A new thermos bottle capable of improving the measurement accuracy of lithology density logging instrument Pe value

Abstract

The utility model provides a new thermos bottle that can improve lithology density logging instrument Pe value measurement precision, include: barrel body include: the coaxial sleeve of outer tube is located in instrument shell; The coaxial sleeve of inner tube is located in outer tube, and there is gap between the outer wall of inner tube and outer tube, and the inner tube is used for setting detector; The first end of the first closed structure is closed barrel body; The second closed structure is connected with outside vacuumizing device, and the gap is vacuumized; Wherein, hollow structure is set up on the barrel body, and beryllium layer is installed in the hollow structure; Beryllium window is set up on instrument shell, and beryllium layer is opposite to detector and beryllium window respectively. So as to open hollow structure and install beryllium layer at the corresponding detector and beryllium window of instrument shell of barrel body, not only can the heat of superhigh temperature be isolated by vacuum gap and closed structure, and the detector is protected, but also can the low energy gamma ray absorption be reduced by beryllium layer, and the ray is detected smoothly, so as to improve Pe value measurement precision.

Description

Technical Field

[0001] This utility model relates to the field of nuclear logging instrument technology, and more specifically, to a novel thermos bottle that can improve the accuracy of Pe value measurement in lithology density logging instruments. Background Technology

[0002] (1) Measurement principle of lithology density logging tool: Lithology density logging uses a gamma source (cesium-137, emitting 0.662 MeV gamma rays) to emit medium-energy gamma rays into the formation. The gamma rays interact with the formation material primarily through two processes: Compton effect: closely related to formation electron density, mainly used to measure formation volume density.

[0003] The photoelectric effect is closely related to the atomic number Z of the formation elements, and its strength is characterized by the photoelectric absorption cross-section index Pe. The Pe value is highly sensitive to lithology. Instruments typically employ dual detectors (long source spacing and short source spacing) and energy window segmentation techniques (e.g., setting high-energy windows and low-energy windows) to acquire density and Pe value information separately. The Pe value is obtained by measuring information such as the gamma-ray count rate in the low-energy window and processing it through a specific algorithm. Therefore, detecting low-energy gamma rays (typically below 200 keV) is crucial for calculating the Pe value.

[0004] To ensure the transmittance of the instrument to low-energy gamma rays, a beryllium window is usually set on the outer shell of the instrument at the corresponding position of the detector window. Beryllium is a light metal with an atomic number Z=4, so its absorption of low-energy gamma photons is very weak, which allows low-energy gamma photons carrying lithological (Pe value) information to pass through the beryllium window in large quantities and be accurately recorded by the detector.

[0005] (2) The necessity of using new thermos bottles for thermal management of logging tools in high-temperature environments: Generally, high-temperature lithology density logging tools operate at temperatures not exceeding 175°C, and their electronic components and detectors function normally within this temperature range, thus eliminating the need for new insulated bottles. However, for ultra-high-temperature lithology density logging tools, the well environment temperature is much higher (generally exceeding 175°C, and in some cases reaching 260°C). At this ambient temperature, most electronic components and detectors cannot function properly and may even be damaged. In such cases, it is essential to install the detectors and electronic components inside a new insulated bottle with a heat absorber to slow down the rate of temperature rise within the bottle, thereby ensuring the instrument's effective measurement time in ultra-high-temperature environments.

[0006] (3) The impact of the new type of thermos bottle on the measurement of lithological density instruments: The influence of metal Dewar flasks on Pe measurements is negative and multifaceted, mainly manifested in the following aspects: Impact 1: Directly contributes to high photoelectric effect signal (most significant impact) Gamma rays emitted from the source, after interacting with the geological material, must pass through the metal wall of the new thermos bottle before being received by the detector. Low-energy gamma rays undergo a strong photoelectric effect with the high-Z metal outer shell of the new thermos bottle, resulting in significant absorption. This leads to a decrease in the count rate of low-energy gamma rays received by the detector. This directly results in a substantial reduction in the instrument's accuracy in measuring the Pe value.

[0007] Impact 2: Changes in the instrument's energy spectrum response and detection characteristics "Hardened" energy spectrum: The metal walls of the new thermos bottle preferentially absorb low-energy gamma rays, causing the average energy of the gamma rays that can penetrate it and enter the formation or return to the detector to "harden" (increase). This changes the inherent shape of the instrument's energy spectrum, rendering the count rate calculation model based on the standard energy window invalid.

[0008] (4) Improvement measures for existing technologies: Given the impact of the novel thermos bottle's metal casing on Pe value measurement, existing technologies can mitigate this impact through the following measures: One approach is to optimize the thermos bottle's casing structure by using materials with lower Z-values, such as titanium alloys (TA2, TA18, or TC4) instead of traditional austenitic stainless steel (AISI 321 or AISI 316L). However, this optimization offers limited improvement to Pe value measurement accuracy; instruments with the novel thermos bottle structure still exhibit insufficient Pe value measurement accuracy compared to those without it. Another approach is to reduce the thickness of the novel thermos bottle casing structure while maintaining the same material to reduce its attenuation of low-energy gamma rays. However, this inevitably leads to a decrease in the structural strength of the novel thermos bottle and is therefore less commonly used.

[0009] In summary, existing ultra-high temperature lithological density logging tools have the following shortcomings in Pe value measurement: 1. Due to the attenuation effect of the new thermos bottle body on low-energy gamma rays, the ultra-high temperature lithology density logging tool is significantly less accurate in measuring Pe value than the general high temperature lithology density logging tool. 2. Optimizing the material of the new thermos bottle body can reduce the impact of the new thermos bottle on the accuracy of Pe value measurement to some extent, but the improvement is limited and does not fundamentally solve the problem.

[0010] Based on the above situation, there is an urgent need for a new type of thermos bottle that can improve the accuracy of Pe value measurement in lithology density logging tools in order to solve the problems in the existing technology. Utility Model Content

[0011] The main objective of this invention is to provide a novel thermos bottle that can improve the accuracy of Pe value measurement in lithology density logging tools, thereby at least solving the problem that the novel thermos bottle body affects the accuracy of Pe value measurement in ultra-high temperature lithology density logging tools in the prior art.

[0012] To achieve the above objectives, this utility model provides a novel thermos bottle that improves the accuracy of Pe value measurement in lithology density logging tools, comprising: a cylindrical body coaxially fitted inside an instrument housing; the cylindrical body comprising: an outer cylinder coaxially fitted inside the instrument housing; an inner cylinder coaxially fitted inside the outer cylinder, with a gap between the outer wall of the inner cylinder and the interior of the outer cylinder, the inner cylinder being used to house a detector; a first sealing structure fixedly disposed at a first end of the cylindrical body for sealing the first end of the cylindrical body; and a second sealing structure disposed at a second end of the cylindrical body for connecting to an external vacuum pumping device to evacuate the gap; wherein, the cylindrical body has a perforated structure in which a beryllium layer is installed; the instrument housing has a beryllium window, the beryllium layer being opposite to the detector and the beryllium window respectively.

[0013] Optionally, the beryllium layer includes a first beryllium layer and a second beryllium layer, and the outer cylinder includes: an interconnecting cylinder; a first outer cylinder, the first end of which is sleeved on the outer wall of the second end of the interconnecting cylinder; and a second outer cylinder, the second end of which is sleeved on the outer wall of the first end of the interconnecting cylinder; wherein, a first perforated structure is formed on the interconnecting cylinder, the first beryllium layer is installed at the first perforated structure, and the inner wall of the outer edge of the first beryllium layer is fixed to the outer wall of the edge of the first perforated structure, and the first beryllium layer is opposite to the beryllium window.

[0014] Optionally, the inner cylinder includes: an inner cylinder body, which is fitted inside the outer cylinder, and there is a gap between the outer wall of the inner cylinder body and the inner wall of the outer cylinder; a fixing plate, which is an annular plate with a through hole in the middle, and a second hollow structure is formed on the inner cylinder body, and the bottom wall of the outer edge of the fixing plate is fixed to the outer wall of the edge of the second hollow structure; wherein, the second beryllium layer is disposed at the through hole, and the outer wall of the second beryllium layer is fixed to the bottom wall of the inner edge of the fixing plate, and the second beryllium layer is opposite to the first beryllium layer and the detector respectively.

[0015] Optionally, after the first beryllium layer and the second beryllium layer are fixed, the outer wall of the layer not attached to the interconnecting cylinder or the fixing plate is silver-plated; the inner wall of the interconnecting cylinder and the outer wall of the fixing plate are silver-plated.

[0016] Optionally, the outer wall of the first beryllium layer does not extend beyond the outer wall of the interconnecting cylinder, and the inner wall of the second beryllium layer does not extend beyond the inner wall of the fixing plate.

[0017] Optionally, the first closed structure includes: A first end cap is disposed at the second end of the first outer cylinder and the second end of the inner cylinder on the same side. The first end cap is used to seal one end of the gap and the first end of the inner cylinder.

[0018] Optionally, the second sealing structure includes: an inner cylinder cap disposed at the first end of the inner cylinder, the inner cylinder cap including a circular sealing plate and a plurality of teeth evenly distributed on the outer edge of the circular sealing plate, the circular sealing plate being used to seal the first end of the inner cylinder, and the edges of the plurality of teeth abutting against the inner wall of the outer cylinder; a second end cap, the first end of the second end cap being sleeved on the second end of the second outer cylinder; a connector being fixedly connected to the second end face of the second end cap; wherein, an air extraction nozzle is disposed on the second end cap, the air extraction nozzle being connected to an external vacuum device.

[0019] Optionally, the second end cap is further provided with a getter assembly that communicates with the gap.

[0020] Optionally, spacers and reflective screens are alternately arranged in the gap between the inner cylinder and the outer cylinder; The spacer is either polyester cloth or fiberglass cloth; the reflective screen is aluminum foil.

[0021] This utility model discloses a novel thermos bottle for improving the accuracy of Pe value measurement in lithology density logging instruments. The bottle comprises: a cylindrical body coaxially fitted inside an instrument housing; the cylindrical body includes: an outer cylinder coaxially fitted inside the instrument housing; an inner cylinder coaxially fitted inside the outer cylinder, with a gap between the outer wall of the inner cylinder and the interior of the outer cylinder, the inner cylinder housing a detector; a first sealing structure fixedly disposed at a first end of the cylindrical body for sealing the first end; and a second sealing structure disposed at a second end of the cylindrical body for connecting to an external vacuum pump to evacuate the gap; wherein the cylindrical body has a perforated structure in which a beryllium layer is installed; the instrument housing has a beryllium window, the beryllium layer being opposite to the detector and the beryllium window respectively. By coaxially fitting the outer and inner cylinders to form a cylinder body, a first sealing structure seals the first end of the cylinder body, a second sealing structure seals the second end of the cylinder body, and a vacuum is drawn between the inner and outer cylinders by connecting to the outside. At the same time, a perforated structure is opened in the cylinder body corresponding to the detector and the beryllium window of the instrument shell to install a beryllium layer. The vacuum gap and the sealing structure isolate ultra-high temperature heat transfer and protect the detector, while the beryllium layer reduces the absorption of low-energy gamma rays, ensuring that the rays can be detected smoothly. This improves the accuracy of Pe value measurement, provides reliable data for judging the oil and gas potential of the reservoir, determining the effective reservoir range, and formulating oil and gas exploration and development plans, and avoids the impact of lithological misjudgment or well logging data deviation on exploration efficiency and development benefits. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings: Figure 1 This is a schematic diagram of the cross-sectional structure of an optional thermos bottle according to an embodiment of the present utility model; Figure 2 yes Figure 1 Enlarged view of region A in the middle; Figure 3 yes Figure 1 Enlarged view of region B in the middle; Figure 4 This is a schematic diagram of an optional inner cylinder cross-sectional structure according to an embodiment of the present utility model; Figure 5 yes Figure 4 Schematic diagram of the SS section; Figure 6 This is a schematic diagram of an optional inner cylinder cap along the axial direction of the thermos bottle according to an embodiment of the present utility model; Figure 7 This is a schematic diagram showing the optional spacer and reflective screen arranged in the gap according to an embodiment of the present utility model.

[0023] Figure label: 10. Outer cylinder; 11. Interconnecting cylinder; 12. First outer cylinder; 13. Second outer cylinder; 14. First beryllium layer; 15. First weld; 16. First alloy brazing filler metal; 20. Inner cylinder; 21. Inner cylinder body; 22. Fixing plate; 23. Second beryllium layer; 24. Second weld; 25. Second alloy brazing filler metal; 30. First sealing structure; 31. First end cap; 40. Second sealing structure; 41. Inner cylinder cover; 42. Second end cap; 43. Vacuum nozzle; 44. Getter assembly; 45. Connector; 50. Spacer; 60. Reflector. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] like Figures 1-7 As shown, a novel thermos bottle that can improve the accuracy of Pe value measurement in lithology density logging tools includes: A cylindrical body, which is coaxially sleeved inside the instrument housing; The cylindrical body includes: Outer cylinder 10, which is coaxially sleeved inside the instrument housing; Inner cylinder 20, which is coaxially sleeved inside outer cylinder 10, and there is a gap between the outer wall of inner cylinder 20 and the interior of outer cylinder 10. The inner cylinder 20 is used to house detectors. A first sealing structure 30 is fixedly disposed at the first end of the cylinder and is used to seal the first end of the cylinder. The second sealing structure 40 is disposed at the second end of the cylinder and is used to connect with an external vacuum pumping device to evacuate the gap. The cylindrical body has a hollow structure in which a beryllium layer is installed; the instrument shell has a beryllium window, and the beryllium layer is opposite to the detector and the beryllium window respectively.

[0026] Specifically, in ultra-high temperature lithology density logging scenarios, the instrument casing is a pressure-bearing casing made of high-strength stainless steel to protect the internal thermos bottle and logging components from the complex downhole environment (such as high pressure and impact). To ensure that low-energy gamma rays can effectively penetrate to achieve Pe value measurement, a beryllium window is specially provided on the instrument casing. The beryllium window is made of beryllium material with atomic number Z=4, which has extremely weak absorption of low-energy gamma photons, allowing low-energy gamma rays carrying lithology information to smoothly enter the interior of the instrument casing.

[0027] The outer cylinder 10, coaxially fitted within the instrument housing, employs a double-layer sealed structure, consisting of an outer cylinder 10 and an inner cylinder 20. This provides thermal insulation protection for the internal detector in ultra-high temperature environments and ensures the accuracy of Pe value measurements by reducing the absorption of low-energy gamma rays. The outer cylinder 10, coaxially fitted within the instrument housing, is made of austenitic stainless steel AISI 321. This material has a thermal conductivity of approximately 16.2 W / m*K at room temperature, lower than martensitic and duplex stainless steels, effectively reducing end-heat conduction between the inner and outer cylinders 10 and minimizing the transfer of external high temperatures to the interior. The outer cylinder 10 and inner cylinder 20 together form a sealed interlayer space, a key outer structure for achieving thermal insulation and a vacuum environment. The inner cylinder 20, coaxially fitted within the outer cylinder 10, encloses a space within its inner wall for housing core logging components such as detectors and electronic devices. A gap exists between the outer wall of the inner cylinder 20 and the inner wall of the outer cylinder 10. The inner cylinder 20 is also made of austenitic stainless steel AISI 321, which works in conjunction with the outer cylinder 10 to achieve double-layer heat insulation.

[0028] The first sealing structure 30 is fixed to the first end of the cylinder and sealed using argon arc welding. The second sealing structure 40 is located at the second end of the cylinder and is sealed to the outer cylinder 10 via argon arc welding. It is also connected to an external vacuum device to evacuate the gap between the inner and outer cylinders 10. This vacuuming operation creates a high vacuum in the gap, thereby isolating the inner and outer cylinders 10 from convective heat transfer and most of the gas heat conduction.

[0029] A perforated structure is created on the cylinder body, corresponding to the beryllium window on the detector in the inner cylinder 20 and the instrument housing. This provides a penetration channel for low-energy gamma rays, preventing the original metal material of the cylinder body from blocking the rays and ensuring that the low-energy gamma rays carrying lithological (Pe value) information can smoothly reach the detector, thus clearing obstacles for accurate Pe value measurement. The beryllium layer is installed in the perforated structure and is sealed to the interconnecting cylinder 11 of the outer cylinder 10 and the fixing plate 22 of the inner cylinder 20 by brazing. Beryllium has an atomic number of only 4 (Z=4), and its absorption capacity for low-energy gamma photons is extremely weak, which can minimize the absorption of low-energy gamma rays carrying Pe value information by the cylinder body material.

[0030] Within the inner cylinder 20, from the second closed structure 40 to the first closed structure 30, a detector assembly (including a shield and a detector, with a shield opening on the side facing the instrument to contact the ground for X-ray transmission), electronic components, a heat absorber, and a heat insulation sleeve are sequentially installed. The thermos bottle is entirely installed inside the instrument casing.

[0031] This application constructs a cylinder body by coaxially sleeved outer cylinder 10 and inner cylinder 20. The first end of the cylinder body is sealed by a first sealing structure 30, and the second end of the cylinder body is sealed by a second sealing structure 40. The cylinder body is connected to the outside to evacuate the gap between the inner and outer cylinders 10. At the same time, a perforated structure is opened in the cylinder body at the beryllium window corresponding to the detector and the instrument shell to install a beryllium layer. The vacuum gap and the sealing structure isolate ultra-high temperature heat transfer and protect the detector. The beryllium layer reduces the absorption of low-energy gamma rays, ensuring that the rays can be detected smoothly. This improves the accuracy of Pe value measurement and provides reliable data for judging the oil and gas potential of the reservoir, determining the effective reservoir range, and formulating oil and gas exploration and development plans. It avoids the impact of lithological misjudgment or well logging data deviation on exploration efficiency and development benefits.

[0032] In one possible implementation, the beryllium layer includes a first beryllium layer 14 and a second beryllium layer 23, and the outer cylinder 10 includes: Interconnected tube 11; The first outer cylinder 12, the first end of the first outer cylinder 12 is sleeved on the outer wall of the second end of the interconnecting cylinder 11; The second outer cylinder 13, the second end of the second outer cylinder 13 is sleeved on the outer wall of the first end of the interconnecting cylinder 11; The interconnecting cylinder 11 has a first hollow structure, the first beryllium layer 14 is installed at the first hollow structure, and the inner wall of the outer edge of the first beryllium layer 14 is fixed to the outer wall of the edge of the first hollow structure. The first beryllium layer 14 is opposite to the beryllium window.

[0033] Specifically, the connecting cylinder 11 has a circular structure and is made of the same material as the first outer cylinder 12 and the second outer cylinder 13, all of which are austenitic stainless steel AISI 321. The first outer cylinder 12 and the second outer cylinder 13 are assembled with the connecting cylinder 11 by a sleeve connection: the first end of the first outer cylinder 12 is sleeved on the outer wall of the second end of the connecting cylinder 11, and the second end of the second outer cylinder 13 is sleeved on the outer wall of the first end of the connecting cylinder 11. After the sleeve connection, the sealing is further reinforced by welding (such as argon arc welding). The weld formed by welding the first outer cylinder 12 to the connecting cylinder 11 and the second outer cylinder 13 to the connecting cylinder 11 is the first weld 15. The sleeve connection combined with welding can ensure the structural strength of the outer cylinder 10 to cope with the high pressure and vibration conditions downhole, and also ensure the sealing performance of the outer cylinder 10, providing a basis for the subsequent cooperation with the inner cylinder 20 to form a gap, and to isolate convective heat transfer and gas heat conduction through vacuuming.

[0034] The first perforated structure on the interconnecting cylinder 11 is positioned, shaped, and sized to match the detector's detection range and the size of the beryllium window on the instrument housing. This ensures that low-energy gamma rays (typically below 200 keV) carrying Pe value information can completely cover the detector's receiving surface, preventing ray blockage due to misalignment or dimensional deviation of the perforated structure. The first beryllium layer 14, approximately 0.5 mm thick, is installed at the first perforated structure. Its outer edge and inner wall are fixed to the outer wall of the first perforated structure using a brazing process. The brazing process uses a first alloy filler metal 16, ensuring a seamless weld to prevent air leakage after subsequent vacuuming, which would compromise the heat insulation effect, and also avoiding the impact of high welding temperatures on the beryllium layer's performance.

[0035] In one possible implementation, the inner cylinder 20 includes: The inner cylinder body 21 is sleeved inside the outer cylinder 10, and there is a gap between the outer wall of the inner cylinder body 21 and the inner wall of the outer cylinder 10. The fixing plate 22 is an annular plate with a through hole in the middle. The inner cylinder body 21 has a second hollow structure. The bottom wall of the outer edge of the fixing plate 22 is fixed to the outer wall of the edge of the second hollow structure. The second beryllium layer 23 is disposed at the through hole, and the outer edge of the second beryllium layer 23 is fixed to the bottom wall of the inner edge of the fixing plate 22. The second beryllium layer 23 is opposite to the first beryllium layer 14 and the detector.

[0036] Specifically, the inner cylinder 20 provides a stable installation space for the detector and works with the outer cylinder 10 to achieve heat insulation. Through the second beryllium layer 23 and the first beryllium layer 14 of the outer cylinder 10, a complete penetration channel for low-energy gamma rays is formed, ensuring the accuracy of Pe value measurement. The inner cylinder body 21 is the main frame of the inner cylinder 20, made of the same austenitic stainless steel AISI321 material as the outer cylinder 10. It is fitted inside the outer cylinder 10, with a gap between its outer wall and the inner wall of the outer cylinder 10. This gap is the area for subsequent vacuuming. The vacuum environment further isolates convective heat transfer and gas heat conduction, creating a suitable operating temperature environment for the detector.

[0037] The fixing plate 22 is an annular plate with a through hole in the middle, also made of austenitic stainless steel AISI 321. It serves as the mounting carrier for the second beryllium layer 23 and simultaneously achieves a sealed connection with the inner cylinder body 21. The second hollow structure on the inner cylinder body 21 has a shape and size that matches the outer contour of the fixing plate 22 and the detection range of the detector, ensuring that the fixing plate 22 can completely cover the second hollow structure after installation. The bottom wall of the outer edge of the fixing plate 22 is fixed to the outer wall of the edge of the second hollow structure using argon arc welding. After welding, a second weld 24 is formed, which not only ensures the structural strength of the fixing plate 22 and the inner cylinder body 21 to withstand the high pressure and vibration conditions downhole, but also seals the gap at the second hollow structure to prevent air leakage in the vacuum environment between the inner and outer cylinders 10 and avoid the failure of the heat insulation effect.

[0038] The second beryllium layer 23, approximately 0.5 mm thick, is made of high-purity beryllium. Its outer edge is fixed to the bottom wall of the inner edge of the fixing plate 22 via brazing. The connection is achieved using a second alloy brazing filler metal 25. During brazing, the filler metal is heated to its melting point (lower than the melting points of beryllium and stainless steel) to prevent high-temperature damage to the brittle and thin second beryllium layer 23. Simultaneously, the alloy brazing filler metal fills the gap between the second beryllium layer 23 and the through-hole of the fixing plate 22, achieving a seal that neither disrupts the vacuum environment nor obstructs the radiation penetration path.

[0039] Furthermore, the second beryllium layer 23 is opposite to the first beryllium layer 14 and the detector, respectively, ensuring that the low-energy gamma rays after passing through the strata can sequentially penetrate the beryllium window of the instrument shell, the first beryllium layer 14 of the outer cylinder 10, the vacuum gap between the inner and outer cylinders 10, and the second beryllium layer 23 of the inner cylinder 20, and finally be accurately received by the detector, forming an unobstructed and low-loss ray propagation channel. This structurally solves the interference of the high Z metal material of the inner cylinder 20 of the traditional thermos bottle on the Pe value measurement, while taking into account the heat insulation, sealing and structural stability of the inner cylinder 20.

[0040] In one possible implementation, after the first beryllium layer 14 and the second beryllium layer 23 are fixed, the outer wall that is not attached to the interconnecting cylinder 11 or the fixing plate 22 is silver-plated. The inner wall of the interconnecting cylinder 11 and the outer wall of the fixing plate 22 are silver-plated.

[0041] Specifically, after the first beryllium layer 14 and the second beryllium layer 23 are fixed, their outer walls that are not attached to the interconnecting cylinder 11 or the fixing plate 22 are silver-plated. At the same time, the inner wall of the interconnecting cylinder 11 and the outer wall of the fixing plate 22 are also silver-plated to reduce radiative heat transfer between the inner and outer cylinders 10 of the thermos bottle, because silver has an extremely low thermal emissivity and can efficiently reflect heat. The silver plating on the non-attached outer walls of the first beryllium layer 14 and the second beryllium layer 23, as well as the inner wall of the interconnecting cylinder 11 and the outer wall of the fixing plate 22, can work in conjunction with the reflective screen 60 and the spacer layer between the inner and outer cylinders 10 to further reduce the efficiency of heat transfer from the outer cylinder 10 to the inner cylinder 20 through radiation in ultra-high temperature environments. This will not affect the penetrability of the beryllium layer to low-energy gamma rays to ensure the accuracy of Pe value measurement, and will also enhance the overall heat insulation effect of the thermos bottle, ensuring that the detector and electronic devices in the inner cylinder 20 can work normally in ultra-high temperature well environments where the well temperature exceeds 175°C and some reach 260°C.

[0042] In one possible implementation, the outer wall of the first beryllium layer 14 does not extend beyond the outer wall of the interconnecting cylinder 11, and the inner wall of the second beryllium layer 23 does not extend beyond the inner wall of the fixing plate 22.

[0043] Specifically, a recess is formed in the middle of the outer surface of the interconnecting cylinder 11 by milling. This recess is used to install the first beryllium layer 14, i.e., the outer beryllium plate. The depth of the recess is adapted to the thickness of the first beryllium layer 14, which is about 0.5 mm. This ensures that the outer wall of the first beryllium layer 14 does not exceed the outer wall of the interconnecting cylinder 11 after installation. This avoids the first beryllium layer 14 protruding and causing assembly interference between the outer cylinder 10 and the coaxially fitted instrument housing. It ensures that the outer cylinder 10 can be smoothly fitted into the instrument housing and maintain coaxiality. At the same time, it reduces the friction and collision damage to the first beryllium layer 14 due to protrusion during downhole operations, thereby ensuring the overall structural stability of the outer cylinder 10 and the integrity of the low-energy gamma ray penetration channel.

[0044] A recess is formed on the inner surface of the fixing plate 22 through milling. This recess is used to install the second beryllium layer 23, i.e., the inner beryllium plate. The depth of the recess is adapted to the thickness of the second beryllium layer 23, ensuring that its inner wall does not exceed the inner wall of the fixing plate 22. This design prevents the second beryllium layer 23 from protruding into the inner side of the fixing plate 22, preventing spatial interference with the detector installed in the inner cylinder 20. It ensures that the detector is stably installed in the designed position and that the detection surface maintains a preset distance from the second beryllium layer 23. At the same time, it ensures that low-energy gamma rays can pass through the second beryllium layer 23 and be transmitted to the detector without obstruction, avoiding deviation or loss of the ray propagation path, and further ensuring the accuracy of Pe value measurement.

[0045] In one possible implementation, the first closed structure 30 includes: A first end cap 31 is disposed at the second end of the first outer cylinder 12 and the second end of the inner cylinder 20 on the same side. The first end cap 31 is used to seal one end of the gap and the first end of the inner cylinder 20.

[0046] Specifically, the first end cap 31 covers both the end opening of the first outer cylinder 12 and the end opening of the inner cylinder 20. It seals one end of the gap between the inner and outer cylinders 10 through a sealing connection with the second end of the first outer cylinder 12 (such as argon arc welding), and seals the first end of the inner cylinder 20 through a sealing fit with the second end of the inner cylinder 20 (welding of the same material or assisted by a sealing element). This isolates the detector installed inside the inner cylinder 20 from external impurities, moisture and high temperature. Finally, through double sealing, it ensures both the heat insulation effect of the thermos bottle and the stability of the detector's working environment.

[0047] In one possible implementation, the second closure structure 40 includes: The inner cylinder cover 41 is disposed at the first end of the inner cylinder 20. The inner cylinder cover 41 includes a circular sealing plate and a plurality of teeth evenly distributed on the outer edge of the circular sealing plate. The circular sealing plate is used to seal the first end of the inner cylinder 20, and the edges of the plurality of teeth abut against the inner wall of the outer cylinder 10. The second end cap 42, the first end of the second end cap 42 is sleeved on the second end of the second outer cylinder 13; the second end face of the second end cap 42 is fixedly connected to the connector 45. The second end cap 42 is provided with an air extraction nozzle 43, which is connected to an external vacuum device.

[0048] Specifically, the inner cylinder cap 41 is located at the first end of the inner cylinder 20. Its circular sealing plate directly seals the end opening of the inner cylinder 20, achieving a seal on the inner cylinder 20 and preventing external impurities from entering the inner cylinder 20 and affecting the detector's operation. Multiple toothed edges evenly distributed along the outer edge of the circular sealing plate abut against the inner wall of the outer cylinder 10, which not only assists in positioning the coaxiality of the inner cylinder 20 and the outer cylinder 10, but also reserves a channel for subsequent vacuuming without completely sealing the gap. The first end of the second end cap 42 is sleeved onto the second end of the second outer cylinder 13. The connector 45, which is fixed to the inner cylinder 20, is used to connect with other components of the instrument (such as signal cable assemblies, support and positioning assemblies, and power supply assemblies) to ensure the overall assembly stability of the thermos bottle. At the same time, the suction nozzle 43 on the second end cap 42 can be connected to an external vacuum device. After the first sealing structure 30 and the inner cylinder cap 41 have completed the sealing of one end of the cylinder, the air in the gap is extracted through the suction nozzle 43 to form a vacuum environment to block heat conduction.

[0049] In one possible implementation, the second end cap 42 is further provided with a getter assembly 44 that communicates with the gap.

[0050] Specifically, the getter assembly 44, which communicates with the gap, is provided on the second end cap 42. The main body of the getter assembly 44 is made of stainless steel, and a titanium-containing getter is fixed in its concave space. After the suction nozzle 43 is clamped, the getter is activated by heating the outer shell of the getter assembly 44 to maintain a stable vacuum state inside for a long time. The getter can adsorb the trace amounts of gas remaining in the gap and slowly released during long-term use, avoiding gas accumulation that would cause the gap vacuum to decrease, thereby maintaining the stability of the vacuum environment and ensuring the heat insulation effect of the multi-layer insulation structure. Combined with the initial vacuum extraction completed by the suction nozzle 43, the two work together to quickly establish a low-pressure environment through the suction nozzle 43 and rely on the getter to adsorb gas for a long time to continuously maintain a high vacuum state in the gap, ensuring that the thermos bottle has reliable heat insulation performance during long-term operation of the ultra-high temperature well, and providing temperature protection for the stable operation of the detector in the inner cylinder 20.

[0051] In one possible implementation, spacers 50 and reflective screens 60 are alternately arranged in the gap between the inner cylinder 20 and the outer cylinder 10; The spacer 50 is either polyester cloth or fiberglass cloth; the reflective screen 60 is aluminum foil.

[0052] Specifically, aluminum foil, serving as the reflector 60, possesses high reflectivity and low emissivity, effectively reflecting heat and reducing radiative heat transfer. Polyester cloth or fiberglass cloth, serving as the spacer 50, has low thermal conductivity and a small contact area with the reflector 60, reducing heat conduction between the reflectors 60. The alternating arrangement of these two materials forms a multi-layered structure, gradually weakening heat transfer. Simultaneously, the mesh structure of the spacer 50 prevents a sharp increase in vacuum resistance and a decrease in vacuum level when the number of reflector 60 layers is too large, ensuring that the vacuum level within the gap remains at a low pressure. This keeps the equivalent thermal conductivity of the vacuum layer relatively constant. Ultimately, in conjunction with the vacuuming and getter designs, the insulation effect of the thermos bottle is maximized, ensuring the normal operation of the detector in the inner cylinder 20 in the ultra-high temperature well environment.

[0053] The welding steps for the thermos bottle include: S1. Process the following components according to the design dimensions: first outer cylinder 12, first beryllium layer 14, interconnecting cylinder 11, second outer cylinder 13, inner cylinder body 21, second beryllium layer 23, fixing plate 22, first end cap 31, inner cylinder cover 41, second end cap 42, suction nozzle 43, connector 45, and getter assembly 44. S2. The first beryllium layer 14 is brazed to the interconnecting cylinder 11, and the second beryllium layer 23 is brazed to the fixing plate 22 respectively. S3. The first beryllium layer 14, which is not attached to the outer wall of the interconnecting cylinder 11, the second beryllium layer 23, which is not attached to the inner wall of the fixing plate 22, and the inner wall of the interconnecting cylinder 11 and the outer wall of the fixing plate 22 are silver-plated. S4. The inner cylinder body 21, the fixing plate 22 and the inner cylinder cover 41 are argon arc welded together. S5. Spacers 50 (polyester cloth or fiberglass cloth) and reflectors 60 (aluminum foil) are alternately wrapped around the outer surface of the inner cylinder body 21 and the areas on both sides of the fixing plate 22 to form a multi-layer heat insulation structure. S6. Insert the interconnecting cylinder 11 into the inner cylinder body 21, and insert the first outer cylinder 12 and the second outer cylinder 13 from both sides respectively. S7, the two sides of the interconnecting cylinder 11 are respectively welded to the first outer cylinder 12 and the second outer cylinder 13; S8. Install the first end cap 31 and weld it to the inner cylinder body 21 and the first outer cylinder 12 (argon arc welding). S9. Flame brazing the suction nozzle 43 to the second end cap 42 using silver-based brazing filler metal; Argon arc welding the getter assembly 44 to the second end cap 42. S10. Install the second end cap 42 and argon arc weld it to the second outer cylinder 13; S11. Place the welded inner and outer cylinder 10 components into a high-temperature furnace for high-temperature baking and degassing. Then, draw a vacuum through the vacuum nozzle 43. After the vacuum level meets the standard, use a special hydraulic clamp to seal the vacuum nozzle 43. S12. High-temperature heating activates the getter in the getter assembly 44; S13. Argon arc weld the second end cap 42 to the connector 45.

[0054] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A novel thermos bottle that can improve the accuracy of Pe value measurement in lithology density logging tools, characterized in that, include: A cylindrical body, which is coaxially sleeved inside the instrument housing; The cylindrical body includes: The outer cylinder is coaxially sleeved inside the instrument housing; An inner cylinder is coaxially sleeved inside the outer cylinder, and there is a gap between the outer wall of the inner cylinder and the interior of the outer cylinder. The inner cylinder is used to house a detector. A first sealing structure is fixedly disposed at the first end of the cylinder and is used to seal the first end of the cylinder. The second sealing structure is disposed at the second end of the cylinder and is used to connect with an external vacuum pumping device to evacuate the gap. The cylindrical body has a hollow structure in which a beryllium layer is installed; the instrument shell has a beryllium window, and the beryllium layer is opposite to the detector and the beryllium window respectively.

2. The new thermos bottle capable of improving the measurement accuracy of Pe value of litho density logging instrument according to claim 1, characterized in that, The beryllium layer includes a first beryllium layer and a second beryllium layer, and the outer cylinder includes: Interconnected tube; A first outer cylinder, the first end of which is sleeved on the outer wall of the second end of the interconnecting cylinder; The second outer cylinder has its second end sleeved on the outer wall of the first end of the interconnecting cylinder; The interconnected cylinder has a first hollow structure, the first beryllium layer is installed at the first hollow structure, and the inner wall of the outer edge of the first beryllium layer is fixed to the outer wall of the edge of the first hollow structure. The first beryllium layer is opposite to the beryllium window.

3. The novel thermos bottle according to claim 2, which improves the accuracy of Pe value measurement in lithology density logging tools, is characterized in that... The inner cylinder includes: The inner cylinder body is fitted inside the outer cylinder, and there is a gap between the outer wall of the inner cylinder body and the inner wall of the outer cylinder. The fixing plate is an annular plate with a through hole in the middle. The inner cylinder body has a second hollow structure. The bottom wall of the outer edge of the fixing plate is fixed to the outer wall of the edge of the second hollow structure. The second beryllium layer is disposed at the through hole, and the outer edge of the second beryllium layer is fixed to the bottom wall of the inner edge of the fixing plate. The second beryllium layer is opposite to the first beryllium layer and the detector.

4. The novel thermos bottle according to claim 3, which improves the accuracy of Pe value measurement in lithology density logging tools, is characterized in that... After the first beryllium layer and the second beryllium layer are fixed, the outer wall that is not attached to the interconnecting cylinder or the fixing plate is silver-plated. The inner wall of the interconnecting cylinder and the outer wall of the fixing plate are silver-plated.

5. The new thermos bottle capable of improving the measurement accuracy of Pe value of litho density logging instrument according to claim 3, characterized in that, The outer wall of the first beryllium layer does not extend beyond the outer wall of the interconnecting cylinder, and the inner wall of the second beryllium layer does not extend beyond the inner wall of the fixing plate.

6. The novel thermos bottle according to claim 2, which improves the accuracy of Pe value measurement in lithology density logging tools, is characterized in that... The first closed structure includes: A first end cap is disposed at the second end of the first outer cylinder and the second end of the inner cylinder on the same side. The first end cap is used to seal one end of the gap and the first end of the inner cylinder.

7. The new thermos bottle capable of improving the measurement accuracy of Pe value of litho density logging instrument according to claim 6, characterized in that, The second closed structure includes: An inner cylinder cover is disposed at the first end of the inner cylinder. The inner cylinder cover includes a circular sealing plate and a plurality of teeth evenly distributed on the outer edge of the circular sealing plate. The circular sealing plate is used to seal the first end of the inner cylinder, and the edges of the plurality of teeth abut against the inner wall of the outer cylinder. The second end cap has its first end fitted onto the second end of the second outer cylinder; the second end face of the second end cap is fixedly connected to a connector. The second end cap is provided with an air extraction nozzle, which is connected to an external vacuum device.

8. The new thermos bottle capable of improving the measurement accuracy of Pe value of litho density logging instrument according to claim 7, characterized in that, The second end cap is also provided with a getter assembly that communicates with the gap.

9. The novel thermos bottle according to claim 1, which improves the accuracy of Pe value measurement in lithology density logging tools, is characterized in that... Spacers and reflective screens are alternately arranged in the gap between the inner cylinder and the outer cylinder; The spacer is either polyester cloth or fiberglass cloth; the reflective screen is aluminum foil.

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