EP0295134A2
Expired / Lapsed
EP
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Nuclear magnetic resonance sensing apparatus and methods
Assignee: Numar Corp
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Filing: 1988-06-10
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Granted: —
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Expires: 2008-06-10
Abstract
Abstract NMR sensing apparatus, which may be used in well logging, includes a magnet arrangement (10) for generating a static magnetic field in a toroidal region (9) containing materials to be analyzed. The magnet arrangement (10) includes at least four magnets arranged along a longitudinal axis (11) which may coincide with the axis of, for example, a bore hole (7) being investigated. A coil arrangement (16) is used both for generating an r.f. magnetic field in the region (9) so as to excite nuclei of the materials to be analyzed, and for receiving NMR signals from the excited nuclei. An indication of the properties of the materials being analyzed is then obtained from the received NMR signals by means of a computer (32).
Inventors
- 👤 Zvi Taicher
- 👤 Shmuel Shtrikman
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 06:14
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/18; G01V3/32; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/38; G01R33/383
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
110 words
Nuclear magnetic resonance sensing apparatus comprising: at least four magnets (10) operative to generate a static magnetic field in a region (9) remote therefrom containing materials sought to be analyzed, the at least four magnets (10) being arranged along a longitudinal axis (11) and being magnetized in magnetization directions extending generally parallel to said longitudinal axis (11); means (16,20,24) for generating a radio frequency magnetic field in said remote region (9) for exciting nuclei of the materials sought to be analyzed; and means (16,20,26) for receiving nuclear magnetic resonance signals from the excited nuclei and for providing an output indication of the properties of the materials sought to be analyzed.
Claim 2
Dependent Claim
110 words
Nuclear magnetic resonance sensing apparatus comprising: at least four magnets (10) operative to generate a static magnetic field in a region (9) remote therefrom containing materials sought to be analyzed, the at least four magnets (10) being arranged along a longitudinal axis (11) and being magnetized in magnetization directions extending generally parallel to said longitudinal axis (11); means (16,20,24) for generating a radio frequency magnetic field in said remote region (9) for exciting nuclei of the materials sought to be analyzed; and means (16,20,26) for receiving nuclear magnetic resonance signals from the excited nuclei and for providing an output indication of the properties of the materials sought to be analyzed.
Claim 3
Dependent Claim
50 words
Apparatus according to claim 1, wherein said at least four magnets comprise a first pair of magnets (110,112) having opposite magnetization directions and being spaced along the longitudinal axis (11), and a second pair of magnets (114,116) disposed intermediate the first pair of magnets (110,112) along the longitudinal axis (11).
Claim 4
Dependent Claim
30 words
Apparatus according to claim 2, wherein said second pair of magnets (124,126) have magnetization directions opposite to the magnetization directions of adjacent ones of the first pair of magnets (120,122).
Claim 5
Dependent Claim
30 words
Apparatus according to claim 2, wherein said second pair of magnets (114,116) have magnetization directions parallel to the magnetization directions of adjacent ones of the first pair of magnets (110,112).
Claim 6
Dependent Claim
23 words
Apparatus according to any one of the preceding claims, wherein said at least four magnets (10) are each of generally circular cylindrical configuration.
Claim 7
Dependent Claim
19 words
Apparatus according to any one of the preceding claims, wherein said at least four magnets (10) comprise permanent magnets.
Claim 8
Dependent Claim
19 words
Apparatus according to any one of claims 1 to 5, wherein said at least four magnets (10) comprise electromagnets.
Claim 9
Dependent Claim
30 words
Apparatus according to any one of the preceding claims, wherein said at least four magnets (10) are operative for generating a static magnetic field in a well bore hole (7).
Claim 10
Dependent Claim
52 words
Apparatus according to any one of the preceding claims, comprising means for displacing said at least four magnets (10), said means for generating a radio frequency magnetic field and said receiving means along a bore hole (7), thereby to enable a plurality of nuclear magnetic resonance measurements to be carried out therealong.
Claim 11
Dependent Claim
173 words
Nuclear magnetic resonance sensing apparatus comprising: at least four ferrite permanent magnets (10) operative to generate a static magnetic field in a region (9) remote therefrom containing materials sought to be analyzed, said at least four ferrite permanent magnets (10) being of generally cylindrical configuration, the at least four ferrite permanent magnets (10) being arranged along a longitudinal axis and being magnetized in magnetization directions extending generally parallel to said longitudinal axis; means (16,20,24) for generating a radio frequency magnetic field in said remote region (9) for exciting nuclei of the materials sought to be analyzed, said generating means comprising at least one coil (16) wound about the surface of said at least four ferrite permanent magnets (10) whereby the coil turns lie in planes substantially perpendicular to said longitudinal axis intermediate the magnets; and receiving means (16,20,26) for receiving, via said at least one coil (16), nuclear magnetic resonance signals from the materials to be analyzed and for providing an output indication of the properties of the materials sought to be analyzed.
Claim 12
Dependent Claim
173 words
Nuclear magnetic resonance sensing apparatus comprising: at least four ferrite permanent magnets (10) operative to generate a static magnetic field in a region (9) remote therefrom containing materials sought to be analyzed, said at least four ferrite permanent magnets (10) being of generally cylindrical configuration, the at least four ferrite permanent magnets (10) being arranged along a longitudinal axis and being magnetized in magnetization directions extending generally parallel to said longitudinal axis; means (16,20,24) for generating a radio frequency magnetic field in said remote region (9) for exciting nuclei of the materials sought to be analyzed, said generating means comprising at least one coil (16) wound about the surface of said at least four ferrite permanent magnets (10) whereby the coil turns lie in planes substantially perpendicular to said longitudinal axis intermediate the magnets; and receiving means (16,20,26) for receiving, via said at least one coil (16), nuclear magnetic resonance signals from the materials to be analyzed and for providing an output indication of the properties of the materials sought to be analyzed.
Claim 13
Dependent Claim
22 words
Apparatus according to claim 10, wherein said at least four ferrite permanent magnets (10) have an overall configuration of a circular cylinder.
Claim 14
Dependent Claim
53 words
Apparatus according to claim 10 or claim 11, comprising means for displacing said at least four ferrite permanent magnets (10), said means for generating a radio frequency magnetic field and said receiving means along a bore hole (7), thereby to enable a plurality of nuclear magnetic resonance measurements to be carried out therealong.
Claim 15
Independent Claim
162 words
A method of nuclear magnetic resonance sensing comprising the steps of: providing at least four magnets (10) defining a longitudinal axis (11) and having substantially uniform magnetization and magnetization directions extending generally parallel to said longitudinal axis (11); causing said at least four magnets (10) to generate a static magnetic field of generally uniform amplitude in a region (9) remote therefrom containing materials sought to be analyzed, said static magnetic field having a static field direction perpendicular to said longitudinal axis (11) in said remote region (9); generating a radio frequency magnetic field in said remote region for exciting nuclei of the materials sought to be analyzed and having a radio frequency magnetic field direction substantially perpendicular to said static field direction and parallel to said longitudinal axis (11); receiving nuclear magnetic resonance signals from the excited nuclei; and providing in response to the received nuclear magnetic resonance signals an output indication of the properties of the materials sought to be analyzed.
Claim 16
Independent Claim
162 words
A method of nuclear magnetic resonance sensing comprising the steps of: providing at least four magnets (10) defining a longitudinal axis (11) and having substantially uniform magnetization and magnetization directions extending generally parallel to said longitudinal axis (11); causing said at least four magnets (10) to generate a static magnetic field of generally uniform amplitude in a region (9) remote therefrom containing materials sought to be analyzed, said static magnetic field having a static field direction perpendicular to said longitudinal axis (11) in said remote region (9); generating a radio frequency magnetic field in said remote region for exciting nuclei of the materials sought to be analyzed and having a radio frequency magnetic field direction substantially perpendicular to said static field direction and parallel to said longitudinal axis (11); receiving nuclear magnetic resonance signals from the excited nuclei; and providing in response to the received nuclear magnetic resonance signals an output indication of the properties of the materials sought to be analyzed.
Claim 17
Dependent Claim
34 words
A method according to claim 13, wherein said step of generating a static magnetic field comprises the step of generating a static magnetic field in the region (9) surrounding a well bore hole (7).
Claim 18
Dependent Claim
56 words
A method according to claim 13 or claim 14, comprising the steps of generating the static magnetic field, generating the radio frequency magnetic field and receiving the nuclear magnetic resonance signals at a plurality of locations along a bore hole (7), thereby to enable a plurality of nuclear magnetic resonance measurements to be carried out therealong.
Claim 19
Independent Claim
97 words
A method of well logging using nuclear magnetic resonance and comprising the steps of: generating a static magnetic field substantially perpendicular to the axis of a bore hole (7) in a region (9) surrounding the bore hole which region includes materials sought to be analyzed; generating a radio frequency magnetic field in said region (9) in a direction substantially parallel to the axis (11) of the bore hole (7) and substantially perpendicular to the static magnetic field for exciting nuclei of the materials sought to be analyzed; and receiving nuclear magnetic resonance signals from the excited nuclei.
Claim 20
Independent Claim
97 words
A method of well logging using nuclear magnetic resonance and comprising the steps of: generating a static magnetic field substantially perpendicular to the axis of a bore hole (7) in a region (9) surrounding the bore hole which region includes materials sought to be analyzed; generating a radio frequency magnetic field in said region (9) in a direction substantially parallel to the axis (11) of the bore hole (7) and substantially perpendicular to the static magnetic field for exciting nuclei of the materials sought to be analyzed; and receiving nuclear magnetic resonance signals from the excited nuclei.
Claim 21
Dependent Claim
34 words
A method according to claim 16, comprising the step of providing an output indication of the properties of the materials sought to be analyzed on the basis of the received nuclear magnetic resonance signals.
Claim 22
Independent Claim
214 words
A method of nuclear magnetic resonance sensing comprising the steps of: providing at least four non-conductive permanent magnets (10) of generally cylindrical configuration and defining a longitudinal axis (11), said at least four permanent magnets (10) having substantially uniform magnetization in a direction extending generally along a magnetization axis parallel to said longitudinal axis (11); causing said at least four magnets (10) to generate a static magnetic field of generally uniform amplitude which is substantially azimuthally symmetric with respect to said longitudinal axis (11) in a generally toroidal region (9) centred about said longitudinal axis (11) and remote therefrom, said region (9) containing materials sought to be analyzed, said static magnetic field having a static field direction perpendicular to said longitudinal axis (11) in said remote region; generating a radio frequency magnetic field of generally uniform and azimuthally symmetric amplitude in said remote region (9) for exciting nuclei of the materials sought to be analyzed and having a radio frequency magnetic field direction substantially perpendicular to said static field direction and substantially parallel to said longitudinal axis (11); receiving nuclear magnetic resonance signals from the materials sought to be analyzed; and providing in response to the received nuclear magnetic resonance signals an output indication of the properties of the materials sought to be analyzed.
Claim 23
Independent Claim
214 words
A method of nuclear magnetic resonance sensing comprising the steps of: providing at least four non-conductive permanent magnets (10) of generally cylindrical configuration and defining a longitudinal axis (11), said at least four permanent magnets (10) having substantially uniform magnetization in a direction extending generally along a magnetization axis parallel to said longitudinal axis (11); causing said at least four magnets (10) to generate a static magnetic field of generally uniform amplitude which is substantially azimuthally symmetric with respect to said longitudinal axis (11) in a generally toroidal region (9) centred about said longitudinal axis (11) and remote therefrom, said region (9) containing materials sought to be analyzed, said static magnetic field having a static field direction perpendicular to said longitudinal axis (11) in said remote region; generating a radio frequency magnetic field of generally uniform and azimuthally symmetric amplitude in said remote region (9) for exciting nuclei of the materials sought to be analyzed and having a radio frequency magnetic field direction substantially perpendicular to said static field direction and substantially parallel to said longitudinal axis (11); receiving nuclear magnetic resonance signals from the materials sought to be analyzed; and providing in response to the received nuclear magnetic resonance signals an output indication of the properties of the materials sought to be analyzed.
References Cited (Backward Citations)
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