An experimental device and method for monitoring oil, gas and water components in a wellbore

Abstract

The application discloses a kind of oil and gas water component monitoring experimental device and experimental method in wellbore, specifically relates to monitoring equipment technical field, including wellbore, single-mode laser, polarization maintaining fiber, Brillouin optical time domain reflectometer, condensate gas tank, pressurized driving device, formation water tank, condensate oil tank, natural gas tank, conveying device, oil-gas-water separator and waste oil tank, polarization maintaining fiber is spirally wound outside wellbore, and the both ends of polarization maintaining fiber are respectively connected with single-mode laser and Brillouin optical time domain reflectometer;Pressurized driving device is used to condensate gas to be pressurized to higher than condensate gas dew point pressure, and drive condensate gas to leave condensate gas tank;Conveying device is used to formation water tank formation water, condensate oil tank condensate oil and natural gas tank natural gas are respectively conveyed to wellbore, and wellbore outlet is connected with waste oil tank by oil-gas-water separator.The application can be real-time captured and dynamically tracked to oil-gas-water three-phase fluid in wellbore, measurement is accurate, experimental device structure is simple, and installation is convenient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of monitoring equipment, in particular to a device and method for monitoring oil, gas and water components in a wellbore. BACKGROUND

[0002] In the development process of condensate gas reservoirs, the fluid flow in the actual wellbore presents highly complex dynamic characteristics, and its flow state is influenced and coupled by multiple factors such as formation energy attenuation, water cut change, gas-liquid ratio fluctuation, etc. At the same time, the oil, gas and water three-phase fluid in the wellbore shows significant dynamic evolution characteristics.

[0003] However, the current monitoring technology has inherent limitations in real-time, continuity and accuracy. Traditional monitoring methods are difficult to realize real-time capture and dynamic tracking of oil, gas and water three-phase fluid, which leads to the difficulty in meeting the needs of timely identification and effective management of oil, gas and water three-phase fluid in actual production. At the same time, the existing indoor experimental research is mostly carried out under idealized conditions such as low pressure and normal temperature, which is significantly different from the complex working conditions of high temperature, high pressure and strong coupling of multiple phases in the actual wellbore, which makes the experimental research results face great challenges in actual engineering application, and it is difficult to directly guide the field production practice. SUMMARY

[0004] The purpose of the present application is to provide a device and method for monitoring oil, gas and water components in a wellbore, which can solve the problems existing in the prior art, can realize real-time capture and dynamic tracking of oil, gas and water three-phase fluid in the wellbore, has high measurement accuracy, and has simple structure and convenient installation.

[0005] To achieve the above purpose, the present application provides the following solutions:

[0006] The application provides a kind of wellbore oil, gas and water component monitoring experimental device, including wellbore, single mode laser, polarization maintaining fiber, Brillouin optical time domain reflectometer, condensate tank, pressurized driving device, formation water tank, condensate tank, natural gas tank, conveying device, oil-gas-water separator and waste oil tank, the polarization maintaining fiber is spirally wound outside the wellbore, the input end of the polarization maintaining fiber is connected with the single mode laser, and the output end of the polarization maintaining fiber is connected with the Brillouin optical time domain reflectometer;The two ends of the wellbore are closed;The condensate tank is connected with the bottom of the wellbore and communicates, and the condensate tank is used to contain condensate gas, the pressurized driving device is connected with the condensate tank, for pressurizing condensate gas, so that the pressure of pressurized condensate gas is higher than the dew point pressure of condensate gas, and the pressurized condensate gas is driven to leave the condensate tank;The formation water tank, the condensate tank and the natural gas tank are all connected with the bottom of the wellbore and communicate, and the formation water tank, the condensate tank and the natural gas tank are all connected with the conveying device, the conveying device is used to convey the formation water of the formation water tank, the condensate oil of the condensate tank and the natural gas of the natural gas tank to the wellbore respectively, the oil-gas-water separator is connected with the top of the wellbore and communicates, and the oil outlet of the oil-gas-water separator is connected with the waste oil tank and communicates.

[0007] Preferably, the top of the wellbore has an oil nozzle, which is connected with the oil-gas-water separator and communicates.

[0008] Preferably, it further includes a waste water tank, the water outlet of the oil-gas-water separator is connected with the waste water tank and communicates, and the gas outlet of the oil-gas-water separator communicates with the outside.

[0009] Preferably, it further includes a first pressure gauge and a second pressure gauge, the first pressure gauge is connected with the condensate tank for monitoring the pressure in the condensate tank, and the second pressure gauge is connected with the formation water tank for monitoring the pressure in the formation water tank.

[0010] Preferably, the pressurized driving device includes a pressurized piston and a piston driving device, the piston driving device is connected with the pressurized piston, the pressurized piston is arranged in the condensate tank, and the edge of the pressurized piston is closely attached to and slidingly connected with the inner side wall of the condensate tank.

[0011] Preferably, the conveying device is a double-cylinder pump.

[0012] Preferably, the polarization maintaining fiber is fixedly pasted outside the wellbore by adhesive.

[0013] Preferably, the wellbore includes a top cover, a cylinder body and a bottom cover, the top cover and the bottom cover are both threadedly connected with the cylinder body.

[0014] Preferably, the condensate tank, the formation water tank, the condensate tank and the natural gas tank are all made of steel.

[0015] The application also provides an experimental method using the experimental device for monitoring oil, gas and water components in a wellbore, comprising the following steps:

[0016] Step one, calibrate the fluid density parameter range and the forward Brillouin scattering light frequency shift parameter range of each of the oil, gas and water three phases;

[0017] Calibration of formation water: start the single-mode laser and the Brillouin optical time domain reflectometer, open the outlet valve of the formation water tank, and then start the conveying device to convey the formation water in the formation water tank to the wellbore at a constant pressure, the laser in the single-mode laser is transmitted to the wellbore by the polarization maintaining optical fiber, and the scattered frequency shifted laser is received by the Brillouin optical time domain reflectometer again through the polarization maintaining optical fiber; the forward Brillouin scattering light frequency shift data measured by the Brillouin optical time domain reflectometer is combined with the formula to obtain the first formation water density data; after obtaining multiple formation water density data by repeating the above test, the formation water density range is determined, and the functional relationship between the Brillouin scattering light frequency shift and the formation water density is established;

[0018] Calibration of condensate oil: start the single-mode laser and the Brillouin optical time domain reflectometer, open the outlet valve of the condensate oil tank, and then start the conveying device to convey the condensate oil in the condensate oil tank to the wellbore at a constant pressure, the laser in the single-mode laser is transmitted to the wellbore by the polarization maintaining optical fiber, and the scattered frequency shifted laser is received by the Brillouin optical time domain reflectometer again through the polarization maintaining optical fiber; the forward Brillouin scattering light frequency shift data measured by the Brillouin optical time domain reflectometer is combined with the formula to obtain the first condensate oil density data; after obtaining multiple condensate oil density data by repeating the above test, the formation water density range is determined, and the functional relationship between the Brillouin scattering light frequency shift and the condensate oil density is established;

[0019] Calibration of natural gas: start the single-mode laser and the Brillouin optical time domain reflectometer, open the outlet valve of the natural gas tank, and then start the conveying device to convey the natural gas in the natural gas tank to the wellbore at a constant pressure, the laser in the single-mode laser is transmitted to the wellbore by the polarization maintaining optical fiber, and the scattered frequency shifted laser is received by the Brillouin optical time domain reflectometer again through the polarization maintaining optical fiber; the forward Brillouin scattering light frequency shift data measured by the Brillouin optical time domain reflectometer is combined with the formula to obtain the first natural gas density data; after obtaining multiple natural gas density data by repeating the above test, the formation water density range is determined, and the functional relationship between the Brillouin scattering light frequency shift and the natural gas density is established;

[0020] After obtaining the results of the oil, gas and water three-phase calibration, the pressurized driving device is opened to pressurize the condensate gas of the condensate tank with the outlet closed, so that the pressure of the pressurized condensate gas is higher than the dew point pressure of the condensate gas;

[0021] In step three, the single-mode laser and the Brillouin optical time domain reflectometer are opened, the outlet valve of the condensate tank is opened, the pressurized condensate gas flows into the wellbore, then the conveying device is started and the outlet valve of the formation water tank is opened, so that the formation water flows into the wellbore at a constant pressure;

[0022] In step four, the waste oil tank is observed, and when the first drop of oil appears in the waste oil tank, the time T1 at this moment is recorded, then whether the frequency shift characteristics of the oil, gas and water three-phase appear in the forward Brillouin scattering light frequency shift recorded in the Brillouin optical time domain reflectometer is observed, if yes, the time T2 at this moment is recorded, until the condensate gas in the condensate tank is completely discharged, the experiment is ended, and after the experiment is ended, the conveying device is stopped, and the wellbore is cleaned and dried.

[0023] In step five, the oil, gas and water three-phase component change from the time T2 to the end of the experiment can be obtained by using the optical frequency shift data measured by the Brillouin optical time domain reflectometer and combining the previously established function relationship between the Brillouin scattering light frequency shift and the density of the oil, gas and water three-phase.

[0024] The present application has the following technical effects compared with the prior art:

[0025] The present application provides a wellbore oil, gas and water component monitoring experiment device and experiment method, a polarization maintaining optical fiber is spirally wound on the wellbore to form a distributed optical fiber sensor, a single-mode laser is used to inject pulsed light into the polarization maintaining optical fiber, and then a Brillouin optical time domain reflectometer is used to detect the forward Brillouin scattering light frequency shift amount in the optical fiber, the density data of the oil, gas and water three-phase is calculated according to the frequency shift amount, and finally the experiment is carried out by using condensate gas, and the components of the oil, gas and water three-phase are identified according to different density data; the experiment device has a simple structure and can be quickly installed, disassembled, cleaned and maintained; a single-mode laser, a polarization maintaining optical fiber and a Brillouin optical time domain reflectometer are used to build an oil, gas and water three-phase component monitoring experiment device which is not affected by mechanical factors and temperature and pressure, after the function relationship between the Brillouin scattering light frequency shift and the density of the oil, gas and water three-phase is established, the proportion of the components of the fluid in the wellbore can be determined according to the length of time when a certain phase density data appears during the experiment; the strain measurement range of the polarization maintaining optical fiber can generally reach from a micro-strain of one millionth to a nanoscale strain, and the polarization maintaining optical fiber is safe and reliable, does not need to be frequently calibrated, has higher data signal transmission capacity, and effectively reduces the error of the experimental measurement data; and the polarization maintaining optical fiber has strong anti-interference ability and is suitable for various complex environments. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0027] Figure 1 It is a structural schematic diagram of an oil-gas-water component monitoring experimental device in a wellbore.

[0028] Figure 2 It is an explosion view of a wellbore.

[0029] Figure 3 It is a front view of a wellbore or a bottom cover.

[0030] In the figure: 1-wellbore; 2-single-mode laser; 3-polarization maintaining optical fiber; 4-BOTDR (Brillouin Optical Time Domain Reflectometer); 5-condensate tank; 6-pressurized driving device; 7-pressurized piston; 8-formation water tank; 9-condensate oil tank; 10-natural gas tank; 11-conveying device; 12-oil-gas-water separator; 13-waste oil tank; 14-waste water tank; 15-first pressure gauge; 16-second pressure gauge; 17-oil nozzle; 18-top cover; 19-cylinder body; 20-bottom cover; 21-gluing position; 22-screw hole. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the scope of protection of the present application.

[0032] The present application aims to provide an oil-gas-water component monitoring experimental device in a wellbore and an experimental method, so as to solve the problems in the prior art, to realize real-time capturing and dynamic tracking of oil-gas-water three-phase fluid in a wellbore, to achieve high measurement accuracy, and to have a simple structure and convenient installation.

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the present application will be described in further detail below with reference to the drawings and specific embodiments.

[0034] Embodiment 1

[0035] The present embodiment provides an oil-gas-water component monitoring experimental device in a wellbore, which comprises a wellbore, a single-mode laser, a polarization maintaining optical fiber, a BOTDR (Brillouin Optical Time Domain Reflectometer), a condensate tank, a pressurized driving device, a pressurized piston, a formation water tank, a condensate oil tank, a natural gas tank, a conveying device, an oil-gas-water separator, a waste oil tank, a waste water tank, a first pressure gauge, a second pressure gauge, an oil nozzle, a top cover, a cylinder body, a bottom cover, a gluing position and a screw hole. Figure 1As shown, it comprises a wellbore 1, a single-mode laser 2, a polarization maintaining optical fiber 3, a Brillouin optical time domain reflectometer 4, a condensate tank 5, a pressurized driving device 6, a formation water tank 8, a condensate oil tank 9, a natural gas tank 10, a conveying device 11, an oil-gas-water separator 12 and a waste oil tank 13, the polarization maintaining optical fiber 3 is spirally wound outside the wellbore 1, the input end of the polarization maintaining optical fiber 3 is connected with the single-mode laser 2, and the output end of the polarization maintaining optical fiber 3 is connected with the Brillouin optical time domain reflectometer 4; both ends of the wellbore 1 are closed; the condensate tank 5 is connected with and communicates with the bottom of the wellbore 1, the condensate tank 5 is used for containing condensate, the pressurized driving device 6 is connected with the condensate tank 5 and is used for pressurizing the condensate so that the pressure of the pressurized condensate is higher than the dew point pressure of the condensate and the pressurized condensate is driven to leave the condensate tank 5; the formation water tank 8, the condensate oil tank 9 and the natural gas tank 10 are all connected with and communicate with the bottom of the wellbore 1, the formation water tank 8, the condensate oil tank 9 and the natural gas tank 10 are all connected with the conveying device 11, the conveying device 11 is used for conveying the formation water of the formation water tank 8, the condensate oil of the condensate oil tank 9 and the natural gas of the natural gas tank 10 to the wellbore 1 respectively, the oil-gas-water separator 12 is connected with and communicates with the top of the wellbore 1, and the oil outlet of the oil-gas-water separator 12 is connected with and communicates with the waste oil tank 13. The polarization maintaining optical fiber 3 spirally wound on the wellbore 1 forms a distributed optical fiber sensor, the single-mode laser 2 is used for injecting pulsed light into the polarization maintaining optical fiber 3, and the Brillouin optical time domain reflectometer 4 is used for detecting the frequency shift amount of the forward Brillouin scattering light in the optical fiber, the density data of the three phases of oil, gas and water are calculated according to the frequency shift amount, and finally the experiment is carried out using condensate gas, and the components of the three phases of oil, gas and water are identified according to different density data; the experimental device has simple structure and can be quickly installed, disassembled, cleaned and maintained; the single-mode laser 2, the polarization maintaining optical fiber 3 and the Brillouin optical time domain reflectometer 4 are used to build an experimental device for monitoring the components of oil, gas and water which is not affected by mechanical factors and temperature and pressure, a functional relationship between the frequency shift of Brillouin scattering light and the densities of oil, gas and water is established, and during the experiment, the proportion of the components of the fluid in the wellbore 1 can be determined according to the length of time when a certain phase density data appears; the strain measurement range of the polarization maintaining optical fiber 3 can usually reach from a micro-strain of one millionth to a nano-strain, and it is safe and reliable, does not need to be frequently corrected, has higher data signal transmission capacity and effectively reduces the error of experimental measurement data; and the polarization maintaining optical fiber 3 has strong anti-interference ability and is suitable for various complex environments.

[0036] The essence of Brillouin scattering is that when the incident light wave passes through the medium, the elastic acoustic wave field inside the medium interacts with the light wave field, generates phonon or magnon, thereby causing a kind of nonlinear scattering phenomenon of light scattering, and the frequency of the scattered light will be shifted compared with the incident light. The size of the Brillouin scattering light frequency shift is related to the sound speed, and the sound speed is related to the elastic properties and density of the medium. Therefore, different substances can be identified by measuring the forward Brillouin scattering light frequency shift. The Brillouin optical time domain reflectometer 4 measures the amount of Brillouin scattering light frequency shift by using this characteristic.

[0037] The pressurizing driving device 6 is connected with the condensate gas tank 5, and is used for pressurizing the condensate gas, so that the pressure of the pressurized condensate gas is higher than the dew point pressure of the condensate gas, and part of the gas phase in the condensate gas is prevented from being condensed into liquid phase, thereby ensuring the accuracy of the experiment.

[0038] The formation water in the formation water tank 8 is configured with appropriate ion concentrations according to the formation conditions of the research area; the natural gas in the natural gas tank 10 and the condensate oil in the condensate oil tank 9 are configured according to the natural gas and crude oil samples actually extracted in the research area; and the condensate gas in the condensate gas tank 5 is prepared by mixing and heating and pressurizing the natural gas and the crude oil according to the gas-oil ratio and the dew point pressure under the formation conditions of the research area, so as to reduce the deviation from the complex working conditions such as high temperature, high pressure and multiphase flow in the actual wellbore 1.

[0039] It is further preferred in the embodiment of the present embodiment that the top of the wellbore 1 is provided with a choke 17, and the choke 17 is connected and communicated with the oil-gas-water separator 12.

[0040] It is further preferred in the embodiment of the present embodiment that the wellbore oil-gas-water component monitoring experiment device further comprises a waste water tank 14, the water outlet of the oil-gas-water separator 12 is connected and communicated with the waste water tank 14, and the gas outlet of the oil-gas-water separator 12 is communicated with the outside. The waste water tank 14 and the waste oil tank 13 are used for containing the formation water and the crude oil separated by the oil-gas-water separator 12, so as to prevent the pollution of the experimental environment and the damage of the equipment, and the separated natural gas can be directly discharged to the atmosphere.

[0041] It is further preferred in the embodiment of the present embodiment that the wellbore oil-gas-water component monitoring experiment device further comprises a first pressure gauge 15 and a second pressure gauge 16, the first pressure gauge 15 is connected with the condensate gas tank 5, and is used for monitoring the pressure in the condensate gas tank 5, and the second pressure gauge 16 is connected with the formation water tank 8, and is used for monitoring the pressure in the formation water tank 8.

[0042] It is further preferred in the embodiment of the present embodiment that the pressurizing driving device 6 comprises a pressurizing piston 7 and a piston driving device, the piston driving device is connected with the pressurizing piston 7, the pressurizing piston 7 is arranged in the condensate gas tank 5, and the edge of the pressurizing piston 7 is tightly attached to and slidably connected with the inner side wall of the condensate gas tank 5.

[0043] Further preferably in the embodiments of the present embodiment, the delivery device 11 is a double-cylinder pump.

[0044] Further preferably in the embodiments of the present embodiment, the polarization maintaining optical fiber 3 is fixed and pasted outside the wellbore 1 by an adhesive. The wellbore 1 uniformly spirally winds the polarization maintaining optical fiber 3 from top to bottom, and the wellbore 1 is made of steel, Figure 1 and Figure 2 The black and white dots are the adhesive bonding sites 21 (i.e. the places where the polarization maintaining optical fiber 3 is adhered by the adhesive), and the adhesive bonding sites 21 are uniformly distributed around the wellbore 1. The black color is the visible adhesive bonding site 21 under the main viewing angle, and the white color is the invisible back adhesive bonding site 21 under the main viewing angle. Except for the black and white small dots, there is no difference.

[0045] Further preferably in the embodiments of the present embodiment, as shown in Figures 2-3 The wellbore 1 includes a top cover 18, a barrel 19 and a bottom cover 20, and the top cover 18 and the bottom cover 20 are both threadedly connected with the barrel 19. The top cover 18 and the bottom cover 20 of the wellbore 1 are both provided with threads, and the top cover 18 and the bottom cover 20 can be tightened counterclockwise during use and loosened clockwise after use for disassembly. The wellbore 1 has a detachable function, which is convenient for daily maintenance and cleaning. The top cover 18 and the bottom cover 20 are the same, and both are designed with two closable screw holes 22 for connecting pipelines or installing other accessories (such as oil nozzles 17) and the like.

[0046] Further preferably in the embodiments of the present embodiment, the materials of the condensate gas tank 5, the formation water tank 8, the condensate oil tank 9 and the natural gas tank 10 are all steel.

[0047] Embodiment 2

[0048] The present embodiment provides an experimental method for monitoring the oil, gas and water components in the wellbore by using the experimental device of embodiment 1, which includes the following steps:

[0049] Step one, calibrate the fluid density parameter range and the forward Brillouin scattering light frequency shift parameter range of each of the oil, gas and water three phases;

[0050] Calibrating formation water: start the single mode laser 2 and the Brillouin optical time domain reflectometer 4, only open the outlet valve of the formation water tank 8, then start the conveying device 11 to convey the formation water in the formation water tank 8 to the wellbore 1 at a constant pressure, the laser in the single mode laser 2 is transmitted to the wellbore 1 by the polarization maintaining optical fiber 3, and the scattered frequency-shifted laser is received by the Brillouin optical time domain reflectometer 4 again through the polarization maintaining optical fiber 3; the forward Brillouin scattered light frequency shift data measured by the Brillouin optical time domain reflectometer 4, combined with formula 1 and formula 2, obtains the first formation water density data; after obtaining multiple formation water density data by repeating the above test, the formation water density range is determined, after the end, the single mode laser 2, the Brillouin optical time domain reflectometer 4, the conveying device 11 and the outlet valve of the formation water tank 8 are closed, and the function relationship between the measured data and the Brillouin scattered light frequency shift and the formation water density is established;

[0051] Calibrating condensate oil: start the single mode laser 2 and the Brillouin optical time domain reflectometer 4, only open the outlet valve of the condensate oil tank 9, then start the conveying device 11 to convey the condensate oil in the condensate oil tank 9 to the wellbore 1 at a constant pressure, the laser in the single mode laser 2 is transmitted to the wellbore 1 by the polarization maintaining optical fiber 3, and the scattered frequency-shifted laser is received by the Brillouin optical time domain reflectometer 4 again through the polarization maintaining optical fiber 3; the forward Brillouin scattered light frequency shift data measured by the Brillouin optical time domain reflectometer 4, combined with formula 1 and formula 2, obtains the first condensate oil density data; after obtaining multiple condensate oil density data by repeating the above test, the formation water density range is determined, after the end, the single mode laser 2, the Brillouin optical time domain reflectometer 4, the conveying device 11 and the outlet valve of the condensate oil tank 9 are closed, and the function relationship between the measured data and the Brillouin scattered light frequency shift and the condensate oil density is established;

[0052] Calibrating natural gas: start the single mode laser 2 and the Brillouin optical time domain reflectometer 4, only open the outlet valve of the natural gas tank 10, then start the conveying device 11 to convey the natural gas in the natural gas tank 10 to the wellbore 1 at a constant pressure, the laser in the single mode laser 2 is transmitted to the wellbore 1 by the polarization maintaining optical fiber 3, and the scattered frequency-shifted laser is received by the Brillouin optical time domain reflectometer 4 again through the polarization maintaining optical fiber 3; the forward Brillouin scattered light frequency shift data measured by the Brillouin optical time domain reflectometer 4, combined with formula 1 and formula 2, obtains the first natural gas density data; after obtaining multiple natural gas density data by repeating the above test, the formation water density range is determined, after the end, the single mode laser 2, the Brillouin optical time domain reflectometer 4, the conveying device 11 and the outlet valve of the natural gas tank 10 are closed, and the function relationship between the measured data and the Brillouin scattered light frequency shift and the natural gas density is established;

[0053] The function relationship between the forward Brillouin scattered light frequency shift and the sound velocity is as follows:

[0054] (1)

[0055] wherein:

[0056] V B is the Brillouin scattering light frequency shift, Hz;

[0057] n eff is the effective refractive index of the optical fiber core, dimensionless;

[0058] V A is the sound wave propagation speed in the optical fiber, m / s;

[0059] λ p is the pump light wavelength, m;

[0060] The sound speed V A is a function of the density p and the elastic modulus of the material as follows:

[0061] (2)

[0062] wherein:

[0063] V A is the sound wave propagation speed in the optical fiber, m / s;

[0064] K is the bulk Young's modulus of the fluid medium, MPa;

[0065] p is the density of the fluid medium, kg / m 3 ;

[0066] Step two, after obtaining the results of the oil, gas and water three-phase calibration, open the pressurizing driving device 6 to pressurize the condensate gas of the condensate gas tank 5 with the outlet closed, so that the pressure of the pressurized condensate gas is higher than the dew point pressure of the condensate gas;

[0067] Step three, open the single-mode laser 2 and the Brillouin optical time domain reflectometer 4, open the outlet valve of the condensate gas tank 5, so that the pressurized condensate gas flows into the wellbore 1, then start the conveying device 11 and open the outlet valve of the formation water tank 8, maintain the value of the second pressure gauge 16 until the experiment is completed, in the process of the condensate gas entering the wellbore 1, the pressure decreases, the oil phase and the gas phase in the condensate gas will separate out, plus the formation water flowing from the formation water tank 8, the wellbore 1 is in a mixed state of oil, gas and water three phases;

[0068] Step four, observe the waste oil tank 13, record the time T1 when the first drop of oil appears in the waste oil tank 13, then observe whether the frequency shift characteristics of the oil, gas and water three phases appear in the forward Brillouin scattering light frequency shift recorded in the Brillouin optical time domain reflectometer 4, if they appear, record the time T2 at this moment, until the condensate gas in the condensate gas tank 5 is completely discharged, the experiment is completed, after the experiment is completed, shut down the conveying device 11, and clean and dry the wellbore 1;

[0069] Step five, using the light frequency shift data measured in the Brillouin optical time domain reflectometer 4, combining the previously established function relationship between the Brillouin scattering light frequency shift and the density of oil, gas and water, the component change of oil, gas and water from T2 to the end of the experiment can be calculated, that is, the component change rule of oil, gas and water in the wellbore 1 under simulated formation conditions when the condensate gas reservoir encounters water invasion.

[0070] The principles and implementation manners of the present application are described by using specific examples in the present application, and the above examples are only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed. In conclusion, the content of the present specification should not be understood as a limitation of the present application.

Claims

1. A method for monitoring oil, gas, and water components in a wellbore, characterized in that: An experimental device for monitoring oil, gas, and water components inside a wellbore is used. This device includes a wellbore, a single-mode laser, a polarization-maintaining fiber, a Brillouin optical time-domain reflectometer, a condensate gas tank, a pressurization drive device, a formation water tank, a condensate oil tank, a natural gas tank, a conveying device, an oil-gas-water separator, and a waste oil tank. The polarization-maintaining fiber is spirally wound around the outside of the wellbore. The input end of the polarization-maintaining fiber is connected to the single-mode laser, and the output end is connected to the Brillouin optical time-domain reflectometer. The wellbore is closed at both ends. The condensate gas tank is connected to and communicates with the bottom of the wellbore, and is used to hold condensate gas. The pressurization drive device is connected to the... The condensate gas tank is connected to pressurize the condensate gas, making the pressure of the pressurized condensate gas higher than its dew point pressure, and driving the pressurized condensate gas out of the condensate gas tank; the formation water tank, the condensate oil tank, and the natural gas tank are all connected to and communicate with the bottom of the wellbore; the formation water tank, the condensate oil tank, and the natural gas tank are all connected to the conveying device; the conveying device is used to convey the formation water from the formation water tank, the condensate oil from the condensate oil tank, and the natural gas from the natural gas tank to the wellbore respectively; the oil-gas-water separator is connected to and communicates with the top of the wellbore; the oil outlet of the oil-gas-water separator is connected to and communicates with the waste oil tank. It also includes the following steps: Step 1: Calibrate the fluid density parameter range and forward Brillouin scattering frequency shift parameter range for each of the three phases: oil, gas, and water. Formation water calibration: The single-mode laser and the Brillouin optical time-domain reflectometer are activated, the outlet valve of the formation water tank is opened, and then the conveying device is activated to deliver the formation water in the formation water tank to the wellbore at a constant pressure. The laser light from the single-mode laser is transmitted to the wellbore through the polarization-maintaining fiber, and the laser light after generating a diffused frequency shift is received by the Brillouin optical time-domain reflectometer through the polarization-maintaining fiber. The forward Brillouin scattered light frequency shift data measured by the Brillouin optical time-domain reflectometer is combined with the formula to obtain the formation water density data. After repeated testing to obtain multiple formation water density data, the formation water density range is determined, and a functional relationship between the Brillouin scattered light frequency shift and the formation water density is established. Calibration of condensate oil: The single-mode laser and the Brillouin optical time-domain reflectometer are activated, the outlet valve of the condensate oil tank is opened, and then the conveying device is activated to deliver the condensate oil in the condensate oil tank to the wellbore at a constant pressure. The laser light from the single-mode laser is transmitted to the wellbore through the polarization-maintaining fiber, and the laser light after generating a diffused frequency shift is received by the Brillouin optical time-domain reflectometer through the polarization-maintaining fiber. The forward Brillouin scattered light frequency shift data obtained by the Brillouin optical time-domain reflectometer is combined with the formula to obtain the first condensate oil density data. After repeated testing to obtain multiple condensate oil density data, the formation water density range is determined, and a functional relationship between the Brillouin scattered light frequency shift and the condensate oil density is established. Natural gas calibration: The single-mode laser and the Brillouin optical time-domain reflectometer are activated, the outlet valve of the natural gas tank is opened, and then the conveying device is activated to deliver the natural gas in the natural gas tank to the wellbore at a constant pressure. The laser light from the single-mode laser is transmitted to the wellbore through the polarization-maintaining fiber, and the laser light after generating a diffused frequency shift is received by the Brillouin optical time-domain reflectometer through the polarization-maintaining fiber. The forward Brillouin scattered light frequency shift data measured by the Brillouin optical time-domain reflectometer is combined with the formula to obtain the first natural gas density data. After repeated testing to obtain multiple natural gas density data, the formation water density range is determined, and a functional relationship between the Brillouin scattered light frequency shift and the natural gas density is established. Step 2: After obtaining the three-phase calibration results of oil, gas and water, turn on the pressurization drive device to pressurize the condensate gas in the condensate gas tank with the outlet closed, so that the pressure of the pressurized condensate gas is higher than the dew point pressure of the condensate gas. Step 3: Turn on the single-mode laser and the Brillouin optical time domain reflectometer, open the outlet valve of the condensate gas tank to allow the pressurized condensate gas to flow into the wellbore, then start the conveying device and open the outlet valve of the formation water tank to keep the formation water flowing into the wellbore at a constant pressure. Step 4: Observe the waste oil tank. Record the time T1 after the first drop of oil appears in the waste oil tank. Then observe whether the frequency shift of the forward Brillouin scattered light recorded by the Brillouin optical time domain reflectometer shows the frequency shift characteristics of the three phases of oil, gas and water. If it does, record the time T2. Continue until all the condensate gas in the condensate gas tank is discharged. The experiment ends. After the experiment, shut down the conveying device and clean and dry the well. Step 5: Using the optical frequency shift data measured in the Brillouin optical time domain reflectometer, combined with the previously established functional relationship between the Brillouin scattering optical frequency shift and the densities of the three phases of oil, gas, and water, calculate the component changes of the three phases of oil, gas, and water from time T2 to the end of the experiment. This will give the variation law of the three components of oil, gas, and water in the wellbore when the condensate gas reservoir encounters water invasion under simulated formation conditions.

2. The experimental method for monitoring oil, gas, and water components in a wellbore according to claim 1, characterized in that: The top of the wellbore has an oil nozzle, which is connected and communicates with the oil-gas-water separator.

3. The experimental method for monitoring oil, gas, and water components in a wellbore according to claim 2, characterized in that: It also includes a wastewater tank, the outlet of the oil-gas-water separator is connected to and communicates with the wastewater tank, and the gas outlet of the oil-gas-water separator is connected to the outside.

4. The experimental method for monitoring oil, gas and water components in the wellbore according to claim 1, characterized in that: It also includes a first pressure gauge and a second pressure gauge. The first pressure gauge is connected to the condensate gas tank and is used to monitor the pressure inside the condensate gas tank. The second pressure gauge is connected to the formation water tank and is used to monitor the pressure inside the formation water tank.

5. The experimental method for monitoring oil, gas, and water components in a wellbore according to claim 1, characterized in that: The pressurization drive device includes a pressurization piston and a piston drive device. The piston drive device is connected to the pressurization piston. The pressurization piston is disposed inside the condensate tank, and the edge of the pressurization piston is tightly fitted and slidably connected to the inner wall of the condensate tank.

6. The experimental method for monitoring oil, gas, and water components in a wellbore according to claim 1, characterized in that: The conveying device is a dual-cylinder pump.

7. The experimental method for monitoring oil, gas and water components in the wellbore according to claim 1, characterized in that: The polarization-maintaining optical fiber is fixedly attached to the outside of the wellbore using adhesive.

8. The experimental method for monitoring oil, gas and water components in a wellbore according to claim 1, characterized in that: The well casing includes a top cover, a cylinder body, and a bottom cover, both of which are threadedly connected to the cylinder body.

9. The experimental method for monitoring oil, gas, and water components in a wellbore according to claim 1, characterized in that: The condensate gas tank, the formation water tank, the condensate oil tank, and the natural gas tank are all made of steel.

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