An ultrasonic flowmeter having a measuring tube, a control unit, at least one first ultrasonic measuring unit and a second ultrasonic measuring unit, the measuring tube having a measuring tube interior and a measuring tube longitudinal axis, wherein each of the ultrasonic measuring units is arranged on the measuring tube, wherein each ultrasonic measuring unit has a first ultrasonic transducer and a second ultrasonic transducer, the first and the second ultrasonic transducers spanning a sound measuring section with a sound axis. The sound measuring section and the sound axis penetrate the measuring tube interior for carrying out ultrasonic measurements. To provide an ultrasonic flowmeter for reliable measurement of a multi-phase medium, the sound axis of the first ultrasonic measuring unit and the sound axis of the second ultrasonic measuring unit span a sound measuring plane which extends substantially parallel to the longitudinal axis of the measuring tube.

A nuclear magnetic measuring device includes a measuring device having a control unit, a generator unit, a receiving unit, and a measuring signal path with an excitation signal path and a reaction signal path. A first switch is arranged such that, in a first state, the generator unit is connected to the excitation signal path and, in a second state, it is connected to a bypass signal path. A second switch is arranged such that, in the first state, the receiving unit is connected to the reaction signal path and, in a second state, it is connected to the bypass signal path. The control unit (i) controls the switches such that a part of the measuring signal path is bypassed, (ii) generates a test excitation signal, (iii) receives a test reaction signal, and (iv) determines an unstable property of the measuring signal path using the test excitation and reaction signals.

A nuclear magnetic measuring device includes a measuring device having a control unit, a generator unit, a receiving unit, and a measuring signal path with an excitation signal path and a reaction signal path. A first switch is arranged such that, in a first state, the generator unit is connected to the excitation signal path and, in a second state, it is connected to a bypass signal path. A second switch is arranged such that, in the first state, the receiving unit is connected to the reaction signal path and, in a second state, it is connected to the bypass signal path. The control unit (i) controls the switches such that a part of the measuring signal path is bypassed, (ii) generates a test excitation signal, (iii) receives a test reaction signal, and (iv) determines an unstable property of the measuring signal path using the test excitation and reaction signals.

A method for operating a flowmeter for determining the flow of a multiphase medium flowing through a measuring tube using a first and a second measuring device, one of which operates on a tomographic measuring principle and one of which uses a measuring principle based on nuclear magnetic resonance. The first measuring device operates in a different manner from the second measuring device, e.g., using a measuring device operating on the measuring principle of pre-magnetization contrast measurement and having a pre-magnetization section with a constant magnetic field. The magnetic field has at least one component perpendicular to the direction of flow of the multi-phase medium and is generated by using magnetic field generating elements, which are arranged around the measuring tube. Additionally, an assembly for exciting nuclear spin by a RF excitation pulse or a RF excitation pulse sequence is part of the measuring device.

A method for operating a flowmeter for determining the flow of a multiphase medium flowing through a measuring tube using a first and a second measuring device, one of which operates on a tomographic measuring principle and one of which uses a measuring principle based on nuclear magnetic resonance. The first measuring device operates in a different manner from the second measuring device, e.g., using a measuring device operating on the measuring principle of pre-magnetization contrast measurement and having a pre-magnetization section with a constant magnetic field. The magnetic field has at least one component perpendicular to the direction of flow of the multi-phase medium and is generated by using magnetic field generating elements, which are arranged around the measuring tube. Additionally, an assembly for exciting nuclear spin by a RF excitation pulse or a RF excitation pulse sequence is part of the measuring device.

Method of determining a velocity profile of a fluid flowing through a conduit, the method including applying a saturation pulse on spins of magnetic field-sensitive nuclei in the fluid, measuring a signal of the fluid to determine position of the magnetic field-sensitive nuclei, the measurement carried out at a recovery time TR and at a distance d within the conduit, determining within the conduit a radial distance r characterized by a local minimum in the measured signal, wherein the radial distance r is measured from the center of the conduit, and determining a velocity profile of the fluid at the radial distance, based on the magnetic field-sensitive nuclei.

Method of determining a velocity profile of a fluid flowing through a conduit, the method including applying a saturation pulse on spins of magnetic field-sensitive nuclei in the fluid, measuring a signal of the fluid to determine position of the magnetic field-sensitive nuclei, the measurement carried out at a recovery time TR and at a distance d within the conduit, determining within the conduit a radial distance r characterized by a local minimum in the measured signal, wherein the radial distance r is measured from the center of the conduit, and determining a velocity profile of the fluid at the radial distance, based on the magnetic field-sensitive nuclei.

Disclosed herein are a method and apparatus for measuring flow using an electromagnetic resonance phenomenon. The flowmeter includes an RF resonator in the form of a cylinder into which a transmission antenna for forming a magnetic field in a preset frequency range and a reception antenna for measuring a response signal are inserted, the RF resonator being shielded from an external magnetic field; and a processor for measuring the flow in a pipe that passes through the RF resonator based on the response signal. The RF resonator includes circular holes in the two bases of the cylinder so as to enable the pipe to pass through the RF resonator, and is formed with a first body and a second body, which are split in the height direction of the cylinder and are coupled using a coupling member so as to wrap the outer circumferential surface of the pipe.

Disclosed herein are a method and apparatus for measuring flow using an electromagnetic resonance phenomenon. The flowmeter includes an RF resonator in the form of a cylinder into which a transmission antenna for forming a magnetic field in a preset frequency range and a reception antenna for measuring a response signal are inserted, the RF resonator being shielded from an external magnetic field; and a processor for measuring the flow in a pipe that passes through the RF resonator based on the response signal. The RF resonator includes circular holes in the two bases of the cylinder so as to enable the pipe to pass through the RF resonator, and is formed with a first body and a second body, which are split in the height direction of the cylinder and are coupled using a coupling member so as to wrap the outer circumferential surface of the pipe.

A wireline or logging while drilling device includes: a first coil configured to vary the intensity of a main magnetic field so as to produce phase modulation of signals emitted by spins in a sensitive volume; and a second coil configured to excite the spins in the sensitive volume in an inverse ratio of gyromagnetic constants of the spins; and receive signals from the spins displaced in frequency from the Larmor frequency of the spins by the phase modulation produced by the first coil.