Corrosion and scaling experiment system for oilfield water injection pipeline

Abstract

The utility model discloses a corrosion and scaling experiment system for an oilfield water injection pipeline, and relates to the technical field of pipeline corrosion experiment devices. The system comprises an injection water tank, a formation water tank, an injection water pump and a formation water pump, a main pipeline is sequentially provided with a first durometer, a hanging piece branch pipe, a pressure gauge, a back-pressure valve, a second durometer and a flow meter, the main pipeline between the first durometer and the back-pressure valve is further provided with a heat exchange pipe, and the main pipeline is further sequentially provided with a mixing tank and a mixing pump from a three-way pipe to the first durometer. The device is reasonable in structure and simple to operate; the pressure gauge is matched with the back pressure valve, so that the required pressure can be selected during an experiment, and the heat exchange tube is matched with the thermometer, so that the required temperature can be selected during the experiment; the use of the first hardness meter and the second hardness meter makes the hardness measurement more convenient, rapid, real-time and efficient, and the use of the mixing box and the mixing pump can measure the scaling and corrosion rate after the formation water and the injection water are uniformly mixed.

Description

Technical Field

[0001] The utility model relates to the technical field of pipeline corrosion experimental devices, in particular to an oilfield water injection pipeline corrosion and scaling experimental system. Background Art

[0002] As oilfield production enters its mid-to-late stages and oil pressure declines, water injection is a primary method for enhancing oil recovery in most onshore oilfields. During the water injection process, substandard water quality, temperature, and pressure fluctuations in the injected water can cause electrochemical corrosion and scaling of the injection string, impacting its lifespan and ensuring proper stratified injection. Corrosion primarily manifests as pitting corrosion and even perforation on the inner wall of the injection string. Scaling causes increased injection pressure and prevents testing tools from being lowered or properly seated, leading to workovers and significant waste. Traditionally, measuring the corrosion and scaling rates of downhole tubing in water injection wells involves first attaching two types of hanging devices to the tubing at different depths during workovers. These devices are then lowered into the wellbore along with the tubing and then pulled out after a period of time. Each measurement is not only time-consuming, labor-intensive, and incurs significant workover costs, but also compromises the effectiveness of the injection well.

[0003] Currently, a common laboratory method is a static scaling test, where formation water and injection water are poured into a beaker at varying ratios and the amount of scaling is measured at different times. This test does not allow for dynamic scaling or dynamic scaling rates. Prior art discloses an oilfield water injection scaling test device with application number 201820414515.X. However, this device determines scaling based on real-time weight changes in the pipeline, which is significantly affected by factors such as current stability and can only measure scale adhering to the pipe wall. Temperature variations in different formations, and even in the same formation during different production stages, also affect this test. Corrosion is another factor that can affect pipelines. Utility Model Content

[0004] The purpose of this utility model is to provide an oilfield water injection pipeline corrosion and scaling test system in order to solve the above problems. The system is simple to operate and determines the scaling and corrosion rate of the pipeline by setting the temperature, pressure, the ratio of injection water to formation water, and whether the two are pre-mixed.

[0005] The utility model achieves the above-mentioned purpose through the following technical solutions:

[0006] A corrosion and scaling test system for an oilfield water injection pipeline comprises an injection water tank, a formation water tank, an injection water pump, and a formation water pump. The injection water pump outlet and the formation water pump inlet are connected to the injection water tank and the formation water tank respectively via a branch pipe. The injection water pump outlet and the formation water pump outlet are connected to a tee pipe via a branch pipe and are connected to a main pipeline. A first hardness tester, a hanging branch pipe, a pressure gauge, a back pressure valve, a second hardness tester, and a flow meter are sequentially provided on the main pipeline. A heat exchange pipe is further provided on the main pipeline between the first hardness tester and the back pressure valve. The back pressure valve is used to increase the pressure in the test pipeline. The pressure gauge is used to determine the required pressure. Two hardness testers are used to measure the hardness in the test liquid. A mixing box and a mixing pump are further sequentially provided on the main pipeline from the tee pipe to the first hardness tester. The mixing box and the mixing pump are both connected to the main pipeline via a branch pipe, so that when necessary, formation water and injection water can be mixed in advance before the experiment.

[0007] Furthermore, the heat exchange tube is connected to a heat exchanger and a heat exchange pump, and the heat exchange tube is used to adjust the temperature of the solution in the main pipeline.

[0008] Furthermore, the main pipeline is connected to the mixing box through two branch pipes, and an agitator is also provided in the mixing box.

[0009] Furthermore, the inlet branch of the mixing box is provided with an inlet valve, the outlet branch is provided with an outlet valve, and the main pipeline is further provided with a first valve, which is provided in the middle part of the connection point between the two branches of the mixing box on the main pipeline.

[0010] Furthermore, the main pipeline is connected to the mixing pump through two branch pipes, and the inlet branch pipe of the mixing pump is provided with a second valve, which is used to close the branch pipe when the mixing pump is turned off, so that the fluid is transported by the main pipeline; the main pipeline is also provided with a third valve, which is provided in the middle part of the connection point of the two branches of the mixing pump on the main pipeline, and is used to close the main pipeline when the mixing pump is in use, so that the fluid is transported by the branch pipe where the mixing pump is located.

[0011] Furthermore, a valve is provided on the hanging plate branch pipe, through which a hanging plate and a temperature sensor can be placed in the main pipeline. The hanging plate is used to measure the corrosion rate under experimental conditions. Hanging plates of corresponding materials (carbon steel, copper, etc.) can be placed according to specific needs. The temperature sensing end of the temperature sensor is placed in the main pipeline through the hanging plate branch pipe to measure and control the actual temperature of the mixed liquid.

[0012] Furthermore, the outer wall of the heat exchange tube is provided with a thermal insulation layer.

[0013] Furthermore, a water collecting tank is provided at the outlet end of the main pipeline for collecting mixed water after the test.

[0014] The beneficial effects of the utility model are as follows:

[0015] The utility model can carry out the experiment under the required pressure conditions by arranging the back pressure valve and the pressure gauge; the coordinated use of the heat exchange tube and the temperature sensor enables the experiment to be carried out under the required temperature conditions; the use of the first hardness meter and the second hardness meter makes it easier to measure the hardness difference of the experimental fluid before and after the test section, and then calculate the scaling rate according to the experimental time and the flow rate of the experimental fluid fed back by the flow meter; the arrangement of the hanging piece can test the corrosion rate under the conditions; the coordination of the mixing box and the mixing pump enables the system to measure the scaling and corrosion rates of the formation water and the injection water after they are evenly mixed. In short, the system is simple to operate and has a high accuracy rate, and is fully capable of measuring the corrosion and scaling conditions of the injected water on the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is an overall schematic diagram of the utility model;

[0017] Figure 2 for Figure 1 Schematic diagram of part A;

[0018] In the figure: 1 is the injection water tank; 2 is the formation water tank; 3 is the mixing tank; 4 is the agitator; 5 is the temperature sensor; 6 is the mixing pump; 7 is the first hardness tester; 8 is the second hardness tester; 9 is the flow meter; 10 is the pressure gauge; 11 is the outlet valve; 12 is the first valve; 13 is the inlet valve; 14 is the heat exchange pipe; 15 is the hanging plate branch pipe; 16 is the hanging plate; 17 is the back pressure valve; 18 is the heat exchanger; 19 is the injection water pump; 20 is the formation water pump; 21 is the third valve; 22 is the second valve; 23 is the tee pipe; 24 is the water collecting tank; 25 is the heat exchange pump; 26 is the insulation layer; 27 is the main pipeline. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be noted that the terms "first", "second" and "third" are only used to facilitate the description of the present invention and simplify the description, and cannot be understood as indicating or implying relative importance.

[0021] See Figure 1-2 , the utility model provides a technical solution:

[0022] An oilfield water injection pipeline corrosion and scaling experimental system includes an injection water tank 1, a formation water tank 2, an injection water pump 19, and a formation water pump 20. The outlet of the injection water pump 19 and the inlet of the formation water pump 20 are respectively connected to the injection water tank 1 and the formation water tank 2 via a branch pipe. The outlet of the injection water pump 19 and the outlet of the formation water pump 20 are connected to a tee pipe 23 via a branch pipe and are connected to a main pipeline 27. The main pipeline 27 is sequentially provided with a first hardness tester 7, a hanging branch pipe 15, a pressure gauge 10, a back pressure valve 17, a second hardness tester 8, and a flow meter 9. The main pipeline 27 between the first hardness tester 7 and the back pressure valve 17 is also provided with a heat exchange pipe 14. The main pipeline 27 is also sequentially provided with a mixing box 3 and a mixing pump 6 from the tee pipe 23 to the first hardness tester 7. The mixing box 3 and the mixing pump 6 are both connected to the main pipeline 27 via a branch pipe.

[0023] The heat exchange tube 14 is connected to a heat exchanger 18 and a heat exchange pump 25. The main pipeline 27 is connected to the mixing box 3 via two branch pipes. The mixing box 3 is also provided with an agitator 4. The inlet branch pipe of the mixing box 3 is provided with an inlet valve 13, and the outlet branch pipe is provided with an outlet valve 11. The main pipeline 27 is also provided with a first valve 12, which is located in the middle of the connection point between the two branches of the mixing box 3 on the main pipeline 27. The main pipeline 27 is connected to the mixing pump 6 via two branch pipes. The inlet branch pipe of the mixing pump 6 is provided with a second valve 22. The main pipeline 27 is also provided with a third valve 21, which is located in the middle of the connection point between the two branches of the mixing pump 6 on the main pipeline 27. A valve is provided on the hanging plate branch pipe 15, through which a hanging plate 16 and a temperature sensor 5 can be placed in the main pipeline 27. The temperature sensing end of the temperature sensor 5 is placed in the main pipeline 27 through the hanging plate branch pipe 15; an insulation layer 26 is provided on the outer wall of the heat exchange tube 14; and a water collecting tank 24 is provided at the outlet end of the main pipeline 27.

[0024] When using this utility model, there are different operating methods according to different needs:

[0025] 1. Measure the scaling and corrosion of the pipeline during the mixing process of formation water and injection water: Place injection water and formation water in corresponding containers and measure their hardness in advance. Open the hanging plate branch pipe 15 and install the weighed hanging plate 16, then close its valves. Close the inlet valve 13, outlet valve 11, and second valve 22. Open the first valve 12 and third valve 21. Start the injection water pump 19, formation water pump 20, and heat exchange pump 25. Adjust the injection water pump 19 and formation water pump 20 so that the injection water and formation water enter the main pipeline 27 in the required ratio. At this time, The average hardness of the mixed water is calculated based on the pre-measured hardness of the injection water and formation water and the ratio between the two, with the value of the first hardness meter 7 as a reference; the back pressure valve 17 and the heat exchanger 18 are adjusted so that the temperature and pressure in the main pipeline 27 reach the required values, and the experiment is started. The reading changes of the second hardness meter 8, the value of the flow meter 9 and the experimental time are recorded, and the scaling rate can be calculated. After the experiment is completed, the hanging piece 16 is removed, cleaned, dried and weighed, and the corrosion rate can be calculated based on the weight difference before and after the hanging piece 16, the hanging piece area and the test time.

[0026] 2. Measure the scaling and corrosion of the pipeline after the formation water and injection water are evenly mixed: Prepare the injection water and formation water in the corresponding containers, open the coupon branch pipe 15, install the weighed coupon 16, and close its valves. Open the inlet valve 13, outlet valve 11, and second valve 22, close the first valve 12 and third valve 21, start the injection water pump 19 and formation water pump 20, and adjust the injection water pump 19 and formation water pump 20 so that the injection water and formation water enter the mixing box 3 in the required ratio. Turn on the agitator 4 to allow for even mixing. Then, turn on the mixing pump 6 and heat exchange pump 25. Adjust the back pressure valve 17 and heat exchanger 18 so that the temperature and pressure in the main pipeline 27 reach the required values. Start the experiment, record the reading of the first hardness tester 7, the change in the reading of the second hardness tester 8, the flow meter value, and the experiment time, and calculate the scaling rate. After the experiment, remove the coupon 16, clean it, dry it, and weigh it. The corrosion rate can be calculated based on the weight difference before and after the coupon 16, the coupon area, and the experiment time.

[0027] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0028] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An oilfield water injection pipeline corrosion and scaling experimental system, comprising an injection water tank (1), a formation water tank (2), an injection water pump (19), and a formation water pump (20), wherein the outlet of the injection water pump (19) and the inlet of the formation water pump (20) are respectively connected to the injection water tank (1) and the formation water tank (2) via a branch pipe, and the outlet of the injection water pump (19) and the outlet of the formation water pump (20) are connected to a tee pipe (23) via a branch pipe and are connected to a main pipeline (27), characterized in that: The main pipeline (27) is provided with a first hardness tester (7), a hanging plate branch pipe (15), a pressure gauge (10), a back pressure valve (17), a second hardness tester (8), and a flow meter (9) in sequence. The main pipeline (27) between the first hardness tester (7) and the back pressure valve (17) is also provided with a heat exchange pipe (14). The main pipeline (27) is also provided with a mixing box (3) and a mixing pump (6) in sequence from the three-way pipe (23) to the first hardness tester (7). The mixing box (3) and the mixing pump (6) are both connected to the main pipeline (27) through a branch pipe.

2. The oilfield water injection pipeline corrosion and scaling experimental system according to claim 1 is characterized in that: The heat exchange tube (14) is connected to a heat exchanger (18) and a heat exchange pump (25).

3. The oilfield water injection pipeline corrosion and scaling experimental system according to claim 1 is characterized in that: The main pipeline (27) is connected to the mixing box (3) through two branch pipes, and a stirrer (4) is also provided in the mixing box (3).

4. The oilfield water injection pipeline corrosion and scaling experimental system according to claim 3 is characterized in that: The inlet branch pipe of the mixing box (3) is provided with an inlet valve (13), the outlet branch pipe is provided with an outlet valve (11), and the main pipeline (27) is also provided with a first valve (12). The first valve (12) is arranged in the middle part of the connection point of the two branches of the mixing box (3) on the main pipeline (27).

5. The oilfield water injection pipeline corrosion and scaling experimental system according to claim 1 is characterized in that: The main pipeline (27) is connected to the mixing pump (6) through two branch pipes. The inlet branch pipe of the mixing pump (6) is provided with a second valve (22). The main pipeline (27) is also provided with a third valve (21). The third valve (21) is arranged in the middle part of the connection point between the two branch pipes of the mixing pump (6) and the main pipeline (27).

6. The oilfield water injection pipeline corrosion and scaling experimental system according to claim 1 is characterized in that: The hanging piece branch pipe (15) is provided with a valve, and the hanging piece (16) and the temperature sensor (5) can be placed in the main pipeline (27) through the hanging piece branch pipe (15), and the temperature sensing end of the temperature sensor (5) is placed in the main pipeline (27) through the hanging piece branch pipe (15).

7. An oilfield water injection pipeline corrosion and scaling experimental system according to claim 1 or 2, characterized in that: The outer wall of the heat exchange tube (14) is provided with a thermal insulation layer (26).

8. The oilfield water injection pipeline corrosion and scaling experimental system according to claim 1 is characterized in that: A water collecting tank (24) is provided at the outlet end of the main pipeline (27).

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