coefficients in the time domain. This embodiment includes quantizing the coefficients of the Fourier transform and the discrete cosine transform. One embodiment of the method is adapted to transmit resistivity measurements made by an LWD instrument in pressure modulation telemetry so that while-drilling images of a wellbore can be generated.

Abstract: The present invention describes a method and apparatus to control the effect of contact impedance on a formation resistivity measurement during a logging-while-drilling operation. The control of contact impedance is accomplished by maintaining a substantially zero difference in potential between two monitor electrodes positioned on the resistivity logging tool near a current electrode. The tool can employ a ring electrode configuration and/or a button electrode, configuration. The ring electrode configuration incorporates two pairs of ring monitor electrodes on each side of a ring current electrode. The button electrode configuration incorporates. a monitor electrode, surrounded by a current electrode, surrounded by a second monitor electrode. Insulation gaps are positioned between each electrode to separate the electrodes. A variable current is supplied to the current electrode in each configuration to maintain the same potential at each monitor electrode.

Abstract: A method of removing excess MCrAlY overlay coating from within a cooling hole of an aluminide coated gas turbine engine component is disclosed. The method includes providing a gas turbine engine component having an internal surface (4), an outer surface (6) and a root end (8). The component also includes at least one cooling hole (10) extending from the internal surface (4) to the outer surface (6), wherein the internal surface(4) of the component is coated with a corrosion resistant aluminide coating. An MCrAlY overlay coating (12) is also located on the outer surface (6) and inside a portion of the cooling hole (10).

Abstract: Method and apparatus for fishing for and/or communicating with subsurface apparatus. In a preferred embodiment, a subsurface logging-while-drilling (LWD) or measuring-while-drilling (MWD) apparatus is placed in tandem with a drill string near the bottom of a borehole. The LWD apparatus includes a surface retrievable component such as a nuclear source carrier with a fishing head facing upwardly. The carrier is releasably secured within the LWD apparatus with means such as a shear pin. A wireline conveyed tool having a downwardly facing latching mechanism includes a downhole powered latch for telescopically extending beyond the fishing head, forcing a latching lug radially inwardly below the fishing head, and moving axially upward to latch the fishing head. Further upward latch movement causes the fishing head to move upwardly until the shear pin shears which releases the carrier from the subsurface apparatus. The wireline tool with the attached carrier is then brought to surface with the wireline cable.