Abstract: A system for communicating between a first location and a second location comprises a jointed tubular string having a first section and a second section connected at a connection joint, with the tubular string having a fluid in an internal passage thereof. A first acoustic transducer is mounted in the internal passage of the first section proximate the connection joint, and a second acoustic transducer is mounted in the internal passage of the second section proximate the connection joint. A signal transmitted from the first location to the second location is transmitted across the connection joint as an acoustic signal in the fluid from the first acoustic transducer to the second acoustic transducer.

Abstract: Cross-component measurements made at a plurality of toolface angles are processed to remove bias. The amplitude of the resulting sinusoid is used to estimate a distance to an interface in an earth formation.

Abstract: An acoustic transducer on a downhole tool sends an acoustic wave through a sensor plate in contact with drilling fluid. Vibrations of the sensor plate are indicative of the impedance of the borehole plate that may be associated with gas influx. A processor analyzes the vibrations and uses an estimated Q of the vibrations to determine gas influx. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: This invention provides a measurement-while-drilling (MWD) downhole assembly for use in drilling boreholes which utilizes directional formation evaluation devices on a rotating assembly in conjunction with toolface orientation sensors. The data from the toolface orientation sensors are analyzed by a processor and toolface angle measurements are determined at defined intervals. Formation evaluation sensors operate substantially independently of the toolface orientation sensors and measurements of the formation evaluation sensors are analyzed in combination with the determined toolface angle to obtain formation parameters.

Abstract: A formation pressure testing while drilling device on a bottomhole assembly makes measurements of fluid pressure during drilling of a borehole. Based on the pressure measurements, drilling direction can be altered to maintain the wellbore in a desired relation to a fluid contact. Acoustic transmitters and/or receivers on the bottomhole assembly can provide additional information about bed boundaries, faults and gas-water contacts.

Abstract: The invention is a method and apparatus for determining an electrical property a formation surrounding a borehole with a measuring-while-drilling device. The apparatus an antenna configuration disposed along the outer face of an extendable stabilizer joined to a rotatable drill collar. Typically, two receivers and two transmitters are spaced along the longitudinal axis of the drill collar, with the two receivers spaced symmetrically in between the two transmitters. Alternatively, receivers and transmitters can be spaced along the circumference, possibly over multiple stabilizers. Multiple assemblies can be used. Data can be obtained with the transmitter-receiver assembly held in a stationary position or rotating circumferentially. Apparatus can be operated in a “broadside” configuration, an “endfire” configuration, or a configuration in which transmitter coils and receiver coils are oriented orthogonally to each other.

Abstract: A method and apparatus for obtaining a resistivity measurement of an earth formation surrounding a borehole in an MWD device uses an electrode for injecting current into the earth formation and an electrode for obtaining a responsive signal from the borehole. The electrodes are located on the drill bit arm or blade. Measured resistivity values are obtained at the location of the drill bit. Measurements can be taken in both oil-based mud and water-based mud environments. Maximum or minimum resistivity can be used to best represent the resistivity of the surrounding formation.

Abstract: A formation pressure testing while drilling device on a bottomhole assembly makes measurements of fluid pressure during drilling of a borehole. Based on the pressure measurements, drilling direction can be altered to maintain the wellbore in a desired relation to a fluid contact. Acoustic transmitters and/or receivers on the bottomhole assembly can provide additional information about bed boundaries, faults and gas-water contacts.

Abstract: This invention provides a measurement-while-drilling (MWD) downhole assembly for use in drilling boreholes which utilizes directional formation evaluation devices on a rotating assembly in conjunction with toolface orientation sensors. The data from the toolface orientation sensors are analyzed by a processor and toolface angle measurements are determined at defined intervals. Formation evaluation sensors operate substantially independently of the toolface orientation sensors and measurements of the formation evaluation sensors are analyzed in combination with the determined toolface angle to obtain formation parameters.

Abstract: A method and apparatus for obtaining a resistivity measurement of an earth formation surrounding a borehole in an MWD device uses an electrode for injecting current into the earth formation and an electrode for obtaining a responsive signal from the borehole. The electrodes are located on the drill bit arm or blade. Measured resistivity values are obtained at the location of the drill bit. Measurements can be taken in both oil-based mud and water-based mud environments. Maximum or minimum resistivity can be used to best represent the resistivity of the surrounding formation.

Abstract: A wellbore imaging tool is provided which is sensitive to magnetic permeability changes in the wellbore wall. In one embodiment, the measuring array comprises a transmitter coil, an array of receiver coils, and a signal processor. The transmitter coil generates an oscillating magnetic field in the wellbore wall, and each of the receiver coils generates a voltage indicative of a direct inductive coupling strength between the receiver coil and the transmitter coil. Variations in the magnetic permeability of the wellbore wall will cause the direct inductive coupling strength between the transmitter and receiver coils to vary accordingly. The signal processor is coupled to each of the receiver coils to determine the direct inductive coupling strength and configured to convert it into a pixel value for each of the receiver coils. The pixel value may represent the magnetic permeability of a wall region proximate to the receiver coil, or it may represent the direct inductive coupling strength.

Abstract: An azimuthally sensitive LWD tool is disclosed, comprising a transmitting antenna, a receiving antenna, wherein the receiving antenna is azimuthally focused so as to be more sensitive to changes in magnetic flux in a particular azimuthal segment of the antenna and means for measuring current induced in the receiving antenna as a result of current flowing through said transmitting antenna.

Abstract: The present disclosure is directed to a method of obtaining a different radial depth of investigation from an induction log. A typical induction log is moved along a well borehole to obtain two logs one being at a medium depth and the other being at a larger depth of investigation. By utilization of data from the two curves, the present disclosure enables determination of a log at some other depth i.e. a different radius of investigation which is between the medium and deep depths of investigation.

Abstract: In a resistivity log, a curve is obtained showing the values of resistivity where adjacent beds impact the measured resistivity. The curve as a function of well depth is first converted into a rectangularized curve so that the interfaces of the adjacent strata are located, and by a suitable number of iterations, a correction factor is applied. The corrected rectangular log is obtained with a correction coefficient computed at each depth. For each computation, the impact of all the strata within a specified depth window is considered, while strata beyond that window are simplified by representing the strata beyond the window with single equivalent bed values to reduce the number of computations required. This then provides a resistivity log which is substantially free of shoulder bed effect.

Abstract: In an MWD system, a mandrel for connection to the drill bit is set forth which supports shallow, intermediate and deep measuring resistivity systems. By transmitting upwardly and downwardly in alternate fashion, and receiving the transmitted signal at pairs of receiver coils, transmitted signal phase shift and attenuation are measured. A method of measuring is set forth which includes making resistivity measurements close to the drill bit at increasing ranges from the borehole so that formation resistivity prior to fluid invasion is obtained. Measurements are thus provided of formation resistivity before, during and after fluid invasion. The method also accommodates formations which have a relative dip angle with respect to the well borehole.

Abstract: The present system is directed to an improved dipmeter system including plural sensors on isolated pads around a sonde. An independent output is formed from each of the sensor pads, and each output is provided to its own adjustable high pass filter. The several high pass filters delete low frequency constituents in the sensor signals. Then, the signals are provided to a dipmeter computer to determine depth with greater accuracy. As a variation, the high pass filters can be selectively adjusted to provide an adjustable frequency for the filters, and one version utilizes the derivative of the dipmeter signal as a function of velocity or time.

Abstract: A logging apparatus for measurement of earth formation resistivity is disclosed. The apparatus includes an elongated sonde having an insulated section and an electrically isolated conductive pad mounted for lateral extension into contact with a borehole wall. The electrically isolated conductive pad includes a plurality of current electrodes disposed longitudinally along the pad and a return electrode disposed on the reverse face thereof. A focussing section is utilized to provide varying depths of investigation by electrode current to preferably permit measurement of earth formation resistivity in the mudcake, flush zone, and uninvaded formation. In a preferred embodiment of the present invention, the conductive pad includes a pair of hingeably mounted sections which permit the apparatus to accommodate varying radii of curvature of boreholes.

Abstract: A coil array which is installed on a MWD drill collar for use in a resistivity logging system. The drill collar is provided with upper and lower coil support rings. These are toroids which support individual coil segments, and are connected by suitable magnetic shorting bars. The coil segments and shorting bars inscribe a specified solid angle or azimuthal extent. By connecting the outputs of the several coils through a combining circuit, the coils on a single coil form can be connected in series additive, or subtractive relationship. Through the use of two such coil forms with aligned coils on each, an azimuthally oriented window is thereby defined. By proper switching multiple azimuthally oriented windows can be made operative so that there is an azimuthal orientation to the current flow pattern relative to the MWD resistivity logging tool.

Abstract: High resolution induction logs (28) are obtained through borehole casing (15) by magnetically saturating the casing (15), logging with a tool (10) having different transmitter (35a, 35b)-to-receiver (40) coil spacings, and determining the formation (30) conductivities as a function of the coil spacings, coil frequency, and phase difference between the signals at these spacings. The logging is preferably done at an intermediate frequency which gives good resolution but is little affected by the saturated casing.

Abstract: A method and apparatus are disclosed for measurement of earth formation dip utilizing sonic techniques. At least three electroacoustic devices are utilized, each having an electroacoustic transmitter and a pair of electroacoustic receivers. The electroacoustic receivers are both located on one side of the transmitter and are preferably located vertically adjacent along a line with the transmitter. Transmitted acoustic energy is detected by the receivers and the elapsed time between detection by a first receiver and detection by a second receiver is determined. A correlation of the variations in elapsed times for each of the three electroacoustic devices is then utilized to calculate the formation dip at various depths.