Nuclear magnetic resonance sensing device for downhole measurements
A nuclear magnetic resonance device for subterranean characterization includes a tool body, a peripheral measurement device, and a controller. The tool body includes a permanent magnet located therein, permanent magnet inducing a static magnetic field (B 0 ) in a region of interest. The peripheral measurement device is coupled to the tool body. The measurement device includes a radio frequency coil controllable to generate a radio frequency magnetic field (B 1 ) in the region of interest, receive a response signal, or both. The controller is communicatively coupled to the radio frequency coil and controllable to drive the radio frequency coil, process the response signal, or both.
1. A nuclear magnetic resonance device for subterranean characterization of a formation and a formation fluid, comprising:
a tool body;
a controller;
a measurement device coupled to and extendable from the tool body, the measurement device including a radio frequency coil that generates a radio frequency magnetic field (B 1 ) in response to a signal from the controller without a permanent magnet; and
a permanent magnet coupled to the tool body and separate from the measurement device, the permanent magnet generating a static magnetic field (B 0 ) in a magnetic field shape.
2. The device of claim 1 , wherein the permanent magnet comprises a transversal dipole magnet and the measurement device comprises a transversal dipole antenna, or the permanent magnet comprises a longitudinal magnet and the measurement device comprises a transversal dipole antenna.
3. The device of claim 1 , wherein B 0 is substantially orthogonal to B 1 in a region of interest.
4. The device of claim 1 , wherein the tool body is coupled to a wireline.
5. The device of claim 1 , wherein the radio frequency coil is controllable to receive a signal produced by nuclear spin induced by B 0 , B 1 , or both.
6. The device of claim 1 , wherein the measurement device comprises a soft magnetic material.
7. The device of claim 1 , wherein the radio frequency coil is drivable at an adjustable frequency and pulse scheme.
8. The device of claim 1 , wherein the permanent magnet is located within the tool body.
9. A nuclear magnetic resonance device for subterranean characterization of a formation and a formation fluid, comprising:
a tool body comprising a permanent magnet located therein, the permanent magnet inducing a static magnetic field (B 0 );
a peripheral measurement device coupled to the tool body, the measurement device comprising a radio frequency coil that is controllable to generate a radio frequency magnetic field (B i ) in the region of interest without a permanent magnet in the peripheral measurement device, receive a response signal, or both; and
a controller communicatively coupled to the radio frequency coil, the controller is controllable to drive the radio frequency coil, process the response signal, or both.
10. The device of claim 9 , wherein the measurement device is extendable towards the region of interest.
11. The device of claim 9 , wherein the radio frequency coil comprises a radial coil, a tangential coil, or both.
12. The device of claim 9 , wherein the radio frequency coil is controllable to deliver nuclear magnetic resonance pulses to the region of interest.
13. The device of claim 9 , wherein the measurement device comprises a soft magnetic material.
14. The device of claim 9 , wherein B 0 is substantially orthogonal to B 1 in a region of interest.
15. The device of claim 9 , wherein the radio frequency coil is located on a surface of the measurement device or embedded within the measurement device.
16. A method of characterizing a subterranean formation with nuclear magnetic resonance, comprising:
inducing a static magnetic field (B 0 ) via a permanent magnet coupled to or within a tool body of a nuclear magnetic resonance device, wherein the static field is induced within the tool body and within the subterranean formation;
generating a radio frequency magnetic field (B 1 ) via only a first radio frequency coil located in a measurement device coupled to and extendable from the tool body of the nuclear magnetic resonance device; and
receiving a nuclear magnetic resonance response signal via the radio frequency coil or a second radio frequency coil.
17. The method of claim 16 , further comprising driving the radio frequency coil at an adjustable frequency, pulse scheme, or both.
18. The method of claim 16 , further comprising moving the nuclear magnetic resonance device into a region of a well approximate to an area of interest.
19. The method of claim 16 , further comprising extending the measurement device from the nuclear magnetic resonance device towards a wellbore wall.
20. The method of claim 16 , further comprising processing the nuclear magnetic resonance response signal into well characterization data.