Abstract: A method for determining a property of formations surrounding an earth borehole being drilled with a drill bit at the end of a drill string, using drilling fluid that flows downward through the drill string, exits through the drill bit, and returns toward the earth's surface in the annulus between the drill string and the periphery of the borehole, including the following steps: obtaining, downhole near the drill bit, a pre-bit sample of the mud in the drill string as it approaches the drill bit; obtaining, downhole near the drill bit, a post-bit sample of the mud in the annulus, entrained with drilled earth formation, after its egression from the drill bit; implementing pre-bit measurements on the pre-bit sample; implementing post-bit measurements on the post-bit sample; and determining a property of the formations from the post-bit measurements and the pre-bit measurements.

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 technique enables sensing one or more wellbore parameters along a specific well zone. A section of instrumented coiled tubing is provided with a sensor array extending along its exterior. The sensor array is designed to sense well fluid related parameters and may comprise an optical fiber sensor. A cross-over allows the sensor array to communicate with a surface location via a control line routed along a coiled tubing interior.

Abstract: An NMR measurement apparatus is potentially subject to relative motion between the apparatus and a sample. The measurement apparatus includes at least one magnet, at least one coil and circuitry that is coupled to the magnet(s) and coil(s). The circuitry is adapted to use the magnet(s) and coil(s) to perform at least one NMR measurement and indicate the results of the NMR measurement(s). The results are then analyzed to determine an effect of the motion on the measurement(s).

Abstract: An NMR measurement apparatus is potentially subject to relative motion between the apparatus and a sample. The measurement apparatus includes at least one magnet, at least one coil and circuitry that is coupled to the magnet(s) and coil(s). The circuitry is adapted to use the magnet(s) and coil(s) to perform at least one NMR measurement and indicate the results of the NMR measurement(s). The results are then analyzed to determine an effect of the motion on the measurement(s).

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: 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: 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 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 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: 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 is directed to a nuclear magnetic resonance logging-while-drilling tool. The tool comprises a drill bit, drill string, a plurality of RF antennas, and at least one gradient coil. The tool further comprises a plurality of magnets that are polarized in a direction parallel to the longitudinal axis of the tool but opposite to each other. The configuration of magnets and antennas provides for at least two NMR regions of investigation.

Abstract: There are many natural pauses during rotary drilling operations where a portion of the drill string remains stationary. Pauses include drill pipe connections, circulating time, and fishing operations. These pauses are used to obtain formation evaluation measurements that take a long time or that benefit from a quiet environment, as opposed to the naturally noisy drilling environment. Various techniques that are sensitive to the mud flow, weight-on-bit, or motion of the drill string may be used alone or in combination to identify the drilling mode and control the data acquisition sequence.

Abstract: The present invention is directed to a method for computing a distribution of spin—spin relaxation times. The spin-echo amplitudes are obtained by hardware integration of the receiver voltages over a time window. A linear operator is utilized to map a relaxation-time distribution to spin-echoes, produce a singular value decomposition (SVD) of the linear operator, determine vectors of the SVD, and compress the spin-echo data using the vectors. To eliminate a telemetry bottleneck, the T2 spectrum is computed downhole and transmitted to the surface.