Device for simulating bacterial corrosion of oil and gas field and testing method

Abstract

The invention relates to the technical field of metal corrosion testing, in particular to a device for simulating bacterial corrosion of an oil and gas field and a testing method. The device comprises a sample carrier assembly and a rotary driving assembly which are mounted in a reaction kettle, one end of a central column of the sample carrier assembly is connected with an upper disc, the other end of the central column of the sample carrier assembly is connected with a lower disc, the upper disc, the lower disc and the central column are respectively provided with at least one sample hole group, and each sample hole group comprises a plurality of sample holes which are arranged at equal intervals; the rotation driving assembly is installed on the sample carrier assembly and can drive the sample carrier assembly to rotate with the axis of the center column as the center line. According to the testing method, the device is used for enabling a sample to rotate in a corrosion solution so as to simulate liquid flow in a pipeline in actual use, and sample hole groups at different positions can simulate different positions of the pipeline; and the bacterial corrosion conditions at different flow rates and different working condition positions can be tested and simulated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal corrosion testing, in particular to a device and a testing method for simulating bacterial corrosion in oil and gas fields. BACKGROUND

[0002] China is rich in shale gas reserves, which is one of the main energy sources at present. However, in the process of shale gas development, the large-scale repeated use of fracturing fluid, combined with the complex formation of biological community, leads to the entry of bacteria into the ground gathering system during the return flow process in some gas wells, resulting in pitting corrosion perforation failure of shale gas ground gathering pipelines, causing serious economic losses and environmental pollution. Therefore, it is very important to study the growth and reproduction of bacteria and effectively protect them from corrosion to ensure the safe operation of shale gas gathering pipelines.

[0003] Currently, the immersion method is mainly used to study the weight loss rate of metal pipes in bacterial solution. In actual application, the liquid in the pipeline is not static, but has a certain flow rate, and the ordinary immersion method does not take into account the actual working conditions of the pipeline. The pipeline may be horizontal, vertical or at various angles. If it is simply immersed, it is not comprehensive and cannot reflect the possible changes in different positions of the pipeline. Therefore, this testing method is single and cannot reflect the coupling of various corrosion factors. For example, the coupling of sand layer and bacteria, the influence of flow rate, the influence of corrosion position, etc. Under the synergistic effect of bacterial corrosion, flow rate and position difference, the corrosion rate may be several times or even dozens of times higher than before, which makes the conclusions obtained by the study seriously inconsistent with the actual situation, seriously affecting the understanding of the rules of bacterial corrosion and the research and development of corrosion prevention measures. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a device and a testing method for simulating bacterial corrosion in oil and gas fields, to solve the problem that the existing device cannot simulate bacterial corrosion under different flow rates and different working conditions.

[0005] The technical solution of the present application to solve the above technical problem is as follows:

[0006] The present application provides a device for simulating bacterial corrosion in oil and gas fields, comprising a reaction kettle and an electrode testing system, and further comprising a sample carrier assembly and a rotary drive assembly installed in the reaction kettle.

[0007] The sample carrier assembly comprises a center column, one end of the center column is connected with an upper disc, the other end is connected with a lower disc, and at least one sample hole group is formed on the upper disc, the lower disc and the center column, respectively, each sample hole group comprises a plurality of sample holes arranged at equal intervals.

[0008] The rotating drive assembly is installed on the sample carrier assembly and can drive the sample carrier assembly to rotate with the axis of the center column as the center line.

[0009] The device can rotate the sample in the corrosion solution, simulate the liquid flow in the pipeline in actual use, and the sample hole groups at different positions can simulate different positions of the pipeline.

[0010] On the basis of the above technical scheme, the application can also be improved as follows.

[0011] Further, the sample holes on the upper disc have openings facing the lower disc, the sample holes on the lower disc have openings facing the upper disc, and the sample holes on the upper disc and the lower disc correspond one by one; the sample holes opened on the center column have openings facing the direction radially outward of the center column.

[0012] The beneficial effect of the above further scheme is that the samples at different positions can be stably placed in the sample holes.

[0013] Further, the center column has a hollow structure and both ends are open ends; the two ends of the center column respectively pass through the center positions of the upper disc and the lower disc and are fixed;

[0014] The rotating drive assembly comprises a rotating rod, a rotating disc and a mounting rod; one end of the rotating rod is rotatably connected to the center of one side of the rotating disc, and the other end is connected to a power device; one end of the mounting rod is fixed to the center of the other side of the rotating disc, and the other end of the mounting rod penetrates the center column and is fixed to the lower disc.

[0015] The beneficial effect of the above further scheme is that the center column has a hollow structure, the wires connected to the samples can pass through the center column, which can reduce the degree of exposure of the wires to the corrosion solution and prolong the service life of the wires.

[0016] Further, the diameters of the upper disc and the lower disc are equal; the rotating drive assembly further comprises at least two auxiliary mounting rods, and the at least two auxiliary mounting rods are arranged in central symmetry about the center of the rotating disc; one end of each auxiliary mounting rod is fixedly connected to the rotating disc, and the other end is fixedly connected to the upper disc and the lower disc.

[0017] The beneficial effect of the above further scheme is that by arranging the auxiliary mounting rods, the stability of the rotation of the sample carrier assembly can be further ensured.

[0018] Further, the electrode test system comprises a reference electrode, an auxiliary electrode and an electrochemical workstation; the reference electrode and the auxiliary electrode are installed in the reaction kettle; the electrochemical workstation is located outside the reaction kettle, and the reference electrode and the auxiliary electrode are connected with the electrochemical workstation through wires; the electrochemical workstation can be connected with a sample through wires.

[0019] The beneficial effect of the above further scheme is that the sample can be effectively tested, and the test result is more accurate.

[0020] The application further provides a test method for simulating bacterial corrosion of an oil and gas field, which adopts the device as described above, and comprises the following steps:

[0021] Step 1: placing a sample in the sample hole, placing the sample carrier assembly in the reaction kettle containing a corrosion solution, and immersing the sample;

[0022] Step 2: rotating the sample carrier assembly by using the rotary drive assembly;

[0023] Step 3: after rotation, testing the current, potential distribution and electrochemical information of the sample by using the electrode test system, and observing the change of the bacterial corrosion product to obtain the corrosion result of the sample.

[0024] The beneficial effect of the above scheme is that the rotation speed of the sample carrier assembly can be adjusted, so that the interface corrosion kinetic information and the corrosion difference between different rotation speeds can be determined, and the inhibition mechanism of the corrosion inhibitor on the bacterial metal corrosion can be evaluated.

[0025] Further, the corrosion solution comprises a sodium chloride solution and a bacterial-containing medium; the mass percentage of sodium chloride in the sodium chloride solution is 1%, 3.5%, 5% or 10%, the bacteria are one or more of sulfate-reducing bacteria, iron bacteria and saprophytic bacteria, and the volume percentage of the bacteria in the bacterial-containing medium is 1%, 5% or 10% of the volume of the corrosion solution.

[0026] The beneficial effect of the above further scheme is that the above corrosion solution can accurately simulate the condition of the liquid in the pipeline in actual use.

[0027] Further, after the step 1 is completed, the reaction kettle is sealed first, nitrogen is introduced into the reaction kettle until the oxygen in the reaction kettle is completely discharged, and then the step 2 is performed.

[0028] The beneficial effect of the above further scheme is that the above operation can accurately simulate the anaerobic environment in the pipeline in actual use.

[0029] Further, the test environment temperature of the test method is 35 DEG C.

[0030] The beneficial effect of the above further scheme is that the above temperature can accurately simulate the anaerobic environment in the pipeline in actual use.

[0031] Further, the electrode test system comprises a reference electrode, an auxiliary electrode and an electrochemical workstation; in step 3, after the rotation is completed, the sample, the reference electrode and the auxiliary electrode are respectively connected with the electrochemical workstation located outside the reaction kettle through wires, the polarization curve of the sample is tested through the electrochemical workstation, and the surface corrosion product morphology of the sample is observed.

[0032] The beneficial effect of the above further scheme is that the corrosion condition of the sample can be effectively judged by testing the polarization curve. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The structure diagram of the sample carrier assembly in the device for simulating the bacterial corrosion of the oil and gas field of the application;

[0034] Figure 2 The structure diagram of the device for simulating the bacterial corrosion of the oil and gas field of the application;

[0035] Figure 3 The polarization curve measured in Example 1 of the device for simulating the bacterial corrosion of the oil and gas field of the application;

[0036] Figure 4 The surface corrosion product morphology diagram of the sample tested in Example 1 of the test method for simulating the bacterial corrosion of the oil and gas field of the application on the 7th day;

[0037] Figure 5 The surface corrosion product morphology diagram of the sample tested in Example 1 of the test method for simulating the bacterial corrosion of the oil and gas field of the application on the 14th day.

[0038] In the drawings, the components represented by each reference numeral are listed as follows:

[0039] 1, upper disc; 11, sample hole;

[0040] 2, center column; 3, lower disc; 4, mounting plate; 5, booster pump; 6, pressure gauge;

[0041] 7, rotating rod; 71, rotating disc; 72, mounting rod; 73, auxiliary mounting rod;

[0042] 8, reference electrode; 9, auxiliary electrode; 10, nitrogen cylinder; 12, relay; 13, reaction kettle; 14, electrochemical workstation. DETAILED DESCRIPTION

[0043] The principles and features of the present application are described below in conjunction with the accompanying drawings, which are only used to explain the present application and not intended to limit the scope of the present application.

[0044] As shown in Figure 1 and 2 The device for simulating bacterial corrosion of oil and gas field of the present application comprises a reaction kettle 13 and an electrode test system; further comprises a sample carrier assembly and a rotating drive assembly installed in the reaction kettle 13; the sample carrier assembly comprises a center column 2, one end of the center column 2 is connected with an upper disc 1, the other end is connected with a lower disc 3, and at least one sample hole group is respectively arranged on the upper disc 1, the lower disc 3 and the center column 2, each sample hole group comprises a plurality of sample holes 11 arranged at equal intervals; the rotating drive assembly is installed on the sample carrier assembly and can drive the sample carrier assembly to rotate with the axis of the center column 2 as the center line.

[0045] The device for simulating bacterial corrosion of oil and gas field of the present application can rotate the sample in the corrosion solution through the sample carrier assembly and the rotating device to simulate the liquid flow in the pipeline in actual use; at least one sample hole group is respectively arranged on the upper disc 1, the lower disc 3 and the center column 2, which can simulate different positions of the pipeline. In this way, the device of the present application can make the test environment more similar to the actual use environment, so that the measured results are more accurate and have more reference value. At the same time, the sample carrier assembly and the electrode test system are arranged in the reaction kettle 13, so that after rotation, the sample does not need to be removed, but can be directly connected with the motor test system through the lead wire for measurement, further ensuring the stability of the test results.

[0046] In the above embodiment, preferably, the sample holes 11 on the upper disc 1 have openings facing the lower disc 3, the sample holes 11 on the lower disc 3 have openings facing the upper disc 1, and the positions of the sample holes 11 on the upper disc 1 and the lower disc 3 correspond one by one; the sample holes 11 arranged on the center column 2 have openings facing the direction radially outward of the center column 2; when the sample holes 11 are located on the upper disc 1, the top of the pipeline can be simulated, when the sample holes 11 are located on the center column 2, the side surface of the pipeline can be simulated, and when the sample holes 11 are located on the lower disc 3, the bottom of the pipeline can be simulated; which can ensure that the samples at different positions can be stably placed in the sample holes 11.

[0047] In the above embodiment, preferably, the number of sample holes 11 in each sample hole group is three, which can facilitate repeated experiments and avoid special cases.

[0048] Further preferably, the sample hole 11 has a size of 1 cm in length, 1 cm in width and 1.2 cm in depth. The sample hole 11 with the above size can accommodate a sample of a sufficient size, so that the test result is accurate and effective. The sample holes 11 can prevent the samples in the sample holes 11 from affecting each other and from being corroded in gaps during electrochemical testing

[0049] Further preferably, the distance between the adjacent sample holes 11 is 0.5 cm. The sample holes 11 with the distance can effectively prevent the samples in the adjacent sample holes 11 from affecting each other and from being corroded in gaps during electrochemical testing.

[0050] In the above embodiment, preferably, the sample holes 11 in each sample hole group are arranged in a straight line on the upper disc 1, the central column 2 and the lower disc 3. In the upper disc 1 and the lower disc 3, the straight line along which the sample holes 11 are arranged in each group is a straight line passing through a diameter of the disc. In the central column 2, the straight line along which the sample holes 11 are arranged in each group is a straight line parallel to the axis of the central column 2. Such an arrangement can better simulate the actual position of the pipeline.

[0051] In the above embodiment, preferably, the sample hole 11 is a cuboid hole and has a depth higher than the height of the sample. In this way, the corrosion products can be easily fixed on the surface of the sample, and the sample will not fall off during rotation.

[0052] In the above embodiment, preferably, the central column 2 has a hollow structure and is open at both ends. The central column 2 penetrates the center of the upper disc 1 and the lower disc 3 and is fixed. The central column 2 has a hollow structure, so that the lead connected to the sample can pass through the central column 2. In this way, the degree of exposure of the lead to the corrosion solution can be reduced, and the service life of the lead can be prolonged.

[0053] In the above embodiment, preferably, the rotation driving assembly includes a rotation rod 7, a rotation disc 71 and a mounting rod 72. One end of the rotation rod 7 is rotatably connected to the center of one side of the rotation disc 71, and the other end is connected to the power device. One end of the mounting rod 72 is fixed to the center of the other side of the rotation disc 71, and the other end of the mounting rod 72 penetrates the central column 2 and is fixed to the lower disc 3 through a flange. Through the cooperation of the mounting rod 72 and the central column 2, the rotation rod 7 can drive the sample carrier assembly to rotate and ensure the stability of the rotation.

[0054] It should be noted that, since the center column 2 is also provided for the wire to pass through, the installation rod 72 has a gap between the inner wall of the center column 2; the wire connected with the sample passes through the open end of the lower end of the center column 2 into the center column 2, and the fixed connection of the installation rod 72 with the lower disc 3 does not affect the wire to enter the center column 2. When in the center column 2, the wire wound on the installation rod 72 is not connected with the external test system during the rotation of the sample carrier assembly, but is connected after the rotation is stopped, so that the rotation of the sample carrier assembly does not affect the wire.

[0055] In the above embodiment, preferably, a rotating member is arranged on the cover (not shown in the figure) of the reaction kettle 13, and the rotating member is connected with the rotating rod 7 to drive the rotating rod 7 to rotate. The rotating member on the cover is a conventional component of the reaction kettle 13, and the power for rotation is obtained by being connected with the relay 12.

[0056] In the above embodiment, preferably, the diameters of the upper disc 1 and the lower disc 3 are equal; the rotating drive assembly further comprises at least two auxiliary installation rods 73, and the at least two auxiliary installation rods 73 are arranged in central symmetry about the center of the rotating disc 71; one end of each auxiliary installation rod 73 is fixedly connected with the rotating disc 71, and the other end is fixedly connected with the upper disc 1 and the lower disc 3; by arranging the auxiliary installation rod 73, the stability of the rotation of the sample carrier assembly can be further ensured.

[0057] The other end of each auxiliary installation rod 73 can pass through the upper disc 1 and the lower disc 3 and be fixed therewith. However, considering that the sample holes 11 are arranged on the upper disc 1 and the lower disc 3, the direct fixation of the auxiliary installation rod 73 with the upper disc 1 and the lower disc 3 can affect the sample. Therefore, it is further preferred that installation plates 4 are arranged at the corresponding positions of the side portions of the upper disc 1 and the lower disc 3, the installation plates 4 extend along the radial direction of the disc and are limited, and holes are arranged on the installation plates 4, and one auxiliary installation rod 73 passes through the corresponding upper and lower installation plates 4 of the upper disc 1 and the lower disc 3 and is fixed.

[0058] In the above embodiment, preferably, the electrode test system comprises a reference electrode 8, an auxiliary electrode 9 and an electrochemical workstation 14; the reference electrode 8 and the auxiliary electrode 9 are installed in the reaction kettle 13, and the electrochemical workstation 14 is located outside the reaction kettle 13; the sample, the reference electrode 8 and the auxiliary electrode 9 are respectively connected with the electrochemical workstation 14 through wires; in this way, the sample can be effectively tested, and the test result is more accurate.

[0059] In the above embodiment, preferably, in order to ensure the effectiveness of the test and provide an experimental environment more in line with the actual use conditions of the pipeline, the device of the present application further comprises a nitrogen gas pipeline, one end of the nitrogen gas pipeline is connected with the nitrogen cylinder 10, and the other end is located in the reaction kettle 13, so that nitrogen gas can be introduced into the reaction kettle 13 to provide an oxygen-free environment.

[0060] Further preferably, the nitrogen pipeline is provided with a booster pump 5, and is also provided with a valve, which can control and monitor the input of nitrogen.

[0061] Further preferably, at the same time, the reaction kettle 13 is also provided with a pressure gauge 6 to monitor the pressure in the reaction kettle 13.

[0062] The test method for simulating bacterial corrosion of oil and gas fields of the present application is tested by using the device as described above, and the test method comprises the following steps:

[0063] Step 1, place the sample in the sample hole 11, place the sample carrier assembly in the reaction kettle 13 containing the corrosion solution, and immerse the sample.

[0064] Step 2, rotate the sample carrier assembly by using the rotary drive assembly.

[0065] Step 3, after rotation, test the current, potential distribution and electrochemical information of the sample by using the electrode test system, and observe the change of the bacterial corrosion product, to obtain the corrosion result of the electrochemical electrode sample.

[0066] The test method for simulating bacterial corrosion of oil and gas fields of the present application can adjust the rotation speed of the sample carrier assembly, so as to clearly determine the interface corrosion kinetics information and the corrosion difference between different rotation speeds, and also can evaluate the corrosion inhibition mechanism of the corrosion inhibitor on the bacterial metal corrosion.

[0067] In the above method of the present application, preferably, the corrosion solution comprises a sodium chloride solution and a culture medium containing bacteria; the mass percentage of sodium chloride in the sodium chloride solution is 1%, 3.5%, 5% or 10%, the type of bacteria is one or more of sulfate-reducing bacteria, iron bacteria and saprophytic bacteria, and the volume percentage of bacteria in the culture medium containing bacteria is 1%, 5% or 10% of the volume of the corrosion solution.

[0068] Further preferably, the corrosion solution comprises a sodium chloride solution and a culture medium containing sulfate-reducing bacteria; the concentration of the sodium chloride solution is 0.1 mol / L, and the volume percentage of the culture medium containing sulfate-reducing bacteria is 10% of the volume of the corrosion solution; the composition of the corrosion solution can effectively simulate the composition of the liquid inside the pipeline in actual use, so that the test result is more accurate and reliable.

[0069] In the above embodiment, preferably, after step 1 is completed, the reaction kettle 13 is first sealed, after a period of sealing, nitrogen is introduced into the reaction kettle 13 until the oxygen in the reaction kettle 13 is completely discharged, in this process, the exhaust port of the reaction kettle 13 is open, and the oxygen can be discharged through the exhaust port. When the oxygen is completely discharged, the exhaust port is closed, and then step 2 is performed.

[0070] In the above embodiment, preferably, the test environment temperature of the test method is 35 DEG C; the temperature is similar to the environment temperature of the pipeline in actual use.

[0071] In the above embodiment, preferably, the electrode test system comprises a reference electrode 8, an auxiliary electrode 9 and an electrochemical workstation 14; after the rotation is completed, the sample, the reference electrode 8 and the auxiliary electrode 9 are respectively connected to the electrochemical workstation 14 located outside the reaction kettle 13 through wires, and the polarization curve of the sample is tested through the electrochemical workstation 14; thus, the polarization curve measured is more accurate and reliable.

[0072] Preferably, in the actual test, the time for oxygen removal by nitrogen gas is 3 hours.

[0073] Preferably, in the test, the rotation speed of the sample carrier assembly is 7 r / min; the rotation speed is similar to the liquid flow rate in the pipeline in actual use.

[0074] Preferably, in the test, the sample is soaked in the corrosion solution for 14 days; the time can make the sample be fully corroded, so that the test result obtained is more accurate.

[0075] Preferably, the material in the sample is J55, P110, N80, 3Cr, 5Cr, 9Cr, 13Cr alloy steel or stainless steel.

[0076] It should be noted that before the test by the method of the present application, the sample suitable for the device of the present application also needs to be prepared.

[0077] The specific preparation method of the sample is that the pipeline material to be tested is cut into a structure suitable for the internal shape of the sample hole 11, then the sandpaper of #240, #400, #600, #800, #1000 and #1200 is used for polishing in sequence, and one end of the wire is welded on the surface of the sample. Then, the sample is packaged and cured by using epoxy resin.

[0078] Preferably, the pipeline material is cut into a cube.

[0079] The prepared sample is placed in the sample hole 11, and the other end of the wire is inserted into the hollow structure of the center column 2 and wound on the mounting rod 72.

[0080] The technical solutions of the present application are illustrated by specific embodiments as follows.

[0081] Embodiment

[0082] The device for simulating the bacterial corrosion of the oil and gas field in the embodiment is specifically constructed as follows:

[0083] The sample carrier assembly of the embodiment comprises a center column 2, which is hollow and has open ends. The center column 2 penetrates the center of the upper disc 1 and the lower disc 3 and is fixed. The upper disc 1 and the lower disc 3 have the same diameter. The lower disc 3 is horizontally placed, and the upper surface of the lower disc 3 is parallel to the lower surface of the upper disc 1. The orthographic projection of the upper disc 1 from top to bottom is completely coincident with the lower disc 3. Two mounting plates 4 are symmetrically arranged on the side of the upper disc 1 and the lower disc 3, respectively. Holes are formed in each mounting plate 4. The mounting plates 4 on the upper disc 1 and the lower disc 3 are in corresponding positions.

[0084] A sample hole group is formed on the upper disc 1, the lower disc 3 and the center column 2, respectively. Each sample hole group comprises three sample holes 11 arranged at equal intervals. The sample holes 11 on the upper disc 1 have openings facing the lower disc 3. The sample holes 11 on the lower disc 3 have openings facing the upper disc 1. The sample holes 11 on the upper disc 1 and the lower disc 3 are in one-to-one correspondence. The sample holes 11 on the center column 2 have openings facing the radial outward direction of the center column 2.

[0085] The sample holes 11 on the upper disc 1, the center column 2 and the lower disc 3 are arranged in a straight line. On the upper disc 1 and the lower disc 3, the straight line in which the sample holes 11 are arranged is a diameter of the disc. On the center column 2, the straight line in which the sample holes 11 are arranged is parallel to the axis of the center column 2.

[0086] The sample hole 11 is a cubic hole with a size of 1 cm in length, 1 cm in width and 1.2 cm in depth. The distance between the two closest edges of adjacent sample holes 11 is 0.5 cm.

[0087] The rotating drive assembly of the embodiment comprises a rotating rod 7, a rotating disc 71, a mounting rod 72 and two auxiliary mounting rods 73. One end of the rotating rod 7 is rotatably connected to the center of one side of the rotating disc 71, and the other end is connected to a rotating member on the cover of the reaction kettle 13. The rotating member is connected to the relay 12. One end of the mounting rod 72 is fixed to the center of the other side of the rotating disc 71, and the other end penetrates the center column 2 and is fixed to the lower disc 3. The two auxiliary mounting rods 73 are centrally symmetrically arranged about the center of the rotating disc 71. One end of each auxiliary mounting rod 73 is fixedly connected to the rotating disc 71, and the other end penetrates a group of mounting plates 4 corresponding in position on the upper disc 1 and the lower disc 3 and is fixed.

[0088] When the sample is placed in the sample hole 11, the wire welded on the sample hole 11 penetrates the inside of the center column 2 and is wound on the mounting rod 72.

[0089] The electrode testing system in the apparatus of this embodiment includes a reference electrode 8, an auxiliary electrode 9, and an electrochemical workstation 14. The reference electrode 8 and auxiliary electrode 9 are installed inside a reactor 13, while the electrochemical workstation 14 is located outside the reactor 13. During testing, the sample, reference electrode 8, and auxiliary electrode 9 are connected to the electrochemical workstation 14 via wires. In this embodiment, the auxiliary electrode 9 is a platinum electrode, and the reference electrode 8 is a saturated calomel reference electrode.

[0090] The device of this embodiment also includes a nitrogen pipeline, one end of which is connected to the nitrogen bottle 10 and the other end is located in the reactor 13; a booster pump 5 and a valve are provided on the nitrogen pipeline; and a pressure gauge 6 is also provided on the reactor 13.

[0091] The pipe material tested in this embodiment is P110 steel, which is placed in the sample hole 11 on the lower disc 3. The test position is the bottom of the simulated pipe. The specific test steps using the device of this embodiment are as follows:

[0092] (1) Sample Preparation: Cut the pipe material to be tested into cubes measuring 1 cm × 1 cm × 1 cm. Then, polish them using sandpaper #240, #400, #600, #800, #1000, and #1200, respectively. After polishing, weld one end of the wire to the surface. Then, encapsulate and cure the pipe material with epoxy resin to obtain a sample. In this example, three identical samples were prepared as parallel test specimens.

[0093] (2) Preparation before the test: Place the prepared sample in the three sample holes 11 on the lower disk 3. Insert the other end of the wire into the hollow structure of the center column 2 and wrap it around the mounting rod 72. Add a sodium chloride solution with a concentration of 0.1 mol / L to the reactor 13. After the sample carrier assembly is connected to the rotating device, place it into the reactor 13. The sodium chloride solution must be immersed in the sample.

[0094] (3) Experiment: The reactor 13 was sealed and nitrogen was introduced for deoxygenation for 3 hours. After deoxygenation, 10% of the total amount of the culture medium containing sulfate-reducing bacteria was poured into the sodium chloride solution and the rotation speed was set to 7 r / min. The experiment was then started. The temperature was maintained at about 35°C throughout the entire experimental process.

[0095] (4) Testing: After 14 days of immersion, the rotation is stopped, and the reference electrode 8, the auxiliary electrode 9 and the sample are connected to the electrochemical workstation 14 to perform a polarization curve test.

[0096] When the test begins, first stabilize at open circuit potential for 30 minutes to maintain the temperature, then at a potential range of -500 to 500 mV (relative to open circuit potential) at 0.33 mVs -1 The polarization curve test was carried out at a scan rate of 1.

[0097] The polarization curve obtained by the test of the embodiment is shown in Figure 3 Figure 3 It can be seen that the test result of the embodiment belongs to the corresponding range, and it can be seen that the reliability and accuracy of the obtained data are high.

[0098] (5) Observation: After 7 days and 14 days of immersion, 2 samples were taken out, the bacteria were fixed with 2.5% glutaraldehyde, and then dehydrated with 50%, 70%, 90%, and 100% ethanol in sequence, and then the corrosion products were observed by scanning electron microscope.

[0099] The morphology of the corrosion products obtained by the test of the embodiment on the 7th day and the 14th day is shown in Figure 4 and Figure 5 Figure 4 and Figure 5 It can be seen that the test result of the embodiment belongs to the corresponding range, and it can be seen that the reliability and accuracy of the obtained data are high.

[0100] It can be seen from the above embodiments that the device for simulating bacterial corrosion of oil and gas fields of the application can effectively simulate the liquid flow in the pipeline in actual use, and can also simulate different positions of the pipeline. Therefore, when the device is used for testing, the test result is more objective and effective. Moreover, the device of the application has the advantages of simple structure and easy installation, and can be directly installed in a conventional high-temperature and high-pressure reaction kettle.

[0101] Meanwhile, the test method for simulating bacterial corrosion of oil and gas fields of the application limits the composition of the corrosion solution, the rotation speed and the immersion time, so that the test environment is more similar to the actual use environment, so that the measured result is more accurate and has more reference value.

[0102] In the description of the application, it should be noted that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0103] ​​In addition, the terms "first", "second", etc. are used herein only to describe different instances, and do not imply or suggest relative importance or a number of the technical features indicated. Thus, the features defined with "first", "second", etc. can include at least one of the features explicitly or implicitly. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0104] In the present application, unless otherwise explicitly specified and limited, the "on" or "under" of a first feature to a second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the "over", "above" and "on" of the first feature to the second feature can be that the first feature is directly above or obliquely above the second feature, or only means that the first feature is horizontally higher than the second feature. The "under", "below" and "under" of the first feature to the second feature can be that the first feature is directly below or obliquely below the second feature, or only means that the first feature is horizontally lower than the second feature.

[0105] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, different embodiments or examples described in the present application and the features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0106] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0107] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An apparatus for simulating bacterial corrosion in oil and gas fields, comprising a reactor (13) and an electrode test system; characterized in that, Also include the sample carrier assembly and rotating drive assembly installed in the reactor (13); the sample carrier assembly includes a central column (2), one end of the central column (2) is connected with the upper disc (1), the other end is connected with the lower disc (3); The upper disc (1), the lower disc (3) and the central column (2) are respectively provided with at least one sample hole group, each sample hole group includes a plurality of sample holes (11) arranged at equal intervals; The rotating drive assembly is installed on the sample carrier assembly and can drive the sample carrier assembly to rotate with the axis of the central column (2) as the center line.

2. The apparatus of claim 1, wherein, The sample hole (11) located on the upper disc (1) opens towards the lower disc (3), the sample hole (11) located on the lower disc (3) opens towards the upper disc (1), and the positions of the sample holes (11) on the upper disc (1) and the lower disc (3) correspond one by one; the sample hole (11) opened on the central column (2) opens towards the direction radially outward of the central column (2).

3. The apparatus of claim 1, wherein the apparatus is configured to simulate bacterial corrosion in an oil and gas field. The central column (2) is hollow structure, both ends are open end; the central column (2) penetrates the center position of the upper disc (1) and the lower disc (3) respectively and is fixed; The rotating drive assembly includes a rotating rod (7), a rotating disc (71) and a mounting rod (72); one end of the rotating rod (7) is rotatably connected with one side center of the rotating disc (71), the other end is connected with a power device; one end of the mounting rod (72) is fixed on the other side center of the rotating disc (71), the other end of the mounting rod (72) penetrates the central column (2) and is fixed with the lower disc (3).

4. The apparatus of claim 3, wherein the apparatus is configured to simulate bacterial corrosion in an oil and gas field. The diameters of the upper disc (1) and the lower disc (3) are equal; the rotating drive assembly further includes at least two auxiliary mounting rods (73), and the at least two auxiliary mounting rods (73) are arranged in central symmetry about the center of the rotating disc (71); one end of each auxiliary mounting rod (73) is fixedly connected with the rotating disc (71), the other end is fixedly connected with the upper disc (1) and the lower disc (3).

5. The apparatus according to claims 1 to 4, characterized in that The electrode test system includes a reference electrode (8), an auxiliary electrode (9) and an electrochemical workstation (14); the reference electrode (8) and the auxiliary electrode (9) are installed in the reactor (13); the electrochemical workstation (14) is located outside the reactor (13), the reference electrode (8) and the auxiliary electrode (9) are respectively connected with the electrochemical workstation (14) through wires; the electrochemical workstation (14) can be connected with the sample through wires.

6. A method of testing for bacterial corrosion in an oil and gas field, characterized in that, The device of any one of claims 1-5 is used for testing, and the testing method comprises the following steps: Step 1, placing the sample in the sample hole (11), placing the sample carrier assembly in the reactor (13) containing the corrosion solution, and immersing the sample; Step 2, rotating the sample carrier assembly by the rotating drive assembly; Step 3: After the rotation is completed, the electrode testing system is used to test the current, potential distribution and electrochemical information of the sample, and the changes in bacterial corrosion products are observed to obtain the results of the corrosion condition of the sample.

7. The method of claim 6, wherein the method is used to simulate bacterial corrosion in an oil and gas field. The corrosion solution includes a sodium chloride solution and a culture medium containing bacteria; the mass percentage of sodium chloride in the sodium chloride solution is 1%, 3.5%, 5% or 10%, the bacteria are one or more of sulfate-reducing bacteria, iron bacteria, and saprophytic bacteria, and the volume percentage of bacteria in the culture medium containing bacteria is 1%, 5% or 10% of the volume of the corrosion solution.

8. The method of claim 6, wherein the method is used to simulate bacterial corrosion in an oil and gas field. After the completion of step 1, the reactor (13) is sealed, and nitrogen is introduced into the reactor (13) until the oxygen in the reactor (13) is completely discharged, and then step 2 is performed.

9. The method of claim 6, wherein the method is used to simulate bacterial corrosion in an oil and gas field. The test environment temperature of the test method is 35°C.

10. The method of claim 6, wherein the method is used to simulate bacterial corrosion in an oil and gas field. The electrode testing system includes a reference electrode (8), an auxiliary electrode (9) and an electrochemical workstation (14); in step 3, after the rotation is completed, the sample, the reference electrode 8 and the auxiliary electrode (9) are respectively connected to the electrochemical workstation (14) located outside the reactor (13) through wires, the polarization curve of the sample is tested by the electrochemical workstation (14), and the surface corrosion product morphology of the sample is observed.

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