CN102587893B - Optic fiber temperature pressure sensor and probe thereof - Google Patents

Abstract

An optical fiber temperature and pressure sensor probe, which includes a main body protection sleeve and a main body sleeve fixedly arranged at one end of the main body protection sleeve, and is characterized in that optical fiber Fabry-Perot cavity protection sleeves are respectively fixedly arranged at both ends of the main body sleeve The sleeve and the fiber grating protector, the fiber Fabry Perot cavity protection sleeve is inserted into the main body protection sleeve; the end of the fiber Fabry Perot cavity protection sleeve opposite to the main body sleeve is fixed with a quartz glass inlet Pressure tube; a ferrule is fixedly arranged in the main body sleeve, and a quartz glass capillary and a first optical fiber segment and a second optical fiber segment inserted and fixed from both ends of the quartz glass capillary are arranged in the ferrule, and are kept in the quartz glass capillary The spaced first fiber segment and the second fiber segment form a fiber Fabry-Perot cavity; a grating is arranged on the first fiber segment as an optical fiber temperature sensor.

Description

An optical fiber temperature and pressure sensor and its probe

technical field

The invention relates to an optical fiber temperature and pressure sensor and a probe thereof.

Background technique

At present, in the downhole temperature and pressure monitoring of heavy oil wells in my country, electronic sensors are mainly used. However, the downhole environment of heavy oil wells is very harsh. Downhole high temperature, high pressure and liquid gas corrosion can easily lead to the failure of downhole sensors. Electronic sensors often use storage measurement. This measurement method needs to put the sensor in a thermos bottle and then put it downhole. , measured within a certain period of time, beyond this period of time, the sensor must be taken out from the downhole, otherwise it will fail, and real-time online monitoring cannot be realized. At present, there are some electronic sensors in foreign countries that can achieve real-time online monitoring, but when using this kind of sensor for measurement, the sensor also needs to be placed in a thermos bottle, and there is also a time limit for measurement, so long-term real-time online monitoring cannot be achieved.

Optical fiber sensor, because it uses quartz glass optical fiber as the core component of the sensor, its resistance to high temperature, high pressure and liquid gas corrosion is much higher than that of electronic sensors. At present, there are two types of optical fiber sensors used in oil well measurement: optical fiber grating sensors and optical fiber Fabry-Perot cavity sensors. The fiber grating sensor is sensitive to the measured parameter through the special packaging of the fiber grating, and measures the size and direction of the measured parameter through the change of the fiber grating wavelength, such as temperature, strain, stress, displacement, velocity and acceleration. The packaging method of the fiber grating determines the performance of the fiber grating sensor, such as measurement accuracy, range, stability, working environment influence, service life and so on. At present, there are generally two packaging methods for fiber gratings: glue packaging and metallization packaging. Glue encapsulation is the method of fixing both ends of the grating with glue, and metallization encapsulation is the method of plating the two ends of the grating with a metal layer by electroless plating, and then using the metal layer for welding and fixing. However, fiber grating sensors encapsulated by glue and metallization will have obvious creep phenomenon in high temperature environment, that is, the fixed point of the package will move, which will cause zero drift, which will have a great impact on the accuracy and stability of the sensor. It is not suitable for the measurement of oil well downhole environment. Relatively speaking, the core element of the optical fiber Fabry-Perot cavity sensor currently used for oil well measurement is made of high-purity quartz glass. The traditional structure is generally to fix two single-mode quartz optical fibers on the inside a quartz glass tube. This sensor has the advantages of high temperature resistance, large measuring range, high precision, good stability and repeatability, and long service life. However, the packaging method of the optical fiber Fabry-Perot cavity and the metal casing has always been sealed and fixed by glue or metallized packaging. It has been found in the long-term application of the oil field that these two connection methods are not suitable for oil wells. Stable, very easy to cause leakage at the packaging position, because the glue will chemically react with the liquid and gas components in the oil well at high temperature, that is, the liquid and gas components will corrode the glue, and the liquid and gas in the oil well will flow into the sensor along the corroded part Internally, resulting in damage to the optical fiber Fabry-Perot cavity sensor and interruption of signal transmission; while the sensor probe of the metallized package is easily corroded by downhole liquid and gas at the metallized package part, and is also easy to leak. Considering that the glass solder used in glass welding has the characteristics of high temperature resistance, corrosion resistance, and good sealing performance, the best solution for the packaging of optical fiber Fabry-Perot cavity sensors is to use glass welding to connect the optical fiber Fabry-Perot cavity to the sensor. The metal parts are sealed together. However, the material of the optical fiber Fabry-Perot cavity is mainly quartz glass, and its thermal expansion coefficient is very different from that of metal. When the glass is welded, the high temperature and rapid cooling of the welding part can easily cause the optical fiber Fabry-Perot cavity to collapse. damage, causing it to fail or unable to withstand high temperature and pressure.

On the other hand, the packaging method of the traditional optical fiber Fabry-Perot cavity sensor determines that the core element of the sensor cannot be disassembled after being connected to the metal shell, and the sensor must be packaged as a whole before testing and calibration can be performed. If the sensor fails or is damaged during the process, the entire sensor must be scrapped, which greatly reduces the yield and prolongs the product production cycle.

Contents of the invention

The purpose of the present invention is to provide a practical optical fiber temperature and pressure sensor probe for oil wells, which adopts the packaging process of glass welding and mechanical clamping and sealing, and has the advantages of small radial size, good sealing performance, high measurement accuracy, long service life, long-term It has the characteristics of good monitoring stability and is suitable for real-time online measurement of all fluid pressure and temperature. The core component of the sensor probe is an independent component, which can be tested and calibrated independently, and can be used for oil well measurement after being packaged and connected with a metal casing.

The technical solution adopted in the present invention is: an optical fiber temperature and pressure sensor probe, which includes a main body protection sleeve and a main body sleeve fixedly arranged at one end of the main body protection sleeve, and is characterized in that two ends of the main body sleeve are respectively fixed with Optical fiber Fabry-Perot cavity protection sleeve and fiber grating protection piece, the optical fiber Fabry-Perot cavity protection sleeve is inserted into the main body protection sleeve;

A quartz glass inlet pressure tube is fixedly arranged on the end of the optical fiber Fabry-Perot cavity protection sleeve opposite to the main sleeve;

The ferrule is fixedly arranged in the main body sleeve, the first optical fiber section and the second optical fiber section inserted and fixed by the quartz glass capillary and the two ends of the quartz glass capillary are arranged in the ferrule, and the first optical fiber section which is kept at intervals in the quartz glass capillary An optical fiber segment and a second optical fiber segment form an optical fiber Fabry-Perot cavity; the fit between the ferrule and the quartz glass capillary is clearance fit and sealed and fixed by glass solder welding;

A grating is arranged on the first fiber segment, and both ends of the grating are bonded to the fiber grating protection member with a high-temperature sealant to keep the grating bent in a certain arc and in a free state without force, as a fiber temperature sensor.

The specific feature of this scheme is that an intermediate sleeve is sheathed outside the optical fiber temperature sensor, and the intermediate sleeve is respectively connected with the main protective sleeve and the outer sleeve. The intermediate sleeve has an inner hole capable of accommodating the grating protector, and the diameter of the inner hole is larger than the outer diameter of the grating protector.

The grating protector is divided into three parts: the head part, the middle part and the tail part. The head part and the tail part are in the shape of a cylinder, and the middle part is in the shape of a truncated cylinder. A long groove for accommodating the grating is arranged on the surface of the grating protector parallel to its central axis.

The main protection sleeve and the middle sleeve are fixed by screw connection, and high-temperature sealant is applied on the thread to ensure its sealing performance; the middle sleeve and the outer sleeve are fixed by thread connection, and high-temperature sealant is applied on the thread, To ensure its sealing performance.

The connecting pipe is connected with the middle sleeve and the outer sleeve at the same time. The connection between the connecting pipe and the intermediate sleeve and the outer sleeve is fixed by thread compression mechanical seal; the thread compression mechanical seal is fixed by using compression nut, snap ring and ferrule to form a wedge-type clamping structure.

The middle sleeve, the outer sleeve and the connecting pipe are all made of stainless steel. The ferrule material can be metal, ceramic or glass. The inner diameter of the ferrule is about 0.35 mm, and the length of the inner hole of the ferrule is about 2 mm. The distance between the end faces of the first fiber segment and the second fiber segment, that is, the cavity length of the fiber Fabry-Perot cavity is in the range of 100 μm to 150 μm.

The first fiber segment and the second fiber segment of the quartz glass capillary are fixed together by laser welding, and the end faces of the two fiber segments are spaced apart in the capillary to form a cavity with a certain length. The two sections of optical fiber are single-mode silica glass optical fibers, and the coating layer of the single-mode silica glass optical fiber is a high temperature resistant material, such as polyimide. The inner diameter of the quartz glass capillary is about 0.15-0.2mm, the outer diameter is about 0.3mm, and the material is high-purity quartz glass.

The main body sleeve and ferrule are sealed and fixed by glass solder welding. The glass solder is a high-temperature glass solder with a melting point of 500°C.

A wedge clamping structure is formed between the main body protection sleeve and the main body sleeve through a compression nut, a snap ring and a ferrule, and a thread compression mechanical seal is formed and fixed.

A pressure inlet is provided on the side wall at the end of the main body protection sleeve corresponding to the quartz glass pressure inlet tube.

The quartz glass pressure inlet tube and the optical fiber Fabry-Perot cavity protection sleeve are welded together by glass solder to realize sealing and fixing.

The optical fiber Fabry-Perot cavity protection sleeve and the main body sleeve are fixed through threaded connection, and play a role in protecting the optical fiber Fabry-Perot cavity during testing, calibration, packaging and use. The fiber grating protection part is fixed with the main body sleeve through threaded connection. The fiber grating protection part is made of Invar.

In the optical fiber Fabry-Perot cavity protection sleeve, when the measurement environment is lower than 150°C, it can be filled with silicone oil or other medium that does not chemically react with quartz glass as a protection medium and as a pressure transfer medium. In the case of measuring environment higher than 150°C, no protective medium is injected.

The connection method using the wedge-type clamping structure formed by the compression nut, the snap ring and the ferrule can also be used as the connection method between the core component of the sensor probe and the testing and calibration device. The core element of the sensor probe includes an optical fiber Fabry Perot cavity, a ferrule, a main body sleeve, a protective sleeve for the optical fiber Fabry Perot cavity, a quartz glass pressure inlet tube and a fiber grating protection piece. The core element of the sensor can be used as an independent sensor probe, and can be tested and calibrated.

Features and effects of the present invention: The optical fiber temperature and pressure sensor probes proposed by the present invention are sealed and fixed by glass solder welding at the parts in contact with the measurement medium. In view of the material of the glass solder, the sealed parts can withstand high temperature and high pressure and underground liquids. gas corrosion. Long-term downhole experiments have proved that the sealing part can withstand high temperature of 320°C and high pressure of 100Mpa. The optical fiber pressure sensor uses a quartz glass capillary as the elastic element, uses a ferrule with an inner diameter of 0.35mm to match the outer diameter of the quartz glass capillary, and uses high-temperature glass solder with a melting point of 500°C to weld the quartz glass capillary and ferrule. After welding The solder melts and accumulates between the outer surface of the quartz glass capillary and the inner hole surface of the ferrule, ensuring that when the temperature changes drastically, the force generated by the size change of the inner diameter of the ferrule mainly acts on the glass solder instead of directly acting on the quartz glass On the capillary, thereby avoiding the damage or leakage of the quartz glass capillary caused by temperature shock. Moreover, after welding, the 2mm-long inner hole is filled with glass solder, which ensures the sealing performance at room temperature and high temperature. Long-term experiments can prove that the optical fiber Fabry-Perot cavity pressure sensor proposed by the invention can withstand high temperature and high pressure, has high measurement accuracy, good repeatability and long service life.

The fiber optic temperature sensor uses a fiber grating as the sensing element and a grating protection with a special structure, which is characterized by a central through hole and a slot from the outer surface to the central through hole. This special structure is convenient for bonding the grating on At both ends of the central through hole, the slotted structure facilitates the packaging operation in the direction perpendicular to the central hole, that is, the radial direction, and makes the grating have a bending space along the slotted direction, so that the grating can always be in a free state without force , high measurement accuracy and long service life. The fiber optic temperature sensor, fiber grating, and the fiber optic pressure sensor, fiber Fabry-Perot cavity, are integrated on the core element of the sensor probe. The optical fiber pressure sensor is packaged with a fiber optic Fabry Perot cavity protection sleeve, which plays the role of transmitting pressure and protecting the fiber optic Fabry Perot cavity, and avoids the optical fiber Fabry Perot cavity Damage to the cavity. The optical fiber temperature sensor is fixed on the fiber grating protective part by high temperature sealant, and makes it slightly bent to maintain a free state without force. The optical fiber grating protective part is made of Invar, and the linear expansion coefficient of this material is It tends to zero, that is, its linear dimension basically does not change with temperature changes. This packaging method ensures that the fiber grating will not be stressed due to the size change of the fiber grating protection, that is, the grating will not be changed by external force. The change of the central wavelength is only linear with the temperature change, so that more accurate temperature information can be obtained. The core element of the sensor has small axial and radial dimensions, and it is easy to install during testing, calibration and packaging. The core element of the sensor probe can be tested and calibrated as an independent fiber optic temperature and pressure sensor, and then the qualified core element of the sensor probe is selected and packaged with a metal shell to make a finished product, which overcomes the traditional optical fiber sensor probe in testing and calibration. And the disadvantages of complex installation during packaging, easy damage and inability to replace core components after damage, shorten the product production cycle and improve the yield.

Between the main protection sleeve and the middle sleeve, as well as between the middle sleeve and the outer sleeve, the connection method of screw connection, glue sealing and fixing is adopted, between the connecting pipe and the middle sleeve, and between the connecting pipe and the outer layer The connection between the sleeves is fixed by thread compression and mechanical seal. In this way, the internal structure of the sensor probe is not in contact with the harsh downhole environment during measurement, and the measurement accuracy of the sensor is ensured during the long-term downhole measurement process. and service life.

Description of drawings

Fig. 1 is a cross-sectional view of the fiber optic temperature and pressure sensor probe of the present invention; Fig. 2 is a cross-sectional view of the core element of the fiber optic temperature and pressure sensor probe of the present invention; Part A is an enlarged view; Fig. 4 is a sectional view of the connecting part of the sensor probe intermediate sleeve and the outer layer sleeve and the coupling pipe of the present invention, that is, the enlarged view of part B in Fig. 1; Fig. 5 is an optical fiber method of the sensor probe of the present invention The sectional view of the connecting part of the Bry-Perot cavity protection sleeve and the quartz glass pressure inlet tube, that is, the enlarged view of part C in Fig. 2; Fig. 6 is the sectional view of the connecting part between the fiber-optic Fabry-Perot cavity and the ferrule of the sensor probe of the present invention Figure, that is, the enlarged view of part D in Fig. 2; Fig. 7 is a cross-sectional view of the connection part between the ferrule and the main body sleeve of the sensor probe of the present invention, that is, the enlarged view of part E in Fig. 2; Fig. 8 is the optical fiber Fabry-Perot of the present invention The principle structure diagram of the cavity; Fig. 9 is a three-dimensional structure diagram of the optical fiber temperature sensor of the present invention; Fig. 10 is a 14-hour continuous test cavity length data diagram of the optical fiber pressure sensor of the present invention under 300°C and 30Mpa environment.

In the figure: 1-first fiber segment; 2-fiber grating; 3-fiber grating protection; 4-first snap ring; 5-first ferrule; 6-first compression nut; 7-main body sleeve; 8-ferrule; 9-quartz glass capillary; 10-second fiber segment; 11-optical fiber Fabry-Perot cavity protection sleeve; 12-quartz glass inlet pressure tube; 13-main body protection sleeve; 14-inlet pressure 15-middle sleeve; 16-second ferrule; 17-second compression nut; 18-outer sleeve; 19-compression screw; 20-connection pipe; 21-third snap ring; 22- The third ferrule; 23-the second snap ring; 24-welding point; 25-welding point; 26-welding point; 27-first optical fiber coating; 28-welding point; 29-welding point; Optical fiber coating layer; 31-first optical fiber end face; 32-second optical fiber end face; 33-glue bonding point; 34-glue bonding point.

Detailed ways

As shown in Figures 1 and 2, an optical fiber temperature and pressure sensor probe includes an intermediate sleeve 15, an outer sleeve 18, a connecting pipe 20, a main body protection sleeve 13, and a main body fixed at one end of the main body protection sleeve 13. Sleeve 7, the two ends of the main sleeve 7 are respectively fixed with a fiber optic Fabry-Perot cavity protection sleeve 11 and a fiber grating protection member 3, and the fiber optic Fabry-Perot cavity protection sleeve 11 is inserted into the main body protection sleeve In 13 : a quartz glass pressure inlet tube 12 is fixedly installed on the end of the optical fiber Fabry-Perot cavity protection sleeve 11 opposite to the main body sleeve 7 .

As shown in Figures 7 and 8, a ferrule 8 is fixedly arranged in the main body sleeve 7, and a quartz glass capillary 9 and the first optical fiber segment 1 inserted and fixed from both ends of the quartz glass capillary 9 and The second fiber segment 10, the first fiber segment 1 and the second fiber segment 10 kept spaced apart in the quartz glass capillary 9 form a fiber Fabry-Perot cavity. The main body sleeve 7 and the ferrule 8 are sealed and fixed by glass solder welding. The glass solder is a high-temperature glass solder with a melting point of 500°C.

As shown in FIG. 6 , the ferrule 8 and the quartz glass capillary 9 are gap-fitted and sealed and fixed by glass solder welding; the material of the ferrule 8 can be metal, ceramics or glass. The inner diameter of the ferrule 8 is about 0.35mm, and the inner hole length of the ferrule 8 is about 2mm.

As shown in Figure 9, a fiber grating 2 is arranged on the first fiber segment 1, and both ends of the fiber grating 2 are bonded to the fiber grating protection member 3 with a high-temperature sealant to keep the fiber grating 2 bent in a certain arc, And in a free state without stress, it can be used as an optical fiber temperature sensor. The grating protection part 3 is divided into three parts: the head part, the middle part and the tail part. The head part and the tail part are in the shape of a cylinder, and the middle part is in the shape of a truncated cylinder. A long groove for accommodating the grating is arranged on the surface of the grating protection part 3 parallel to its central axis, with a width of 1mm.

As shown in Figure 8, the quartz glass capillary 9 is fixed together with the first optical fiber section 1 and the second optical fiber section 10 by laser welding, and the end faces of the two sections of optical fibers are spaced apart in the quartz glass capillary 9 to form a space with a certain length. cavity. The first fiber section 1 and the second fiber section 10 are single-mode silica glass fibers, and the coating layer of the single-mode silica glass fibers is a high temperature resistant material, such as polyimide. The quartz glass capillary 9 has an inner diameter of about 0.15-0.2 mm, an outer diameter of about 0.3 mm, and is made of high-purity quartz glass.

As shown in FIGS. 1 and 3 , a wedge clamping structure is formed between the main body protection sleeve 13 and the main body sleeve 7 through the first compression nut 6 , the first snap ring 4 and the first ferrule 5 . The shown main body protective sleeve 13 is a metal protective shell.

As shown in FIG. 1 , a pressure inlet 14 is provided on the side wall at the end of the main body protection sleeve 13 corresponding to the quartz glass pressure inlet tube 12 .

As shown in FIG. 4 , the quartz glass pressure inlet tube 12 and the optical fiber Fabry-Perot cavity protection sleeve 11 are welded together by glass solder to realize sealing and fixing. The optical fiber Fabry-Perot cavity protection sleeve 11 is screwed and fixed to the main body sleeve 7 to protect the optical fiber Fabry-Perot cavity during testing, calibration, packaging and use. The fiber grating protection member 3 is fixed to the main body sleeve 7 through threaded connection. The fiber grating protection member 3 is made of Invar.

In the optical fiber Fabry-Perot cavity protection sleeve 11, when the measurement environment is lower than 150°C, it can be filled with silicone oil or other medium that does not chemically react with quartz glass as a protective medium, and at the same time as a protective medium. pressure transmission medium. In the case of measuring environment higher than 150°C, no protective medium is injected.

The structure of the optical fiber Fabry-Perot cavity is shown in Figure 7, including a section of quartz glass capillary 9, a first optical fiber section 1 and a second optical fiber section 10. In this application example, the inner diameter of the quartz glass capillary is 0.15~0.2mm, The outer diameter is about 0.3mm. First, the coating layers 27 and 30 at one end of the first optical fiber segment 1 and the second optical fiber segment 10 are stripped, and the smooth end faces 31 and 32 are processed by cutting or grinding with a cleaver, and then the first optical fiber segment 1 and the second optical fiber segment Two optical fiber sections 10 are respectively inserted from the two ends of the quartz glass capillary tube 9 and fixed together by laser welding points 28 and 29. A cavity with a certain length is formed, that is, the fiber Fabry-Perot cavity. The distance of this cavity is the cavity length of the fiber-optic Fabry-Perot cavity. In this application example, the cavity The long range is 100μm~150μm. When the external pressure acts on the quartz glass capillary 9, the change of the axial length of the quartz glass capillary 9 has a linear relationship with the change of the external pressure, and the change of the axial length of the quartz glass capillary 9 has a linear relationship with the change of the cavity length of the optical fiber Fabry-Perot cavity. Linear relationship, that is, the cavity length of the optical fiber Fabry-Perot cavity has a linear relationship with the external pressure change.

The external demodulator sends out a bunch of optical signals, which are transmitted to the optical fiber Fabry-Perot cavity through the first optical fiber section 1, and the optical signal is reflected back to the first optical fiber section 1 through the second optical fiber section 10, and then transmitted back to the external demodulator. The cavity length information of the optical fiber Fabry-Perot cavity is thus obtained, and the external pressure change information can be obtained by monitoring the cavity length change information of the optical fiber Fabry-Perot cavity.

During the measurement, the external fluid medium is introduced through the pressure inlet 14, and the pressure is transmitted to the optical fiber Fabry-Perot cavity to realize the measurement.

The optical fiber Fabry-Perot cavity pressure sensor proposed by the present invention changes in the cavity length data of the 14-hour continuous test at 300°C and 30Mpa environment as shown in Figure 9. The pressure measurement coefficient of the pressure sensor is 354nm/Mpa, and the range is 0- 100Mpa, it can be seen from the data shown in Figure 9 that the cavity length variation error of the optical fiber Fabry-Perot cavity pressure sensor proposed by the present invention is less than 5nm, that is, the pressure measurement error is less than 0.015Mpa, and the measurement accuracy error is less than 0.02% FS. Good sealing performance in high-pressure environment, no damage or failure phenomenon, which fully demonstrates that the optical fiber pressure sensor proposed by the present invention has the characteristics of high precision, good sealing performance in long-term high-temperature and high-pressure environment, good service life and long-term reliability, etc., especially suitable for high temperature and high pressure oil well measurement environment.

Claims (8)

1. An optical fiber temperature and pressure sensor probe, which comprises a main body protection sleeve and a main body sleeve fixedly arranged at one end of the main body protection sleeve, is characterized in that an optical fiber Fabry-Perot cavity is respectively fixedly arranged at the main body sleeve two ends The protective sleeve and the fiber grating protective piece, the optical fiber Fabry-Perot cavity protective sleeve is inserted into the main body protective sleeve; A quartz glass inlet pressure tube is fixedly arranged on the end of the optical fiber Fabry-Perot cavity protection sleeve opposite to the main sleeve; The ferrule is fixedly arranged in the main body sleeve, the first optical fiber section and the second optical fiber section inserted and fixed by the quartz glass capillary and the two ends of the quartz glass capillary are arranged in the ferrule, and the first optical fiber section which is kept at intervals in the quartz glass capillary An optical fiber segment and a second optical fiber segment form an optical fiber Fabry-Perot cavity; the fit between the ferrule and the quartz glass capillary is clearance fit and sealed and fixed by glass solder welding; A grating is arranged on the first fiber segment, and both ends of the grating are bonded to the fiber grating protection member with a high-temperature sealant and the grating is kept bent in a certain arc, and is in a free state without force, as an optical fiber temperature sensor; The grating protection part is divided into three parts: the head part, the middle part and the tail part. The head part and the tail part are in the shape of a cylinder, and the middle part is in the shape of a truncated cylinder. A long groove for accommodating the grating is arranged on the surface of the grating protection part parallel to its central axis; the ferrule The inner diameter is 0.35mm, and the inner hole length of the ferrule is 2mm; the inner diameter of the quartz glass capillary is 0.15-0.2mm, the outer diameter is 0.3mm, and the material is high-purity quartz glass. 2. The optical fiber temperature and pressure sensor probe according to claim 1, characterized in that an intermediate sleeve is sheathed outside the optical fiber temperature sensor, and the intermediate sleeve is respectively connected with the main protective sleeve and the outer sleeve. 3. The optical fiber temperature and pressure sensor probe according to claim 1, characterized in that the main body protection sleeve and the intermediate sleeve are fixed through threaded connection, and a high-temperature sealant is applied on the thread to ensure its sealing performance; the intermediate sleeve and the The outer sleeve is fixed by thread connection, and high-temperature sealant is applied on the thread to ensure its sealing performance. 4. The optical fiber temperature and pressure sensor probe according to claim 1, characterized in that the connecting pipe is connected with the middle sleeve and the outer sleeve at the same time; The mechanical seal is fixed; the main body protection sleeve and the main body sleeve are fixed by thread compression mechanical seal. 5. The fiber optic temperature and pressure sensor probe according to claim 4, characterized in that the mechanical seal is fixed by thread compression, that is, the compression nut, snap ring and ferrule form a wedge-type clamping structure. 6. The optical fiber temperature and pressure sensor probe according to claim 1, characterized in that the distance between the end faces of the first fiber segment and the second fiber segment, that is, the cavity length of the fiber Fabry-Perot cavity, is in the range of 100 μm to 150 μm. 7. The optical fiber temperature and pressure sensor probe according to claim 1, characterized in that the main body sleeve and the ferrule are sealed and fixed by glass solder welding; the quartz glass inlet pressure tube and the optical fiber Fabry-Perot cavity protection sleeve pass through The glass solder is welded together to realize sealing and fixing; the optical fiber Fabry-Perot cavity protection sleeve is fixed with the main body sleeve through threaded connection, and the optical fiber grating protection part is fixed with the main body sleeve through threaded connection; The quartz glass capillary is fixed together with the first optical fiber section and the second optical fiber section by laser welding, the first optical fiber section and the second optical fiber section are single-mode quartz glass optical fibers, and the coating layer of the single-mode quartz glass optical fiber is High temperature resistant material polyimide. 8. An optical fiber temperature and pressure sensor, characterized in that it comprises the optical fiber temperature and pressure sensor probe as claimed in claim 1.