GB1396642A - Borehole gamma ray spectroscopy - Google Patents
Borehole gamma ray spectroscopyInfo
- Publication number
- GB1396642A GB1396642A GB1507873A GB1507873A GB1396642A GB 1396642 A GB1396642 A GB 1396642A GB 1507873 A GB1507873 A GB 1507873A GB 1507873 A GB1507873 A GB 1507873A GB 1396642 A GB1396642 A GB 1396642A
- Authority
- GB
- United Kingdom
- Prior art keywords
- spectrum
- comparison
- borehole
- gamma ray
- gate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000001730 gamma-ray spectroscopy Methods 0.000 title 1
- 238000001228 spectrum Methods 0.000 abstract 10
- 230000015572 biosynthetic process Effects 0.000 abstract 4
- 238000005755 formation reaction Methods 0.000 abstract 4
- 239000000203 mixture Substances 0.000 abstract 4
- 239000002131 composite material Substances 0.000 abstract 3
- 230000005251 gamma ray Effects 0.000 abstract 3
- FVAUCKIRQBBSSJ-UHFFFAOYSA-M sodium iodide Chemical compound [Na+].[I-] FVAUCKIRQBBSSJ-UHFFFAOYSA-M 0.000 abstract 3
- 239000000463 material Substances 0.000 abstract 2
- 230000001360 synchronised effect Effects 0.000 abstract 2
- XQPRBTXUXXVTKB-UHFFFAOYSA-M caesium iodide Chemical compound [I-].[Cs+] XQPRBTXUXXVTKB-UHFFFAOYSA-M 0.000 abstract 1
- 238000004590 computer program Methods 0.000 abstract 1
- 239000008710 crystal-8 Substances 0.000 abstract 1
- 238000010586 diagram Methods 0.000 abstract 1
- 238000000084 gamma-ray spectrum Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 abstract 1
- 235000009518 sodium iodide Nutrition 0.000 abstract 1
- 229910052722 tritium Inorganic materials 0.000 abstract 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V5/00—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity
- G01V5/04—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging
- G01V5/08—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays
- G01V5/10—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources
- G01V5/101—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources and detecting the secondary Y-rays produced in the surrounding layers of the bore hole
Landscapes
- Physics & Mathematics (AREA)
- High Energy & Nuclear Physics (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Geophysics And Detection Of Objects (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
Abstract
1396642 Borehole logging apparatus TEXACO DEVELOPMENT CORP 29 March 1973 15078/73 Heading G1A In a method for determining the unknown composition of earth formations surrounding a well borehole, standard gamma ray energy spectra of materials postulated to be in the formations surrounding a borehole are provided, gamma ray energy spectra of the unknown materials in the formation surrounding a borehole are obtained, each unknown gamma ray spectrum is compared with a composite standard spectrum comprising a weighted mixture of said standard spectra at a selected number of energy levels, and the characteristics of the composite spectrum are varied and the above composition is repeated in an iterative manner to achieve an optimized comparison. As shown, a sonde 5 contains a pulsed neutron source 11, e.g. a denterium-tritium accelerator and a gamma ray detector e.g. a sodium iodide or cesium iodide crystal 8 and a photo-multiplier 9. The output of the photo-multiplier is fed to an amplifier 13 and discriminator 14 whose output is applied to a gate 15 which is synchronized with the pulsed neutron source with an appropriate delay. The output of the gate 15 is applied to a driver 16 which supplies the signals to the surface via a cable 6. The signals pass to a pulse height analyzer 23 via a gate 40 synchronized with the gate 15. The analyzer 23 includes a plurality of channels whose outputs are applied to a comparison computer 42 which also receives the standard spectra from a source 30. These standard spectra are obtained using the same sonde in a borehole surrounded by formations of known composition. The results of the comparison are recorded at 46. The outputs of the pulse height analyzer 23 may be applied to a second recorder 27 for subsequent comparison at a later time. Details of the computer program flow diagrams and the comparison operation are described with reference to, Figs. 2-5 (not shown). Basically, each unknown spectrum is compared with a weighted composite spectrum and this latter spectrum is altered and the comparison repeated in an iterative manner until the best fit has been found. The principle of least squares is used.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1507873A GB1396642A (en) | 1973-03-29 | 1973-03-29 | Borehole gamma ray spectroscopy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1507873A GB1396642A (en) | 1973-03-29 | 1973-03-29 | Borehole gamma ray spectroscopy |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1396642A true GB1396642A (en) | 1975-06-04 |
Family
ID=10052629
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1507873A Expired GB1396642A (en) | 1973-03-29 | 1973-03-29 | Borehole gamma ray spectroscopy |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1396642A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1988008143A2 (en) * | 1987-04-14 | 1988-10-20 | Compagnie Generale Des Matieres Nucleaires | Method and apparatus for evaluating the rare metal content of a natural geological formation |
| EP0465276A2 (en) * | 1990-05-09 | 1992-01-08 | Schlumberger Limited | Method for determining oil and water saturation in earth formation surrounding a borehole |
| EP0621494A1 (en) * | 1993-04-23 | 1994-10-26 | Schlumberger Limited | Method of gain regulation for downhole spectroscopy tools without using a calibration source |
-
1973
- 1973-03-29 GB GB1507873A patent/GB1396642A/en not_active Expired
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1988008143A2 (en) * | 1987-04-14 | 1988-10-20 | Compagnie Generale Des Matieres Nucleaires | Method and apparatus for evaluating the rare metal content of a natural geological formation |
| FR2614111A1 (en) * | 1987-04-14 | 1988-10-21 | Cogema | METHOD AND APPARATUS FOR EVALUATING THE RARE METAL CONTENT OF A NATURAL GEOLOGICAL FORMATION |
| WO1988008143A3 (en) * | 1987-04-14 | 1988-12-15 | Cogema | Method and apparatus for evaluating the rare metal content of a natural geological formation |
| EP0296894A2 (en) * | 1987-04-14 | 1988-12-28 | Compagnie Generale Des Matieres Nucleaires (Cogema) | Method and apparatus for determining the grade of a rare metal in a geological formation |
| EP0296894A3 (en) * | 1987-04-14 | 1989-01-11 | Compagnie Generale Des Matieres Nucleaires (Cogema) | Method and apparatus for determining the grade of a rare metal in a geological formation |
| AU600579B2 (en) * | 1987-04-14 | 1990-08-16 | Compagnie Generale Des Matieres Nucleaires (Cogema) S.A. | Method and apparatus for evaluating the rare metal content of a natural geological formation |
| EP0465276A2 (en) * | 1990-05-09 | 1992-01-08 | Schlumberger Limited | Method for determining oil and water saturation in earth formation surrounding a borehole |
| EP0465276A3 (en) * | 1990-05-09 | 1993-01-13 | Schlumberger Limited | Method for determining oil and water saturation in earth formation surrounding a borehole |
| EP0621494A1 (en) * | 1993-04-23 | 1994-10-26 | Schlumberger Limited | Method of gain regulation for downhole spectroscopy tools without using a calibration source |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |