Abstract: Methods and apparatus are disclosed for minimizing or eliminating an undesired axial electric current induced along a subsurface borehole in the process of subsurface measurements with transmitter and/or receiver antennas which are substantially time varying magnetic dipoles with their dipole moments aligned at an angle to the axis of the borehole. Some antennas are disposed within the borehole on instruments having a non-conductive support member. One instrument includes a conductive all-metal body with an antenna adapted for induction frequencies. Antenna shields adapted for controlled current flow are also provided with an all-metal instrument. Methods include providing an alternate path for the current along the instrument body. Another method includes emitting a controlled current to counter the undesired current. Another method corrects for the effect of the current using a superposition technique.

Abstract: Systems and methods for downhole communication and measurement utilizing an improved metallic tubular having an elongated body with tubular walls and a central bore adapted to receive a run-in tool. The tubular including slotted stations to provide through-tubular signal transmission and/or reception. Hydraulic isolation between the interior and exterior of the tubular is provided by pressure barrier means at the slotted stations. Sensors and/or sources are mounted on the run-in tool, which is adapted for transmission through a drill string to engage within the tubular in alignment with the slotted stations. A run-in tool configuration includes a modulator for real-time wireless communication with the surface and/or remote downhole tools. A tubular and run-in tool configuration also includes inductive couplers for wireless signal data transfer. A method for measuring a formation characteristic utilizing a run-in tool adapted with an interchangeable end segment for multi-mode downhole transport.

Abstract: Systems and methods for downhole communication and measurement utilizing an improved metallic tubular having an elongated body with tubular walls and a central bore adapted to receive a run-in tool. The tubular including slotted stations to provide through-tubular signal transmission and/or reception. Hydraulic isolation between the interior and exterior of the tubular is provided by pressure barrier means at the slotted stations. Sensors and/or sources are mounted on the run-in tool, which is adapted for transmission through a drill string to engage within the tubular in alignment with the slotted stations. A run-in tool configuration includes a modulator for real-time wireless communication with the surface and/or remote downhole tools. A tubular and run-in tool configuration also includes inductive couplers for wireless signal data transfer. A method for measuring a formation characteristic utilizing a run-in tool adapted with an interchangeable end segment for multi-mode downhole transport.

Abstract: Systems and methods for downhole communication and measurement utilizing an improved metallic tubular having an elongated body with tubular walls and a central bore adapted to receive a run-in tool. The tubular including slotted stations to provide through-tubular signal transmission and/or reception. Hydraulic isolation between the interior and exterior of the tubular is provided by pressure barrier means at the slotted stations. Sensors and/or sources are mounted on the run-in tool, which is adapted for transmission through a drill string to engage within the tubular in alignment with the slotted stations. A run-in tool configuration includes a modulator for real-time wireless communication with the surface and/or remote downhole tools. A tubular and run-in tool configuration also includes inductive couplers for wireless signal data transfer. A method for measuring a formation characteristic utilizing a run-in tool adapted with an interchangeable end segment for multi-mode downhole transport.

Abstract: Systems and methods for downhole communication and measurement utilizing an improved metallic tubular having an elongated body with tubular walls and a central bore adapted to receive a run-in tool. The tubular including slotted stations to provide through-tubular signal transmission and/or reception. Hydraulic isolation between the interior and exterior of the tubular is provided by pressure barrier means at the slotted stations. Sensors and/or sources are mounted on the run-in tool, which is adapted for transmission through a drill string to engage within the tubular in alignment with the slotted stations. A run-in tool configuration includes a modulator for real-time wireless communication with the surface and/or remote downhole tools. A tubular and run-in tool configuration also includes inductive couplers for wireless signal data transfer. A method for measuring a formation characteristic utilizing a run-in tool adapted with an interchangeable end segment for multi-mode downhole transport.

Abstract: Methods and apparatus are disclosed for minimizing or eliminating an undesired axial electric current induced along a subsurface borehole in the process of subsurface measurements with transmitter and/or receiver antennas which are substantially time varying magnetic dipoles with their dipole moments aligned at an angle to the axis of the borehole. Some antennas are disposed within the borehole on instruments having a non-conductive support member. One instrument includes a conductive all-metal body with an antenna adapted for induction frequencies. Antenna shields adapted for controlled current flow are also provided with an all-metal instrument. Methods include providing an alternate path for the current along the instrument body. Another method includes emitting a controlled current to counter the undesired current. Another method corrects for the effect of the current using a superposition technique.

Abstract: Methods and apparatus are disclosed for minimizing or eliminating an undesired axial electric current induced along a subsurface borehole in the process of subsurface measurements with transmitter and/or receiver antennas which are substantially time varying magnetic dipoles with their dipole moments aligned at an angle to the axis of the borehole. Some antennas are disposed within the borehole on instruments having a non-conductive support member. One instrument includes a conductive all-metal body with an antenna adapted for induction frequencies. Antenna shields adapted for controlled current flow are also provided with an all-metal instrument. Methods include providing an alternate path for the current along the instrument body. Another method includes emitting a controlled current to counter the undesired current. Another method corrects for the effect of the current using a superposition technique.