Gas lift drainage gas production scaling simulation evaluation test device and method

Abstract

The invention discloses a gas lift drainage gas production scaling simulation evaluation test device and method. The simulation evaluation test device comprises a high-pressure simulation scaling reaction unit and a low-pressure simulation scaling reaction unit which are communicated with each other, and the high-pressure simulation scaling reaction unit is communicated with a gas storage and supply unit and a liquid storage and supply unit; the high-pressure simulation scaling reaction unit comprises a temperature regulation control box A, and a simulation scaling reactor A is arranged in the temperature regulation control box A; the low-pressure simulation scaling reaction unit comprises a temperature regulation control box B, and a simulation scaling reactor B is arranged in the temperature regulation control box B; a throttling pressure reducing valve and a throttling pipeline are arranged on a pipeline for communicating the high-pressure simulation scaling reaction unit and the low-pressure simulation scaling reaction unit, and the throttling pressure reducing valve is arranged in a temperature regulation control box A; and the throttling pipeline is arranged in the temperature regulation control box B. Real-time observation of temperature and pressure changes, fluid flowing and produced fluid scaling in a gas well and a ground pipeline system in the drainage gas production process is simulated.

Description

Technical Field

[0001] The present invention belongs to the technical field of scale prevention in gas field development, and relates to a simulation evaluation test device and method for scale formation in gas lift drainage gas production. Background Art

[0002] With the continuous exploitation of gas fields, gas wells will gradually produce water. To improve the recovery rate of water-bearing gas reservoirs and achieve stable production and restart of gas wells, drainage gas production is generally adopted. Since gas field water contains a large amount of acidic gases such as H2S and CO2 and scale-forming ions, with high salinity and strong corrosiveness, there are generally scale deposition and blockage problems in the wellbore and ground system equipment and pipelines during the drainage gas production process. During the drainage gas production process, due to changes in system pressure, temperature, flow rate, and flow pattern, a large amount of dissolved gases such as H2S and CO2 escape from the water, resulting in changes in the original equilibrium conditions, which are extremely likely to form carbonate and sulfate precipitates, and attach to the inner wall of the pipeline with the help of crystal nuclei such as sediment and corrosion products, causing scale deposition and blockage in the gas wellbore and ground equipment and pipelines. Especially for high-temperature water-producing gas wells, the scale deposition and blockage problems are more prominent. To solve the scale deposition and blockage problems during the drainage gas production process of high-temperature water-producing gas wells, it is urgent to carry out research on scale simulation and screening evaluation of scale and corrosion inhibitors to provide a theoretical basis for the analysis of the causes of gas well scale deposition and blockage and the formulation of scale prevention and plug removal measures.

[0003] In recent years, a number of patents and patent applications for scale simulation evaluation devices and methods have been filed in China. For example: the invention patent with the patent publication number CN 108071381 A discloses a scale simulation device and method; the invention patent with the patent publication number CN104316647A discloses a test device and method for simulating scale formation; the invention patent with the patent publication number CN113006768A discloses a gas well scale simulation device and simulation method. Through the research on the background situation and technical solutions of the above patents, it is found that the above invention patents mainly focus on the scale simulation and chemical agent evaluation devices and methods in the processes such as oilfield injection-production and gas well production, which are relatively general, lack strong pertinence, have poor practicability, and cannot well simulate the scale formation process of the wellbore and ground equipment caused by the destruction of the original chemical equilibrium conditions due to changes in pressure, temperature, flow rate, flow pattern, gas composition, and CO 2 partial pressure, etc. There is less prior art on the simulation scale formation and chemical agent evaluation devices and methods for wellbores and the ground during the drainage gas production process of high-temperature water-producing gas wells containing H 2 S and CO 2 acidic gases. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: aiming at containing H 2 S and CO 2There is little prior art on the simulation scale formation and chemical agent evaluation device and method for the wellbore and surface during the gas drainage and gas production process of high-temperature acid gas production water wells.

[0005] In a first aspect, the present invention provides a gas lift drainage and gas production scale formation simulation evaluation test device, including a data monitoring and acquisition processing unit, a high-pressure simulation scale formation reaction unit and a low-pressure simulation scale formation reaction unit that are interconnected, and the high-pressure simulation scale formation reaction unit is connected to a gas storage and supply unit and a liquid storage and supply unit;

[0006] The high-pressure simulation scale formation reaction unit includes a temperature regulation and control box A, and a simulation scale formation reactor A is arranged in the temperature regulation and control box A; the low-pressure simulation scale formation reaction unit includes a temperature regulation and control box B, and a simulation scale formation reactor B is arranged in the temperature regulation and control box B;

[0007] A throttling pressure reducing valve and a throttling pipeline are arranged on the pipeline connecting the high-pressure simulation scale formation reaction unit and the low-pressure simulation scale formation reaction unit. The throttling pressure reducing valve is arranged in the temperature regulation and control box A; the throttling pipeline is arranged in the temperature regulation and control box B;

[0008] The data monitoring and acquisition processing unit is communicatively connected to the high-pressure simulation scale formation reaction unit, the low-pressure simulation scale formation reaction unit, the gas storage and supply unit and the liquid storage and supply unit.

[0009] As a possible design, the gas storage and supply unit includes a simulated gas lift gas storage cylinder and a simulated natural gas storage cylinder. The simulated gas lift gas storage cylinder is connected to the lower part of the simulation scale formation reactor A, and the simulated natural gas storage cylinder is connected to the upper part of the simulation scale formation reactor A.

[0010] As a possible design, the liquid storage and supply unit includes a simulated gas field water storage tank and a corrosion and scale inhibitor storage tank. Both the simulated gas field water storage tank and the corrosion and scale inhibitor storage tank are connected to the upper part of the simulation scale formation reactor A.

[0011] As a possible design, a vacuum pump is connected to the simulation scale formation reactor A through a vacuum inlet valve, and the vacuum pump is placed outside the temperature regulation and control box A.

[0012] As a possible design, a stirrer is arranged in the simulation scale formation reactor A, and a first pressure sensor and a first temperature sensor are arranged on the simulation scale formation reactor A; a second pressure sensor and a second temperature sensor are arranged in the simulation scale formation reactor B.

[0013] As a possible design, the stirrer rotates by double magnet coupling, and a specimen hanging structure is arranged at the stirring end of the stirrer.

[0014] As a possible design, the simulated scaling reactor B is made of a transparent material.

[0015] In a second aspect, the present invention provides a scaling simulation evaluation test method for gas production by drainage, comprising the following steps:

[0016] S1. Open the throttling and pressure-reducing valve, evacuate the simulated scaling reactors A and B to a set vacuum degree, then close the throttling and pressure-reducing valve, and start the data monitoring and acquisition and processing unit;

[0017] S2. Start the temperature regulation and control box A. The liquid storage and supply unit sequentially adds a corrosion inhibitor and scale inhibitor and simulated gas field water to the simulated scaling reactor A. The gas storage and supply unit adds simulated natural gas to the simulated scaling reactor A to form a gas well fluid. When the pressure and temperature in the simulated scaling reactor A reach the first set value, stop the gas storage and supply unit and the liquid storage and supply unit, and keep the temperature constant for the first set time;

[0018] S3. The gas storage and supply unit introduces simulated gas lift gas into the simulated scaling reactor A. When the pressure and temperature in the simulated scaling reactor A rise to the second set value, observe the scaling situation in the simulated scaling reactor A after keeping the temperature constant for the second set time;

[0019] S4. Open the throttling and pressure-reducing valve and start the temperature regulation and control box B. When the pressures of the simulated scaling reactor A and the simulated scaling reactor B reach equilibrium and both pressures also reach the third set value, observe the scaling situations in the simulated scaling reactor A, the simulated scaling reactor B, and the throttling pipeline. At the same time, take out the liquid in the simulated scaling reactor B and analyze the calcium ion content in the liquid to obtain the scale inhibition rate of the corrosion inhibitor and scale inhibitor.

[0020] As a possible design, the calculation method of the scale inhibition rate of the corrosion inhibitor and scale inhibitor is as follows:

[0021]

[0022] Where M 2 —Calcium ion concentration in water when adding the corrosion inhibitor and scale inhibitor; M 1 —Calcium ion concentration in water without adding the corrosion inhibitor and scale inhibitor; M 0 —Calcium ion concentration in the simulated gas field water.

[0023] As a possible design, the simulated natural gas includes methane, hydrogen sulfide, and carbon dioxide; preferably, the simulated gas lift gas contains at least carbon dioxide.

[0024] The beneficial effects of the present invention are:

[0025] The present invention uses a columnar reactor to simulate downhole tubing, uses high-pressure gas introduced into the bottom of the reactor to simulate gas lift, uses stirring and regulation to control the pressure and temperature of the fluid in the reactor, and simulates the condition changes of the wellbore fluid during the gas lift drainage process; uses the throttling pressure reduction and temperature regulation control of the throttle valve and throttle pipe section to simulate the temperature, pressure changes and fluid flow process in the ground equipment pipeline system during the drainage gas production process, realizes the visualization of the gas field water scaling process, and can perform real-time observation on the scaling process of the produced fluid during the drainage gas production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 It is a connection schematic diagram of the gas lift drainage gas production scaling simulation evaluation test device provided by the embodiment of the present invention.

[0028] Among them, the reference numerals in the figure are as follows:

[0029] 1 - simulated gas lift gas storage cylinder; 2 - simulated natural gas storage cylinder; 3 - first simulated gas field water storage tank; 4 - second simulated gas field water storage tank; 5 - corrosion inhibitor and scale inhibitor storage tank; 6 - peristaltic pump; 7 - vacuum pump; 8 - vacuum inlet valve; 9 - gas booster pump; 10 - temperature regulation control box A; 11 - temperature regulation control box B; 12 - stirrer; 13 - simulated gas lift valve; 14 - sewage discharge outlet valve; 15 - liquid sampling outlet valve; 16 - throttling pressure reduction valve; 17 - gas outlet valve; 18 - first pressure sensor; 19 - second pressure sensor; 20 - first temperature sensor; 21 - second temperature sensor; 22 - safety valve; 23 - throttle pipeline; 24 - stop valve; 25 - tail gas treatment unit; 26 - data monitoring and acquisition processing unit; 27 - simulated scaling reactor A; 28 - simulated scaling reactor B. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0031] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0032] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0033] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more, unless otherwise specifically defined.

[0034] Due to the fact that the gas field water contains a large amount of H 2 S, CO 2 acid gases and scaling ions, with high salinity and strong corrosiveness, there are common problems of scaling and blockage in the wellbore and surface system equipment and pipelines during the process of gas drainage and gas production. During the process of gas drainage and gas production, due to the changes in system pressure, temperature, flow rate, and flow pattern, a large amount of H 2 S and CO 2 dissolved gases escape from the water, resulting in a change in the original equilibrium conditions, which is extremely likely to form carbonate and sulfate precipitates, and attach to the inner wall of the pipeline with the help of crystal nuclei such as sediment and corrosion products, causing scaling and blockage of the gas wellbore and surface equipment and pipelines. Especially for high-temperature gas wells with water production, the problem of scaling and blockage is more prominent.

[0035] Currently, it is mainly for the scaling simulation and chemical agent evaluation devices and methods in the processes such as oilfield injection-production and gas well production, which are relatively general, lack pertinence, have poor practicability, and cannot well simulate the scaling process of the wellbore and surface equipment caused by the changes in pressure, temperature, flow rate, flow pattern, gas composition, and CO 2 partial pressure, etc., resulting in the destruction of the original chemical equilibrium conditions.

[0036] Regarding the above problems, such as Figure 1As shown in the figure, an embodiment of the present invention provides a scaling simulation evaluation test device for gas lift drainage gas production, including a high-pressure simulated scaling reaction unit and a low-pressure simulated scaling reaction unit that are interconnected. The high-pressure simulated scaling reaction unit is connected to a gas storage and supply unit and a liquid storage and supply unit.

[0037] The high-pressure simulated scaling reaction unit and the low-pressure simulated scaling reaction unit respectively simulate the gas lift drainage gas production process in gas wells under different pressure conditions, which are used to reflect the scaling conditions of the wellbore and surface equipment, and can be used for evaluating the scale inhibition performance of corrosion and scale inhibitors.

[0038] As Figure 1 shown, the high-pressure simulated scaling reaction unit includes a temperature regulation and control box A10, and a simulated scaling reactor A 27 is arranged inside the temperature regulation and control box A10; the low-pressure simulated scaling reaction unit includes a temperature regulation and control box B11, and a simulated scaling reactor B 28 is arranged inside the temperature regulation and control box B11. Under the condition of realizing pressure regulation, the temperature is adjusted simultaneously to achieve the purpose of adjusting the fluid equilibrium conditions, which is used to simulate the gas lift scale inhibition under different conditions.

[0039] The temperature changes of the gas well wellbore and surface fluid are simulated through the temperature regulation and control of the temperature regulation and control box A10 and the temperature regulation and control box B11.

[0040] A possible implementation mode is that the simulated scaling reactor A 27 is a columnar high-pressure reaction kettle with an observation window and a stirring device (inner diameter is 6.5 cm, height is 15 cm). The kettle body is made of HC alloy material resistant to H 2 S, CO 2 and brine corrosion, with an effective volume of 500 ml and a maximum pressure resistance of 20 Mpa. There are various interfaces for gas-liquid fluid inlet and outlet (sampling, sampling and pressure relief), sewage discharge, vacuum pumping, temperature measurement, pressure measurement and safety valve 22, etc. inside the kettle body; the kettle body adopts a quick-opening structure design, which is convenient for disassembly, and combined with a cold light source, the corrosion and scaling conditions of the gas-liquid fluid inside the kettle body can be clearly observed.

[0041] The simulated scaling reactor B28 is a fully transparent reactor, which consists of a transparent cylinder, a pull rod and upper and lower end sleeves, and the internal scaling situation can be clearly observed. The volume is 2000 ml, and the maximum pressure resistance is 5.0 MPa; there are various interfaces for gas-liquid fluid inlet and outlet (sampling, sampling and pressure relief), sewage discharge, vacuum pumping, pressure measurement, temperature measurement and safety valve 22, etc. inside. The gas outlet of the reactor is connected to the tail gas treatment device, and the discharged acidic natural gas is discharged after being absorbed and treated by alkali solution.

[0042] A possible implementation mode. The temperature range of the temperature regulation control box A10 and the temperature regulation control box B11 is from room temperature to 150 °C, and the temperature control accuracy is ±0.5 °C. There is a lighting structure inside the box, a glass observation window is opened on the box door for observation, and wheels are provided at the bottom of the box for movement.

[0043] As Figure 1 shown, a throttle pressure reducing valve 16 and a throttle pipeline 23 are provided on the pipeline connecting the high-pressure simulated scaling reaction unit and the low-pressure simulated scaling reaction unit. The throttle pressure reducing valve 16 is arranged inside the temperature regulation control box A10; the throttle pipeline 23 is arranged inside the temperature regulation control box B11. The connection or disconnection between the high-pressure simulated scaling reaction unit and the low-pressure simulated scaling reaction unit is controlled by the throttle pressure reducing valve 16 and the throttle pipeline 23, and the throttle pressure reducing process of the ground system during the simulated gas well drainage gas production process is controlled through pressure regulation. The throttle pressure reducing valve 16 and the throttle pipeline 23 are common devices in the art, and their structures are not introduced in detail here.

[0044] In actual application, a stop valve 24 can also be provided on the pipeline connecting the throttle pipeline 23 and the simulated scaling reactor B 28. A tail gas treatment unit 25 is connected to the simulated scaling reactor B 28.

[0045] In order to achieve remote control, timely adjustment and reaction simulation of parameters during the process, such as: temperature, pressure, gas quantity and liquid quantity, as well as the opening and closing of each device. As Figure 1 shown, the above-mentioned gas lift drainage gas production scaling simulation evaluation test device further includes a data monitoring and acquisition processing unit 26, and the data monitoring and acquisition processing unit 26 is communicatively connected to the high-pressure simulated scaling reaction unit, the low-pressure simulated scaling reaction unit, the gas storage and supply unit and the liquid storage and supply unit (not shown in the figure).

[0046] A possible implementation mode. The data monitoring and acquisition processing unit 26 mainly includes a control computer, sensors (pressure, temperature and rotation speed), displays (pressure, temperature and rotation speed), video recording equipment, etc., and can collect, display and store real-time data and images by computer.

[0047] As Figure 1 shown, the gas storage and supply unit includes a simulated gas lift gas storage cylinder 1 and a simulated natural gas storage cylinder 2. The simulated gas lift gas storage cylinder 1 is connected to the lower part of the simulated scaling reactor A 27, and the simulated natural gas storage cylinder 2 is connected to the upper part of the simulated scaling reactor A 27. The simulated natural gas storage cylinder 2 is used to provide natural gas, and the simulated gas lift gas storage cylinder 1 provides gas lift gas. The two are used together to simulate the gas lift drainage process. A simulated gas lift valve 13 is also provided on the pipeline connecting the simulated gas lift gas storage cylinder 1 and the simulated scaling reactor A 27.

[0048] In actual application, according to the required simulated pressure conditions, a gas booster pump 9 can be added at the outlet ends of the simulated gas lift gas storage cylinder 1 and the simulated natural gas storage cylinder.

[0049] As Figure 1 shown, the liquid storage and supply unit includes a simulated gas field water storage tank and an inhibitor storage tank 5. Both the simulated gas field water storage tank and the inhibitor storage tank 5 are connected to the upper part of the simulated scaling reactor A 27. By comparing the test of adding the inhibitor with the blank test without adding the agent, the corrosion inhibition rate and scale inhibition rate of the inhibitor are simulated and evaluated.

[0050] The number of simulated gas field water storage tanks can be multiple, for example: 2, namely the first simulated gas field water storage tank 3 and the second simulated gas field water storage tank 4.

[0051] As is well known in the art, corresponding peristaltic pumps 6 are arranged at the liquid outlet ends of each simulated gas field water storage tank and the inhibitor storage tank 5.

[0052] A sewage outlet valve 14 and a liquid sampling outlet valve 15 can also be provided at the bottom of the simulated scaling reactor A 27 and the simulated scaling reactor B 28. A gas outlet valve 17 is provided on the simulated scaling reactor B 28.

[0053] As Figure 1 shown, a vacuum pump 7 is connected to the simulated scaling reactor A 27 through a vacuum inlet valve 8. The vacuum pump 7 is placed outside the temperature control box A10. It is used to pump out the air in the entire evaluation test device to avoid its influence on the simulation process.

[0054] As Figure 1 shown, a stirrer 12 is arranged inside the simulated scaling reactor A27. A first pressure sensor 18 and a first temperature sensor 20 are arranged on the simulated scaling reactor A 27; a second pressure sensor 19 and a second temperature sensor 21 are arranged inside the simulated scaling reactor B 28. It is used to timely reflect the pressure and temperature changes inside the simulated scaling reactor A 27 and the simulated scaling reactor B 28, and as the basis for opening and closing each valve. The stirrer 12 is used to stir and mix evenly the substances flowing into the simulated scaling reactor A 27. The stirrer 12 can adopt a double-magnet coupling rotation method, and the rotation speed is adjustable from 0 to 1000 rpm.

[0055] A specimen hanging structure is arranged at the stirring end of the stirrer 12. The stirrer 12 can include a stirring motor and blades. The stirring motor and the blades are connected through a stirring rod. A specimen hanging device is arranged on the blades, which is used to simulate dynamic and corrosion coupon tests. The specimen hanging device can be a common device in the art, for example: a hook welded to the blade, and the hook hangs on the corrosion coupon.

[0056] An embodiment of the present invention also provides a method for simulating and evaluating scale formation in gas production with drainage, comprising the following steps:

[0057] S1. Open the throttle pressure reducing valve, evacuate the simulated scale formation reactor A 27 and the simulated scale formation reactor B 28 to a set vacuum degree, then close the throttle pressure reducing valve, and start the data monitoring and acquisition processing unit;

[0058] S2. Start the temperature regulation control box A 10. The liquid storage and supply unit sequentially adds corrosion and scale inhibitor and simulated gas field water to the simulated scale formation reactor A 27. The gas storage and supply unit adds simulated natural gas to the simulated scale formation reactor A 27 to form a gas well fluid. When the pressure and temperature in the simulated scale formation reactor A 27 reach the first set value, stop the gas storage and supply unit and the liquid storage and supply unit, and keep the temperature constant for the first set time;

[0059] S3. The gas storage and supply unit introduces simulated gas lift gas into the simulated scale formation reactor A 27. When the pressure and temperature in the simulated scale formation reactor A 27 rise to the second set value, observe the scale formation situation in the simulated scale formation reactor A 27 after keeping the temperature constant for the second set time;

[0060] S4. Open the throttle pressure reducing valve 16 and start the temperature regulation control box B 11. When the pressures of the simulated scale formation reactor A 27 and the simulated scale formation reactor B 28 reach equilibrium and their pressures also reach the third set value, observe the scale formation situations in the simulated scale formation reactor A 27, the simulated scale formation reactor B 28, and the throttle pipeline 23. At the same time, take out the liquid in the simulated scale formation reactor B 28, analyze the calcium ion content in the liquid, and obtain the scale inhibition rate of the corrosion and scale inhibitor.

[0061] In this step, by controlling the opening degree of the throttle pressure reducing valve 16 and the preset control temperature of the simulated scale formation reactor B 28 box body, the sudden drop of pressure and temperature during the production throttling process and the process of gas escaping from the solution are simulated.

[0062] The third set value is determined by actual tests.

[0063] In this step, to obtain the scale inhibition rate of the corrosion and scale inhibitor, specifically as follows:

[0064] By comparing with the blank test, calculate the scale inhibition rate of the corrosion and scale inhibitor sample. The calculation formula is as follows:

[0065]

[0066] Where: M 2 —Calcium ion concentration in water when adding the corrosion and scale inhibitor; M 1 —Calcium ion concentration in water without adding the corrosion and scale inhibitor; M 0 —Calcium ion concentration in the simulated gas field water.

[0067] Before performing S1, the following operations can also be carried out:

[0068] According to the gas composition of natural gas in the gas well, prepare a multi-component simulated natural gas for standby with a high-pressure gas cylinder; according to the water quality composition of the produced water in the gas well, refer to the SY / T 5673-93 standard to prepare a certain amount of simulated gas field water for standby, and store it separately as two saline solutions of cations and anions; prepare a certain amount of corrosion and scale inhibitor solution for standby. Clean the simulated scaling reactor A 27 and the simulated scaling reactor B with clean water.

[0069] Among them, the gas composition of the simulated natural gas in the gas well contains at least acidic natural gas components such as methane, hydrogen sulfide, and carbon dioxide.

[0070] The simulated gas lift gas contains at least carbon dioxide acidic gas components.

[0071] Experimental example

[0072] 1. Simulation evaluation test of corrosion inhibition performance

[0073] Refer to the petroleum and natural gas industry standard SY / T5273-2000 "Evaluation Method for the Performance of Corrosion Inhibitors for Produced Water in Oilfields" for corrosion evaluation. In the simulated reactor A, hang the weighed metal specimen on the hook of the stirring blade, add 400 ml of simulated gas field water and a certain amount of corrosion inhibitor into the reactor, seal and deoxygenate it, and then introduce simulated natural gas under stirring conditions. Heat and raise the temperature of the simulated reactor A until the pressure and temperature in the reactor reach the test set values, then close the valve to stop gas injection; start timing, and end the test when the corrosion test time reaches the set value. Take out the specimen, weigh it after cleaning and drying with clean water and solvent, and calculate the corrosion rate of the metal specimen and the corrosion inhibition rate of the corrosion inhibitor (compared with the blank test) according to the weight loss of the specimen.

[0074] Evaluation conditions: test pressure: 8.0 MPa; test temperature: 100 °C; test time: 72 h; specimen material: L245NS steel; specimen size: 50 mm × 25 mm × 2.0 mm, total surface area is 28 cm 2 , the gas composition of the simulated natural gas for corrosion evaluation is shown in Table 1, the water quality analysis results of the simulated gas field water are shown in Table 2, and the results of the comparative evaluation test of corrosion inhibition performance are shown in Table 3.

[0075] Table 1 Composition of simulated natural gas for corrosion evaluation

[0076] Component Methane Ethane Propane Hydrogen sulfide Carbon dioxide Nitrogen Mole fraction, % 94.16 0.465 0.389 0.764 2.935 1.287

[0077] Table 2 Water quality of simulated gas field water for corrosion evaluation

[0078] <![CDATA[Sodium + (mg / L)]]> <![CDATA[Ca 2+ (mg / L)]]> <![CDATA[Mg 2+ (mg / L)]]> <![CDATA[HCO 3 - (mg / L)]]> <![CDATA[Cl - (mg / L)]]> Salinity (g / L) 295467 2252 243 683 49867 82.60 g / L

[0079] Table 3 Results of the simulated evaluation test on corrosion inhibition performance

[0080] Inhibitor name Drug dosage Corrosion rate (mm / a) Inhibition rate (%) Specimen surface description Blank 0 0.3812 / Black, severe local corrosion NTX-1 50 mg / L 0.1134 70.25 Bright, uniform corrosion NTX-1 100 mg / L 0.0647 83.30 Bright, uniform corrosion

[0081] 2. Simulated evaluation test on scale inhibition performance of calcium carbonate scale

[0082] For a high-temperature sulfur-containing gas well for drainage gas production in the Sichuan-Chongqing region, the wellhead temperature is as high as over 90°C, the daily gas production is 120,000 m³, and the daily water production is about 200 m³. The analysis results of the gas composition of the natural gas and the gas field water in the gas well are shown in Table 4 and Table 5. Since the production of this gas well started, the wellbore of the gas well and the equipment and pipelines of the surface system have been fouled and blocked many times. To ensure the normal drainage gas production of the gas well, it is necessary to use chemical scale prevention and plug removal technology to maintain production.

[0083] Table 4 Analysis results of the gas composition of the simulated natural gas for the test

[0084] Component Methane Ethane Propane Hydrogen sulfide Carbon dioxide Nitrogen Mole fraction, % 92.389 0.418 0.299 0.902 4.610 1.382

[0085] Table 4 Analysis results of the gas composition of the simulated gas lift gas for the test

[0086] Component Methane Carbon dioxide Nitrogen Mole fraction, % 94.602 3.241 2.157

[0087] Table 5 Analysis data of the water quality composition of the simulated gas field water for the test

[0088]

[0089] Steps of the simulated evaluation test:

[0090] (1) Prepare a simulated natural gas cylinder gas with a pressure of 8 MPa and a volume of 8 L using standard gases. The gas composition is shown in Table 3; prepare a simulated gas field water with a total volume of 2 L using sodium chloride, calcium chloride, magnesium chloride, barium chloride, and sodium bicarbonate. The ion composition is shown in Table 4 (prepare two kinds of brines separately for cations and anions, and then mix them in the reactor before the test); prepare a 1% corrosion and scale inhibitor solution for standby.

[0091] (2) Clean the simulated scale reactors A and B, and use a vacuum pump to evacuate the inside of the reactors; set the temperature of the temperature control boxes of the simulated scale reactors A and B to 120°C and 60°C respectively. Open or close the relevant control valves, start the stirrer of the scale reactor A to stir, and control the rotation speed to 60 revolutions per minute.

[0092] (3) First, add the corrosion and scale inhibitor (not added in the blank test) and the simulated gas field water (two kinds of prepared brines) into the simulated scaling reactor A, and then slowly introduce the simulated natural gas. Stop introducing gas when the pressure reaches 2.0 MPa, and let the gas and liquid mix and dissolve fully for 30 minutes to stabilize. Then continue to introduce the simulated natural gas until the internal pressure of the simulated scaling reactor A reaches 12.0 MPa and the temperature reaches 120 °C, and then stop introducing gas. Carry out a constant-temperature reaction for 12 h under stirring conditions.

[0093] (4) When the constant-temperature reaction time reaches 12 h, open the gas lift gas valve at the lower part of the simulated scaling reactor A, introduce high-pressure gas lift gas into the reactor, and stop introducing gas when the pressure in the simulated scaling reactor A rises to 16 MPa. Continue the constant-temperature reaction for 12 h, and observe the scaling situation of the solution inside the simulated scaling reactor A through the observation window.

[0094] (5) When the constant-temperature reaction time reaches 24 hours, quickly open the throttle valve 18 and the stop valve 24 between the simulated scaling reactor A and the simulated scaling reactor B, and let the gas-liquid fluid in the simulated scaling reactor A flow quickly into the simulated scaling reactor B. After the internal pressures of the simulated scaling reactor A and the simulated scaling reactor B reach equilibrium, observe the scaling situations inside the simulated scaling reactors A and B and the throttling channel (take out the throttling nipple) under the two conditions of not adding the corrosion and scale inhibitor (blank test) and adding the corrosion and scale inhibitor, and take samples from the liquid sampling port of the simulated scaling reactor to analyze the content of scaling calcium ions in the aqueous solution.

[0095] (6) Calculate the scale inhibition rate of the corrosion and scale inhibitor according to the measurement results of the scaling ions (calcium ions) in the solution under the two conditions of the above-mentioned simulated gas field water, blank test and adding the corrosion and scale inhibitor. The results of the simulated evaluation test of the scale inhibition performance are shown in Table 6.

[0096] Table 6 Simulated evaluation results of calcium carbonate scale inhibition performance

[0097]

[0098] As can be seen from the experimental examples, the simulated evaluation test device and method disclosed in the present invention can well simulate the actual situation and are worthy of popularization and use.

[0099] The above-mentioned specific implementation manners further elaborate in detail the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above-mentioned are only the specific implementation manners of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A scaling simulation evaluation test device for gas lift drainage gas production, Characterized in that: It includes a data monitoring and acquisition processing unit, a high-pressure simulated scaling reaction unit and a low-pressure simulated scaling reaction unit that are interconnected, and the high-pressure simulated scaling reaction unit is connected to a gas storage and supply unit and a liquid storage and supply unit; The high-pressure simulated scaling reaction unit includes a temperature regulation control box A, and a simulated scaling reactor A is arranged in the temperature regulation control box A; the low-pressure simulated scaling reaction unit includes a temperature regulation control box B, and a simulated scaling reactor B is arranged in the temperature regulation control box B; A throttling pressure reducing valve and a throttling pipeline are arranged on the pipeline connecting the high-pressure simulated scaling reaction unit and the low-pressure simulated scaling reaction unit. The throttling pressure reducing valve is arranged in the temperature regulation control box A; the throttling pipeline is arranged in the temperature regulation control box B; The data monitoring and acquisition processing unit is communicatively connected to the high-pressure simulated scaling reaction unit, the low-pressure simulated scaling reaction unit, the gas storage and supply unit and the liquid storage and supply unit.

2. The scaling simulation evaluation test device for gas lift drainage gas production according to claim 1, Characterized in that: The gas storage and supply unit includes a simulated gas lift gas storage cylinder and a simulated natural gas storage cylinder. The simulated gas lift gas storage cylinder is connected to the lower part of the simulated scaling reactor A, and the simulated natural gas storage cylinder is connected to the upper part of the simulated scaling reactor A.

3. The scaling simulation evaluation test device for gas lift drainage gas production according to claim 1, Characterized in that: The liquid storage and supply unit includes a simulated gas field water storage tank and an inhibitor storage tank. Both the simulated gas field water storage tank and the inhibitor storage tank are connected to the upper part of the simulated scaling reactor A.

4. The scaling simulation evaluation test device for gas lift drainage gas production according to claim 1, Characterized in that: A vacuum pump is connected to the simulated scaling reactor A through a vacuum inlet valve, and the vacuum pump is placed outside the temperature regulation control box A.

5. The scaling simulation evaluation test device for gas lift drainage gas production according to claim 1, Characterized in that: A stirrer is arranged in the simulated scaling reactor A, and a first pressure sensor and a first temperature sensor are arranged on the simulated scaling reactor A; a second pressure sensor and a second temperature sensor are arranged in the simulated scaling reactor B.

6. The scaling simulation evaluation test device for gas lift drainage gas production according to claim 5, Characterized in that: The stirrer rotates by double magnet coupling, and a specimen hanging structure is arranged at the stirring end of the stirrer.

7. The scaling simulation evaluation test device for gas lift drainage gas production according to claim 1, Characterized in that: The simulated scaling reactor B is made of a transparent material.

8. A scaling simulation evaluation test method for drainage gas production, Characterized in that: It includes the following steps: S1. Open the throttling pressure reducing valve, evacuate the simulated scaling reactors A and B to the set vacuum degree, then close the throttling pressure reducing valve, and start the data monitoring and acquisition processing unit; S2. Start the temperature regulation control box A. The liquid storage and supply unit sequentially adds corrosion and scale inhibitor and simulated gas field water into the simulated scaling reactor A. The gas storage and supply unit adds simulated natural gas into the simulated scaling reactor A to form a gas well fluid by mixing. When the pressure and temperature in the simulated scaling reactor A reach the first set value, stop the gas storage and supply unit and the liquid storage and supply unit, and keep the temperature constant for the first set time; S3. The gas storage and supply unit introduces simulated gas lift gas into the simulated scaling reactor A. When the pressure and temperature in the simulated scaling reactor A rise to the second set value, observe the scaling situation in the simulated scaling reactor A after keeping the temperature constant for the second set time; S4. Open the throttle pressure reducing valve and start the temperature regulation control box B. When the pressures of the simulated scaling reactor A and the simulated scaling reactor B reach equilibrium and their pressures also reach the third set value, observe the scaling situations in the simulated scaling reactor A, the simulated scaling reactor and the throttling pipeline of B. At the same time, take out the liquid in the simulated scaling reactor B and analyze the calcium ion content in the liquid to obtain the scale inhibition rate of the corrosion and scale inhibitor.

9. According to the drainage gas production scaling simulation evaluation test method described in claim 8, characterized in that: The calculation method of the scale inhibition rate of the corrosion and scale inhibitor is as follows: Where M 2 — Calcium ion concentration in water when corrosion and scale inhibitor is added; M 1 — Calcium ion concentration in water without adding corrosion and scale inhibitor; M 0 — Calcium ion concentration in simulated gas field water.

10. According to the drainage gas production scaling simulation evaluation test method described in claim 8, characterized in that: The simulated natural gas includes methane, hydrogen sulfide and carbon dioxide; preferably, the simulated gas lift gas contains at least carbon dioxide.

Images