A simulation measurement device and measurement method for corrosion of a bubble exhaust wellbore

Abstract

The present invention discloses a simulation measurement device and a measurement method for the corrosion of the wellbore of a bubble exhaust well. The simulation unit includes an air compressor, a generating pipe, a gas-liquid separator, a gas cylinder and a water tank. The air compressor and the water tank are respectively connected to the generating pipe through pipelines. An installation bracket is provided in the generating pipe, and a coupon specimen is connected to the installation bracket. A conductivity detector and a heating layer are connected to the inner wall of the generating pipe. A stirrer is installed at the bottom of the generating pipe, and a plurality of viewing windows are provided on the side wall of the generating pipe. The monitoring and adjustment unit includes a liquid pump, a booster pump, a temperature and pressure probe, an industrial camera, a solenoid valve, a computer and a water bath. The gas-liquid separator and the gas cylinder are connected in parallel to the booster pump. The gas-liquid separator is connected to the water tank. The temperature and pressure probe is connected to the side wall of the generating pipe. The industrial camera is located on one side of the viewing window, and the water bath is located outside the water tank to heat the water tank. The present invention can macroscopically simulate the internal environment of the entire gas wellbore and more realistically and effectively simulate the corrosion situation in the gas wellbore.

Description

Technical Field

[0001] The present invention relates to the technical field of corrosion and protection in oil and gas fields, and particularly relates to a simulation measurement device and a measurement method for the corrosion of the wellbore of a foam drainage gas well. Background Art

[0002] With the continuous production of domestic gas wells and the formation of liquid accumulation at the bottom of the gas wellbore, the foam drainage gas production process has gradually matured. Along with it, serious corrosion problems have occurred in the tubing. The tubing of gas wells generally uses some carbon steel materials. Under the influence of the gas-liquid two-phase at the bottom of the wellbore, the corrosion rate of such materials is relatively large. In severe cases, corrosion perforation occurs in local well sections, bringing serious hidden dangers to the safe production of the gas field and causing huge economic losses.

[0003] Some scholars at home and abroad have studied the devices and methods for measuring the corrosion rate of the wellbore under flowing conditions through experiments. Liu Hui et al. established a set of devices that can be used to simulate the corrosion process of tubing by the accumulated water in the well under wet gas conditions containing accumulated water in the well and gas-liquid two-phase foam flow conditions under gas-liquid two-phase flow conditions, and can be used to screen and evaluate corrosion inhibitors. Guo Gang et al. disclosed an oil and gas wellbore corrosion simulation evaluation system, which mainly simulates the dynamic erosion corrosion of metal coupons by fluids. By changing factors such as fluid velocity, pressure, and temperature, tests on the corrosion rate of oil and casing pipes, research on corrosion behavior and corrosion mechanism, and evaluation of the effect of anti-corrosion measures are carried out. Hu Degao et al. considered the influence of changes in fluid velocity, temperature, and pressure inside the wellbore on the corrosion rate in the conventional evaluation method, and established a full-scale corrosion simulation evaluation device, which can macroscopically simulate the internal environment of the entire gas wellbore and more truly and effectively simulate the corrosion situation in the gas wellbore.

[0004] Chinese Patent CN202110975010.7 discloses a simulation device for the dissolved oxygen corrosion of the entire wellbore string of an injection well. By establishing a functional relationship between the well depth and the experimental time during the injection process, and combining the corrosion electrochemistry theory, the dissolved oxygen corrosion rate of the entire wellbore string of the injection well is calculated through the primary experimental data, greatly reducing the number of experiments and significantly reducing the experimental time and experimental cost, but the measurement situation is single.

[0005] The purpose of monitoring the corrosion of oil and gas wellbores is to reveal and master the corrosion process and state of the oilfield production system. At present, the monitoring of the corrosion of oil and gas wellbores is roughly divided into on-site monitoring and indoor simulation. For indoor simulation, the existing simulation methods cannot comprehensively consider various changing factors of the gas wellbore. There are many factors affecting the corrosion of downhole tubing, such as the content of H2S and CO2 in natural gas, tubing materials, whether corrosion inhibitors are added, etc. Especially for foam drainage gas production wells, there is no reliable model that can truly reflect the corrosion of pipelines caused by foam drainage production.

[0006] Therefore, how to provide a simulation measurement device and method for the corrosion of the bubble drainage wellbore is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides a simulation measurement device and method for the corrosion of the bubble drainage wellbore, which can observe the corrosion of the gas wellbore and measure the corrosion rate under different flow states, detect the interaction relationship between the wellbore corrosion and the gas-liquid two-phase, and can be used in various production conditions such as foam drainage gas production, normal production, and liquid accumulation. At the same time, by changing the gas-liquid flow rate, the production conditions of different well sections can be simulated.

[0008] To achieve the above object, the present invention adopts the following technical solution: A simulation measurement device for the corrosion of the bubble drainage wellbore, which includes:

[0009] A simulation unit, the simulation unit includes an air compressor, a generating pipe, a gas-liquid separator, a gas cylinder and a water tank. The air compressor and the water tank are respectively connected to the generating pipe through pipelines. An installation bracket is provided in the generating pipe, and a plurality of coupon specimens are connected to the installation bracket. A conductivity detector and a heating layer are connected to the inner wall of the generating pipe. A stirrer is installed at the bottom of the generating pipe, and a plurality of visual windows are opened on the side wall of the generating pipe, and the visual windows correspond to the positions of the coupon specimens;

[0010] A monitoring and adjusting unit, the monitoring and adjusting unit includes a liquid pump, a booster pump, a temperature and pressure probe, an industrial camera, a solenoid valve, a computer and a water bath. The liquid pump is connected to the pipeline between the water tank and the generating pipe. The booster pump is connected to the pipeline between the air compressor and the generating pipe. The generating pipe is connected to the inlet of the gas-liquid separator. The gas outlet of the gas-liquid separator and the gas cylinder are connected in parallel to the booster pump to form a gas recovery system. The liquid outlet of the gas-liquid separator is connected to the water tank to form a liquid recovery system. The temperature and pressure probe is connected to the side wall of the generating pipe. The industrial camera is located on one side of the visual window. There are a plurality of solenoid valves, and the plurality of solenoid valves are respectively connected to the pipelines between the generating pipe and the liquid pump, the booster pump, and the gas-liquid separator. The water bath is located outside the water tank to heat the water tank. The computer is respectively electrically connected to the heating layer, the liquid pump, the booster pump, the temperature and pressure probe, the industrial camera, the solenoid valve, the water bath, the conductivity detector and the stirrer.

[0011] The beneficial effects of the present invention are as follows: The mounting bracket is used to connect the coupon specimens. The corrosion conditions of the coupon specimens at different positions are used to simulate the corrosion conditions of different well sections. The industrial camera can observe and record the surface state of the coupon specimens through the viewing window. The conductivity detector is used to measure the conductivity value of the fluid in the pipe in real time and transmit it to the computer for data analysis, so as to measure the liquid carrying capacity and liquid drainage capacity of the foam in the case of foam flow, and thus evaluate the stability of the foaming agent. The gas cylinder can use different gases as the gas source to simulate different formation environments; after the gas-liquid two-phase is separated in the gas-liquid separator, the liquid phase can be transported back to the water tank through the pipeline to form the reuse of the liquid. The separated gas can be directly discharged through the valve or can be input into the system again through the booster pump to form the reuse of the gas; the rotation speed of the stirrer is controlled by the computer to quickly generate foam; the water tank can be heated and cooperate with the heat tracing layer in the generating pipe to keep the system temperature constant; the solenoid valve can be controlled by the computer to accurately open and close.

[0012] Preferably, the pipelines between the liquid pump, the booster pump and the generating pipe are connected by three-way joints. The generating pipe is a stainless steel pipe. The bottom end of the generating pipe is connected with a stirrer, and the top end of the generating pipe is connected with a pressure relief valve. A pressure gauge is connected to the pressure relief valve.

[0013] Preferably, the mounting bracket is a stainless steel bracket. A plurality of coupon mounting platforms are axially distributed on the mounting bracket corresponding to the generating pipe. The coupon mounting platforms are connected with a plurality of coupon specimens by screws. A plastic spacer is provided between the coupon specimens and the coupon mounting platforms.

[0014] Preferably, the test probe on the conductivity detector is axially connected to the inner wall of the generating pipe corresponding to the generating pipe. A sapphire prism is fixedly connected to the viewing window.

[0015] Preferably, a liquid flowmeter is connected to the pipeline between the liquid pump and the generating pipe, a gas flowmeter is connected to the pipeline between the booster pump and the generating pipe, and a liquid flowmeter is connected to the pipeline between the gas-liquid separator and the water tank.

[0016] Preferably, a check valve is connected to the pipeline between the gas cylinder and the booster pump, a ball valve is connected to the pipeline between the air compressor and the booster pump, and a ball valve is connected to the outlet pipeline of the gas-liquid separator.

[0017] Preferably, a discharge valve is connected to the pipeline connected to the gas outlet of the gas-liquid separator.

[0018] The present invention also discloses a measurement method for a simulation measurement device of wellbore corrosion in a foam drainage well, and there are two measurement cases:

[0019] The corrosion rate measurement conditions when gas-liquid two-phase flow with liquid accumulation scours the wellbore and the corrosion rate measurement conditions when foam drainage gas production fluid scours the wellbore;

[0020] When simulating and measuring the corrosion rate of the wellbore scoured by gas-liquid two-phase flow with liquid accumulation, the following steps are included:

[0021] Step 1: Measure the surface area S of the prepared coupon specimen and weigh it to obtain its mass M;

[0022] Step 2: Place the coupon specimen on the installation bracket inside the generating pipe and regulate the system temperature through a water bath and a heat tracing layer;

[0023] Step 3: After the temperature is constant, start the liquid pump to first transport a certain amount of the liquid to be measured into the generating pipe, then close the liquid pump, start the air compressor and the booster pump to supply gas to the system. The gas rises after being humidified by the liquid and scours the coupon specimen;

[0024] Step 4: During this period, the corrosion condition of the surface of the coupon specimen can be observed through the viewing window to simulate the corrosion of the coupon by wet air when there is liquid accumulation in the wellbore. After a continuous set time t, stop the air compressor and the booster pump, take out the coupon specimen, weigh the mass m of the coupon specimen. The mass loss per unit time and unit area of the coupon specimen, (M - m) / t / S, is the corrosion rate of the coupon specimen;

[0025] When simulating and measuring the corrosion rate of the wellbore scoured by foam drainage gas production fluid, the following steps are included:

[0026] Step a: Measure the surface area S of the prepared coupon specimen and weigh it to obtain its mass M;

[0027] Step b: Place the coupon specimen in step a on the installation bracket inside the generating pipe and regulate the system temperature through a water bath and a heat tracing layer;

[0028] Step c: After the temperature is constant, start the air compressor and the booster pump to continuously supply gas to the system. Start the liquid pump to transport a certain amount of the liquid to be measured and then close it. The liquid to be measured generates foam under the action of continuous gas supply and a stirrer. Adjust the position of the coupon specimen on the installation bracket to simulate the corrosion of the wellbore under production conditions in different environments, simulating the corrosion of the wellbore by the liquid, the corrosion of the foam flow pattern, and the corrosion of the wet gas on the wellbore after the foam breaks;

[0029] Step d: During the test, observe the change in foam morphology through the visual window to obtain the foam size distribution, uniformity, formation process, drainage and dispersion processes, and decay period. In the stage without foam, observe the surface corrosion of the coupon specimen; at the same time, obtain the conductivity data of different pipe sections through the conductivity detector to judge the foam height, the liquid carrying gradient of the foam, and the drainage capacity of the foam, and then judge the stability of the foam displacement; after the continuous set time t, stop the air compressor and the booster pump, take out the coupon specimen, weigh the mass m of the coupon specimen, and the mass loss of the coupon specimen per unit time and per unit area (M - m) / t / S is the corrosion rate of the coupon specimen. Brief Description of the Drawings

[0030] Figure 1 It is a schematic structural diagram of a simulation measurement device for the corrosion of the wellbore of a foam drainage gas well according to the present invention;

[0031] Figure 2 It is a schematic diagram of the generating pipe of a simulation measurement device for the corrosion of the wellbore of a foam drainage gas well according to the present invention;

[0032] Figure 3 It is an enlarged schematic diagram at position A of a simulation measurement device for the corrosion of the wellbore of a foam drainage gas well according to the present invention;

[0033] Figure 4 It is a schematic diagram of the visual window of a simulation measurement device for the corrosion of the wellbore of a foam drainage gas well according to the present invention;

[0034] Figure 5 It is the surface corrosion morphology of the coupon specimen J55 after 7 days in a specific embodiment of the present invention;

[0035] Figure 6 It is the corrosion pit depth of the coupon specimen of J55 carbon steel in different corrosion times in a specific embodiment of the present invention;

[0036] Figure 7 It is the foam morphology during the foam stability period in a specific embodiment of the present invention.

[0037] 1 Air compressor, 2 Ball valve, 3 Booster pump, 4 Gas flowmeter, 5 Solenoid valve, 6 Stirrer, 7 Generating pipe, 8 Visual window, 9 Pressure relief valve, 10 Check valve, 11 Gas-liquid separator, 12 Liquid flowmeter, 13 Computer, 14 Water bath, 15 Gas cylinder, 16 Liquid pump, 17 Temperature and pressure probe, 18 Heat tracing layer, 19 Industrial camera, 20 Water tank, 21 Drain valve, 701 Mounting bracket, 702 Conductivity detector, 703 Coupon specimen, 704 Screw, 705 Plastic spacer, 706 Coupon mounting table, 707 Test probe, 708 Sapphire prism. Detailed Description of the Invention

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] Refer to the attached drawings of the present invention Figures 1 to 7 , according to an embodiment of the present invention, a simulation measurement device for corrosion of a bubble drainage wellbore includes:

[0040] A simulation unit, which includes an air compressor 1, a generating pipe 7, a gas-liquid separator 11, a gas cylinder 15 and a water tank 20. The air compressor 1 and the water tank 20 are respectively connected to the generating pipe 7 through pipelines. An installation bracket 701 is provided in the generating pipe 7, and a coupon specimen 703 is connected to the installation bracket 701. A conductivity detector 702 and a heating layer 18 are connected to the inner wall of the generating pipe 7. A stirrer 6 is installed at the bottom of the generating pipe 7, and a plurality of visual windows 8 are opened on the side wall of the generating pipe. The visual windows 8 correspond to the positions of the coupon specimens 703;

[0041] Among them, the gas cylinder can use different gases as the gas source to simulate different formation environments;

[0042] A monitoring and regulating unit, which includes a liquid pump 16, a booster pump 3, a temperature and pressure probe 17, an industrial camera 19, a solenoid valve 5, a computer 13 and a water bath 14. The liquid pump 16 is connected to the pipeline between the water tank 20 and the generating pipe 7, and the booster pump 3 is connected to the pipeline between the air compressor 1 and the generating pipe 7. The generating pipe 7 is connected to the inlet of the gas-liquid separator 11. The gas outlet of the gas-liquid separator 11 and the gas cylinder 15 are connected in parallel to the booster pump 3 to form a gas recovery system, and the liquid outlet of the gas-liquid separator 11 is connected to the water tank 20 to form a liquid recovery system. The temperature and pressure probe 17 is connected to the side wall of the generating pipe 7. The industrial camera 19 is located on one side of the visual window 8. There are a plurality of solenoid valves 5, and the plurality of solenoid valves 5 are respectively connected to the pipelines between the generating pipe 7 and the liquid pump 16, the booster pump 3, and the gas-liquid separator 11. The water bath 14 is located outside the water tank 20 to heat the water tank. The computer 13 is electrically connected to the heating layer 18, the liquid pump 16, the booster pump 3, the temperature and pressure probe 17, the industrial camera 19, the solenoid valve 5, the water bath 14, the conductivity detector 702 and the stirrer 6 by electrical signals.

[0043] In the present invention, after the gas-liquid two-phase is separated in the separator, the liquid phase can be transported to the water tank by opening the valve and using the high pressure inside the separator to form the reuse of the liquid. The separated gas can be directly discharged through the valve or can be input into the system again through the booster pump to form the reuse of the gas;

[0044] In some other embodiments, the pipelines among the liquid pump 16, the booster pump 3 and the generating pipe 7 are connected through a tee joint. The generating pipe 7 is a stainless-steel pipe. A stirrer 6 is connected to the bottom end of the generating pipe 7, and a pressure relief valve 9 is connected to the top end of the generating pipe 7. A pressure gauge is connected to the pressure relief valve 9.

[0045] In some other specific embodiments, the mounting bracket 701 is a stainless-steel bracket. A plurality of coupon mounting platforms 706 are axially distributed on the mounting bracket 701 at intervals corresponding to the generating pipe 7. Six coupon specimens 703 are connected to the coupon mounting platforms 706 through screws 704. A plastic spacer 705 is provided between the coupon specimens 703 and the coupon mounting platforms 706. The coupon mounting platforms are divided into upper, middle and lower layers, which can simulate the coupon corrosion conditions in different well sections.

[0046] In some other embodiments, the test probe 707 on the conductivity detector 702 is axially connected to the inner wall of the generating pipe 7 corresponding to the generating pipe 7. A sapphire prism 708 that can withstand high temperature and high pressure is fixedly connected to the viewing window 8. A light source is added on one side, and an industrial camera is placed on the other side. When there is foam, the change of the shape and size of the foam with time can be observed during foaming. When there is no foam, the corrosion condition of the coupon can be observed.

[0047] In some other specific embodiments, a liquid flowmeter 12 is connected to the pipeline between the liquid pump 16 and the generating pipe 7, a gas flowmeter 4 is connected to the pipeline between the booster pump 3 and the generating pipe 7, and a liquid flowmeter 12 is connected to the pipeline between the gas-liquid separator 11 and the water tank 20. This facilitates the calculation of the flow rate.

[0048] In some other embodiments, a check valve 10 is connected to the pipeline between the gas cylinder 15 and the booster pump 3. The check valve ensures the stability of the system and prevents backflow. A ball valve 2 is connected to the pipeline between the air compressor 1 and the booster pump 3, and a ball valve is connected to the liquid outlet pipeline of the gas-liquid separator 11. It serves as a pipeline switch.

[0049] In some other embodiments, a discharge valve 21 is connected to the pipeline connected to the gas outlet of the gas-liquid separator 11, and the gas can be directly discharged.

[0050] In the present invention, the pressure relief valve ensures the safe progress of the experiment; the check valve ensures that the fluid does not flow in the reverse direction and ensures the normal operation of the experiment; the solenoid valve can be controlled by a computer to accurately open and close. The outlet pipe of the air compressor and the inlet and outlet pipes of the liquid pump can use PU pipes, and the rest of the pipelines in the system are all stainless steel metal pipes. Connect the air compressor and the booster pump with a PU pipe, connect the booster pump, the gas flowmeter and the tee joint in sequence with stainless steel metal pipes, connect the third interface of the tee joint to the generating pipe, connect the bottom end of the generating pipe to the stirrer, connect the top end to the pressure relief valve and the gas-liquid separator. The gas outlet end of the gas-liquid separator is connected to the gas cylinder and then to the booster pump to form a gas recovery system, and the liquid outlet end of the gas-liquid separator is connected to the water tank to form a liquid recovery system.

[0051] A method for simulating and measuring the corrosion rate when gas-liquid two-phase flow with liquid accumulation scours the wellbore is as follows:

[0052] Measure the surface area S of the treated carbon steel coupon specimen and weigh its mass as M. Place it on the coupon installation platform 706 inside the stainless steel generating pipe 7. Regulate the system temperature through the water bath 14 and the heat tracing layer 18. First, pump a certain amount of the liquid to be measured into the stainless steel generating pipe 7 by opening the liquid pump 16, then close the liquid pump 16, and open the air compressor 1 and the booster pump 3 to supply gas to the system. The gas rises and scours the coupon after being humidified by the liquid. During this period, the corrosion situation of the coupon specimen surface can be observed through the viewing window 8 to simulate the corrosion of the coupon by humid air when there is liquid accumulation in the wellbore. After a continuous set time t, stop the gas-liquid pump, take out the coupon, and weigh the coupon specimen to get the mass m. The mass loss of the coupon specimen per unit time per unit area, (M - m) / t / S, is the corrosion rate of the coupon specimen.

[0053] A method for simulating and measuring the corrosion rate when foam drainage gas production fluid scours the wellbore is as follows:

[0054] Measure the surface area S of the processed carbon steel coupon, weigh it to obtain its mass M, place it on the coupon mounting platform 706 inside the stainless steel reaction tube 7, regulate the system temperature through the water bath 14 and the heat tracing layer 18. After the temperature is constant, turn on the air compressor 1 and the booster pump 3 to continuously supply gas to the system. Start the liquid pump 16 to transport a certain amount of the test liquid and then turn it off. The test liquid generates foam under the continuous supply of gas and the action of the stirrer 6. The position of the coupon mounting platform 706 can be adjusted to simulate the corrosion of the wellbore under production conditions in different environments, and it can simulate the corrosion of the wellbore by the liquid, the corrosion of the foam flow state, and the corrosion of the wet gas on the wellbore after the foam breaks; during the test, the change of the foam morphology can be observed through the viewing window 8, such as the foam size distribution, uniformity, formation process, liquid drainage and dispersion process, and decay period, etc. In the stage without foam, the surface corrosion of the coupon can be observed; at the same time, the conductivity data of different pipe sections can be obtained through the conductivity measuring device 702, so as to judge the foam height, the carrying gradient of the foam to the liquid, the liquid drainage ability of the foam, etc., and judge the stability of the foam exclusion; after the continuous set time t, stop the gas-liquid pump, take out the coupon, weigh the coupon specimen to obtain the mass m, and the mass loss of the coupon specimen per unit time per unit area (M - m) / t / S is the corrosion rate of the coupon specimen.

[0055] The foam exhaust wellbore corrosion monitoring device provided by the present invention can simulate the foaming and corrosion laws under different gas flow rates (0 - 10 m 3 / min), liquid flow rates (0 - 1 L / min), high temperatures (room temperature - 150 °C), and high pressures (atmospheric pressure - 30 MPa), and can conduct experimental studies on different materials and different solutions. The device is monitored in real time through the computer 13, so that the device can operate safely and can record and process the detection data. Specific embodiments

[0057] 1. Specimen preparation

[0058] The test aqueous solution selects a simulated formation aqueous solution with a salinity of 33000 mg / L, and the formula is shown in Table 2, and the addition amount of foam exclusion A is 0.5%. The material of the test coupon selects J55 carbon steel, and its chemical composition (by mass fraction) is shown in Table 3. The size of the test coupon is 50 mm × 10 mm × 3 mm. Take 9 coupons, after sequentially degreasing and drying all the coupons, polish them with sandpapers of 400, 800, 1000, and 1500 grits in turn, clean them with distilled water and anhydrous ethanol, and weigh them after drying in the air for standby.

[0059] Table 1 Formula of the simulated formation aqueous solution with a salinity of 33000 mg / L

[0060] Salinity (mg / L) <![CDATA[Na2SO4(g)]]> NaCl (g) <![CDATA[NaHCO3(g)]]> <![CDATA[CaCl2(g)]]> <![CDATA[MgCl2(g)]]> Distilled water (L) 33000 0.122 9.2514 0.0316 6.8669 0.2949 0.5

[0061] Table 2 Chemical composition (mass%) of the specimen material

[0062]

[0063] 2. Installation

[0064] Connect the devices in the order from left to right and from bottom to top. Add a certain amount of formation water into the stainless steel generating pipe 7, and place the prepared 9 coupon specimens in three layers on the Figure 1 Figure 2 installation bracket in the generating pipe 7. Keep the temperatures of the constant temperature water bath and the stainless steel pipe heat tracing layer constant at room temperature of 25°C, and conduct the experiment under atmospheric pressure conditions.

[0065] 3. Observation

[0066] Adjust the flow rate of the gas booster pump 3 to 2 L / min, the stirring rate to 8000 ± 20 r / min, and the simulated operation time to 7 days. During this period, the formation water can be supplemented into the generating pipe by opening the liquid pump to prevent the liquid accumulation from decreasing due to the gas carrying away the water. After the reaction ends, calculate the corrosion rate of the coupon, and at the same time use an industrial camera to study the morphology.

[0067] 4. Experimental Results

[0068] Table 3 shows the corrosion rate of J55 in the simulated gas well with liquid accumulation for 7 days.

[0069] Table 3 Corrosion Rate of J55 Coupons after 7 Days

[0070]

[0071] Table 4 Measurement Results of Conductivity during the Stable Period

[0072]

[0073] The results in Table 3 show that under the conditions of 25°C and simulating wellbore liquid accumulation with 33000 mg / L of formation water, after 7 days of foam drainage production, the corrosion rate of the J55 carbon steel coupons corroded by the lower-layer foam immersion is significantly greater than that of the upper and middle layers; Figure 5 Figure 6 The results show that under these conditions, the local corrosion of the surface of the lower-layer J55 carbon steel coupons is serious, and the corrosion pits are deeper, indicating serious pitting corrosion. Figure 7 The results show that under these conditions, after the foam reaches the stable period, the diameter of the lower-layer foam is small, the contact is tight, and there is obvious liquid between the bubbles. The diameter of the upper-layer foam is large, the contact is relatively tight, the voids between the bubbles increase, and the liquid content is very low; as can be seen from Table 4, under these conditions, when the foam reaches the stable period, its liquid-carrying capacity is good and the foaming height is high. In summary, under the conditions of foam drainage gas production, the metal pipes at the lower end of the foam are more likely to be corroded.

[0074] ​When conducting the corrosion simulation experiment of gas-lift gas production through the corrosion simulation device, it is possible to simultaneously operate the gas and liquid to simulate the situation without liquid accumulation at the bottom of the wellbore, or to inject simulated water into the pipeline in advance and then introduce gas to simulate the situation with liquid accumulation at the bottom of the wellbore. It is also possible to add reagents such as foam drainage agents and condensate oil to simulate other production situations at the bottom of the wellbore. By setting the temperature regulation and pressure regulation unit, the corrosion change conditions at different pressures and temperatures can be simulated. Both the gas and liquid phases can be selected for recycling and reuse to conduct long-term sealed experiments. The change of foam morphology and the corrosion situation of the coupon can be macroscopically observed through the viewing window.

[0075] For the devices and usage methods disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method section.

[0076] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A simulation measurement device for corrosion of a bubble drainage wellbore, characterized in that, Comprising: A simulation unit, the simulation unit includes an air compressor (1), a generating pipe (7), a gas-liquid separator (11), a gas cylinder (15) and a water tank (20). The air compressor (1) and the water tank (20) are respectively connected to the generating pipe (7) through pipelines. An installation bracket (701) is provided in the generating pipe (7). A plurality of coupon specimens (703) are connected to the installation bracket (701). A plurality of coupon installation platforms (706) are axially spaced and distributed on the installation bracket (701) corresponding to the generating pipe (7). The coupon installation platforms (706) are connected to a plurality of coupon specimens (703) through screws (704). A conductivity detector (702) and a heat tracing layer (18) are connected to the inner wall of the generating pipe (7). A stirrer (6) is installed at the bottom of the generating pipe (7). A plurality of visual windows (8) are provided on the side wall of the generating pipe (7), and the visual windows (8) correspond to the positions of the coupon specimens (703). A monitoring and regulating unit, the monitoring and regulating unit includes a liquid pump (16), a booster pump (3), a temperature and pressure probe (17), an industrial camera (19), a solenoid valve (5), a computer (13) and a water bath (14). The liquid pump (16) is connected to the pipeline between the water tank (20) and the generating pipe (7). The booster pump (3) is connected to the pipeline between the air compressor (1) and the generating pipe (7). The generating pipe (7) is connected to the inlet of the gas-liquid separator (11). The gas outlet of the gas-liquid separator (11) and the gas cylinder (15) are connected in parallel to the booster pump (3) to form a gas recovery system. The liquid outlet of the gas-liquid separator (11) is connected to the water tank (20) to form a liquid recovery system. The temperature and pressure probe (17) is connected to the side wall of the generating pipe (7). The industrial camera (19) is located on one side of the visual window (8). There are a plurality of solenoid valves (5), and the plurality of solenoid valves (5) are respectively connected to the pipelines between the generating pipe (7) and the liquid pump (16), the booster pump (3), and the gas-liquid separator (11). The water bath (14) is located outside the water tank (20) to heat the water tank. The computer (13) is electrically connected to the heat tracing layer (18), the liquid pump (16), the booster pump (3), the temperature and pressure probe (17), the industrial camera (19), the solenoid valve (5), the water bath (14), the conductivity detector (702) and the stirrer (6) through electrical signals.

2. The simulation measurement device for the corrosion of the wellbore of a bubble drainage well according to claim 1, wherein, The pipelines between the liquid pump (16), the booster pump (3) and the generating pipe (7) are connected through a tee joint. The generating pipe (7) is a stainless steel pipe. A stirrer (6) is connected to the bottom end of the generating pipe (7). A pressure relief valve (9) is connected to the top end of the generating pipe (7), and a pressure gauge is connected to the pressure relief valve (9).

3. The simulation measurement device for corrosion of the wellbore of a bubble exhaust well according to claim 2, wherein The installation bracket (701) is a stainless steel bracket, and a plastic spacer (705) is provided between the coupon specimen (703) and the coupon installation platform (706).

4. The simulation measurement device for corrosion of the bubble drainage wellbore according to claim 3, characterized in that The test probe (707) on the conductivity detector (702) is axially connected to the inner wall of the generating tube (7) corresponding to the generating tube (7), and a sapphire prism (708) is fixedly connected to the visual window (8).

5. The simulation measurement device for corrosion of the wellbore of a bubble drainage well according to claim 4, characterized in that, A liquid flowmeter (12) is connected to the pipeline between the liquid pump (16) and the generating tube (7), a gas flowmeter (4) is connected to the pipeline between the booster pump (3) and the generating tube (7), and a liquid flowmeter (12) is connected to the pipeline between the gas-liquid separator (11) and the water tank (20).

6. The simulation measurement device for corrosion of the wellbore of a bubble drainage well according to claim 5, wherein, A check valve (10) is connected to the pipeline between the gas cylinder (15) and the booster pump (3), a ball valve (2) is connected to the pipeline between the air compressor (1) and the booster pump (3), and a ball valve (2) is connected to the outlet pipeline of the gas-liquid separator (11).

7. The simulation measurement device for corrosion of the wellbore of a bubble drainage well according to claim 6, wherein, A discharge valve (21) is connected to the pipeline connected to the gas outlet of the gas-liquid separator (11).

8. A measuring method for a simulation measuring device of corrosion in the wellbore of a bubble exhaust well as described in any one of claims 1-7, characterized in that, Including: There are the corrosion rate measurement situations when the gas-liquid two-phase with liquid accumulation scours the wellbore and when the foam drainage gas production fluid scours the wellbore. When simulating and measuring the corrosion rate of the gas-liquid two-phase with liquid accumulation scouring the wellbore, it includes the following steps: Step 1: Measure the surface area S of the processed coupon specimen and weigh its mass as M. Step 2: Place the coupon specimen on the installation bracket inside the generating tube, and regulate the system temperature through the water bath and the heat tracing layer. Step 3: Wait for the temperature to be constant, then turn on the liquid pump to first transport a certain amount of the liquid to be measured into the generating tube. After turning off the liquid pump, turn on the air compressor and the booster pump to supply gas to the system. The gas rises after being humidified by the liquid and scours the coupon specimen. Step 4: During this period, the corrosion condition of the surface of the coupon specimen can be observed through the visual window to simulate the corrosion of the coupon by the wet air when there is liquid accumulation in the wellbore. After a continuous set time t, stop the air compressor and the booster pump, take out the coupon specimen, and weigh the mass m of the coupon specimen. The mass loss of the coupon specimen per unit time and per unit area, (M - m) / t / S, is the corrosion rate of the coupon specimen. When simulating and measuring the corrosion rate of the foam drainage gas production fluid scouring the wellbore, it includes the following steps: Step a: Measure the surface area S of the processed coupon specimen and weigh its mass as M. Step b: Place the coupon specimen in step a on the installation bracket inside the generating tube, and regulate the system temperature through the water bath and the heat tracing layer. Step c: Wait for the temperature to be constant, turn on the air compressor and the booster pump to continuously supply gas to the system, start the liquid pump to transport a certain amount of the liquid to be measured and then turn it off. The liquid to be measured generates foam under the action of continuous gas supply and the stirrer. Adjust the position of the coupon specimen on the installation bracket to simulate the corrosion of the wellbore under production conditions in different environments, simulating the corrosion of the wellbore by the liquid, the corrosion of the foam flow state, and the corrosion of the wet gas to the wellbore after the foam breaks. Step d: During the test, observe the changes in the foam morphology through the visual window to obtain the foam size distribution, homogeneity, formation process, drainage and dispersion processes, and decay period. In the stage without foam, observe the surface corrosion of the coupon specimens; at the same time, obtain the conductivity data of different pipe sections through the conductivity detector to judge the foam height, the carrying gradient of the foam on the liquid, and the drainage capacity of the foam, and then judge the stability of the foam slugging. After the continuous set time t, stop the air compressor and the booster pump, take out the coupon specimens, weigh the mass m of the coupon specimens, and the mass loss of the coupon specimens per unit time and unit area, (M - m) / t / S, is the corrosion rate of the coupon specimens.

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