CN108538535B - Eccentric nuclear magnetic resonance logging instrument and nuclear magnetic resonance permanent magnet thereof - Google Patents
Eccentric nuclear magnetic resonance logging instrument and nuclear magnetic resonance permanent magnet thereof Download PDFInfo
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- CN108538535B CN108538535B CN201810182614.4A CN201810182614A CN108538535B CN 108538535 B CN108538535 B CN 108538535B CN 201810182614 A CN201810182614 A CN 201810182614A CN 108538535 B CN108538535 B CN 108538535B
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- 238000005481 NMR spectroscopy Methods 0.000 title claims abstract description 57
- 229910052751 metal Inorganic materials 0.000 claims abstract description 11
- 239000002184 metal Substances 0.000 claims abstract description 11
- 229910052755 nonmetal Inorganic materials 0.000 claims abstract description 10
- 239000007769 metal material Substances 0.000 claims abstract description 9
- 230000004323 axial length Effects 0.000 claims description 10
- KPLQYGBQNPPQGA-UHFFFAOYSA-N cobalt samarium Chemical compound [Co].[Sm] KPLQYGBQNPPQGA-UHFFFAOYSA-N 0.000 claims description 8
- 229910000938 samarium–cobalt magnet Inorganic materials 0.000 claims description 8
- 238000009434 installation Methods 0.000 claims description 4
- 238000009826 distribution Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 6
- 238000005520 cutting process Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000005253 cladding Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000008093 supporting effect Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000002633 protecting effect Effects 0.000 description 1
- 230000011218 segmentation Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
- H01F7/02—Permanent magnets [PM]
- H01F7/0273—Magnetic circuits with PM for magnetic field generation
- H01F7/0278—Magnetic circuits with PM for magnetic field generation for generating uniform fields, focusing, deflecting electrically charged particles
- H01F7/0284—Magnetic circuits with PM for magnetic field generation for generating uniform fields, focusing, deflecting electrically charged particles using a trimmable or adjustable magnetic circuit, e.g. for a symmetric dipole or quadrupole magnetic field
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
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- Engineering & Computer Science (AREA)
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- Mining & Mineral Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geophysics (AREA)
- Electromagnetism (AREA)
- Power Engineering (AREA)
- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
The embodiment of the application provides an eccentric nuclear magnetic resonance logging instrument and a nuclear magnetic resonance permanent magnet thereof, wherein the eccentric nuclear magnetic resonance permanent magnet comprises a main permanent magnet made of a non-metal material; two ends of the main permanent magnet are respectively and symmetrically provided with an auxiliary permanent magnet made of metal; the main permanent magnet and the auxiliary permanent magnet are coaxial and separated from each other by a specified distance; the magnetic field direction of the main permanent magnet is perpendicular to the axial direction of the main permanent magnet and points to a specific direction; in the particular direction, the secondary permanent magnet has a magnetic field direction that coincides with the primary permanent magnet. The embodiment of the application can reduce or not increase the size of the nuclear magnetic resonance permanent magnet while obtaining the axial uniform magnetic field meeting the requirement of the preset length.
Description
Technical Field
The application relates to the technical field of nuclear magnetic resonance logging equipment, in particular to an eccentric nuclear magnetic resonance logging instrument and a nuclear magnetic resonance permanent magnet thereof.
Background
The nuclear magnetic resonance permanent magnet is a key part on the nuclear magnetic resonance logging instrument. When nuclear magnetic resonance logging is carried out, the nuclear magnetic resonance permanent magnet can generate a gradient magnetic field in the stratum to polarize hydrogen atoms in the stratum in the transverse direction, so that the hydrogen atoms in the stratum can be polarized in different magnetic field strengths on different radial depths, and the purpose of measuring petroleum physical information of the stratum in different depths is achieved.
In the process of implementing the present application, the inventors of the present application have studied and found that: the existing nuclear magnetic resonance permanent magnet is mostly made of nonmetal materials, and the magnetic field intensity of the permanent magnet made of nonmetal materials is relatively weak, so that the nuclear magnetic resonance permanent magnet can reach an axial uniform magnetic field meeting the preset length requirement, the size of the nuclear magnetic resonance permanent magnet needs to be increased generally, and the volume of the nuclear magnetic resonance logging instrument is increased.
Disclosure of Invention
An object of the embodiment of the application is to provide an eccentric nuclear magnetic resonance logging instrument and a nuclear magnetic resonance permanent magnet thereof, so that the size of the nuclear magnetic resonance permanent magnet is reduced or not increased while an axial uniform magnetic field meeting the preset length requirement is obtained.
In order to achieve the above object, in one aspect, an embodiment of the present application provides an eccentric nmr permanent magnet, including a main permanent magnet made of a non-metallic material; two ends of the main permanent magnet are respectively and symmetrically provided with an auxiliary permanent magnet made of metal; the main permanent magnet and the auxiliary permanent magnet are coaxial and separated from each other by a specified distance; the magnetic field direction of the main permanent magnet is perpendicular to the axial direction of the main permanent magnet and points to a specific direction; in the particular direction, the secondary permanent magnet has a magnetic field direction that coincides with the primary permanent magnet.
In the eccentric nuclear magnetic resonance permanent magnet of the embodiment of this application, main permanent magnet has first top surface and first bottom surface of going up, first top surface of going up is the N utmost point just first bottom surface of going down is the S utmost point, the middle part of first top surface of going up forms the transmitting antenna mounted position of nuclear magnetic resonance logging instrument, the radial dimension of first bottom surface of going down is greater than the radial dimension of first top surface of going up.
In the eccentric type nuclear magnetic resonance permanent magnet of this application embodiment, main permanent magnet includes integrated into one piece's upper part and lower part, the upper part is that the cross-section is isosceles trapezoid's straight quadrangular prism, the lower part is that the cross-section is rectangular straight quadrangular prism, the lower bottom surface of upper part with the last top surface coincidence of lower part.
In the eccentric type nuclear magnetic resonance permanent magnet of the embodiment of this application, vice permanent magnet includes the cylindricality supporter, and the cladding cylindricality magnet structure on the cylindricality supporter lateral surface just is fixed in it, the cylindricality magnet structure has top surface and second bottom surface down on the second, the radial dimension of top surface on the second with the radial dimension of top surface is the same on the first, the radial dimension of bottom surface under the second with the radial dimension of first bottom surface is the same.
In the eccentric type nuclear magnetic resonance permanent magnet of the embodiment of the application, the cylindrical magnet structure is formed by bonding samarium cobalt magnetic sheets.
In the eccentric nuclear magnetic resonance permanent magnet of the embodiment of the application, the axial length of the main permanent magnet is 0.8-1 m, and the axial length of the main permanent magnet is 20 cm.
On the other hand, the embodiment of the application provides an eccentric nuclear magnetic resonance logging instrument, which is provided with an eccentric nuclear magnetic resonance permanent magnet, wherein the eccentric nuclear magnetic resonance permanent magnet comprises a main permanent magnet made of a non-metal material; two ends of the main permanent magnet are respectively and symmetrically provided with an auxiliary permanent magnet made of metal; the main permanent magnet and the auxiliary permanent magnet are coaxial and separated from each other by a specified distance; the magnetic field direction of the main permanent magnet is perpendicular to the axial direction of the main permanent magnet and points to a specific direction; in the particular direction, the secondary permanent magnet has a magnetic field direction that coincides with the primary permanent magnet.
In the eccentric nuclear magnetic resonance logging instrument of the embodiment of the application, main permanent magnet has first top surface and first bottom surface of going up, first top surface of going up is the N utmost point just first bottom surface of going down is the S utmost point, the middle part of first top surface of going up forms the transmitting antenna mounted position of nuclear magnetic resonance logging instrument, the radial dimension of first bottom surface of going down is greater than the radial dimension of first top surface of going up.
In the eccentric nuclear magnetic resonance logging instrument of this application embodiment, main permanent magnet includes integrated into one piece's upper part and lower part, the upper part is that the cross-section is isosceles trapezoid's straight quadrangular prism, the lower part is that the cross-section is rectangular straight quadrangular prism, the lower bottom surface of upper part with the last top surface coincidence of lower part.
In the eccentric nuclear magnetic resonance logging instrument of the embodiment of the application, vice permanent magnet includes the column support body, and the cladding the cylindric magnet structure on it is just fixed in to the column support body lateral surface, the cylindric magnet structure has top surface and second bottom surface down on the second, the radial dimension of top surface on the second with the radial dimension of top surface is the same on the first, the radial dimension of bottom surface under the second with the radial dimension of first bottom surface is the same.
In the eccentric nuclear magnetic resonance logging instrument of the embodiment of the application, the cylindrical magnet structure is formed by bonding samarium-cobalt magnetic sheets.
In the eccentric nuclear magnetic resonance logging instrument of the embodiment of the application, the axial length of the main permanent magnet is 0.8-1 m, and the axial length of the main permanent magnet is 20 cm.
According to the technical scheme provided by the embodiment of the application, in the embodiment of the application, because the auxiliary permanent magnet is made of metal, the magnetic field intensity of the auxiliary permanent magnet is larger than that of the main permanent magnet made of nonmetal under the same size, and in a specific direction (namely the magnetic field direction of the main permanent magnet), the auxiliary permanent magnet has the magnetic field direction consistent with that of the main permanent magnet, so that the magnetic field distribution of the main permanent magnet in the axial direction can be better adjusted by adjusting the distance between the auxiliary permanent magnet and the main permanent magnet under the condition of not increasing the size of the eccentric type nuclear magnetic resonance permanent magnet (even reducing the size of the eccentric type nuclear magnetic resonance permanent magnet), and an axial uniform magnetic field meeting the requirement of the preset length can be obtained.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without any creative effort. In the drawings:
fig. 1 is a schematic perspective view of an eccentric nmr permanent magnet according to an embodiment of the present application;
FIG. 2 is a schematic radial cross-sectional view of a main permanent magnet of an eccentric NMR permanent magnet according to an embodiment of the present disclosure;
FIG. 3 is a schematic radial cross-sectional view of a secondary permanent magnet of an eccentric NMR permanent magnet according to an embodiment of the present disclosure;
FIG. 4 is a schematic perspective view of an eccentric NMR permanent magnet according to another embodiment of the present disclosure;
FIG. 5 is a graph of the axial iso-field distribution of a magnetic field produced by a single permanent magnet of the prior art;
FIG. 6 is a distribution diagram of the axial iso-field lines of a magnetic field generated by the eccentric NMR permanent magnet of the embodiment of the present application;
FIG. 7 is a schematic diagram of a nuclear magnetic resonance tool according to an embodiment of the present application.
Detailed Description
In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application. For example, in the following description, forming the second component over the first component may include embodiments in which the first and second components are formed in direct contact, embodiments in which the first and second components are formed in non-direct contact (i.e., additional components may be included between the first and second components), and so on.
Also, for ease of description, some embodiments of the present application may use spatially relative terms such as "above …," "below …," "top," "below," etc., to describe the relationship of one element or component to another (or other) element or component as illustrated in the various figures of the embodiments. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or components described as "below" or "beneath" other elements or components would then be oriented "above" or "over" the other elements or components.
The inventor of the present application has found that: although the magnetic field intensity of the permanent magnet made of metal is relatively stronger, the nuclear magnetic resonance principle requires that the transmitting antenna is positioned in the middle of the permanent magnet, and the radio-frequency signal of the transmitting antenna is vertical to the magnetic field of the permanent magnet; when the transmitting antenna is located at the center of the metal permanent magnet, serious shielding interference can be caused to radio frequency signals transmitted by the transmitting antenna. Therefore, most of the eccentric nmr permanent magnets of the prior art are made of non-metal materials (e.g., metal oxide materials). However, no matter how long the axial dimension of the eccentric nmr permanent magnet of the conventional monolithic structure is, the axial magnetic field near both ends of the magnet is always deformed (as shown in fig. 5), thereby affecting the uniformity of the axial magnetic field. Therefore, to make the eccentric nmr permanent magnet reach an axial uniform magnetic field that meets the preset length requirement, the axial dimension of the eccentric nmr permanent magnet generally needs to be increased, resulting in an increase in the volume of the eccentric nmr logging tool.
To solve this problem, the eccentric nmr permanent magnet of the eccentric nmr logging tool in some embodiments of the present application may include a main permanent magnet made of a non-metallic material; two ends of the main permanent magnet are respectively and symmetrically provided with an auxiliary permanent magnet made of metal; the main permanent magnet and the auxiliary permanent magnet are coaxial and separated from each other by a specified distance; the magnetic field direction of the main permanent magnet is perpendicular to the axial direction of the main permanent magnet and points to a specific direction; in the particular direction, the secondary permanent magnet has a magnetic field direction that coincides with the primary permanent magnet.
Because the auxiliary permanent magnet is made of metal, the magnetic field intensity of the auxiliary permanent magnet is larger than that of the main permanent magnet made of nonmetal under the same size, and the auxiliary permanent magnet has the same magnetic field direction with the main permanent magnet in a specific direction (namely the magnetic field direction of the main permanent magnet), the axial magnetic field distribution of the main permanent magnet can be better adjusted by adjusting the distance between the auxiliary permanent magnet and the main permanent magnet under the condition of not increasing the size of the eccentric nuclear magnetic resonance permanent magnet (even reducing the size of the eccentric nuclear magnetic resonance permanent magnet), and thus an axial uniform magnetic field meeting the preset length requirement can be obtained, for example, as shown in fig. 6. As can be seen from a comparison between fig. 5 and 6, the field intensity distribution of the axial magnetic field in the vicinity of both ends of the eccentric type nmr permanent magnet shown in fig. 6 is more uniform.
It is not preferable to replace the sub permanent magnet with a non-metal material. Because the strength of the secondary permanent magnet made of non-metallic materials is weaker, the corresponding technical effect can not be achieved. In this case, the magnetic field length of the segmented non-metallic permanent magnet is weaker than the magnetic field strength of the single non-metallic permanent magnet before the segmentation, and therefore, the axial magnetic field distribution of the eccentric nmr permanent magnet is deteriorated instead of achieving the corresponding technical effect.
Referring to fig. 1 and 2, in an embodiment, the main permanent magnet 1 may have a first upper top surface and a first lower bottom surface, the first upper top surface is an N pole, and the first lower bottom surface is an S pole, a transmitting antenna installation position of the nmr logging instrument is formed in a middle of the first upper top surface, and a radial dimension of the first lower bottom surface is greater than a radial dimension of the first upper top surface, so as to enhance a magnetic flux at the transmitting antenna installation position, thereby facilitating improvement of a resolution of the nmr logging instrument. Correspondingly, as shown in fig. 1 and 3, the auxiliary permanent magnets 21 and 22 may include a cylindrical support body 31, and a cylindrical magnet structure 32 covering and fixed on an outer side surface of the cylindrical support body 31, where the cylindrical magnet structure 32 has a second upper top surface and a second lower bottom surface, a radial dimension of the second upper top surface is the same as a radial dimension of the first upper top surface, and a radial dimension of the second lower bottom surface is the same as a radial dimension of the first lower bottom surface, so as to better adjust an axial magnetic field distribution of the main permanent magnet 1.
With continued reference to fig. 1 and 2, in one embodiment, the main permanent magnet 1 includes an upper portion and a lower portion which are integrally formed, the upper portion is a straight quadrangular prism with an isosceles trapezoid cross section, the lower portion is a straight quadrangular prism with a rectangular cross section, and a lower bottom surface of the upper portion coincides with an upper top surface of the lower portion. When manufacturing the main permanent magnet 1, a regular quadrangular prism structure may be manufactured, and then the main permanent magnet 1 shown in fig. 1 and 2 may be formed by a process such as cutting. Therefore, the radial size of the first lower bottom surface of the main permanent magnet 1 is larger than that of the first upper top surface of the main permanent magnet, the main body part which is in a regular quadrangular prism shape is easy to process and can be reserved more, and the requirement of the magnetic field intensity is met.
In one embodiment, the cylindrical magnet structure 32 shown in FIG. 3 is preferably formed of bonded samarium cobalt magnetic sheets. Because samarium cobalt magnetic sheet not only magnetic field intensity is stronger still to temperature variation insensitivity, consequently cylindrical magnet structure 32 adopts samarium cobalt magnetic sheet can be favorable to realizing the stable magnetic field of high resolution. However, samarium cobalt magnetic flakes have poor mechanical properties (e.g., impact and strain resistance), and therefore require the use of a cylindrical support 31 that is compatible with mechanically good materials (e.g., metals such as iron) for support and protection. In addition, in an embodiment, preferably, for better supporting and protecting effects, the cylindrical supporting body 31 may be cylindrical, and correspondingly, the main body of the cylindrical magnet structure 32 may be cylindrical. In manufacturing, the cylindrical magnet structure 32 may be formed on the cylindrical support body 31, and then, as necessary, the desired upper and lower top and bottom surfaces may be formed on the cylindrical magnet structure 32 by a cutting process or the like. Generally, the upper cutting height of the cylindrical magnet structure 32 is 1/16-1/12 of the outer diameter of the cylinder, and the lower cutting height of the cylindrical magnet structure 32 is 1/8-1/6 of the outer diameter of the cylinder, and the upper cutting height is the diameter, and can be determined according to actual needs.
Of course, in other embodiments, the eccentric nmr permanent magnet may also be manufactured into other shapes, such as shown in fig. 4, to meet practical needs.
In some embodiments, preferably, in consideration of the actual requirement of the nmr logging tool, the axial length of the main permanent magnet may be 0.8-1 m, the axial length of the main permanent magnet may be about 20cm, and the total length of the eccentric nmr permanent magnet may be 2-3 m.
In some embodiments, in the eccentric nmr logging tool, the primary permanent magnet and the secondary permanent magnet of the eccentric nmr permanent magnet are aligned along an axial direction of the nmr logging tool. In actual use, the eccentric nmr tool is placed longitudinally into a vertical well (as shown in fig. 7), because the well used for eccentric nmr logging is generally a vertical well. In this way, the main permanent magnet and the sub-permanent magnet of the eccentric nuclear magnetic resonance permanent magnet are arranged substantially in the longitudinal direction, and are detected by the static magnetic field as shown in fig. 6.
It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a component or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such component or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method or apparatus that comprises the element.
All the embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments, and the relevant points may be referred to the part of the description of the method embodiment.
The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.
Claims (10)
1. An eccentric nuclear magnetic resonance permanent magnet is characterized by comprising a main permanent magnet made of a non-metal material; two ends of the main permanent magnet are respectively and symmetrically provided with an auxiliary permanent magnet made of metal; the main permanent magnet and the auxiliary permanent magnet are coaxial and separated from each other by a specified distance; the magnetic field direction of the main permanent magnet is perpendicular to the axial direction of the main permanent magnet and points to a specific direction; in the particular direction, the secondary permanent magnet has a magnetic field direction that coincides with the primary permanent magnet;
the main permanent magnet is provided with a first upper top surface and a first lower bottom surface, the first upper top surface is an N pole, the first lower bottom surface is an S pole, the middle part of the first upper top surface forms the installation position of a transmitting antenna of the nuclear magnetic resonance logging instrument, and the radial size of the first lower bottom surface is larger than that of the first upper top surface.
2. An eccentric nmr permanent magnet according to claim 1, wherein the main permanent magnet comprises an upper part and a lower part which are integrally formed, the upper part is a straight quadrangular prism with an isosceles trapezoid cross section, the lower part is a straight quadrangular prism with a rectangular cross section, and the lower bottom surface of the upper part coincides with the upper top surface of the lower part.
3. An eccentric nmr permanent magnet according to claim 1, wherein the secondary permanent magnet comprises a cylindrical support body, and a cylindrical magnet structure covering and fixed to an outer side surface of the cylindrical support body, the cylindrical magnet structure having a second upper top surface having a radial dimension same as that of the first upper top surface, and a second lower bottom surface having a radial dimension same as that of the first lower bottom surface.
4. An eccentric nmr permanent magnet according to claim 3 wherein the cylindrical magnet structure is bonded from samarium cobalt magnetic sheets.
5. An eccentric NMR permanent magnet according to claim 1, wherein the axial length of the main permanent magnet is 0.8 to 1m, and the axial length of the main permanent magnet is 20 cm.
6. An eccentric nuclear magnetic resonance logging instrument is provided with an eccentric nuclear magnetic resonance permanent magnet, and is characterized in that the eccentric nuclear magnetic resonance permanent magnet comprises a main permanent magnet made of a non-metal material; two ends of the main permanent magnet are respectively and symmetrically provided with an auxiliary permanent magnet made of metal; the main permanent magnet and the auxiliary permanent magnet are coaxial and separated from each other by a specified distance; the magnetic field direction of the main permanent magnet is perpendicular to the axial direction of the main permanent magnet and points to a specific direction; in the particular direction, the secondary permanent magnet has a magnetic field direction that coincides with the primary permanent magnet;
the main permanent magnet is provided with a first upper top surface and a first lower bottom surface, the first upper top surface is an N pole, the first lower bottom surface is an S pole, the middle part of the first upper top surface forms the installation position of a transmitting antenna of the nuclear magnetic resonance logging instrument, and the radial size of the first lower bottom surface is larger than that of the first upper top surface.
7. An eccentric NMR logging tool as defined in claim 6, wherein the main permanent magnet includes an upper part and a lower part which are integrally formed, the upper part being a straight quadrangular prism having an isosceles trapezoid cross section, the lower part being a straight quadrangular prism having a rectangular cross section, and a lower bottom surface of the upper part coinciding with an upper top surface of the lower part.
8. The eccentric nmr tool of claim 6, wherein the secondary permanent magnet comprises a cylindrical support body, and a cylindrical magnet structure surrounding and secured to an outer side surface of the cylindrical support body, the cylindrical magnet structure having a second upper top surface having a radial dimension that is the same as the radial dimension of the first upper top surface, and a second lower bottom surface having a radial dimension that is the same as the radial dimension of the first lower bottom surface.
9. An eccentric nmr tool according to claim 8, wherein the cylindrical magnet structure is bonded by samarium cobalt magnetic sheets.
10. The eccentric NMR tool of claim 6, wherein the main permanent magnet has an axial length of 0.8 to 1m and an axial length of 20 cm.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810182614.4A CN108538535B (en) | 2018-03-06 | 2018-03-06 | Eccentric nuclear magnetic resonance logging instrument and nuclear magnetic resonance permanent magnet thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810182614.4A CN108538535B (en) | 2018-03-06 | 2018-03-06 | Eccentric nuclear magnetic resonance logging instrument and nuclear magnetic resonance permanent magnet thereof |
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| CN108538535A CN108538535A (en) | 2018-09-14 |
| CN108538535B true CN108538535B (en) | 2020-08-07 |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003303714A (en) * | 2002-04-09 | 2003-10-24 | Sumitomo Special Metals Co Ltd | Bar magnet and magnetic material removing device |
| CN103928211A (en) * | 2014-04-24 | 2014-07-16 | 北京昔光节科贸有限公司 | Permanent magnet for double-sector nuclear magnetic resonance logging instrument |
| CN106285505A (en) * | 2015-06-26 | 2017-01-04 | 中国石油集团长城钻探工程有限公司 | Box cupling magnetic orientation well logging pipe nipple and there is high speed the spread of the rumours logging instrument of this pipe nipple |
| WO2017061992A1 (en) * | 2015-10-06 | 2017-04-13 | Halliburton Energy Services, Inc. | Permanent magnet configuration for nmr logging tool |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6459262B1 (en) * | 2000-04-25 | 2002-10-01 | Baker Hughes Incorporated | Toroidal receiver for NMR MWD |
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2018
- 2018-03-06 CN CN201810182614.4A patent/CN108538535B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003303714A (en) * | 2002-04-09 | 2003-10-24 | Sumitomo Special Metals Co Ltd | Bar magnet and magnetic material removing device |
| CN103928211A (en) * | 2014-04-24 | 2014-07-16 | 北京昔光节科贸有限公司 | Permanent magnet for double-sector nuclear magnetic resonance logging instrument |
| CN106285505A (en) * | 2015-06-26 | 2017-01-04 | 中国石油集团长城钻探工程有限公司 | Box cupling magnetic orientation well logging pipe nipple and there is high speed the spread of the rumours logging instrument of this pipe nipple |
| WO2017061992A1 (en) * | 2015-10-06 | 2017-04-13 | Halliburton Energy Services, Inc. | Permanent magnet configuration for nmr logging tool |
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