摘要:
A disclosed embodiment (Fig. 2) utilizes one or more toroidal coil antennas (205, 215) mounted, in an insulating medium (206), on a drill collar (202) to induce currents which travel in a path that includes the drill collar (202) and earth formations around the drill collar (202). At least one array of electrodes (A1-A20) is provided on at least one stabilizer blade (220A) of the drill collar (202) and is utilized to detect currents transmitted by toroidal coil antennas (205, 215) which return via the formations to the electrodes (A1-A20) laterally; that is, approximately normal to the axis of the drill collar (202). Signal traces are obtained from measurements taken at respective ones of the transducers, and a dip characteristic of the formations is determined from the signal traces and from signals representing the rotational orientation of the drill collar (202).
摘要:
Apparatus and method are disclosed for determining the resistivity of formations surrounding an earth borehole. An electrically conductive metal body (202), such an a drill collar on a drill string, is movable through the borehole. A transmitting toroidal coil antenna (205) is disposed on the body (202) and is energized to induce a current which travels in a path that includes the body (202) and the formations. An electrode (226,227,229,235) is disposed on the body, and a first signal which depends on the electrical effect of the current on the electrode is measured to obtain an indication of the resistivity of the formations. In a form of the invention, a second transmitting toroidal coil antenna (T2) establishes a second current in the body (202) that travels in a path that includes the body (202) and the formations, and a second signal is measured at the electrode (R). A current monitor measures the axial current passing a monitor position on the body, to obtain a monitor current value. A compensated indication of formation resistivity can then be obtained as a function of the first signal, the second signal, and the monitor current value. A local communication system facilitates the ultimate communication of information to the earth's surface.
摘要:
A disclosed embodiment (Fig. 2) utilizes one or more toroidal coil antennas (205, 215) mounted, in an insulating medium (206), on a drill collar (202) to induce currents which travel in a path that includes the drill collar (202) and earth formations around the drill collar (202). At least one array of electrodes (A1-A20) is provided on at least one stabilizer blade (220A) of the drill collar (202) and is utilized to detect currents transmitted by toroidal coil antennas (205, 215) which return via the formations to the electrodes (A1-A20) laterally; that is, approximately normal to the axis of the drill collar (202). Signal traces are obtained from measurements taken at respective ones of the transducers, and a dip characteristic of the formations is determined from the signal traces and from signals representing the rotational orientation of the drill collar (202).
摘要:
Apparatus and method are disclosed for determining the resistivity of formations surrounding an earth borehole. An electrically conductive metal body (202), such an a drill collar on a drill string, is movable through the borehole. A transmitting toroidal coil antenna (205) is disposed on the body (202) and is energized to induce a current which travels in a path that includes the body (202) and the formations. An electrode (226,227,229,235) is disposed on the body, and a first signal which depends on the electrical effect of the current on the electrode is measured to obtain an indication of the resistivity of the formations. In a form of the invention, a second transmitting toroidal coil antenna (T2) establishes a second current in the body (202) that travels in a path that includes the body (202) and the formations, and a second signal is measured at the electrode (R). A current monitor measures the axial current passing a monitor position on the body, to obtain a monitor current value. A compensated indication of formation resistivity can then be obtained as a function of the first signal, the second signal, and the monitor current value. A local communication system facilitates the ultimate communication of information to the earth's surface.
摘要:
A downhole device includes a closed ring of ferromagnetic material mounted on a conductive pipe (39) and a first coil (38B) spirally wound around the closed ring comprising an electrically conductive flat metallic strip (66B) to substantially cover the closed ring.
摘要:
Devices and methods for well logging using a diamond window assembly are provided. A method according to the disclosure includes placing a downhole tool in a wellbore in a geological formation and compressing a window assembly in the downhole tool against the geological formation. The window assembly may include a polycrystalline diamond compound material fused with a monocrystalline diamond window that holds the monocrystalline diamond window in place, despite being compressed against the geological formation. First photonic radiation may be emitted through the monocrystalline diamond window onto the geological formation. Second photonic radiation may be detected through the monocrystalline diamond window. This second photonic radiation may derive from interactions between the first photonic radiation and the geological formation. As such, the second photonic radiation may carry information relating to the composition of the geological formation (e.g., the presence or absence of hydrocarbons).
摘要:
A well-logging tool includes a magnetic field logging tool and a borehole seismic array, which includes a plurality of seismic sensor devices coupled together in series. Each seismic sensor device includes a sensor housing and at least one seismic sensor carried by the sensor housing. A magnetometer is carried by the sensor housing to sense the local magnetic field. A controller cooperates with the magnetic field logging tool to generate a log of the local magnetic field relative to the true earth geographic pole. The controller cooperates with the borehole seismic array to determine an orientation of each seismic sensor device based upon the respective sensed local magnetic field and log of the local magnetic field relative to the earth geographic pole.
摘要:
A method for analyzing fluids using electron-positron annihilation is provided. In one embodiment, the method includes emitting positrons from a radioactive source of a multiphase flow meter and detecting photons generated from annihilation of electrons and the positrons. Detecting the photons can include detecting a first subset of the photons transmitted through a measurement conduit of the multiphase flow meter and detecting a second subset of the photons transmitted through a reference conduit of the multiphase flow meter. The detection of the first and second subsets of photons can then be used in determining a characteristic of a fluid within the measurement conduit. Additional systems, devices, and methods are also disclosed.