1. An apparatus for evaluating an earth formation comprising:
(a) a bottomhole assembly (BHA) conveyed in a borehole in the earth formation, the BHA having a longitudinal axis; and
(b) at least one sensor assembly carried by the BHA, the at least one sensor assembly including
(A) a U-shaped magnet which provides a static magnetic field in a sensitive region in said formation, and
(B) an antenna arrangement which produces a pulsed radio frequency (RF) magnetic field in the sensitive region and receives signals from nuclei in the sensitive region.
2. The apparatus of claim 1 wherein the antenna arrangement further comprises:
(i) a transmitter coil which produces the RF field and,
(ii) a receiver coil having an axis substantially parallel to an axis of the transmitter which receives the signals
3. The apparatus of claim 1 wherein the at least one sensor assembly further comprises a plurality of sensor assemblies circumferentially distributed about the BHA.
4. The apparatus of claim 1 wherein the U-shaped magnet further comprises:
(i) a first magnet and a second magnet having a magnetization direction perpendicular to the longitudinal axis of the BHA, the first and second magnets comprising arms of the U, the first and second magnets having opposite directions of magnetization, and
(ii) a magnetically permeable yoke forming the base of the U.
5. The apparatus of claim 1 wherein said RF magnetic field is produced by activating the antenna arrangement with one of (i) a CPMG sequence, and, (ii) a modified CPMG sequence having a refocusing angle less than 180\xb0.
6. The apparatus of claim 2 wherein the at least one receiver coil is displaced towards a wall of the borehole from the transmitter coil
7. The apparatus of claim 5 wherein a gap between ends of the first and second magnet away from the yoke is adjustable.
8. The apparatus of claim 1 further comprising a processor which determines from the received signals a parameter of interest of the earth formation.
9. The apparatus of claim 8 wherein the parameter of interest is at least one of (i) clay bound water, and, (ii) bulk volume irreducible.
10. The apparatus of claim 1 wherein the at least one sensor assembly is disposed on a substantially non-rotating sleeve.
11. The apparatus of claim 1 wherein the BHA is conveyed into the borehole on a drilling tubular.
12. An apparatus for evaluating an earth formation, the apparatus comprising:
(a) a bottomhole assembly (BHA) conveyed in a borehole in the earth formation, the BHA having a longitudinal axis; and
(b) a sensor assembly carried by the BHA, the sensor assembly including
(A) a magnet configuration which provides a static magnetic field in a sensitive region in the formation,
(B) a transmitter coil having an axis parallel to the longitudinal axis which produces a pulsed radio frequency (RF) magnetic field in the sensitive region, and
(C) at least one receiver coil which receives signals from nuclei in the sensitive region, the at least one receiver coil having an axis substantially orthogonal to an axis of the transmitter coil.
13. The apparatus of claim 12 wherein the at least one receiver coil comprises a plurality of receiver coils disposed about the BHA.
14. The apparatus of claim 12 wherein the at least one receiver coil is extendable away from a drill collar.
15. The apparatus of claim 12 wherein said RF magnetic field is produced by activating the transmitter coil with one of (i) a CPMG sequence, and, (ii) a modified CPMG sequence having a refocusing angle less than 180\xb0.
16. The apparatus of claim 12 further comprising a processor which determines from the received signals a parameter of interest of the earth formation.
17. The apparatus of claim 12 wherein the parameter of interest is at least one of (i) clay bound water, and, (ii) bulk volume irreducible.
18. A method of evaluating an earth formation comprising:
(a) conveying a bottomhole assembly (BHA) conveyed in a borehole in the earth formation, the BHA having a longitudinal axis; and
(b) using a U-shaped magnet forming part of at least one sensor assembly carried by the BHA and producing a static magnetic field in a sensitive region in said formation, the static magnetic field in the sensitive region having an azimuthal direction,
(c) producing a pulsed radio frequency (RF) magnetic field in the sensitive region, the RF field having a radial direction in the sensitive region, and
(d) receiving signals from nuclei in the sensitive region,
19. The method of claim 18 wherein the at least one sensor assembly further comprises a plurality of sensor assemblies circumferentially distributed about the BHA.
20. The method of claim 18 further comprising identifying a cross-bedding in the earth formation from analysis of the signals from the plurality of sensor assemblies.
21. The method of claim 18 wherein producing said RF field further comprises using one of (i) a CPMG sequence, and, (ii) a modified CPMG sequence having a refocusing angle less than 180\xb0.
22. The method of claim 18 further comprising determining from the signals from the receiver coil a parameter of interest of the earth formation.
23. The method of claim 22 wherein the parameter of interest is at least one of (i) clay bound water, and, (ii) bulk volume irreducible.
24. A method of evaluating an earth formation, the method comprising:
(a) conveying a bottomhole assembly (BHA) conveyed in a borehole in the earth formation, the BHA having a longitudinal axis; and
(b) using a magnet configuration and producing a static magnetic field in a sensitive region in the formation, the static magnetic field having a radial direction in the sensitive region,
(c) producing a pulsed radio frequency (RF) magnetic field in the sensitive region, and
(d) receiving signals from nuclei in the sensitive region using at least one receiver coil having an axis substantially orthogonal to the longitudinal axis.
25. The method of claim 24 wherein the at least one receiver coil comprises a plurality of receiver coils disposed about the BHA, the method further comprising receiving signals using each of the plurality of receiver coils.
26. The method of claim 25 further comprising identifying a cross-bedding in the earth formation from analysis of the signals received by the plurality of receiver coils.
27. The method of claim 24 further comprising mounting the at least one receiver coil on a member extendable from a drill collar.
28. The method of claim 24 wherein producing the RF magnetic field by using one of (i) a CPMG sequence, and, (ii) a modified CPMG sequence having a refocusing angle less than 180\xb0.
29. The method of claim 24 further comprising determining from the signals from the at least one receiver coil a parameter of interest of the earth formation.
30. The method of claim 29 wherein the parameter of interest is at least one of (i) clay bound water, and, (ii) bulk volume irreducible.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. Control device for supplying an electric motor with IMS technology or the like, characterised in that it provides:
a two-phase or three-phase inverter, on at least two phases a metal path being provided obtained in IMS technology on the inverter power circuit and each one in series with a motor phase;
a thermal sensor for at least one of said paths preferably but not necessarily placed on the metal path itself to perform the measure of its temperature that will also be used for measuring the power transistors temperature.
2. Control device for supplying an electric motor with IMS technology or the like, characterised in that it provides:
a DC controller equipped with a metal path obtained in IMS technology on the controller card and in series with the motor armature;
a thermal sensor preferably but not necessarily placed on the metal path to perform the measure of its temperature that will also be used for measuring the power transistors temperature.
3. Control device for supplying any electric motor realised in IMS technology or the like, characterised in that it provides:
an integrated power module equipped with at least one metal path in series with the power devices or with an external connection terminal;
a thermal sensor preferably but not necessarily placed on the metal path to perform the measure of its temperature that will also be used for measuring the power transistors temperature.
4. Process for measuring the phase currents of an inverter or a DC controller for supplying electric motors characterised in that it provides for measuring the temperature of at least one metal path realised in IMS technology (or the like) as elongation of a connection path between power or adduction devices towards outside and for compensating the voltage drop due to thermal drift of metal path resistivity through software computation and then having the exact phase current measure.
5. Process according to claim 4 characterised in that it provides for measuring the output current of a power module (Power Semiconductor Module) by measuring the temperature of a metal path realised in IMS or DBC technology or the like as elongation of a connection path between power or adduction devices towards outside and for compensating the voltage drop due to thermal drift of metal path resistivity through software computation and then having the exact phase current measure.