GB1384357A - Pulsed neutron porosity and neutron lifetime logging - Google Patents
Pulsed neutron porosity and neutron lifetime loggingInfo
- Publication number
- GB1384357A GB1384357A GB1252773A GB1252773A GB1384357A GB 1384357 A GB1384357 A GB 1384357A GB 1252773 A GB1252773 A GB 1252773A GB 1252773 A GB1252773 A GB 1252773A GB 1384357 A GB1384357 A GB 1384357A
- Authority
- GB
- United Kingdom
- Prior art keywords
- neutron
- time
- porosity
- decay time
- pulses
- 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
- 230000015572 biosynthetic process Effects 0.000 abstract 4
- 238000005755 formation reaction Methods 0.000 abstract 4
- 230000005855 radiation Effects 0.000 abstract 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 abstract 1
- 238000001514 detection method Methods 0.000 abstract 1
- 230000005251 gamma ray Effects 0.000 abstract 1
- 230000005283 ground state Effects 0.000 abstract 1
- 229910052739 hydrogen Inorganic materials 0.000 abstract 1
- 239000001257 hydrogen Substances 0.000 abstract 1
- 230000001678 irradiating effect Effects 0.000 abstract 1
- 238000005259 measurement Methods 0.000 abstract 1
- 238000000034 method Methods 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
- G01V5/102—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 the neutron source being of the pulsed type
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
1384357 Neutron well-logging TEXACO DEVELOPMENT CORP 15 March 1973 [17 May 1972] 12527/73 Heading G1A The porosity of earth formations surrounding a well borehole is measured by irradiating the formation with high energy neutron pulses, detecting during at least two intervals between successive pulses the gamma radiation resulting from the capture of thermalised neutrons, deriving from the measurements the thermal neutron decay time and combining this time with the neutron pulse duration and the number of 7-ray counts occuring during one of the detection intervals to derive a porosity related parameter. As shown, Fig.1, the apparatus consists of a log head containing a pulsed fast neutron source 11 and a detector comprising a scintillator 12 and a photo-multiplier 10. The fast neutrons are thermalised and then captured by the earth formations 3, the excited atoms then returning to the ground state with the emission of a γ-ray. A discriminator 18 rejects low energy pulses produced by background radiation and the remaining pulses are passed to the surface processing circuitry which uses a known sliding gate method involving the opening of three gates 21, 22, 23 in sequence between neutron pulses to produce counts representing the neutron decay characteristics. The processing circuitry 25 determines the thermal neutron decay time and produces a control signal to the neutron source pulsing circuit 14 so that a pulse of neutrons having a length equal to this decay time is emitted by source 11. The gates 21 to 23 are also controlled to open at times and for periods related to the decay time. Signals representing the thermal neutron decay time together with the number of counts received while the first gate 21 is open and the time for which the source is pulsed (if this differs from the decay time) are applied to a porosity computer 26 which determines the neutron moderation time by means of given equations. The moderation time depends on the hydrogen content of the earth formations which is related to the porosity. A recorder 27 plots the neutron decay time and the neutron moderation time (which may be calibrated in terms of porosity) as a function of the depth of the log as determined from the rotation of the cable sheave 9.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US25428172A | 1972-05-17 | 1972-05-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1384357A true GB1384357A (en) | 1975-02-19 |
Family
ID=22963662
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1252773A Expired GB1384357A (en) | 1972-05-17 | 1973-03-15 | Pulsed neutron porosity and neutron lifetime logging |
Country Status (4)
| Country | Link |
|---|---|
| DE (1) | DE2324446A1 (en) |
| FR (1) | FR2184988B1 (en) |
| GB (1) | GB1384357A (en) |
| HU (1) | HU170520B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2173591A (en) * | 1985-04-01 | 1986-10-15 | S I E Inc | Pulsed neutron well-logging method |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2650345C2 (en) * | 1975-11-03 | 1985-08-29 | Texaco Development Corp., White Plains, N.Y. | Method and device for measuring the volume flow rate of water in a borehole area to be investigated |
-
1973
- 1973-03-15 GB GB1252773A patent/GB1384357A/en not_active Expired
- 1973-05-15 DE DE19732324446 patent/DE2324446A1/en active Pending
- 1973-05-17 HU HUTE000714 patent/HU170520B/hu unknown
- 1973-05-17 FR FR7317969A patent/FR2184988B1/fr not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2173591A (en) * | 1985-04-01 | 1986-10-15 | S I E Inc | Pulsed neutron well-logging method |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2324446A1 (en) | 1973-11-29 |
| FR2184988B1 (en) | 1977-02-11 |
| HU170520B (en) | 1977-06-28 |
| FR2184988A1 (en) | 1973-12-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |