http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-2211947-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_70ec63d39d6704bacc5c7068c93ded43 |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/G01V3-32 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/G01N24-00 http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/G01V3-32 |
| filingDate | 1988-11-03^^<http://www.w3.org/2001/XMLSchema#date> |
| inventor | http://rdf.ncbi.nlm.nih.gov/pubchem/patentinventor/MD5_d20d954d25213ad433ad6b1f091428a1 |
| publicationDate | 1989-07-12^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-2211947-A |
| titleOfInvention | Nuclear magnetism borehole logging tool |
| abstract | A borehole logging device is disclosed for measuring the nuclear magnetism response of earth formations following the application of a large magnetic polarising pulse. The device employs a detector that is capable of detecting both sinusoidal and slowly varying changes in magnetic field, the former being caused by precession of mobile nuclei about the earth's magnetic field at their Larmor frequency and decaying with a short relaxation time T2*, and the latter being due to polarisation decay with a long relaxation time T1. Thus both T1 and T2* may be determined in a single measured cycle. Such a detector may be one or more laser-pumped helium magnetometers, or one or more high-temperature Superconducting Quantum Interference Devices (SQUID). The invention uses a micro-miniature Joule-Thomson refrigerator to maintain the high-temperature SQUIDs below their superconducting transition points. The SQUIDs are flux coupled in an axial gradiometer configuration to reduce motion-induced magnetic noise. <IMAGE> |
| priorityDate | 1987-11-05^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
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