High-temperature-resistant carbon sealing optical fiber for oil and gas underground monitoring

Abstract

The invention relates to the technical field of optical fibers, in particular to a high-temperature-resistant carbon sealed optical fiber for oil and gas underground monitoring, which comprises an inner core layer, an inner protective coating layer fixedly sleeved on the inner core layer, a quartz glass cladding layer arranged on the inner protective coating layer, and a gas filling layer arranged between the quartz glass cladding layer and the inner protective coating layer. The quartz glass cladding is fixedly sleeved with a gas carbon sealing layer, an elastic reinforcing layer is fixedly arranged on the gas carbon sealing layer, an anti-scratch wear-resistant outer layer is fixed on the elastic reinforcing layer, a high-temperature-resistant protective layer is arranged between the anti-scratch wear-resistant outer layer and the elastic reinforcing layer, and the inner core layer is made of a high-purity silicon dioxide material. The inner protective coating layer is used for ensuring the transmission efficiency of an optical signal and the thermal shock resistance of the optical fiber, is made of a high-molecular polymer material and has thermal stability and chemical stability; the reliability and durability of the optical fiber in high-temperature, high-pressure and complex environments of oil and gas wells are remarkably improved, and the service life of the optical fiber is prolonged.

Description

Technical Field

[0001] The invention relates to a high temperature resistant carbon sealed optical fiber for monitoring oil and gas underground wells, belonging to the technical field of optical fibers. Background Art

[0002] Optical fiber used for downhole monitoring of oil and gas is a high-tech sensor technology. It is based on the sensing principle of optical fiber and can monitor various physical quantities in oil and gas wells in real time. Optical fiber sensors measure changes in the characteristics of light (such as temperature, pressure, strain, etc.) to accurately monitor downhole temperature, pressure, sound waves and other parameters. Compared with traditional electronic sensors, optical fiber sensors have the advantages of high temperature resistance, corrosion resistance, long-term stability, and real-time data. They provide high-precision and high-sensitivity monitoring methods for oil and gas exploration, development and production. Optical fiber has become an important technical support for the oil and gas industry to improve production efficiency, optimize oil production processes, and ensure safe production. As disclosed in the announcement number (CN204964805U), a high-temperature resistant carbon-sealed optical fiber for oil and gas downhole monitoring includes a glass fiber core, and the glass fiber core is sequentially coated with a quartz glass cladding, a carbon sealing layer, an optical fiber coating layer, and a fluoroplastic reinforcement layer; dopants are provided in the glass fiber core and the quartz glass cladding, and the dopants are one or more of germanium compounds, phosphorus compounds, aluminum compounds, and nitrogen compounds; the optical fiber coating layer is a high-temperature resistant ultraviolet light curing material layer, including a high-temperature resistant inner coating layer and a high-temperature resistant outer coating layer, and the modulus of the high-temperature resistant outer coating layer is higher than the modulus of the high-temperature resistant inner coating layer. The high-temperature resistant carbon-sealed optical fiber for oil and gas downhole monitoring provided by the present invention improves the reliability of the optical fiber in harsh environments such as oil and gas fields, reduces hydrogen loss of the optical fiber, and improves the fatigue resistance of the optical fiber by forming a carbon sealing layer on the surface of the glass fiber core, adopting a high-temperature resistant coating layer structure, and adding a fluoroplastic reinforcement layer.

[0003] As disclosed in announcement number (CN214470933U), a high-temperature carbon sealed optical fiber for oil and gas downhole monitoring includes a heat-resistant layer and a protective sleeve, the interior of the heat-resistant layer is penetrated by a sealing layer, and the interior of the sealing layer is penetrated by a limiting block, the protective sleeve is located inside the limiting block, and the interior of the protective sleeve is penetrated by an insulating layer, the interior of the insulating layer is penetrated by an optical fiber tube, the outer side of the heat-resistant layer is covered with a protective surface layer, and the interior of the protective surface layer is penetrated by an anti-slip strip. The high-temperature carbon sealed optical fiber for oil and gas downhole monitoring has a better guarantee of the stability of the overall structure formed between the optical fiber tube and the insulating layer through the penetration structure, and can provide a more stable insulation effect for the equipment when in use, and has a better guarantee for the overall safety of the equipment. During use, the optical fiber tube has a more comprehensive overall protective effect on the optical fiber, and the high temperature resistance and sealing performance in the center of the equipment are fully guaranteed, and the limiting block also has a better guarantee for the overall anti-extrusion effect of the equipment.

[0004] However, when the above technical solution is used, the complex downhole environment can easily cause damage to the optical fiber, making the optical fiber susceptible to environmental interference and damage. If only high-temperature resistant carbon is used for sealing, as the carbon ages, it is susceptible to invasion by oil, gas and corrosive substances, affecting the service life of the optical fiber, and there are certain disadvantages in the use process.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a high-temperature resistant carbon sealed optical fiber for oil and gas well monitoring in order to solve the above-mentioned problems. It has the advantages of significantly improving the reliability and durability of the optical fiber in the high temperature, high pressure and complex environment of oil and gas wells, and extending the service life of the optical fiber.

[0007] The present invention achieves the above-mentioned purpose through the following technical scheme: a high-temperature resistant carbon sealed optical fiber for oil and gas downhole monitoring, comprising an inner core layer, the inner protective coating layer is fixedly sleeved on the inner core layer, the quartz glass cladding is arranged on the inner protective coating layer, and the gas filling layer is arranged between the quartz glass cladding and the inner protective coating layer, the gas-carbon sealing layer is fixedly sleeved on the quartz glass cladding, the elastic reinforcement layer is fixedly arranged on the gas-carbon sealing layer, the scratch-resistant and wear-resistant outer layer is fixed on the elastic reinforcement layer, and the high-temperature resistant protective layer is arranged between the scratch-resistant and wear-resistant outer layer and the elastic reinforcement layer.

[0008] Furthermore, in order to ensure the efficient transmission of optical signals in optical fibers and improve the thermal shock resistance of optical fibers, it is helpful to reduce the loss of optical signals during transmission, enhance the stability and durability of optical fibers, and thus meet the needs of high-speed, long-distance optical communications and cope with complex and changing environmental conditions. The inner core layer is made of high-purity silica material to ensure the transmission efficiency of optical signals and the thermal shock resistance of optical fibers.

[0009] Furthermore, in order to provide thermal stability and chemical stability and effectively isolate the negative impact of the external environment on the inner core layer, it not only protects the core transmission part of the optical fiber, but also ensures the reliable operation of the optical fiber under harsh conditions, and improves the overall performance and service life of the optical fiber. The inner protective coating layer is a high molecular polymer material with thermal stability and chemical stability, which is used to protect the inner core layer from the influence of the external environment.

[0010] Furthermore, in order to reduce the thermal expansion coefficient of the optical fiber in a high temperature environment, help the optical fiber maintain stability and precision under high temperature conditions, reduce performance degradation caused by thermal expansion and contraction, and ensure the reliable use of the optical fiber in various extreme environments, the gas filling layer is provided with uniform gaps, and the gaps are filled with inert gas to reduce the thermal expansion coefficient of the optical fiber in a high temperature environment.

[0011] Furthermore, in order to effectively isolate the external environment from the damage to the optical fiber, not only the protection ability of the optical fiber is enhanced, but also the stability and durability of the optical fiber in a high temperature environment are improved, ensuring the long-term reliability of the optical fiber signal transmission. The air-carbon sealing layer is made of nano-scale carbon material and has excellent sealing performance and high temperature resistance.

[0012] Furthermore, in order to provide excellent elasticity and strength so as to enhance the stability and resistance to external impact of the optical fiber structure and help the optical fiber maintain stable performance in various complex environments, the elastic reinforcement layer includes the first elastic limiting film layer and the second elastic limiting film layer, the first elastic limiting film layer is located on the outside of the second elastic limiting film layer, and the elastic reinforcement strip is evenly filled between the first elastic limiting film layer and the second elastic limiting film layer.

[0013] Furthermore, in order to ensure that the optical fiber as a whole has excellent thermal stability and thermal shock resistance in a high temperature environment, the high temperature resistance of the optical fiber is improved, its reliability and service life under extreme temperature conditions are enhanced, and the needs of high temperature application environments are met, the high temperature resistant protective layer is an inorganic ceramic material, which is used to ensure the thermal stability and thermal shock resistance of the optical fiber as a whole.

[0014] Furthermore, in order to enhance the wear resistance and scratch resistance of the optical fiber and ensure the long-term stable operation of the optical fiber in various harsh environments, the scratch-resistant and wear-resistant outer layer includes the scratch-resistant inner layer and the scratch-resistant outer layer, both of which are made of highly wear-resistant materials, and the scratch-resistant net is arranged between the scratch-resistant inner layer and the scratch-resistant outer layer, and the scratch-resistant net is made of woven spiral wear-resistant wires that are interlaced with each other.

[0015] The technical effects and advantages of the present invention are as follows: the inner core layer is effectively protected by the inner protective coating layer and the gas filling layer, reducing environmental interference and damage; the quartz glass cladding provides good optical performance and structural support; the gas carbon sealing layer enhances the sealing and high temperature resistance of the optical fiber, effectively preventing the intrusion of corrosive substances such as oil and gas; the elastic reinforcement layer increases the flexibility and tensile strength of the optical fiber, making it more adaptable to the complex geological conditions underground; and the combination of the high temperature resistant protective layer and the anti-scratch and wear-resistant outer layer further enhances the high temperature resistance and wear resistance of the optical fiber, and through the ingenious combination of the multi-layer structure, significantly improves its reliability and durability in the high temperature, high pressure and complex environment of oil and gas wells, and extends its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0017] Figure 2 It is a schematic diagram of the overall cross-sectional structure of the present invention;

[0018] Figure 3 It is a schematic diagram of the connection structure between the gas filling layer and the inner core layer of the present invention;

[0019] Figure 4 is a schematic diagram of the cross-sectional structure of the elastic reinforcing layer of the present invention;

[0020] Figure 5 It is a schematic diagram of the installation structure of the elastic reinforcement strip of the present invention;

[0021] Figure 6 This is a schematic diagram of the cross-sectional structure of the anti-scratch and wear-resistant outer layer of the present invention;

[0022] Figure 7 This is a schematic diagram of the installation structure of the anti-scratch net of the present invention;

[0023] In the figure: 1. inner core layer; 2. inner protective coating layer; 3. quartz glass cladding; 4. gas filling layer; 5. gas carbon sealing layer; 6. elastic reinforcement layer; 601. first elastic limiting film layer; 602. second elastic limiting film layer; 603. elastic reinforcement strip; 7. anti-scratch and wear-resistant outer layer; 701. anti-scratch inner layer; 702. anti-scratch outer layer; 703. anti-scratch net; 8. high temperature resistant protective layer. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] See also Figure 1-Figure 7As shown, a high-temperature resistant carbon sealed optical fiber for oil and gas downhole monitoring comprises an inner core layer 1, an inner protective coating layer 2 is fixedly sleeved on the inner core layer 1, the inner core layer 1 is made of high-purity silica material, which ensures the efficient transmission and thermal shock resistance of optical signals, the inner protective coating layer 2 is made of high molecular polymer material, which provides thermal stability and chemical stability protection for the inner core layer 1, and effectively isolates the influence of the external environment, a quartz glass cladding 3 is arranged on the inner protective coating layer 2, and a gas filling layer 4 is arranged between the quartz glass cladding 3 and the inner protective coating layer 2, and a gas carbon sealing layer 5 is fixedly sleeved on the quartz glass cladding 3, the quartz glass cladding 3 not only enhances the mechanical strength of the optical fiber, but also arranges the gas filling layer 4 between the quartz glass cladding 3 and the inner protective coating layer 2, and reduces the thermal expansion coefficient of the optical fiber at high temperature by filling inert gas. The air-carbon sealing layer 5 adopts nano-scale carbon material, which further improves the protection level of the optical fiber with its excellent sealing and high-temperature resistance. An elastic reinforcement layer 6 is fixed on the air-carbon sealing layer 5, and an anti-scratch and wear-resistant outer layer 7 is fixed on the elastic reinforcement layer 6. A high-temperature resistant protective layer 8 is arranged between the anti-scratch and wear-resistant outer layer 7 and the elastic reinforcement layer 6. The arrangement of the elastic reinforcement layer 6 and the anti-scratch and wear-resistant outer layer 7, supplemented by the high-temperature resistant protective layer 8, provides a strong guarantee for the durability and safety of the optical fiber.

[0026] The inner core layer 1 is made of high-purity silica material, which is used to ensure the transmission efficiency of optical signals and the thermal shock resistance of optical fibers. High-purity silica material has extremely low loss characteristics, which can ensure that optical signals are efficiently and stably transmitted inside the optical fiber, so that monitoring data can be accurately delivered to the receiving end. At the same time, high-purity silica material also gives the optical fiber excellent thermal shock resistance. In the high-temperature environment of oil and gas wells, optical fibers need to withstand tremendous thermal pressure. High-purity silica materials, with their stable physical and chemical properties, can maintain the integrity of the optical fiber structure at extreme temperatures, thereby ensuring the continuous transmission of optical signals, which not only improves the transmission efficiency of optical fibers, but also significantly enhances their thermal shock resistance, providing reliable technical support for monitoring work in oil and gas wells.

[0027] The inner protective coating layer 2 is a high molecular polymer material with thermal and chemical stability, and is used to protect the inner core layer 1 from the external environment. High molecular polymer materials are known for their excellent thermal and chemical stability. In the complex environment of oil and gas wells, optical fibers may encounter a variety of harsh conditions such as high temperature, high pressure, and corrosive gases. The high molecular polymer material, relying on its stable physical and chemical properties, can effectively isolate these external factors from invading the optical fiber and provide a solid protective barrier for the inner core layer 1. At the same time, the high molecular polymer material also has good flexibility and adhesion, and can fit tightly on the surface of the inner core layer 1 to form a continuous and dense protective layer. This feature not only enhances the mechanical strength of the optical fiber, but also further improves its anti-wear, anti-aging and other properties, prolongs the service life of the optical fiber, and improves the thermal stability and chemical stability of the optical fiber.

[0028] The gas-filled layer 4 is provided with uniform gaps inside, and the gaps are filled with inert gas, which is used to reduce the thermal expansion coefficient of the optical fiber in a high-temperature environment, creating a unique microenvironment inside the optical fiber, and the inert gas filled between these gaps, such as argon or nitrogen, plays a vital role. The inert gas has stable chemical properties and extremely low thermal conductivity, and they can effectively slow down the thermal expansion rate of the optical fiber in a high-temperature environment. When the optical fiber is in a high-temperature environment, these inert gases can absorb and disperse the heat generated inside the optical fiber, thereby reducing the thermal expansion coefficient of the optical fiber, maintaining the stability of its structure and the accuracy of its size, and can also provide a certain buffering effect for the optical fiber, reducing the impact and vibration of the external environment on the optical fiber, and further improving the durability and reliability of the optical fiber.

[0029] The gas-carbon sealing layer 5 is made of nano-scale carbon material, which has excellent sealing performance and high temperature resistance. The nano-scale carbon material, with its unique microstructure and excellent physical and chemical properties, gives the gas-carbon sealing layer 5 excellent sealing performance and high temperature resistance. In terms of sealing performance, the nano-scale carbon material can form a tight and continuous coating, effectively isolating the external environment from the erosion of the optical fiber, and ensuring the integrity and stability of the internal structure of the optical fiber. In terms of high temperature resistance, the nano-scale carbon material exhibits amazing thermal stability. Even in extremely high temperature environments, it can maintain structural stability and performance continuity, providing continuous and reliable protection for the optical fiber. In addition, the nano-scale carbon material also has good electrical conductivity and thermal conductivity, which can help the optical fiber to disperse the heat generated inside to a certain extent, further improving its high temperature resistance.

[0030] The elastic reinforcement layer 6 includes a first elastic limiting film layer 601 and a second elastic limiting film layer 602, the first elastic limiting film layer 601 is located outside the second elastic limiting film layer 602, and the first elastic limiting film layer 601 and the second elastic limiting film layer 602 are uniformly filled with elastic reinforcement strips 603, the elastic reinforcement layer 6 is composed of the first elastic limiting film layer 601 and the second elastic limiting film layer 602, the two cooperate with each other to provide additional mechanical strength and toughness for the optical fiber, the first elastic limiting film layer 601 is located outside the second elastic limiting film layer 602, such a layout enables the optical fiber to be first buffered and dispersed by the first elastic limiting film layer 601 when subjected to external force, thereby protecting the internal optical fiber structure from damage. The second elastic limiting film layer 602 serves as the second line of defense, further enhancing the compressive resistance and deformation resistance of the optical fiber. Between the first elastic limiting film layer 601 and the second elastic limiting film layer 602, and the elastic reinforcement strips 603 are uniformly filled. These reinforcing strips are made of highly elastic materials, which not only enhance the overall structural strength of the optical fiber, but also improve its ability to resist vibration and impact. In addition, the presence of the elastic reinforcing layer 6 also helps the dimensional stability of the optical fiber in a high temperature environment, and absorbs and disperses heat through the elastic material inside, further improving the high temperature resistance of the optical fiber and helping the dimensional stability of the optical fiber in a high temperature environment.

[0031] The high temperature resistant protective layer 8 is an inorganic ceramic material, which is used to ensure the overall thermal stability and thermal shock resistance of the optical fiber. The inorganic ceramic material is well-known for its excellent high temperature resistance, high thermal stability and good thermal shock resistance. In the high temperature resistant protective layer 8 of the optical fiber, the inorganic ceramic material can form a solid protective shell, which effectively isolates the high temperature environment from the erosion of the inside of the optical fiber. Even at extremely high temperatures, the inorganic ceramic material can maintain the stability of its structure and the continuity of its performance, ensuring that the optical fiber can work normally. In addition, the inorganic ceramic material also has good chemical stability and corrosion resistance, and can resist the erosion of various corrosive substances in the complex environment of oil and gas wells, further extending the service life of the optical fiber. More importantly, the inorganic ceramic material has a low thermal conductivity, which can reduce the transfer of heat inside the optical fiber to a certain extent, thereby slowing down the thermal expansion rate of the optical fiber and improving its thermal shock resistance.

[0032] The scratch-resistant outer layer 7 includes an anti-scratch inner layer 701 and an anti-scratch outer layer 702. Both the scratch-resistant inner layer 701 and the scratch-resistant outer layer 702 are made of highly wear-resistant materials, and an anti-scratch net 703 is arranged between the scratch-resistant inner layer 701 and the scratch-resistant outer layer 702. The scratch-resistant net 703 is made of interlaced spiral wear-resistant wires. The scratch-resistant inner layer 701 is close to the optical fiber body, and as the first line of defense, it can effectively resist minor scratches and friction from the outside. The scratch-resistant outer layer 702 is located further outside, and its material is tougher and can cope with more serious physical damage. Between the scratch-resistant inner layer 701 and the scratch-resistant outer layer 702, a layer of anti-scratch net 703 is arranged. This layer of anti-scratch net 703 is woven from interlaced spiral wear-resistant wires to form a dense protective net. The spiral wear-resistant wire not only has high wear resistance, but also has a certain elasticity, which can play a buffering role when the optical fiber is impacted by external force, reducing the damage to the optical fiber surface. The multi-layer design of the anti-scratch and wear-resistant outer layer 7 not only improves the wear resistance of the optical fiber, but also enhances its impact and vibration resistance. The optical fiber has a higher mechanical strength, avoids scratch damage, and has a longer service life.

[0033] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0034] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A high temperature resistant carbon sealed optical fiber for oil and gas downhole monitoring, comprising an inner core layer (1), characterized in that: An inner protective coating layer (2) is fixedly sleeved on the inner core layer (1), a quartz glass cladding layer (3) is arranged on the inner protective coating layer (2), and a gas filling layer (4) is arranged between the quartz glass cladding layer (3) and the inner protective coating layer (2), a gas-carbon sealing layer (5) is fixedly sleeved on the quartz glass cladding layer (3), an elastic reinforcement layer (6) is fixedly arranged on the gas-carbon sealing layer (5), an anti-scratch and wear-resistant outer layer (7) is fixed on the elastic reinforcement layer (6), and a high-temperature resistant protective layer (8) is arranged between the anti-scratch and wear-resistant outer layer (7) and the elastic reinforcement layer (6).

2. The high temperature resistant carbon sealed optical fiber for oil and gas downhole monitoring according to claim 1, characterized in that: The inner core layer (1) is made of high-purity silicon dioxide material and is used to ensure the transmission efficiency of optical signals and the thermal shock resistance of the optical fiber.

3. The high temperature resistant carbon sealed optical fiber for oil and gas downhole monitoring according to claim 1, characterized in that: The inner protective coating layer (2) is a high molecular polymer material and is used to protect the inner core layer (1) from being affected by the external environment.

4. The high temperature resistant carbon sealed optical fiber for oil and gas downhole monitoring according to claim 1, characterized in that: The gas filling layer (4) is provided with uniform gaps inside, and the gaps are filled with inert gas to reduce the thermal expansion coefficient of the optical fiber in a high temperature environment.

5. The high temperature resistant carbon sealed optical fiber for oil and gas downhole monitoring according to claim 1, characterized in that: The gas-carbon sealing layer (5) is made of nano-scale carbon material.

6. The high temperature resistant carbon sealed optical fiber for oil and gas downhole monitoring according to claim 1, characterized in that: The elastic reinforcement layer (6) comprises a first elastic limiting film layer (601) and a second elastic limiting film layer (602), wherein the first elastic limiting film layer (601) is located outside the second elastic limiting film layer (602), and an elastic reinforcement strip (603) is evenly filled between the first elastic limiting film layer (601) and the second elastic limiting film layer (602).

7. The high temperature resistant carbon sealed optical fiber for oil and gas downhole monitoring according to claim 1, characterized in that: The high temperature resistant protective layer (8) is made of inorganic ceramic material and is used to ensure the thermal stability and thermal shock resistance of the optical fiber as a whole.

8. The high temperature resistant carbon sealed optical fiber for oil and gas downhole monitoring according to claim 1, characterized in that: The anti-scratch and wear-resistant outer layer (7) comprises an anti-scratch inner layer (701) and an anti-scratch outer layer (702), both of which are made of highly wear-resistant materials, and an anti-scratch net (703) is arranged between the anti-scratch inner layer (701) and the anti-scratch outer layer (702), and the anti-scratch net (703) is made of mutually interlaced spiral wear-resistant wires.

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