Patent US3597681A successfully refreshed from Google Patents.
US3597681A
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Nuclear magnetic well logging
Assignee: Chevron USA Inc
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Filing: 1957-01-30
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Granted: 1971-08-03
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Expires: 1977-01-30
Abstract
Abstract This invention relates to nuclear magnetic resonance well logging where hydrogen nuclei are polarized in a unidirectional field. Free precession of nuclei is established at a measuring level in the well bore by generating a magnetic field at an angle to the unidirectional field and removing the same. Output signals are generated having a frequency characteristic of the precession of the macroscopic moment vector of hydrogen nuclei and a characteristic dependent upon the number of hydrogen nuclei. The output signal is then recorded in correlation with the depth of the measuring level to produce a record indicative of regions in which hydrogen atoms are concentrated.
Inventors
- 👤 William B Huckabay
- 👤 John K Godbey
- 👤 John O Ely
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:18
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/18; G01V3/32
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
167 words
In a system for logging a well bore the improvement which comprises means for producing a unidirectional magnetic field of predetermined maximum strength Ho in formations at a measuring level in said well bore to establish a predominant orientation of those nuclei in said field which possess a magnetic moment, means including a source of spaced oscillatory pulses each producing alternating magnetic fields substantially normal to said unidirectional field at said level and of a frequency of the order of but greater than gamma NaHo/2 pi cycles per second where gamma Na is the gyromagnetic ratio of sodium whereby said predominant orientation of atoms having gyromagnetic ratios greater than that of sodium is disturbed, field detecting means at said level for detecting in the interval following production of two of said alternating fields a varying electromagnetic field having the frequency of said alternating field due substantially entirely to precession of hydrogen nuclei in said unidirectional field, and means for indicating the relative values of said detected fields.
Claim 2
Dependent Claim
167 words
In a system for logging a well bore the improvement which comprises means for producing a unidirectional magnetic field of predetermined maximum strength Ho in formations at a measuring level in said well bore to establish a predominant orientation of those nuclei in said field which possess a magnetic moment, means including a source of spaced oscillatory pulses each producing alternating magnetic fields substantially normal to said unidirectional field at said level and of a frequency of the order of but greater than gamma NaHo/2 pi cycles per second where gamma Na is the gyromagnetic ratio of sodium whereby said predominant orientation of atoms having gyromagnetic ratios greater than that of sodium is disturbed, field detecting means at said level for detecting in the interval following production of two of said alternating fields a varying electromagnetic field having the frequency of said alternating field due substantially entirely to precession of hydrogen nuclei in said unidirectional field, and means for indicating the relative values of said detected fields.
Claim 3
Dependent Claim
167 words
In a system for logging a well bore the improvement which comprises means for producing a unidirectional magnetic field of predetermined maximum strength Ho in formations at a measuring level in said well bore to establish a predominant orientation of those nuclei in said field which possess a magnetic moment, means for producing pulsed alternating magnetic fields substantially normal to said unidirectional field at said level and having frequency components exclusively within the limits of gamma NaHo/2 pi and gamma hHo/2 pi cycles per second where gamma Na is the gyromagnetic ratio for sodium and gamma h is the gyromagnetic ratio for hydrogen whereby said predominant orientation of all nuclei having gyromagnetic ratios greater than that of sodium is disturbed, and detecting means responsive to frequencies within said limits for detecting in the interval following production of two of said alternating fields varying fields due substantially entirely to precession of hydrogen nuclei in said unidirectional field, and means for indicating the relative values of said varying fields.
Claim 4
Dependent Claim
167 words
In a system for logging a well bore the improvement which comprises means for producing a unidirectional magnetic field of predetermined maximum strength Ho in formations at a measuring level in said well bore to establish a predominant orientation of those nuclei in said field which possess a magnetic moment, means for producing pulsed alternating magnetic fields substantially normal to said unidirectional field at said level and having frequency components exclusively within the limits of gamma NaHo/2 pi and gamma hHo/2 pi cycles per second where gamma Na is the gyromagnetic ratio for sodium and gamma h is the gyromagnetic ratio for hydrogen whereby said predominant orientation of all nuclei having gyromagnetic ratios greater than that of sodium is disturbed, and detecting means responsive to frequencies within said limits for detecting in the interval following production of two of said alternating fields varying fields due substantially entirely to precession of hydrogen nuclei in said unidirectional field, and means for indicating the relative values of said varying fields.
Claim 5
Dependent Claim
171 words
In a system for logging a well bore the improvement which comprises means for producing a unidirectional magnetic field of predetermined maximum strength Ho in formations at a measuring level in said well bore to establish a predominant orientation of those nuclei in said field which possess a magnetic moment, means for producing a plurality of time-spaced pulsed alternating magnetic fields substantially normal to said unidirectional field at said lEvel exclusively within the frequency limits of gamma NAHo/2 pi and gamma hHo/2 pi cycles per second where gamma Na is the gyromagnetic ratio for sodium and gamma h is the gyromagnetic ratio for hydrogen whereby said predominant orientation of all nuclei having gyromagnetic ratios greater than that of sodium is disturbed, and detecting means responsive to the frequencies of said plurality of alternating magnetic fields for detecting in the interval following production of said alternating fields varying fields due substantially entirely to precession of hydrogen nuclei in said unidirectional field, and means for indicating the relative values of said varying fields.
Claim 6
Dependent Claim
171 words
In a system for logging a well bore the improvement which comprises means for producing a unidirectional magnetic field of predetermined maximum strength Ho in formations at a measuring level in said well bore to establish a predominant orientation of those nuclei in said field which possess a magnetic moment, means for producing a plurality of time-spaced pulsed alternating magnetic fields substantially normal to said unidirectional field at said lEvel exclusively within the frequency limits of gamma NAHo/2 pi and gamma hHo/2 pi cycles per second where gamma Na is the gyromagnetic ratio for sodium and gamma h is the gyromagnetic ratio for hydrogen whereby said predominant orientation of all nuclei having gyromagnetic ratios greater than that of sodium is disturbed, and detecting means responsive to the frequencies of said plurality of alternating magnetic fields for detecting in the interval following production of said alternating fields varying fields due substantially entirely to precession of hydrogen nuclei in said unidirectional field, and means for indicating the relative values of said varying fields.
Claim 7
Dependent Claim
200 words
In electrical well logging the improvement which comprises an exploring unit suspended at a measuring level in said well bore and including means for producing a unidirectional magnetic field of predetermined maximum strength Ho in formations adjacent thereto to establish a predominant orientation of those nuclei in said field which possess a magnetic moment, coil means in said unit oriented with its axis normal to said unidirectional field at said level, a source of alternating current having a frequency in the order of but greater than gamma NaHo/2 pi cycles per second where gamma Na is the gyromagnetic ratio of sodium, switching means for momentarily connecting said source of alternating current to said coil means to establish an alternating magnetic field normal to said unidirectional field to upset the predominant orientation of atoms having gyromagnetic ratios greater than that of sodium which possess a magnetic moment, detecting means responsive to varying magnetic fields of the frequency of said source of alternating current for detecting in the interval following production of said alternating field a varying electromagnetic field due substantially entirely to precession of hydrogen nuclei in said unidirectional field, and means for indicating the relative values of said varying fields.
Claim 8
Dependent Claim
200 words
In electrical well logging the improvement which comprises an exploring unit suspended at a measuring level in said well bore and including means for producing a unidirectional magnetic field of predetermined maximum strength Ho in formations adjacent thereto to establish a predominant orientation of those nuclei in said field which possess a magnetic moment, coil means in said unit oriented with its axis normal to said unidirectional field at said level, a source of alternating current having a frequency in the order of but greater than gamma NaHo/2 pi cycles per second where gamma Na is the gyromagnetic ratio of sodium, switching means for momentarily connecting said source of alternating current to said coil means to establish an alternating magnetic field normal to said unidirectional field to upset the predominant orientation of atoms having gyromagnetic ratios greater than that of sodium which possess a magnetic moment, detecting means responsive to varying magnetic fields of the frequency of said source of alternating current for detecting in the interval following production of said alternating field a varying electromagnetic field due substantially entirely to precession of hydrogen nuclei in said unidirectional field, and means for indicating the relative values of said varying fields.
Claim 9
Dependent Claim
186 words
In electrical well logging the improvement which comprises an exploring unit suspended at a measuring level in said well bore and including means for producing a unidirectional magnetic field of predetermined maximum strength Ho in formations adjacent thereto to establish a predominant orientation of those nuclei in said field which possess a magnetic moment, coil means in said unit oriented with its axis normal to said unidirectional field at said level, a source of alternating current having a frequency of the order of but greater than gamma NaHo/2 pi cycles per second where gamma Na is the gyromagnetic ratio of sodium, a circuit including indicating means responsive to signals of the frequency of said source of alternating current, a control circuit connected to said source of alternating current, to said coil means, and to said circuit for momentarily applying time-spaced pulses of said alternating current to said coil means and for applying to said circuit in the interval after plural energization of said coil means signals induced in said coil of the frequency of said source due to precession of hydrogen nuclei in said unidirectional field.
Claim 10
Dependent Claim
186 words
In electrical well logging the improvement which comprises an exploring unit suspended at a measuring level in said well bore and including means for producing a unidirectional magnetic field of predetermined maximum strength Ho in formations adjacent thereto to establish a predominant orientation of those nuclei in said field which possess a magnetic moment, coil means in said unit oriented with its axis normal to said unidirectional field at said level, a source of alternating current having a frequency of the order of but greater than gamma NaHo/2 pi cycles per second where gamma Na is the gyromagnetic ratio of sodium, a circuit including indicating means responsive to signals of the frequency of said source of alternating current, a control circuit connected to said source of alternating current, to said coil means, and to said circuit for momentarily applying time-spaced pulses of said alternating current to said coil means and for applying to said circuit in the interval after plural energization of said coil means signals induced in said coil of the frequency of said source due to precession of hydrogen nuclei in said unidirectional field.
Claim 11
Dependent Claim
218 words
In electrical well logging the improvement which comprises an exploring unit suspended at a measuring level in said well bore and including means for producing a unidirectional magnetic field of predetermined maximum strength Ho in formations adjacent thereto to establish a predominant orientation of those nuclei in said field which possess a magnetic moment, coil means in said unit oriented with its axis normal to said unidirectional field at said level, a source of alternating current for producing a white noise signal within the frequency limits of gamma NaHo/2 pi and gamma hHo/2 pi cycles per second where gamma Na is the gyromagnetIc ratio for sodium and gamma h is the gyromagnetic ratio for hydrogen, switching means for repeatedly momentarily connecting said source of alternating current to said coil means to establish a plurality of time-spaced rotating magnetic fields normal to said unidirectional field to upset the predominant orientation of all atoms having gyromagnetic ratios greater than that of sodium in said formations, detecting means responsive to varying magnetic fields of the frequencies within said limits for detecting in the interval following plural applications of said alternating current to said coil means varying magnetic fields due substantially entirely to precession of hydrogen nuclei in said unidirectional field, and means for indicating the relative values of said varying fields.
Claim 12
Dependent Claim
218 words
In electrical well logging the improvement which comprises an exploring unit suspended at a measuring level in said well bore and including means for producing a unidirectional magnetic field of predetermined maximum strength Ho in formations adjacent thereto to establish a predominant orientation of those nuclei in said field which possess a magnetic moment, coil means in said unit oriented with its axis normal to said unidirectional field at said level, a source of alternating current for producing a white noise signal within the frequency limits of gamma NaHo/2 pi and gamma hHo/2 pi cycles per second where gamma Na is the gyromagnetIc ratio for sodium and gamma h is the gyromagnetic ratio for hydrogen, switching means for repeatedly momentarily connecting said source of alternating current to said coil means to establish a plurality of time-spaced rotating magnetic fields normal to said unidirectional field to upset the predominant orientation of all atoms having gyromagnetic ratios greater than that of sodium in said formations, detecting means responsive to varying magnetic fields of the frequencies within said limits for detecting in the interval following plural applications of said alternating current to said coil means varying magnetic fields due substantially entirely to precession of hydrogen nuclei in said unidirectional field, and means for indicating the relative values of said varying fields.
Claim 13
Independent Claim
168 words
A system for logging formations adjacent a well bore which comprises means for generating at a measuring level in said well bore a unidirectional magnetic field having a field strength that does not exceed a predetermined maximum value Ho at any point in said formations to establish a predominant orientation of nuclei in said field, means for applying time-spaced alternating magnetic fields substantially normal to said unidirectional magnetic field at said level having a frequency between an upper frequency f1 gamma hHo/2 pi and a lower frequency f2 gamma NaHo/2 pi where gamma h is the gyromagnetic ratio of hydrogen and gamma Na is the gyromagnetic ratio for sodium to impart energy to said predominantly oriented nuclei to displace them from their predominant orientation, and means for indicating at said frequency the electromagnetic field echoes of the displacement of said nuclei from said predominant orientation following application of said time-spaced alternating magnetic fields for determination of the molecular association of hydrogen atoms in the fields in said formations.
Claim 14
Independent Claim
168 words
A system for logging formations adjacent a well bore which comprises means for generating at a measuring level in said well bore a unidirectional magnetic field having a field strength that does not exceed a predetermined maximum value Ho at any point in said formations to establish a predominant orientation of nuclei in said field, means for applying time-spaced alternating magnetic fields substantially normal to said unidirectional magnetic field at said level having a frequency between an upper frequency f1 gamma hHo/2 pi and a lower frequency f2 gamma NaHo/2 pi where gamma h is the gyromagnetic ratio of hydrogen and gamma Na is the gyromagnetic ratio for sodium to impart energy to said predominantly oriented nuclei to displace them from their predominant orientation, and means for indicating at said frequency the electromagnetic field echoes of the displacement of said nuclei from said predominant orientation following application of said time-spaced alternating magnetic fields for determination of the molecular association of hydrogen atoms in the fields in said formations.
Claim 15
Independent Claim
101 words
A method for logging a well bore in which nuclei in formations adjacent thereto which possess a magnetic moment are polarized in a unidirectional magnetic field in said formations to establish a predominant orientation thereof, the steps which comprise producing a second magnetic field substantially normal to said unidirectional field at said level whereby said predominant orientation of nuclei is disturbed, detecting hydrogen-dependent, varying fields following removal of said second magnetic field to produce a signal due substantially entirely to precession of said nuclei in said unidirectional field, and registering said signal in correlation with the depth of said registering level.
Claim 16
Independent Claim
101 words
A method for logging a well bore in which nuclei in formations adjacent thereto which possess a magnetic moment are polarized in a unidirectional magnetic field in said formations to establish a predominant orientation thereof, the steps which comprise producing a second magnetic field substantially normal to said unidirectional field at said level whereby said predominant orientation of nuclei is disturbed, detecting hydrogen-dependent, varying fields following removal of said second magnetic field to produce a signal due substantially entirely to precession of said nuclei in said unidirectional field, and registering said signal in correlation with the depth of said registering level.
Claim 17
Independent Claim
100 words
A method for logging a well bore in which nuclei in formations adjacent thereto which possess a magnetic moment are polarized in a unidirectional magnetic field in said formations to establish a predominant orientation thereof, the steps which comprise producing pulsed magnetic fields substantially normal to said unidirectional field at said level whereby said predominant orientation of nuclei is disturbed, detecting hydrogen-dependent, varying fields following removal of said pulsed magnetic fields to produce a signal due substantially entirely to precession of said nuclei in said unidirectional field, and measuring said signal in correlation with the depth of said measuring level.
Claim 18
Independent Claim
100 words
A method for logging a well bore in which nuclei in formations adjacent thereto which possess a magnetic moment are polarized in a unidirectional magnetic field in said formations to establish a predominant orientation thereof, the steps which comprise producing pulsed magnetic fields substantially normal to said unidirectional field at said level whereby said predominant orientation of nuclei is disturbed, detecting hydrogen-dependent, varying fields following removal of said pulsed magnetic fields to produce a signal due substantially entirely to precession of said nuclei in said unidirectional field, and measuring said signal in correlation with the depth of said measuring level.
Claim 19
Dependent Claim
181 words
In a system for logging a well bore in which nuclei in formations adjacent thereto which possess a magnetic moment are polarized in a unidirectional magnetic field having a field strength that does not exceed a predetermined maximum value Ho at any point in said formations wherein at a measuring level there is established a predominant orientation of said nuclei, the combination therewith which comprises means for applying time-spaced alternating magnetic fields substantially normal to said unidirectional magnetic field at a measuring level, said alternating magnetic fields having a frequency between an upper frequenCy f1 gamma hHo/2 pi and a lower frequency f2 gamma NaHo/2 pi where gamma h is the gyromagnetic ratio for hydrogen and gamma Na is the gyromagnetic ratio for sodium to impart energy to the predominantly oriented nuclei to displace them from their predominant orientation, detecting means responsive to varying fields following removal of said alternating magnetic fields due substantially entirely to precession of nuclei in said unidirectional magnetic field, and means responsive to said detecting means for registering said output signals as a function of depth.
Claim 20
Dependent Claim
181 words
In a system for logging a well bore in which nuclei in formations adjacent thereto which possess a magnetic moment are polarized in a unidirectional magnetic field having a field strength that does not exceed a predetermined maximum value Ho at any point in said formations wherein at a measuring level there is established a predominant orientation of said nuclei, the combination therewith which comprises means for applying time-spaced alternating magnetic fields substantially normal to said unidirectional magnetic field at a measuring level, said alternating magnetic fields having a frequency between an upper frequenCy f1 gamma hHo/2 pi and a lower frequency f2 gamma NaHo/2 pi where gamma h is the gyromagnetic ratio for hydrogen and gamma Na is the gyromagnetic ratio for sodium to impart energy to the predominantly oriented nuclei to displace them from their predominant orientation, detecting means responsive to varying fields following removal of said alternating magnetic fields due substantially entirely to precession of nuclei in said unidirectional magnetic field, and means responsive to said detecting means for registering said output signals as a function of depth.
Claim 21
Independent Claim
154 words
A method of logging a well bore in which nuclei in formations adjacent thereto which possess a magnetic moment are polarized in a unidirectional magnetic field having a field strength that does not exceed a predetermined maximum value Ho at any point in said formations, the steps which comprise producing a second magnetic field substantially normal to said unidirectional field at a selected level in said well bore having a frequency between an upper frequency f1 gamma hHo/2 pi and a lower frequency f2 gamma NaHo/2 pi where gamma h is the gyromagnetic ratio for hydrogen and gamma Na is the gyromagnetic ratio for sodium whereby the predominant orientation of nuclei is disturbed, generating output signals representative of varying fields following removal of said second magnetic field which are due substantially entirely to precession of said nuclei in said unidirectional field, and registering said signal in correlation with the depth of said selected level.
Claim 22
Independent Claim
154 words
A method of logging a well bore in which nuclei in formations adjacent thereto which possess a magnetic moment are polarized in a unidirectional magnetic field having a field strength that does not exceed a predetermined maximum value Ho at any point in said formations, the steps which comprise producing a second magnetic field substantially normal to said unidirectional field at a selected level in said well bore having a frequency between an upper frequency f1 gamma hHo/2 pi and a lower frequency f2 gamma NaHo/2 pi where gamma h is the gyromagnetic ratio for hydrogen and gamma Na is the gyromagnetic ratio for sodium whereby the predominant orientation of nuclei is disturbed, generating output signals representative of varying fields following removal of said second magnetic field which are due substantially entirely to precession of said nuclei in said unidirectional field, and registering said signal in correlation with the depth of said selected level.
Claim 23
Independent Claim
153 words
The method of identifying at a plurality of measuring levels in a well bore the presence of materials at said measuring levels which include hydrogen nuclei polarized in a unidirectional magnetic field which comprises producing free precession of nuclei of said materials at said measuring level which exhibit a macroscopic magnetic moment by generating at each said measuring level a magnetic field at a substantial angle to said unidirectional magnetic field and abruptly removing said generated magnetic field, selectively generating an output signal having a frequency which is characteristic of the precession of the macroscopic moment vector of hydrogen nuclei produced by said abrupt termination of said field and dependent in amplitude upon the number of hydrogen nuclei, and recording said output signal characteristic of said vector of hydrogen nuclei in correlation with the depths of said measuring levels for production of a record indicative of regions in which hydrogen atoms are concentrated.
Claim 24
Independent Claim
153 words
The method of identifying at a plurality of measuring levels in a well bore the presence of materials at said measuring levels which include hydrogen nuclei polarized in a unidirectional magnetic field which comprises producing free precession of nuclei of said materials at said measuring level which exhibit a macroscopic magnetic moment by generating at each said measuring level a magnetic field at a substantial angle to said unidirectional magnetic field and abruptly removing said generated magnetic field, selectively generating an output signal having a frequency which is characteristic of the precession of the macroscopic moment vector of hydrogen nuclei produced by said abrupt termination of said field and dependent in amplitude upon the number of hydrogen nuclei, and recording said output signal characteristic of said vector of hydrogen nuclei in correlation with the depths of said measuring levels for production of a record indicative of regions in which hydrogen atoms are concentrated.
Claim 25
Independent Claim
131 words
The method of producing at a plurality of measuring levels in a well bore free precession of nuclei of materials of said formations which exhibit a macroscopic magnetic moment and are initially predominantly oriented in a unidirectional magnetic field, which comprises at each of said measuring levels applying to said unidirectional magnetic field which establishes the predominant orientation of said nuclei a second magnetic field at a substantial angle to the direction of said unidirectional magnetic field and abruptly removing said second magnetic field, generating an output signal from the resultant precession of the macroscopic moment vector of hydrogen nuclei, and recording said output signal in correlation with the depths of said measuring levels for producing a record of distinctive character for identification of hydrogen-bearing strata present at said measuring levels.
Claim 26
Independent Claim
131 words
The method of producing at a plurality of measuring levels in a well bore free precession of nuclei of materials of said formations which exhibit a macroscopic magnetic moment and are initially predominantly oriented in a unidirectional magnetic field, which comprises at each of said measuring levels applying to said unidirectional magnetic field which establishes the predominant orientation of said nuclei a second magnetic field at a substantial angle to the direction of said unidirectional magnetic field and abruptly removing said second magnetic field, generating an output signal from the resultant precession of the macroscopic moment vector of hydrogen nuclei, and recording said output signal in correlation with the depths of said measuring levels for producing a record of distinctive character for identification of hydrogen-bearing strata present at said measuring levels.
Claim 27
Independent Claim
126 words
A system for producing signals for the identification of the occurrence of hydrogen-bearing strata in a well bore, the nuclei of such hydrogen-bearing strata possessing a magnetic moment and predominantly oriented in a unidirectional magnetic field, comprising means for generating at each said measuring level a magnetic field at a substantial angle to said unidirectional magnetic fiEld and for abruptly removing said generated magnetic field thereby to produce precession of the macroscopic moment vector of hydrogen, detecting means responsive to said precession of said moment vector of hydrogen for producing an output signal, exhibiting means, and means including connections between said exhibiting means and said detecting means for production in correlation with the depths of said measuring levels indications of the magnitudes of said output signals.
Claim 28
Independent Claim
126 words
A system for producing signals for the identification of the occurrence of hydrogen-bearing strata in a well bore, the nuclei of such hydrogen-bearing strata possessing a magnetic moment and predominantly oriented in a unidirectional magnetic field, comprising means for generating at each said measuring level a magnetic field at a substantial angle to said unidirectional magnetic fiEld and for abruptly removing said generated magnetic field thereby to produce precession of the macroscopic moment vector of hydrogen, detecting means responsive to said precession of said moment vector of hydrogen for producing an output signal, exhibiting means, and means including connections between said exhibiting means and said detecting means for production in correlation with the depths of said measuring levels indications of the magnitudes of said output signals.
References Cited (Backward Citations)
US3250986A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-02 | 1975-02-01 | 1975-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-02 | 1979-02-01 | 1979-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-02 | 1983-02-01 | 1983-08-03 | $7700.00 | Window Closed / Lapsed |