Abstract: A perforating gun assembly that includes at least one component that is constructed from a composite material and that is impermeable to wellbore fluids. The components may include the outer carrier and/or loading tube of a perforating gun, the connecting tubing of a gun release mechanism, and the gun connector used to attach adjacent perforating guns. The composite material is designed to be very brittle under dynamic impact. The component is made impermeable to wellbore fluids by including an impermeable liner therein. The impermeable liner can be bonded to the inner or outer surface of the component or can be embedded within the component. Since it is brittle under dynamic impact, the composite component shatters into small pieces upon detonation of the perforating gun.

Abstract: An assembly for formation and completion of deviated wellbores is disclosed which includes a toolguide and a casing section which can be used together or separately. The toolguide includes a lower orienting section and a whipstock having a sloping face, commonly known as the directional portion of a whipstock. The toolguide is coated with a material such as epoxy or polyurethane to provide a repairable surface and one which can be removed to facilitate removal of the toolguide from the well bore. The lower orienting section has a latch which extends radially outwardly from the section and can be locked in the outwardly biased position.

Abstract: A seismic acquisition system includes one or more perforating shaped charge modules activable to generate seismic signals into an earth sub-surface. The seismic signals are created by perforating jets formed by the perforating shaped charge modules when activated. The perforating jets produce directional seismic signals that reduce the amount of lateral noise. One or more detectors are employed to receive signals reflected from the earth sub-surface in response to the seismic signals.

Abstract: An assembly for formation and completion of deviated wellbores is disclosed which includes a toolguide and a casing section which can be used together or separately. The toolguide includes a lower orienting section and a whipstock having a sloping face, commonly known as the directional portion of a whipstock. The toolguide is coated with a material such as epoxy or polyurethane to provide a repairable surface and one which can be removed to facilitate removal of the toolguide from the well bore. The lower orienting section has a latch which extends radially outwardly from the section and can be locked in the outwardly biased position.

Abstract: An orienter, particularly on coiled tubing or small diameter drill pipe, includes a motor, turbine, or other device for selectively converting the rotational kinetic energy produced from fluid flow through the device to mechanical power, and applying the mechanical power to a downhole tool through a gear train for orienting the downhole tool. The orienter is utilized during directional drilling and other operations such as well intervention, fishing, and multilateral re-entry operations. The downhole tool preferably includes a steerable mud motor. In one embodiment, the direction of the borehole is controlled by azimuthal rotation of the orienter of the present invention in response to downlink commands from the surface by changing fluid flow rate through the orienter in a predefined series of steps.

Abstract: An assembly for formation and completion of deviated wellbores is disclosed which includes a toolguide and a casing section which can be used together or separately. The toolguide includes a lower orienting section and a whipstock having a sloping face, commonly known as the directional portion of a whipstock. The toolguide is coated with a material such as epoxy or polyurethane to provide a repairable surface and one which can be removed to facilitate removal of the toolguide from the well bore. The lower orienting section has a latch which extends radially outwardly from the section and can be locked in the outwardly biased position.

Abstract: A method is disclosed for determining a diameter of a wellbore. The method includes inducing an electromagnetic field in the wellbore and a formation surrounding the wellbore from a first location along the wellbore. At a first time, a phase is measured, with respect to the field at the first location, of a signal induced by the electromagnetic field at a second and at a third location axially spaced apart from the first location and from each other. The measuring is repeated at a second time, and a resistivity of the formation, and the wellbore diameter at the first time and at the second time are determined from the measurements of phase made at the first and at the second times. Any ambiguity in the resistivity is resolved by using resistivity determined from the measurements made at the first time.

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: An NMR logging tool includes at least one antenna and a pulse sequencer. The pulse sequencer is coupled to said at least one antenna and is adapted to receive state descriptors that are indicative of states of an NMR measurement sequence. The pulse sequencer uses the antenna(e) to perform the NMR measurement sequence downhole in a subterranean formation in response to the state descriptors.

Abstract: The present invention is directed to a nuclear magnetic resonance apparatus and method for generating an axisymmetric magnetic field having long, straight contour lines in the resonance region. A magnetically permeable member is used to shape the static magnetic field generated by an array of permanent magnets. The magnetically permeable member minimizes variations of the static magnetic field in the formation due to vertical motion of the apparatus while obtaining a nuclear magnetic resonance measurement. Further, the magnetically permeable member may minimize variations of the static magnetic field in the formation due to lateral motion of the apparatus while obtaining a nuclear magnetic resonance measurement.

Abstract: A down-hole tool includes a first and second portion that are moveable relative to one another, but are electrically coupled together. A rigid tube formed into a helical coil extends between the first and second portions. The helical coil is expandable and compressible in response to movement between the first and second portions. A conductor is positioned within the helically wound tube and is adapted to pass electrical signals between the first and second portions.

Abstract: The present invention is directed to a nuclear magnetic resonance apparatus and method for generating an axisymmetric magnetic field having long, straight contour lines in the resonance region. A magnetically permeable member is used to shape the static magnetic field generated by an array of permanent magnets. The magnetically permeable member minimizes variations of the static magnetic field in the formation due to vertical motion of the apparatus while obtaining a nuclear magnetic resonance measurement. Further, the magnetically permeable member may minimize variations of the static magnetic field in the formation due to lateral motion of the apparatus while obtaining a nuclear magnetic resonance measurement.

Abstract: A hydrostatic transmission system for driving a rotatable member includes a differential having an output coupled with the rotatable member, a first hydrostatic drive having an output coupled to a first input of the differential, and a second hydrostatic drive having an output coupled to a second input of the differential. The output of the first hydrostatic drive is rotatable in a first selected direction and at a first selected speed. The output of the second hydrostatic drive is rotatable in a second selected direction and at a second selected speed. A rotational speed and direction of the output of the differential is related to the algebraic sum of the rotational speeds and directions of the outputs of the hydrostatic drives. In one embodiment, the speeds of the first and second drives are maintained above a minimum stable threshold, while operating the rotatable drive at very low or zero speed, by selecting the first direction to be opposite the second direction.

Abstract: The present invention relates generally to an apparatus and method for obtaining an azimuthally resolved nuclear magnetic resonance measurement of an earth formation traversed by a borehole. The measurement can be made while drilling or using a wireline tool. A receiving rf antenna having a non-axisymmetric response pattern is used to obtain the azimuthally resolved nuclear magnetic resonance measurement. The antenna employs axial currents which excite an azimuthally oriented rf magnetic field. For this situation, the static magnetic field is either radial or axial in its orientation. The antenna generates a relatively long, in axial extent, region of generally uniform static field magnitude and polarization in the formation. The present invention facilitates low profile antenna configurations that can permit dispensing with the reduction of the inner diameter of the drill collar at the rf antenna location.

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 and apparatus for implementing a communication network for well monitoring and control applications where a twisted pair cable bus is used to connect well-related locations. The twisted pair cable bus will exhibit high parallel impedance when used in differential mode and low series impedance in common mode. A bus supervisor and devices connected at nodes can exchange signal transmission. Communication, including data and control, signals and power signals can circulate along the twisted pair cable bus among and between the connected devices.

Abstract: The present invention relates generally to an apparatus and method for obtaining an azimuthally resolved nuclear magnetic resonance measurement of an earth formation traversed by a borehole. The measurement can be made while drilling or using a wireline tool. A receiving rf antenna having a non-axisymmetric response pattern is used to obtain the azimuthally resolved nuclear magnetic resonance measurement. The antenna employs axial currents which excite an azimuthally oriented rf magnetic field. For this situation, the static magnetic field is either radial or axial in its orientation. The antenna generates a relatively long, in axial extent, region of generally uniform static field magnitude and polarization in the formation. The present invention facilitates low profile antenna configurations that can permit dispensing with the reduction of the inner diameter of the drill collar at the rf antenna location.

Abstract: An oil storage vessel (10) comprises a hull (12) of generally tubular form having a double wall defining one or more ballast chambers (14). The orientation of the hull (12) relative to water in which it is floated is controllable by adjusting the content of some or all of the ballast chambers (14). Thus, by suitable manipulation of the ballast chambers (14) the barge (10) may be caused to float generally horizontally, that is, with its longitudinal axis parallel to the surface of the water. In this position, it is particularly useful for transportation of the hull contents. Alternatively, the hull (12) may, be manipulation of the ballast chambers (14) be arranged with its longitudinal axis perpendicular to the surface of the water so that it can be used for collection and storage of liquids such as oil.

Abstract: A capacitive device for measuring the dielectric constant of a two-phase fluid flowing along a pipe, this device comprising two electrodes and power supply system for applying an AC voltage across the two electrodes. A first one of these electrodes forms an excitation electrode disposed at the periphery of a measurement electrode, and the device further comprises apparatus for maintaining the electrodes at the same potential and for measuring the current (i) flowing between the excitation electrode and the measurement electrode, and apparatus for deducing the dielectric constant from the measured current. Application to measuring flow rates of water in hydrocarbon wells, in particular in hydrocarbon wells that slope.

Abstract: A method and apparatus for unplugging a well or pipe obstructed by a gas hydrates. According to the invention, a moving heating element is applied against one end of the hydrate plug, and is displaced axially in the tube or the pipe towards the other end, so as to cause the plug to melt progressively from one end to the other. Application to the oil industry, in particular in off-shore wells.