CN101818640A - Fully distributed device and method for monitoring underground working temperature of oil-water well based on Raman scattered light time-domain reflectometer - Google Patents

Abstract

The invention discloses a fully distributed monitoring device and monitoring method for the downhole operating temperature of oil and water wells based on a Raman scattered light time domain reflectometer, and relates to the technical field of laser monitoring. It solves the problem that the existing downhole temperature monitoring of oil and water wells can only be monitored at a single point and cannot be monitored on-line in real time. The device of the present invention includes a Raman scattered light time domain reflectometer, an amplifier circuit, a data collector and a computer processing system. The method of the present invention is as follows: the laser outputs an optical signal and couples it to the Raman optical fiber arranged on the oil pipe through a wavelength division multiplexer, and at the same time returns the backscattered light through the wavelength division multiplexer and then outputs the signal to the photodetector, the photoelectric The detector detects the backscattered light power and outputs it to the amplifier circuit for amplification, and then outputs it to the data collector and computer processing system to obtain the distance of the oil and water well under the tubing and the corresponding absolute temperature value, and display it on the computer screen to realize distributed, Real-time online monitoring of temperature. The invention is suitable for monitoring the temperature of the downhole working condition of the oil-water well.

Description

A fully distributed monitoring device and monitoring method for downhole temperature of oil and water wells based on Raman scattered optical time domain reflectometer

technical field

The invention relates to the technical field of laser monitoring, in particular to a fully distributed monitoring device and monitoring method for the downhole operating temperature of an oil-water well based on a Raman scattered light time-domain reflectometer.

Background technique

At present, the downhole temperature monitoring technology in oilfields has long used single-point temperature sensors. When the oil and water wells are shut down, the sensor is inserted into the oil casing annulus to detect the temperature of a certain layer. First, this method can only detect a single point. Temperature, that is, the temperature sensor can only be obtained when the temperature sensor is inserted into a certain position; secondly, the production must be stopped during the detection, which not only affects the output, but also the detected temperature data cannot truthfully reflect the temperature information during real production; once again, the single-point temperature The traditional method of monitoring cannot detect the temperature in real time and permanently. It can only detect the temperature at a certain moment, and cannot track the trend of downhole temperature changes in oil and water wells. At the same time, this method cannot monitor the temperature of special working conditions such as well washing.

Contents of the invention

In order to solve the problem that the existing downhole temperature monitoring of oil and water wells can only be monitored at a single point and cannot be monitored on-line in real time, the present invention provides a fully distributed temperature monitoring method based on Raman scattered light time domain reflectometer Monitoring device and monitoring method.

A fully distributed monitoring device of the downhole operating temperature of oil and water wells based on a Raman scattered light time domain reflectometer of the present invention, which includes a Raman scattered light time domain reflectometer, an amplifier circuit, a data collector and a computer processing system, The Raman scattered light time domain reflectometer includes a laser, a wavelength division multiplexer, a Raman optical fiber, a first detector and a second detector, the output beam of the laser is sent to the signal input end of the wavelength division multiplexer, and the wavelength division multiplexer The output/input end of the multiplexer is connected to one end of the Raman fiber, and the Stokes optical signal output end of the wavelength division multiplexer outputs the Stokes optical signal to the optical signal receiving end of the first detector, so The anti-Stokes optical signal output end of the wavelength division multiplexer outputs the anti-Stokes optical signal to the optical signal receiving end of the second detector, and the data output end of the first detector is connected to a signal input of the amplifier circuit end, the data output end of the second detector is connected to the other signal input end of the amplifying circuit, the signal output end of the amplifying circuit is connected to the data input end of the data collector, and the data output end of the data collector is connected to the data of the computer processing system input.

A fully distributed monitoring method based on the Raman scattered optical time domain reflectometer based on the above-mentioned device for downhole working temperature of oil and water wells, characterized in that its monitoring process is:

Step 1: The Raman scattered light time domain reflectometer starts to work, and outputs backscattered light power data. The specific process is: the optical signal output by the laser is coupled into the Raman fiber after passing through the wavelength division multiplexer, and the Raman The optical fiber is laid close to the oil pipe, and the other end of the Raman optical fiber is arranged on the outer surface of the bottom end of the oil pipe. The optical signal coupled into the Raman optical fiber generates backscattered light when it is transmitted in the Raman optical fiber and is input to the WDM The multiplexer, the wavelength division multiplexer simultaneously outputs the Stokes optical signal and the anti-Stokes optical signal, the first detector detects the Stokes optical power and outputs the Stokes optical power data to the amplifier circuit One signal input end, the second detector detects the anti-Stokes optical power and outputs the anti-Stokes optical power data to the other signal input end of the amplifying circuit;

Step 2: The amplifying circuit receives the backscattered light power data and amplifies and outputs it to the data collector, and the data collector collects the data and outputs it to the computer processing system, and the computer processing system is based on the transmission speed of the backscattered light and the The relationship formula 1 between the optical power of scattered light and the absolute temperature at the detection position is processed to obtain the downhole distance of the tubing and the corresponding absolute temperature value. At the same time, the computer processing system displays the change curve of the temperature with the distance on the computer screen to complete the downhole analysis of oil and water. Real-time online monitoring of temperature,

Formula 1: T=-hcΔγ/k{ln[P _a (T)/P _s (T)]-ln(λ _s /λ _a )}, where c is the propagation speed of light in vacuum, Δγ is the partial shifted wave number, k is the Boltzmann constant, P _a (T) is the power of anti-Stokes light, P _s (T) is the power of Stokes light, λ _s is the wavelength of Stokes light, λ _a is the wavelength of anti-Stokes light.

The beneficial effects of the present invention are: the structure of the present invention is simple, the Raman optical fiber realizes the fully distributed continuous temperature sensing, and further enables the present invention to realize the fully distributed temperature monitoring, which solves the problem of traditional single-point temperature monitoring and greatly reduces the In addition, the test accuracy of the present invention is high, the test accuracy can reach 1°C, the spatial resolution can reach 0.5m, and the range can reach 4 kilometers. The size changes the test accuracy and monitoring range; the invention realizes the real-time online monitoring of the oil-water downhole working condition temperature.

Description of drawings

Fig. 1 is a kind of structure schematic diagram of the fully distributed monitoring device of oil-water well downhole operating condition temperature based on Raman scattered optical time domain reflectometer of the present invention; Fig. 2 is the Raman scattered optical fiber 1-3 of the present invention after encapsulation The structural schematic diagram of the cross section, wherein the diameter of the stainless steel seamless pipe a is 1.5mm, the diameter of the inner steel wire of the double-layer steel wire b is 1.1mm, and the diameter of the outer steel wire is 1.2mm. Fig. 3 is the Raman optical fiber 1 of the present invention -3 Schematic diagram of laying on the outer surface of oil pipe H.

Detailed ways

Specific embodiment 1: According to the accompanying drawing 1 of the description, this embodiment will be described in detail. A fully distributed monitoring device for the downhole working temperature of oil and water wells based on Raman scattered light time domain reflectometer described in this embodiment includes a pull Mann scattered light time domain reflectometer 1, amplifying circuit 2, data collector 3 and computer processing system 4, described Raman scattered light time domain reflectometer 1 comprises laser 1-1, wavelength division multiplexer 1-2, pull Mann optical fiber 1-3, first detector 1-4 and second detector 1-5, laser 1-1 output beam to signal input end of wavelength division multiplexer 1-2, said wavelength division multiplexer 1- The output/input end of 2 is connected to one end of the Raman fiber 1-3, and the Stokes optical signal output end of the wavelength division multiplexer 1-2 outputs the Stokes optical signal to the first detector 1-4 The optical signal receiving end of the wavelength division multiplexer 1-2 outputs the anti-Stokes optical signal to the optical signal receiving end of the second detector 1-5, the first The data output end of the detector 1-4 is connected to one signal input end of the amplifying circuit 2, the data output end of the second detector 1-5 is connected to another signal input end of the amplifying circuit 2, and the signal output end of the amplifying circuit 2 is connected to the data The data input end of the collector 3, the data output end of the data collector 3 is connected to the data input end of the computer processing system 4, and the Raman optical fiber 1-3 is used to return the backscattered light of the input optical signal to wavelength division multiplexing device 1-2, the wavelength division multiplexer 1-2 is used to input the signal sent by the laser to the Raman fiber 1-3, and is also used to receive the backscattered light output by the Raman fiber 1-3 and reverse The Stokes beam and the anti-Stokes beam in the scattered light are respectively output, and the computer processing system 4 is used to calculate the distance of the oil-water well under the tubing H and the corresponding absolute temperature value according to the transmission speed and intensity of the backscattered light , is also used to display the distance and the corresponding absolute temperature value on the screen of the computer processing system 4 .

Specific embodiment 2: According to the accompanying drawings 1, 2 and 3 of the description, this embodiment will be described in detail. This embodiment is based on the downhole working conditions of oil and water wells based on the Raman scattered light time domain reflectometer based on the device described in the specific embodiment 1. The fully distributed monitoring method of temperature, its monitoring process is:

Step 1: The Raman scattered light time domain reflectometer 1 starts to work and outputs the backscattered light power data. The specific process is: the optical signal output by the laser 1-1 is coupled to the Raman after passing through the wavelength division multiplexer 1-2 In the optical fiber 1-3, the Raman optical fiber 1-3 is arranged close to the oil pipe H, and the other end of the Raman optical fiber 1-3 is arranged on the outer surface of the bottom end of the oil pipe H, and is coupled to the Raman optical fiber 1-3 When the optical signal in the Raman fiber 1-3 is transmitted, backscattered light is generated and input to the wavelength division multiplexer 1-2, and the wavelength division multiplexer 1-2 simultaneously outputs the Stokes optical signal and the backscattered light For the Stokes optical signal, the first detector 1-4 detects the Stokes optical power and outputs the Stokes optical power data to a signal input end of the amplifier circuit 2, and the second detector 1-5 detects the anti-Stokes Stokes optical power and output anti-Stokes optical power data to another signal input end of the amplifier circuit 2;

Step 2: the amplifying circuit 2 receives the backscattered light power data and amplifies and outputs it to the data collector 3, and the data collector 3 collects the data and outputs it to the computer processing system 4, and the computer processing system is based on the transmission of the backscattered light Velocity and the optical power of the backscattered light and the absolute temperature at the detection position are processed by Formula 1 to obtain the downhole distance h of the tubing H and the corresponding absolute temperature value T. At the same time, the computer processing system 4 displays the change curve of the temperature with the distance in On the computer screen, the real-time online monitoring of the downhole temperature of oil and water is completed,

Formula 1: T=-hcΔγ/k{ln[P _a (T)/P _s (T)]-ln(λ _s /λ _a )}, where c is the propagation speed of light in vacuum, Δγ is the partial shifted wave number, k is the Boltzmann constant, P _a (T) is the power of anti-Stokes light, P _s (T) is the power of Stokes light, λ _s is the wavelength of Stokes light, λ _a is the wavelength of anti-Stokes light.

This embodiment eliminates the influence of the pressure in the oil jacket annulus of the tubing H that changes with depth, and can directly measure the temperature in the oil jacket annulus.

This embodiment utilizes the principle of Raman scattering, and the photodetectors (the first detectors 1-4 and the second detectors 1-5) detect the spontaneous back Raman scattering optical power to realize signal acquisition. The spontaneous back Raman scattered light power formula detected by the photodetector is formula (1), namely:

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; RM</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; v</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}}{\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\mathrm{<span\; class="notranslate">\; exp</span>}<span\; class="notranslate">\; [</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Stokes Raman scattered optical power formula (2):

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; v</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}{\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\mathrm{<span\; class="notranslate">\; exp</span>}<span\; class="notranslate">\; [</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Anti-Stokes Raman scattering optical power formula (3):

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; AS</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; v</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; AS</span>}}{\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; AS</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\mathrm{<span\; class="notranslate">\; exo</span>}<span\; class="notranslate">\; [</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; AS</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the formula, P _RM , _PS and P _AS respectively represent the Raman scattered light, Stokes Raman scattered light and anti-Stokes Raman scattered light power detected by the photodetector; E ₀ represents the incident pump The energy of the light pulse; p _R , p _s , and p _AS respectively represent the backscattering factors of Raman scattered light, Stokes Raman scattered light, and anti-Stokes Raman scattered light in the fiber; Γ _R , Γ _S , Γ _AS respectively represent the backscattering coefficients of Raman scattered light, Stokes Raman scattered light and anti-Stokes Raman scattered light per unit length in the fiber; α ₀ , α _R and α _AS Respectively represent the loss coefficient of the incident pump light, Stokes Raman scattered light and anti-Stokes Raman scattered light per unit length in the fiber; L represents the length of the fiber.

Raman scattered light power is only affected by the temperature T at the detection position when the incident pump light, optical fiber optical path, and detection position are fixed. Further analysis found that although the Stokes Raman scattered light is also affected by temperature, but the affected range is very small, while the anti-Stokes Raman scattered light is greatly affected by the temperature, so in the measurement, the reflection The Stokes Raman scattered light is the effective signal light. The temperature signal modulates the anti-Skers Raman scattered light as it propagates in the sensing fiber. The temperature distribution curve can be obtained by calculation, namely

$\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; h\&Delta;v</span>}}{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}\mathrm{<span\; class="notranslate">\; ln</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; exp</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; h\&Delta;v</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; AS</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ]</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; AS</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

In order to facilitate the use of the formula, the above formula is simplified and sorted to get formula 1:

Formula 1: T＝-hcΔγ/k{ln[P _a (T)/P _s (T)]-ln(λ _s /λ _a )}

It can be seen from formula 1 that the measured temperature can be obtained by detecting the ratio of anti-Stokes light intensity to Storrs light intensity. At the same time, the position information of the temperature point can be obtained from the optical time domain reflectometry (OTDR), which is already very mature at present, to realize spatial positioning. Then the temperature at the corresponding distance can be calculated, and the temperature change curve can be displayed on the screen to realize the real-time online monitoring of the downhole temperature.

According to the optical sensing principle of the Raman optical time domain reflectometer (ROTDR), it is only sensitive to temperature changes, so it is very suitable for temperature measurement in complex underground environments with unknown strains.

In this embodiment, it can be seen from FIG. 2 that after the Raman optical fiber 1-3 is packaged in the stainless steel seamless tube a for protection, and water-blocking ointment is filled between the Raman optical fiber 1-3 and the stainless steel seamless tube a, To ensure the excess length of the optical fiber in the stainless steel tube. In addition, the protective outer layer is formed by double-layer steel wire b twisting, which makes the structure have extremely high tensile and compressive strength; high-strength twisting can resist various harsh conditions and ensure transmission; the structure adopts a sealed design and has electric resistance Chemically corrosive and water and oil repellent. Finally, it can also be encapsulated with a PE sheath on the outside. The above structure enables the Raman optical fiber 1-3 to be protected multiple times, so that the Raman optical fiber 1-3 has excellent durability in complex downhole environments.

In this embodiment, it can be seen from Figure 3 that it should be noted that the Raman optical fibers 1-3 must be laid close to the oil pipe H to accommodate the narrow space between the casings M, and at the same time, the two oil pipes H need to be connected Protective cover O is used at N to protect the Raman optical fibers 1-3. In order to realize distributed temperature measurement, one end of the Raman optical fiber 1-3 needs to be laid on the outer surface of the deepest oil pipe H. Before each tubing H goes downhole, a redundancy of about 15m is required on the ground to ensure that the Raman optical fibers 1-3 are not subjected to excessive tension.

Claims (3)

1. A fully distributed monitoring device based on Raman scattered light time domain reflectometer for oil and water well downhole operating conditions temperature, characterized in that it comprises Raman scattered light time domain reflectometer (1), amplifying circuit (2), Data collector (3) and computer processing system (4), described Raman scattered light time domain reflectometer (1) comprises laser (1-1), wavelength division multiplexer (1-2), Raman optical fiber ( 1-3), a first detector (1-4) and a second detector (1-5), The laser (1-1) outputs the light beam to the signal input end of the wavelength division multiplexer (1-2), and the output/input end of the wavelength division multiplexer (1-2) is connected to the Raman fiber (1-3) At one end, the Stokes optical signal output end of the wavelength division multiplexer (1-2) outputs the Stokes optical signal to the optical signal receiving end of the first detector (1-4), and the wavelength division multiplexer (1-2) The anti-Stokes optical signal output end of the multiplexer (1-2) outputs the anti-Stokes optical signal to the optical signal receiving end of the second detector (1-5), and the first detector (1-4 ) is connected to a signal input end of the amplifying circuit (2), and the data output end of the second detector (1-5) is connected to another signal input end of the amplifying circuit (2), and the signal of the amplifying circuit (2) The output end is connected to the data input end of the data collector (3), and the data output end of the data collector (3) is connected to the data input end of the computer processing system (4). 2. The fully distributed monitoring device of a kind of oil-water well downhole working condition temperature based on Raman scattered light time domain reflectometer according to claim 1, it is characterized in that the outside of Raman optical fiber is packaged with stainless steel seamless pipe (a) , and between the Raman optical fiber (1-3) and the stainless steel seamless tube (a) is filled with water-blocking ointment, the outer layer of the stainless steel seamless tube (a) is twisted with a double-layer steel wire (b ). 3. A kind of oil-water well underground work based on Raman scattered light time-domain reflectometer based on the fully distributed monitoring device of a kind of oil-water well downhole working condition temperature based on Raman scattered light time-domain reflectometer described in claim 2 The fully distributed monitoring method of ambient temperature is characterized in that its monitoring process is: Step 1: The Raman scattered light time domain reflectometer (1) starts to work, and outputs backscattered light power data. The specific process is: the optical signal output by the laser (1-1) passes through the wavelength division multiplexer (1-2) After being coupled into the Raman fiber (1-3), the Raman fiber (1-3) is laid close to the oil pipe (H), and the other end of the Raman fiber (1-3) is laid on the oil pipe ( H) the outer surface of the bottom end, the optical signal coupled into the Raman fiber (1-3) produces backscattered light when it is transmitted in the Raman fiber (1-3) and is input to the wavelength division multiplexer (1- 2), the wavelength division multiplexer (1-2) simultaneously outputs the Stokes optical signal and the anti-Stokes optical signal, and the first detector (1-4) detects the Stokes optical power and outputs the Stokes optical signal Stokes optical power data to a signal input end of the amplifier circuit (2), the second detector (1-5) detects the anti-Stokes optical power and outputs the anti-Stokes optical power data to the amplifier circuit (2) Another signal input terminal of Step 2: the amplifying circuit (2) receives the backscattered optical power data and amplifies and outputs it to the data collector (3), and the data collector (3) collects the data and outputs it to the computer processing system (4), and the computer processing The system (4) processes according to the transmission speed of the backscattered light and the relationship formula 1 between the optical power of the backscattered light and the absolute temperature at the detection position, and obtains the downhole distance h of the tubing (H) and the corresponding absolute temperature value T, and at the same time The computer processing system (4) displays the change curve of temperature with distance on the computer screen, and completes the real-time online monitoring of the downhole temperature of oil and water, Formula 1: T=-hcΔγ/k{ln[P _a (T)/P _s (T)]-ln(λ _s /λ _a )}, where c is the propagation speed of light in vacuum, Δγ is the partial shifted wave number, k is the Boltzmann constant, P _a (T) is the power of anti-Stokes light, P _s (T) is the power of Stokes light, λ _s is the wavelength of Stokes light, λ _a is the wavelength of anti-Stokes light.

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