GB2139745A - Cryogenic cell - Google Patents

Cryogenic cell Download PDF

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Publication number
GB2139745A
GB2139745A GB8409627A GB8409627A GB2139745A GB 2139745 A GB2139745 A GB 2139745A GB 8409627 A GB8409627 A GB 8409627A GB 8409627 A GB8409627 A GB 8409627A GB 2139745 A GB2139745 A GB 2139745A
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GB
United Kingdom
Prior art keywords
chamber
detector
logging tool
cryogenic cell
cell
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.)
Withdrawn
Application number
GB8409627A
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GB8409627D0 (en
Inventor
David William Mellor
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BP PLC
Original Assignee
BP PLC
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by BP PLC filed Critical BP PLC
Priority to GB8409627A priority Critical patent/GB2139745A/en
Publication of GB8409627D0 publication Critical patent/GB8409627D0/en
Publication of GB2139745A publication Critical patent/GB2139745A/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C3/00—Vessels not under pressure
    • F17C3/02—Vessels not under pressure with provision for thermal insulation
    • F17C3/08—Vessels not under pressure with provision for thermal insulation by vacuum spaces, e.g. Dewar flask
    • F17C3/085—Cryostats
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B36/00—Heating, cooling or insulating arrangements for boreholes or wells, e.g. for use in permafrost zones
    • E21B36/003—Insulating arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D19/00—Arrangement or mounting of refrigeration units with respect to devices or objects to be refrigerated, e.g. infrared detectors
    • F25D19/006—Thermal coupling structure or interface
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D3/00—Devices using other cold materials; Devices using cold-storage bodies
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
    • F17C2201/03—Orientation
    • F17C2201/032—Orientation with substantially vertical main axis
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/01—Reinforcing or suspension means
    • F17C2203/014—Suspension means
    • F17C2203/018—Suspension means by attachment at the neck
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/03—Thermal insulations
    • F17C2203/0375—Thermal insulations by gas
    • F17C2203/0387—Cryogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/03—Thermal insulations
    • F17C2203/0391—Thermal insulations by vacuum
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
    • F17C2203/0602—Wall structures; Special features thereof
    • F17C2203/0612—Wall structures
    • F17C2203/0626—Multiple walls
    • F17C2203/0631—Three or more walls
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
    • F17C2203/0634—Materials for walls or layers thereof
    • F17C2203/0636—Metals
    • F17C2203/0639—Steels
    • F17C2203/0643—Stainless steels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2260/00—Purposes of gas storage and gas handling
    • F17C2260/03—Dealing with losses
    • F17C2260/031—Dealing with losses due to heat transfer
    • F17C2260/033—Dealing with losses due to heat transfer by enhancing insulation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2260/00—Purposes of gas storage and gas handling
    • F17C2260/04—Reducing risks and environmental impact
    • F17C2260/042—Reducing risk of explosion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2260/00—Purposes of gas storage and gas handling
    • F17C2260/05—Improving chemical properties
    • F17C2260/053—Reducing corrosion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2270/00—Applications
    • F17C2270/05—Applications for industrial use
    • F17C2270/0518—Semiconductors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2270/00—Applications
    • F17C2270/05—Applications for industrial use
    • F17C2270/0545—Tools

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • General Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geophysics (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • Measurement Of Radiation (AREA)

Abstract

A cryogenic cell comprises (a) a sealed external annular chamber 5, adapted to be maintained under vacuum and to enclose totally (b) a sealed inner chamber 1 adapted for the storage of a solid/liquid refrigerant 2. The external chamber 5 has a well 7 in its upper region immediately above and in contact with the top of the inner chamber 1 which is connected at its lower end to a section 8 containing an adsorbent, the latter being connected at its lower end to a further chamber 10 adapted for the reception of a radiation detector. The cell is suitable for use in maintaining the semi-conductor detector of a neutron logging tool at the required low temperature. <IMAGE>

Description

SPECIFICATION Cryogenic cell This invention relates to a cryogenic cell and more particularlyto a cryogenic cell suitablefor use in a neutron activation analysis borehole logging tool.
Borehole logging tools comprise a probe for insertion down the borehole, the probe comprising a radioactive source of neutrons, a shield against radioactivity and a gamma ray detector.
The neutron curve obtained from the neutrongamma method registers the stimulated emission of gamma rays when the radioactive source is used to bombard the formation surrounding the bore hole with neutrons. It can be interpreted to give an indication ofthe nature ofthe formation. The emission is reduced by the presence of hydrogen and since porous rocks generally contain eitherwaterorhydro- carbons, low readings generally indicate low porosity.
Such tools are widely used forwell logging in the petroleum industry.
Attention is now turning to the in-situ analysis of coal deposits with particular reference to the sulphur content. However, this gives rise to considerable problems. The ten major elements present in coal produce a complex activation gamma spectrum comprising some four hundred gamma lines in the range 0.0 to 10.0 MeV. This implies a mean separation of 25 KeV between lines. In practice, many lines of interestare separated by less than 25 KeV. Therefore it follows that a gamma ray detector with the capability to resolve lines appreciably less than 25 KeV apart is required.
This restricts the choice of detectorto a semiconductor detector and since the latter must be kept at lowtemperatures ( < --180"C) some form of intensive cooling is necessary.
The use of a copper heat sink has been suggested butthis method is not entirely satisfactory since unless the sink is impracticably large a perceptible rise in temperature takes place over a short period oftime.
Another proposal has been to take advantage ofthe latent heat of fusion of substances such as propane and butene-1 with melting points around180 C.
According to one method of operation, the melting hydrocarbon is contained in a Dewarflask and the resulting vapours are allowed to escape. This has the advantage of maintaining the temperature constant over ionger periods but suffers from the disadvantagesofthe loss of refrigerant and more seriously, the production of a potentially explosive gaseous mixture. Another disadvantage lies in the requirement to use liquid nitrogen in order to cool the hydrocarbon to below its melting point. This process preciudes use of the technique in remote areas of the world where liquid nitrogen is unavailable.
It is an object of the present invention to produce a safe, totally enclosed cryogenic activation logging tool which does not sufferfrom the above disadvantages.
Thus according to the present invention there is provided a cryogenic cell comprising (a) a sealed external annular chamber, adapted to be maintained under vacuum and to enclose totally (b) a sealed inner chamber adapted forthe storage of a solid/liquid refrigerant, the external chamber having a well in its upper region immediately above and in contact with the top ofthe inner chamber, the inner chamber being connected at its lower end to a section containing an absorbent, the latter section being connected at its lower end to a further chamber adapted for the reception of a radiation detector.
The outer wall of the external chamber is preferably fabricated from a metal of high tensile strength and relatively low thermal conductivity such as 316 stainless steel.
The wall ofthe internal chamber is preferably fabricated from a material of high thermal conductivity such as copper, and insulated on its external surface.
The well in the external chamber is adapted to receive a "cold finger" and to transmit the ensuing low temperature to the inner chamber so that therefrigerant is substantially solidified before the commencementof operations, although a smalivapour space is preferably left. This eliminates the use of intermediate cryogenic materials such as liquid nitrogen.
The adsorbent in the lowertube acts as a cryopump and adsorbs impurities within the vacuum chamber.
Suitable adsorbents include molecular sieves and activated carbon.
Suitable refrigerants include hydrocarbons such as propane and butene-1.
As stated previously the cryogenic cell is particular lysuitableforuse in maintaining the detectorofa neutron logging tool at the required lowtemperature.
Thus according to another aspect of the present invention there is provided a neutron logging tool comprising a probe containing in sequence from the bottom end (a) a radioactive source of neutrons, (b) a shield against radioactivity, (c) a semi-conductor detectorforgamma radiation, (d) a preamplifier and (e) a cryogenic cell as hereinbefore described for maintaining the detector at a lowtemperature.
A suitable source is a 5Ci Am241-Be neutron source, such as obtained from Amersham International.
The shield is preferably a composite shield assembly comprising a lead scattererfollowed by a polyethylene moderator.
Asuitable detector is a reverse-electrode hyperpure coaxial germanium type. Such detectors are supplied by Canberra Instruments Ltd.
The output of a semi-conductor detectoris ofthe order of picoamps and therefore the preamplifier is necessary. Losses and noise may be reduced by positioning the preamplifier in a separate compartment as physically close to the detector as possible.
The pre-amplifierfield effect transistor (FET) is preferably positioned on the pre-amplifier printed circuit board-this is referred to as a warm FET configura- tion - and avoids the use of a cold FETwithinthe vacuum chamber.
The cryogenic cell may be chilled by commercially available closed cycle coolers comprising cold fingers.
Above the cryogenic cell will be the detector EHT supply, the main amplifier and the cable driverwhich transmits an analogue signal via an ordinary armoured single-core logging cable.
The invention is illustrated with reference to Figures 1 and 2 of the accompanying drawing which are schematic sections of a cryogenic cell.
The cell comprises an inner, oxygen free copper pressure vessel 1 containing mostly solid/liquid prop- ane 2 of 99.99% purity, although a small vapour space 3 is left. The purity level ofthe propane is important to reduce the risks of supercooling and eutectic shifts in melting point. The vessel 1 is surrounded by a layer 4 of aluminised "Mylar" insulating material.
The cell is initially charged with propane and then sealed for life. Alternatively the cell may be charged with butene-1 and then sealed for life. Butene-1 offers approximately 3% improvement in holding time over propane.
The inner vessel 1 is placed within an outer vessel 5 fabricated from 31 6stainless steel and the space 6 between the two vessels is evacuated to provide a vacuum.
The outer vessel 5 has a well 7 provided in its upper end, the bottom of the well being directly above the top ofthe inner vessel 1. The areas of the outer and innervessels in contact arewelded togetherto provide a thermally conducting pathway.
At its lower end, the innervessel is formed into a cylindrical section 8 containing apertures 9 for containing a molecular sieve adsorbentfor removing traces ofimpurities from the vacuum.
A hoilow aluminium block 10 containing a detector 11 is connected to the cylindrical section 8.
In orderto chill the contents of the cell before operating the logging tool,the cold fingershown in Fig. 2 is connected to a closed cycle cooler (not shown) and inserted into the well 6. The finger comprises a steel body 12 and a coppertip 13.

Claims (5)

1. A cryogenic cell comprising (a) a sealed external annular chamber, adapted to be maintained under vacuum and to enclose totally (b) a sealed inner chamberadaptedforthestorage of a solid/liquid refrigerant, the external chamber having a well in its upper region immediately above and in contact with the top of the inner chamber, the inner chamber being connected at its lower end to a section containing an absorbent, the latter section being connected at its lower end to a further chamber adapted for the reception of a radiation detector.
2. A neutron logging tool comprising a probe containing in sequence from the bottom end (al a radioactive source of neutrons, (b) a shield against radioactivity, (c) a semi-conductor detector for gam- ma radiation, (d) a preamplifierand (e) a cryogenic cell according to claim 1 for maintaining the detector at a lowtemperature.
3. A neutron logging tool according to claim 2 wherein the shield is a composite shield assembly comprising a lead scattererfollowed by a polyethylene moderator.
4. A neutron logging tool according to either of claims 2 or 3 wherein the semi-conductor detector is a reverseelectrcde hyperpure co-axial germanium type.
5. A cryogenic cell as hereinbefore described with reference to the accompanying drawing.
GB8409627A 1983-04-16 1984-04-13 Cryogenic cell Withdrawn GB2139745A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8409627A GB2139745A (en) 1983-04-16 1984-04-13 Cryogenic cell

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8310365 1983-04-16
GB8409627A GB2139745A (en) 1983-04-16 1984-04-13 Cryogenic cell

Publications (2)

Publication Number Publication Date
GB8409627D0 GB8409627D0 (en) 1984-05-23
GB2139745A true GB2139745A (en) 1984-11-14

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB8409627A Withdrawn GB2139745A (en) 1983-04-16 1984-04-13 Cryogenic cell

Country Status (1)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0191962A1 (en) * 1983-10-21 1986-08-27 The British Petroleum Company p.l.c. Cryogenic cell
GB2268796A (en) * 1992-07-15 1994-01-19 Outokumpu Instr Oy Mounting of a cooling element
US5349823A (en) * 1992-02-14 1994-09-27 Intel Corporation Integrated refrigerated computer module
US5561984A (en) * 1994-04-14 1996-10-08 Tektronix, Inc. Application of micromechanical machining to cooling of integrated circuits

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0191962A1 (en) * 1983-10-21 1986-08-27 The British Petroleum Company p.l.c. Cryogenic cell
US5349823A (en) * 1992-02-14 1994-09-27 Intel Corporation Integrated refrigerated computer module
GB2268796A (en) * 1992-07-15 1994-01-19 Outokumpu Instr Oy Mounting of a cooling element
GB2268796B (en) * 1992-07-15 1996-11-06 Outokumpu Instr Oy Method for providing cooling and a cooling apparatus suited for the same
US5561984A (en) * 1994-04-14 1996-10-08 Tektronix, Inc. Application of micromechanical machining to cooling of integrated circuits

Also Published As

Publication number Publication date
GB8409627D0 (en) 1984-05-23

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