Abstract: A magnetic susceptibility and conductivity tool (10) which incorporates a transmitter coil (4) energized with a time-varying current from a transmitter coil drive (13). The transmitter coil drive receives a clock signal and induces a data signal (99) including a primary mutual coupling signal and a formation coupling signal. A receiver coil (1) outputs a receiver coil voltage induced by the data signal. A transmitter coil current sense circuit (15) receives current from the transmitter coil and outputs a digital coil current voltage signal. A synthetic null circuit (14) receives the digital current voltage signal and multiplies the digital current voltage signal with a predetermined constant (28) for amplitude of a base primary mutual coupling signal and shifts phase with a predetermined phase offset (27) to output a synthetic null signal (104).

Abstract: A magnetic susceptibility and conductivity tool (10) which incorporates a transmitter coil (4) energized with a time-varying current from a transmitter coil drive (13). The transmitter coil drive receives a clock signal and induces a data signal (99) including a primary mutual coupling signal and a formation coupling signal. A receiver coil (1) outputs a receiver coil voltage induced by the data signal. A transmitter coil current sense circuit (15) receives current from the transmitter coil and outputs a digital coil current voltage signal. A synthetic null circuit (14) receives the digital current voltage signal and multiplies the digital current voltage signal with a predetermined constant (28) for amplitude of a base primary mutual coupling signal and shifts phase with a predetermined phase offset (27) to output a synthetic null signal (104).

Abstract: An inner core barrel assembly incorporates an inner core tube. A body is connected to the inner core tube with a coupling mechanism. The coupling mechanism is configured to maintain a fixed rotational orientation with the inner core tube. The body includes a flow path for liquid within the inner core tube to flow as the inner core barrel assembly descends through a drill string. a core orientation system is contained within the body and positioned within the inner core tube.

Abstract: An inner core barrel assembly incorporates an inner core tube. A body is connected to the inner core tube with a coupling mechanism. The coupling mechanism is configured to maintain a fixed rotational orientation with the inner core tube. The body includes a flow path for liquid within the inner core tube to flow as the inner core barrel assembly descends through a drill string. a core orientation system is contained within the body and positioned within the inner core tube.

Abstract: An inner core barrel assembly incorporates an inner core tube. A body is connected to the inner core tube with a coupling mechanism. The coupling mechanism is configured to maintain a fixed rotational orientation with the inner core tube. The body includes a flow path for liquid within the inner core tube to flow as the inner core barrel assembly descends through a drill string. a core orientation system is contained within the body and positioned within the inner core tube.

Abstract: A check valve may be incorporated in an inner core barrel assembly. The check valve has a valve body defining a fluid flow path and provided with a valve seat. A valve member is located in the valve body and is coupled to the valve body by a coupling mechanism. The coupling mechanism is arranged to allow the valve member to move linearly in an axial direction relative to the valve body on to and off of the valve seat and maintain a fixed rotational relationship with the valve body. A data acquisition system can be held in the valve member and by virtue of the coupling mechanism be maintained rotationally fixed relative to the valve body an inner core tube of an inner core barrel assembly.

Abstract: A check valve may be incorporated in an inner core barrel assembly. The check valve has a valve body defining a fluid flow path and provided with a valve seat. A valve member is located in the valve body and is coupled to the valve body by a coupling mechanism. The coupling mechanism is arranged to allow the valve member to move linearly in an axial direction relative to the valve body on to and off of the valve seat and maintain a fixed rotational relationship with the valve body. A data acquisition system can be held in the valve member and by virtue of the coupling mechanism be maintained rotationally fixed relative to the valve body an inner core tube of an inner core barrel assembly.