A system and method for controlling internal corrosion in a gathering pipeline

Abstract

A gathering pipeline internal corrosion control system and a control method. The gathering pipeline internal corrosion control system comprises: a pipeline network main body, including a gathering trunk line and a station internal collecting pipe with an anticorrosion insulation layer on the inner surface, the output end of the gathering trunk line is in electrical communication with the station internal collecting pipe, the station internal collecting pipe is provided with an electrical connection area, the pipeline network main body is electrically connected with the medium transported in the station internal collecting pipe through the electrical connection area; an auxiliary anode is arranged inside the gathering trunk line; a reference electrode is arranged inside the station internal collecting pipe; a connecting piece is arranged at the end of the pipeline network main body and is arranged to electrically isolate the pipeline network main body and the butt joint pipeline; and a constant potential instrument has an anode connection part, a cathode connection part, a zero connection part and a reference connection part, the anode connection part is electrically connected with the auxiliary anode, the cathode connection part and the zero connection part are both electrically connected with the pipeline network main body, and the reference connection part is electrically connected with the reference electrode. The gathering pipeline internal corrosion control system can solve the problem of accelerated corrosion perforation of the pipeline network main body caused by the failure of the internal coating / inner plating layer.

Description

Technical Field

[0001] This article relates to the field of petroleum equipment technology, and more specifically, to a corrosion control system and method for gathering and transportation pipelines. Background Technology

[0002] With the continuous increase in domestic oil exploration and development efforts, and the application of enhanced oil recovery technologies such as water flooding, carbon dioxide flooding, fire flooding, steam flooding, and polymer flooding, oil well produced materials are becoming more complex, and the internal corrosion environment faced by surface gathering and transportation pipelines is becoming more severe. The problem of internal corrosion failure in gathering and transportation pipelines is becoming increasingly prominent, and internal corrosion has become one of the main factors threatening the integrity of oilfield pipelines.

[0003] In cases of corrosion failure in oilfield gathering and transportation pipelines, corrosion is most severe in water-mixed pipelines and oil gathering pipelines (including production and collection pipelines), accounting for over 70%, followed by injection pipelines (including water injection and polymer injection). These pipeline failures share a common characteristic: high water content and small diameter (below DN200). When the water content exceeds 60%, free water appears inside the pipeline, forming an emulsion of "oil-in-water + free water" or "oil-in-water + water-in-oil". As the water content continues to rise, the free water accumulates. Statistics show that the overall water content in most oilfields exceeds 70%. Therefore, free water is present in all oil gathering pipelines that have experienced internal corrosion failure. Due to the limitations of pipeline geometry, cleaning and internal inspection are often difficult in these pipelines, especially in high water content and high calcium content environments. 2+ / Mg 2+ The combined effects of plasma, bacteria, acidic gases such as H2S-CO2, and scale can induce internal corrosion. Under the influence of temperature, pressure, and Cl... - Under the influence of factors such as plasma, galvanic couples, and occluded cells, internal corrosion develops rapidly until it leads to perforation failure.

[0004] To address the internal corrosion problems caused by small-diameter pipelines and high water content, an increasing number of oilfield gathering and transportation pipelines are adopting protective measures such as applying anti-corrosion and insulating layers (e.g., internal coatings / platings). Internal coatings / platings are a highly effective and relatively economical measure for solving internal corrosion problems in gathering and transportation systems. Statistics show that over 40% of small-diameter gathering and transportation pipelines in domestic oilfields have undergone internal coatings / plating, and the application scale is expanding. Applying internal coatings / platings to small-diameter pipelines will become one of the main measures for controlling internal corrosion in gathering and transportation pipelines in the near future. " / " means "or".

[0005] Due to factors such as on-site construction, production operation, aging of the internal coating / plating layer, and the highly corrosive nature of the transported medium, damage and peeling of the internal coating / plating layer are inevitable. Once damaged, the internal coating / plating layer will form a localized "small anode, large cathode," accelerating internal corrosion and perforation of the pipeline exponentially. There are already cases of internal corrosion and perforation in some oilfield gathering and transportation pipelines with internal coatings / plating layers. As the service life of internally coated / plated pipelines increases, the problem of internal corrosion caused by localized failure of the internal coating / plating layer becomes increasingly prominent. Detection and localized repair of the internal coating / plating layer in in-service pipelines are extremely difficult, and there is currently no mature repair method. Reapplying the internal coating / plating layer is very costly, which oilfields cannot afford. Therefore, an economical and effective measure is urgently needed to control the corrosion and perforation problem of the main pipeline structure at locations where the internal coating / plating layer has failed. Summary of the Invention

[0006] This invention provides an internal corrosion control system for gathering and transportation pipelines, which can solve the problem of accelerated corrosion and perforation of the pipeline body caused by the failure of the internal coating / plating layer.

[0007] This invention also provides a control method for a corrosion control system within a gathering and transportation pipeline.

[0008] The corrosion control system within the anti-corrosion control system of the gathering and transportation pipeline provided in this embodiment of the invention includes: a pipeline body, the pipeline body including a gathering and transportation trunk line with an anti-corrosion and insulating layer on its inner surface and a station manifold with an anti-corrosion and insulating layer on its inner surface, the output end of the gathering and transportation trunk line being connected to the station manifold, the station manifold having an electrical connection area, and the pipeline body being electrically connected to the medium transported inside the station manifold through the electrical connection area; an auxiliary anode, the auxiliary anode being disposed inside the gathering and transportation trunk line and configured to dissipate cathodic protection current to the medium inside the gathering and transportation trunk line; and a reference electrode, the reference electrode being disposed inside the station manifold and configured to acquire the electrical connection area. The system includes: cathode potential information; a connector, correspondingly located at the end of the main body of the pipeline network and configured to electrically isolate the main body of the pipeline network from the connecting pipeline connected to the main body of the pipeline network; and a potentiostat, which has an anode connection part, a cathode connection part, a zero-position connection part, and a reference connection part. The anode connection part is electrically connected to the auxiliary anode, the cathode connection part and the zero-position connection part are both electrically connected to the main body of the pipeline network, and the reference connection part is electrically connected to the reference electrode. The potentiostat is set to preset control potential information and adjusts the output current of the anode connection part according to the cathode potential information to make the cathode potential information consistent with the control potential information.

[0009] In some exemplary embodiments, the corrosion control system inside the gathering and transportation pipeline further includes: a first mounting component disposed on and connected to the gathering and transportation trunk line, an auxiliary anode disposed inside the first mounting component, and an anti-corrosion insulating layer provided on the inner surface of the first mounting component.

[0010] In some exemplary embodiments, the corrosion control system within the gathering and transportation pipeline further includes: a second mounting component disposed in and connected to the manifold within the station, the electrical connection area being located in the second mounting component, and the reference electrode being disposed in the electrical connection area.

[0011] In some exemplary embodiments, both the first mounting component and the second mounting component are tee joints.

[0012] In some exemplary embodiments, the corrosion control system within the gathering and transmission pipeline further includes: a first switching valve located on the gathering and transmission trunk line and on the side of the auxiliary anode away from the station manifold.

[0013] In some exemplary embodiments, the corrosion control system within the gathering and transportation pipeline further includes a second switching valve, disposed in the station manifold and located between the gathering and transportation trunk line and the reference electrode.

[0014] In some exemplary embodiments, the main body of the pipeline network further includes: a gathering and transmission branch line located on the side of the auxiliary anode away from the station manifold and electrically connected to the gathering and transmission trunk line.

[0015] In some exemplary embodiments, the connectors are respectively provided at the ends of the gathering and transmission branch line, the gathering and transmission trunk line and the station manifold, and the inner surface of the connectors is provided with an anti-corrosion and insulating layer.

[0016] In some exemplary embodiments, the manifold in the station is provided with a first welding position and a second welding position. The cathode wiring part and the zero position wiring part are respectively welded to the first welding position and the second welding position one by one through the first cable, and a repair piece is provided at the welding point.

[0017] In some exemplary embodiments, the reference electrode is made of silver or silver chloride, and the distance between the auxiliary anode and the reference electrode is not less than 100 meters.

[0018] The control method of the corrosion control system in the gathering and transportation pipeline proposed in this embodiment of the invention includes: the cathodic protection current emitted from the anode terminal of the potentiostat is dispersed to the medium inside the pipeline body through the auxiliary anode, and dispersed along the axial direction of the pipeline body, flowing into the pipeline body from the failure location of the anti-corrosion insulation layer and the electrical connection area, and then flowing back to the cathode terminal of the potentiostat along the pipeline body to form a closed loop.

[0019] In some exemplary embodiments, after the step of forming a closed loop by flowing back along the main body of the pipeline to the cathode terminal of the potentiostat, the control method further includes:

[0020] Obtain the cathode potential information of the electrical connection region;

[0021] The cathode potential information is compared with the preset control potential information of the potentiostat, and the output current of the anode terminal is adjusted according to the comparison result to make the cathode potential information consistent with the control potential information.

[0022] In some exemplary embodiments, the step of comparing the cathode potential information with the preset control potential information of the potentiostat and adjusting the output current of the anode terminal based on the comparison result includes:

[0023] Based on the fact that the cathode potential information is less than the control potential information, the output current of the anode terminal is reduced;

[0024] Based on the fact that the cathode potential information is greater than the control potential information, the output current of the anode terminal is increased.

[0025] The corrosion control system for gathering and transporting pipelines provided in this embodiment of the invention ensures smooth medium transport in the pipeline network. After the auxiliary anode and reference electrode have made full contact with the transported medium, the potentiostat is activated and adjusted to constant potential operation mode. At this time, the cathodic protection current flows from the anode connection point to the auxiliary anode and then into the medium through the auxiliary anode. Due to the high water content and presence of both anions and cations in the medium, it is a good ionic conductor. The cathodic protection current diffuses through the medium to the surface of the anti-corrosion insulation layer inside the pipeline network that needs protection, and flows into the pipeline network from the damaged location of the anti-corrosion insulation layer and the electrical connection area, providing cathodic protection to the pipeline network and preventing internal corrosion perforation at the damaged location of the anti-corrosion insulation layer. The cathodic protection current, after flowing into the pipeline network, returns to the cathodic connection point along the damaged location of the anti-corrosion insulation layer and the electrical connection area, forming a closed loop. At the same time, the potentiostat monitors the cathode potential information of the reference electrode in the manifold in real time through the reference electrode, and compares it with the control potential information preset by the potentiostat. Based on the comparison result, it automatically adjusts the output current of the anode connection to ensure that the two are consistent, thereby achieving the purpose of effectively controlling the corrosion inside the pipeline. This solution can effectively solve the problem of accelerated corrosion and perforation of the pipeline caused by the failure of the internal anti-corrosion insulation layer.

[0026] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description and the drawings. Attached Figure Description

[0027] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0028] Figure 1 This is a schematic diagram of the corrosion control system in a gathering and transportation pipeline according to an embodiment of the present invention;

[0029] Figure 2 for Figure 1 A schematic diagram of the structure after the first mounting component and the auxiliary anode phase are assembled.

[0030] Figure 3 for Figure 1 A schematic diagram of the structure after the second mounting component and the reference electrode are assembled.

[0031] in, Figures 1 to 3 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0032] 10 First cable, 20 Second cable, 110 Main transmission line, 120 Substation manifold, 130 Branch transmission line, 200 Anti-corrosion insulation layer, 300 Auxiliary anode, 400 Reference electrode, 500 Potentiostat, 510 Anode connection part, 520 Cathode connection part, 530 Zero position connection part, 540 Reference connection part, 610 First mounting component, 620 Second mounting component, 710 First switch valve, 720 Second switch valve, 800 Connector, 900 Repair patch. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

[0034] The corrosion control system for gathering and transportation pipelines provided in this embodiment of the invention, such as Figure 1As shown, it includes: a pipeline main body, comprising a main transmission line 110 with an inner surface having an anti-corrosion insulation layer 200 and a station manifold 120 with an inner surface having an anti-corrosion insulation layer 200; the output end of the main transmission line 110 is connected to the station manifold 120; the station manifold 120 has an electrical connection area, and the pipeline main body is electrically connected to the medium transported inside the station manifold 120 through the electrical connection area; an auxiliary anode 300, which is located inside the main transmission line 110 and configured to dissipate cathodic protection current to the medium inside the main transmission line 110; and a reference electrode 400, which is located inside the station manifold 120 and configured to acquire the cathodic potential information of the electrical connection area; and a connection... Component 800 is located at the end of the main body of the pipeline network and is configured to electrically isolate the main body of the pipeline network from the connecting pipeline connected to the main body of the pipeline network; and potentiostat 500, which has an anode connection part 510, a cathode connection part 520, a zero-position connection part 530 and a reference connection part 540. The anode connection part 510 is electrically connected to the auxiliary anode 300, the cathode connection part 520 and the zero-position connection part 530 are both electrically connected to the main body of the pipeline network, and the reference connection part 540 is electrically connected to the reference electrode 400. The potentiostat 500 is set to preset control potential information and adjusts the output current of the anode connection part 510 according to the cathode potential information to make the cathode potential information consistent with the control potential information.

[0035] In this corrosion control system for the gathering and transportation pipeline, after the auxiliary anode 300 and reference electrode 400 have made full contact with the transported medium, the potentiostat 500 is activated and adjusted to constant potential operation mode. At this time, the cathodic protection current flows from the anode connection point 510 to the auxiliary anode 300 and then into the medium inside the gathering and transportation pipeline. Because the medium has a high water content and contains both anions and cations, it is a good ionic conductor. The cathodic protection current diffuses through the medium to the surface of the anti-corrosion insulation layer 200 inside the pipeline body that needs protection, and flows back into the pipeline body from the damaged location and electrical connection area of ​​the anti-corrosion insulation layer 200, providing cathodic protection to the pipeline body and preventing internal corrosion perforation at the damaged location of the anti-corrosion insulation layer 200. The cathodic protection current, after flowing into the pipeline body, returns to the cathodic connection point 520 along the damaged location and electrical connection area of ​​the anti-corrosion insulation layer 200, forming a closed loop. Meanwhile, the potentiostat 500 monitors the cathode potential information of the reference electrode 400 in the manifold 120 in real time through the reference electrode 400, and compares it with the control potential information preset by the potentiostat 500. Based on the comparison result, the output current of the anode connection part 510 is automatically adjusted to ensure that the two (cathode potential information and control potential information) are consistent, thereby achieving the purpose of effectively controlling the corrosion inside the pipeline. This solution can effectively solve the problem of accelerated corrosion and perforation of the pipeline caused by the failure of the inner anti-corrosion insulation layer 200.

[0036] The anti-corrosion insulation layer 200 is set as an internal coating / internal plating layer.

[0037] In some examples, such as Figure 1 and Figure 2 As shown, the corrosion control system within the gathering and transmission pipeline further includes: a first mounting component 610, which is located on and connected to the gathering and transmission trunk line 110; an auxiliary anode 300 is located inside the first mounting component 610; and the inner surface of the first mounting component 610 is provided with an anti-corrosion insulating layer 200 to ensure that the cathodic protection current can be smoothly dissipated through the auxiliary anode 300, avoiding excessive consumption of the cathodic protection current by the first mounting component 610. Preferably, the first mounting component 610 is installed on the gathering and transmission trunk line 110 near the station manifold 120, the auxiliary anode 300 is screwed onto the first mounting component 610, and a sealing ring is provided between the auxiliary anode 300 and the first mounting component 610 for sealing.

[0038] In some examples, such as Figure 1 and Figure 3 As shown, the corrosion control system for the gathering and transportation pipeline also includes a second mounting component 620, which is located in and connected to the station manifold 120. Preferably, the second mounting component 620 is located in the station manifold 120 away from the gathering and transportation trunk line 110. This improves the dispersion characteristics of the cathodic protection current within the confined space of the station manifold 120, thereby enhancing the internal corrosion control effect. The reference electrode 400 is located on the second mounting component 620, with the electrical connection area being the inner surface of the second mounting component 620. It is electrically connected to the station manifold 120 through the second mounting component 620. The inner surface of the second mounting component 620 does not have an anti-corrosion insulation layer 200, which increases the output of the potentiostat 500, maximizes the cathodic protection range, and avoids the false impression of overprotection, thus preventing a decrease in the output of the potentiostat 500. Furthermore, the reference electrode 400 is screwed onto the second mounting member 620, and a sealing ring is provided between the reference electrode 400 and the second mounting member 620 for sealing.

[0039] In some embodiments, both the first mounting member 610 and the second mounting member 620 are tees.

[0040] In some examples, such as Figure 1 As shown, the corrosion control system within the gathering and transportation pipeline also includes a first switching valve 710. The first switching valve 710 is located on the gathering and transportation trunk line 110, on the side of the auxiliary anode 300 away from the manifold 120 within the gathering station, and is used to temporarily cut off the medium transported by the gathering and transportation trunk line 110. Before installing the first mounting component 610 and the second mounting component 620, the first switching valve 710 should be closed, and the medium downstream of the first switching valve 710 should be slowly drained.

[0041] In some examples, such as Figure 1As shown, the corrosion control system in the gathering and transportation pipeline also includes a second switching valve 720, which is located in the station manifold 120 and between the gathering and transportation trunk line 110 and the reference electrode 400, and is used to temporarily cut off the transported medium.

[0042] In some examples, such as Figure 1 As shown, the main body of the pipeline network also includes: a gathering and transmission branch line 130, which is located on the side of the first switch valve 710 away from the station manifold 120 and is connected to and electrically connected to the gathering and transmission main line 110. There may be one or more gathering and transmission branch lines 130.

[0043] In some examples, such as Figure 1 As shown, the connectors 800 are respectively installed at the ends of the gathering and transmission branch line 130, the gathering and transmission trunk line 110 and the station manifold 120. The inner surface of the connector 800 is provided with an anti-corrosion insulation layer 200. The anti-corrosion insulation layer 200 on the inner surface of the connector 800 electrically isolates the main body of the pipeline to be protected from other metal structures, avoids the loss of cathodic protection current, and also avoids the inner surface of the connector 800 from being corroded and perforated by stray current interference.

[0044] In some examples, such as Figure 1 As shown, the manifold 120 within the station has a first welding position and a second welding position. The cathode connection part 520 and the zero-position connection part 530 are respectively welded to the first welding position and the second welding position one-to-one via the first cable 10, and a repair piece 900 is provided at the welding point. The anode connection part 510 is electrically connected to the auxiliary anode 300 via another first cable 10. The cross-sectional area of ​​the first cable 10 is not less than 10mm. 2 The reference connector 540 is electrically connected to the reference electrode 400 via a second cable 20, the cross-section of which is not less than 4 mm. 2 .

[0045] In some embodiments, the reference electrode 400 is made of silver or silver chloride, the main body of the pipeline is made of steel pipe, the connector 800 is made of flange or joint, the first switch valve 710 and the second switch valve 720 are both made of ball stop valve, and the auxiliary anode 300 is made of rod-shaped mixed metal oxide anode.

[0046] In some embodiments, the distance between the auxiliary anode 300 and the reference electrode 400 is not less than 100 meters, which can increase the output of the potentiostat 500 and maximize the cathodic protection range.

[0047] To ensure effective internal corrosion control and safe system operation, the moisture content of the medium transported in the protected gathering and transportation pipelines should exceed 60%.

[0048] This internal corrosion control system for gathering and transportation pipelines is applicable to both high-water-cut oilfield gathering and transportation steel pipelines (equivalent to the main pipeline network in this application) that have already been coated with an anti-corrosion insulation layer 200 and those that have not been coated with the anti-corrosion insulation layer 200. It is particularly suitable for controlling internal corrosion in high-water-cut oilfield gathering and transportation steel pipelines where the anti-corrosion insulation layer 200 is gradually fading or peeling off. To ensure the effectiveness of internal corrosion control, before using the internal corrosion control system on high-water-cut oilfield gathering and transportation steel pipelines that have not been coated / plated with an internal coating, the anti-corrosion insulation layer 200 should be applied to the gathering and transportation network to be protected.

[0049] An existing gathering and transportation pipeline includes one in-station manifold 120 with a diameter of DN219mm, one gathering and transportation main line 110 with a diameter of DN159mm, and two gathering and transportation branch lines 130, each with a diameter of DN114mm. A first on / off valve 710 is installed near the downstream end of the in-station manifold 120, and a second on / off valve 720 is installed near the downstream end of the gathering and transportation main line 110 for process control. The main operating pressure of the pipeline network is 1.5 MPa, and the operating temperature is 25℃. The transported medium has a high water content, exceeding 70%, and the water contains Cl... - The SRB bacteria content is high, exceeding 100 g / L, and the SRB bacteria content is also high, exceeding 20,000 CFU / mL. The medium is highly corrosive, leading to severe internal corrosion. To control the risk of internal corrosion, a 200mm anti-corrosion insulating layer was applied to the inner wall of the pipeline five years ago using an extrusion coating method. With the extension of service life, phenomena such as peeling and flaking of the inner coating have gradually appeared, and the risk of localized internal corrosion has increased dramatically. Based on this, improvements were made to the gathering and transportation pipeline to form an internal corrosion control system:

[0050] Step 1: Purchase from the market one DN159mm and one DN219mm tee (first mounting part 610 and second mounting part 620), two DN114 insulating connectors (connector 800), one DN159 insulating connector (connector 800), two DN219 insulating connectors (connector 800), one 50V / 50A potentiostat (500 units), and one DN80mm diameter rod-shaped mixed metal oxide anode (auxiliary anode 300) with a cross-sectional area of ​​16mm². 2 and a cross-sectional area of ​​10mm 2 Several cables (first cable 10 and second cable 20), several repair pieces 900, and several DN80mm sealing rings.

[0051] Step 2: Customize one rod-shaped silver / silver chloride reference electrode 400 (reference electrode 400), with a diameter of DN80mm and a length of 100mm. The outer surface of the end has a G21 / 4A external thread with a thread length of 20mm. Machining a G21 / 4A external thread with a thread length of 20mm is done on the end of the rod-shaped mixed metal oxide anode. Machining a DN80mm internal thread through hole with a G21 / 4 internal thread type at the middle position of the ends of the DN159mm and DN219mm tees, and tapping through it.

[0052] Step 3: Apply an inner coating (forming an anti-corrosion insulation layer 200) to the inner surface of the DN114, DN159, and DN219 insulating joints respectively, let them dry, and set them aside; apply an inner coating to the inner surface of the DN159mm tee, let it dry, and mark it as the first mounting part 610, and set it aside; do not apply an inner coating to the inner surface of the DN219mm tee, and mark it as the second mounting part 620.

[0053] Step 4: Temporarily stop the operation of the gathering and transmission pipeline. The first switch valve 710 and the second switch valve 720 are in the open state. The gathering and transmission pipeline is gradually depressurized and vented. Insulating joints with inner coating are installed at the ports of the gathering and transmission branch line 130, the gathering and transmission main line 110, and the station manifold 120, respectively.

[0054] Step 5: Close the first switch valve 710 and the second switch valve 720 respectively to gradually drain the medium transported in the station manifold 120. Install the first mounting component 610 on the gathering and transmission trunk line 110 and the second mounting component 620 on the station manifold 120.

[0055] Step 6: Connect the processed rod-shaped mixed metal oxide anode and rod-shaped silver / silver chloride reference electrode 400 to the first mounting part 610 and the second mounting part 620 respectively by threaded connection, and seal them with sealing rings.

[0056] Step 7: After installing the potentiostat 500, connect the rod-shaped mixed metal oxide anode and the rod-shaped silver / silver chloride reference electrode 400 to the anode wiring section 510 and the reference wiring section 540 of the potentiostat 500 via the first cable 10 and the second cable 20, respectively. The rod-shaped mixed metal oxide anode and the anode wiring section 510 have a cross-sectional area of ​​16 mm². 2 The first cable 10 is connected, and the cathode terminal 520 and the first welding position, as well as the zero terminal 530 and the second welding position, all use a cross-sectional area of ​​16mm². 2 The first cable 10 is connected, and the rod-shaped silver / silver chloride reference electrode 400 and the reference connector 540 adopt a cross-sectional area of ​​10 mm². 2 Connect the second cable 20.

[0057] Step 8: The manifold 120 within the station is equipped with a first welding position and a second welding position. The cathode wiring section 520 and the first welding position, as well as the zero-position wiring section 530 and the second welding position, all use a cross-sectional area of ​​16mm². 2 The first cable 10 is soldered together. Note that the interval between the first and second solder joints should be no less than 20cm. After soldering, the solder joints are repaired with a repair patch 900.

[0058] Step 9: Check the connection circuit. After confirming that the installation is correct, open the first switch valve 710 and the second switch valve 720 to allow the transport medium in the gathering and transportation pipeline to flow smoothly, ensuring that the rod-shaped mixed metal oxide anode and the reference electrode 400 are in full contact with the transported medium.

[0059] Step 10: Start the potentiostat 500, adjust it to constant potential operation mode, and set the control potential to -1200mV (i.e., the control potential information is -1200mV).

[0060] The cathodic protection current flows from the anode connection point 510 to the rod-shaped mixed metal oxide anode, and then into the medium through the rod-shaped mixed metal oxide anode. Because the medium has a high water content and contains both anions and cations, it is a good ionic conductor. The cathodic protection current diffuses through the medium to the surface of the anti-corrosion insulation layer 200 within the main body of the pipeline to be protected, and flows into the main body of the pipeline from the damaged location of the anti-corrosion insulation layer 200 and the second mounting component 620, providing cathodic protection to the main body of the pipeline and preventing internal corrosion perforation at the damaged location of the anti-corrosion insulation layer 200. After flowing into the main body of the pipeline, the cathodic protection current returns to the cathode connection point 520 along the damaged location of the anti-corrosion insulation layer 200 and the second mounting component 620, forming a closed loop. Meanwhile, the potentiostat 500 monitors the cathode potential information of the reference electrode 400 in the manifold 120 in real time through the reference electrode 400, and compares it with the control potential information preset by the potentiostat 500. Based on the comparison result, the output current of the anode connection part 510 is automatically adjusted to ensure that the two are consistent, thereby achieving the purpose of effectively controlling the corrosion inside the pipeline. This solution can effectively solve the problem of accelerated corrosion and perforation of the pipeline caused by the failure of the inner anti-corrosion insulation layer 200.

[0061] The control method (not shown in the figure) for the corrosion control system in the gathering and transportation pipeline proposed in this embodiment of the invention includes:

[0062] The cathodic protection current emitted from the anode connection section 510 of the potentiostat 500 is dispersed to the medium inside the pipeline body through the auxiliary anode 300, and then dispersed along the axial direction of the pipeline body. It flows into the pipeline body from the failure location of the anti-corrosion insulation layer 200 and the electrical connection area, and then flows back to the cathode connection section 520 of the potentiostat 500 along the pipeline body, forming a closed loop.

[0063] The cathodic protection current flows from the anode connection point 510 to the auxiliary anode 300, and then flows into the medium within the gathering and transportation pipeline through the auxiliary anode 300. Because the medium has a high water content and contains both anions and cations, it is a good ionic conductor. The cathodic protection current diffuses through the medium to the surface of the anti-corrosion insulation layer 200 within the main body of the pipeline to be protected, and flows back into the main body of the pipeline from the damaged location and electrical connection area of ​​the anti-corrosion insulation layer 200, providing cathodic protection to the main body of the pipeline and preventing internal corrosion perforation at the damaged location of the anti-corrosion insulation layer 200. The cathodic protection current, after flowing into the main body of the pipeline, returns to the cathodic connection point 520 along the damaged location and electrical connection area of ​​the anti-corrosion insulation layer 200, forming a closed loop.

[0064] After the step of forming a closed loop by flowing back along the main body of the pipeline to the cathode terminal 520 of the potentiostat 500, the control method further includes:

[0065] The cathode potential information of the electrical connection region is obtained through the reference electrode 400;

[0066] The potentiostat 500 compares the cathode potential information with the preset control potential information of the potentiostat 500, and adjusts the output current of the anode terminal 510 according to the comparison result to adjust the cathode potential information to be consistent with the control potential information.

[0067] The reference electrode 400 acquires the cathode potential information of the electrical connection area. The potentiostat 500 compares the cathode potential information with the preset control potential information of the potentiostat 500. Based on the comparison result, the output current of the anode connection part 510 is automatically adjusted to ensure that the two (cathode potential information and control potential information) are consistent, thereby achieving the purpose of more effectively controlling the corrosion inside the pipeline body. This solution can better solve the problem of accelerated corrosion and perforation of the pipeline body caused by the failure of the inner anti-corrosion insulation layer 200.

[0068] In some embodiments, the step of comparing the cathode potential information with the preset control potential information of the potentiostat 500 and adjusting the output current of the anode terminal 510 according to the comparison result includes:

[0069] Based on the fact that the cathode potential information is less than the control potential information, the output current of the anode connection section 510 is reduced;

[0070] Based on the fact that the cathode potential information is greater than the control potential information, the output current of the anode connection section 510 is increased.

[0071] In some embodiments, before the cathodic protection current emitted from the anode connection section 510 of the potentiostat 500 is dissipated to the medium inside the pipeline body through the auxiliary anode 300, the control method further includes: controlling the pipeline body to transport the medium, and after the auxiliary anode 300 and the reference electrode 400 are in contact with the transported medium, starting the potentiostat 500, keeping the potentiostat 500 adjusted to the constant potential operation mode, ensuring that the auxiliary anode 300 smoothly dissipates the cathodic protection current to the medium inside the collection and transmission trunk line 110, and ensuring that the reference electrode 400 smoothly obtains the cathodic potential information of the electrical connection area.

[0072] In the description of this invention, it should be noted that the terms "upper", "lower", "one side", "the other side", "one end", "the other end", "side", "opposite", "four corners", "periphery", "mouth structure", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the structure referred to has a specific orientation, or is constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0073] In the description of the embodiments of the present invention, unless otherwise expressly specified and limited, the terms "connection," "direct connection," "indirect connection," "fixed connection," "installation," and "assembly" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. The terms "installation," "connection," and "fixed connection" can refer to a direct connection or an indirect connection through an intermediate medium, or they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0074] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes to the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be defined by the appended claims.

Claims

1. A corrosion control system for gathering and transportation pipelines, characterized in that, include: The pipeline network body includes a collection and transmission trunk line with an anti-corrosion and insulation layer on its inner surface and an in-station manifold with an anti-corrosion and insulation layer on its inner surface. The output end of the collection and transmission trunk line is connected to the in-station manifold. The in-station manifold is provided with an electrical connection area. The pipeline network body is electrically connected to the medium transported inside the in-station manifold through the electrical connection area. An auxiliary anode is disposed inside the collection and transmission trunk line and configured to dissipate cathodic protection current into the medium inside the collection and transmission trunk line. A reference electrode is disposed in the electrical connection region and configured to acquire cathode potential information of the electrical connection region; A connector is provided at the end of the main body of the pipeline network and is configured to electrically isolate the main body of the pipeline network from the connecting pipeline that is connected to the main body of the pipeline network. and A potentiostat has an anode connection section, a cathode connection section, a zero-position connection section, and a reference connection section. The anode connection section is electrically connected to the auxiliary anode. The cathode connection section and the zero-position connection section are both electrically connected to the main body of the pipeline network. The reference connection section is electrically connected to the reference electrode. The potentiostat is set to preset control potential information and adjusts the output current of the anode connection section according to the cathode potential information to make the cathode potential information consistent with the control potential information. The gathering and transportation pipeline is an oilfield gathering and transportation steel pipeline. The water content of the medium transported by the main body of the pipeline network exceeds 60%. The reference electrode is made of silver or silver chloride. The distance between the auxiliary anode and the reference electrode is not less than 100 meters.

2. The corrosion control system for gathering and transportation pipelines according to claim 1, characterized in that, Also includes: The first mounting component is disposed on and connected to the main collection and transmission line. The auxiliary anode is disposed inside the first mounting component, and the inner surface of the first mounting component is provided with an anti-corrosion and insulating layer.

3. The corrosion control system for gathering and transportation pipelines according to claim 2, characterized in that, Also includes: The second mounting component is located in the manifold within the station and is connected to the manifold within the station. The electrical connection area is located in the second mounting component.

4. The corrosion control system for gathering and transportation pipelines according to claim 3, characterized in that, Both the first mounting component and the second mounting component are tees.

5. The corrosion control system for gathering and transportation pipelines according to any one of claims 1 to 4, characterized in that, Also includes: The first switching valve is located on the main collection and transmission line, and on the side of the auxiliary anode away from the manifold within the station.

6. The corrosion control system for gathering and transportation pipelines according to any one of claims 1 to 4, characterized in that, Also includes: The second switching valve is located in the manifold within the station and between the collection and transmission trunk line and the reference electrode.

7. The corrosion control system for gathering and transportation pipelines according to any one of claims 1 to 4, characterized in that, The main body of the pipeline network also includes: The gathering and transmission branch line is located on the side of the auxiliary anode away from the station manifold and is electrically connected to the gathering and transmission main line.

8. The corrosion control system for gathering and transportation pipelines according to claim 7, characterized in that, The connectors are respectively provided at the ends of the collection and transmission branch line, the collection and transmission trunk line and the station manifold, and the inner surface of the connectors is provided with an anti-corrosion and insulating layer.

9. The corrosion control system for gathering and transportation pipelines according to any one of claims 1 to 4, characterized in that, The station manifold is provided with a first welding position and a second welding position. The cathode wiring part and the zero position wiring part are respectively welded to the first welding position and the second welding position through the first cable, and a repair piece is provided at the welding point.

10. A control method for a corrosion control system applied to a gathering and transportation pipeline as described in any one of claims 1 to 9, characterized in that, include: The cathodic protection current emitted from the anode terminal of the potentiostat is dispersed through the auxiliary anode to the medium inside the pipeline body and dispersed along the axial direction of the pipeline body. It flows into the pipeline body from the failure location of the anti-corrosion insulation layer and the electrical connection area, and then flows back to the cathode terminal of the potentiostat along the pipeline body to form a closed loop.

11. The control method according to claim 10, characterized in that, After the step of forming a closed loop by flowing back along the main body of the pipeline to the cathode terminal of the potentiostat, the control method further includes: Obtain the cathode potential information of the electrical connection region; The cathode potential information is compared with the preset control potential information of the potentiostat, and the output current of the anode terminal is adjusted according to the comparison result to make the cathode potential information consistent with the control potential information.

12. The control method according to claim 11, characterized in that, The step of comparing the cathode potential information with the preset control potential information of the potentiostat, and adjusting the output current of the anode terminal based on the comparison result, includes: Based on the fact that the cathode potential information is less than the control potential information, the output current of the anode terminal is reduced; Based on the fact that the cathode potential information is greater than the control potential information, the output current of the anode terminal is increased.

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