Oil gas leakage treatment method for oil tank operation well of gas station

Abstract

The invention relates to a gas station oil tank operation well oil gas leakage treatment method which comprises the following steps that leakage reasons are analyzed, leakage treatment schemes are selected according to analysis results, and the leakage treatment schemes can be selected independently or in multiple modes; contractor selection is carried out according to the leakage treatment scheme, and construction preparation is carried out; field operation is carried out according to the leakage treatment scheme, electrical connection and equipment debugging are carried out after operation is completed, and whether oil gas leakage exists or not is checked; the construction unit organizes the gas station and the contractor to check and accept the operation well process, electrical and grounding connection conditions and equipment debugging conditions together; the follow-up gas station continuously observes and inspects the process pipeline in the operation well; the problems of oil gas leakage and large oil gas concentration caused by poor connection sealing performance of a process system in the oil tank operation well of the gas station are solved, and meanwhile, the operation and environmental protection risks of the gas station are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas leakage, and in particular relates to an oil and gas leakage control method for an oil tank operating well of a gas station. Background Art

[0002] At present, oil and gas leakage problems occur frequently in oil tank operating wells. The locations and causes of oil and gas leakage are different. When preventing and controlling oil and gas leakage problems, it is necessary to select different flange sealing gaskets and bolts based on the characteristics and applicability of different gaskets, combined with the different connection characteristics of the oil tank ports and process pipelines in the oil tank operating wells of gas stations to meet the sealing requirements of the flanges. At the same time, the process pipeline connection construction procedures and methods are used to achieve tight sealing of the process pipeline connections in the oil tank operating wells, and long-term use without oil and gas leakage, thereby solving the oil and gas leakage problem caused by poor sealing at the flange connections. Summary of the invention

[0003] The present invention solves the technical problem by adopting the following technical solutions:

[0004] The method for controlling oil and gas leakage in the oil tank operating well of a gas station includes the following steps:

[0005] Analyze the cause of the leakage and select a leakage control plan based on the analysis results. The leakage control plan can be selected individually or in multiple options;

[0006] Select contractors according to the leakage control plan and make construction preparations;

[0007] Carry out on-site operations according to the leakage control plan. After the operations are completed, make electrical connections and equipment commissioning, and check whether there are still oil and gas leaks;

[0008] The construction unit organizes the gas station and the contractor to jointly inspect the operating well process, electrical and grounding connections, and equipment commissioning; and the gas station should subsequently conduct continuous observation and inspection of the process pipelines in the operating well.

[0009] Furthermore, the leakage control plan includes flange bolt tightening plan, flange gasket replacement plan, electrical line interface sealing plan, pipeline flange reinstallation plan, and pipe leak repair plan.

[0010] Furthermore, in the flange bolt tightening scheme, the flange bolts are retightened according to the bolt tightening sequence, and the tightening condition of the bolts is rechecked after the bolts are tightened once.

[0011] Furthermore, in the flange gasket replacement plan, if the flange gasket does not use the gasket required by the design or the gasket is aged and not sealed tightly, open the oil tank and pipeline flanges, remove the original gaskets, clean the flange surface, reinstall the gaskets and flange bolts, and retighten them in the bolt tightening sequence. After the bolts are tightened once, the tightening condition of the bolts should be rechecked.

[0012] Furthermore, the electrical circuit interface sealing scheme of the submersible pump and the level meter electrical circuit interface is not sealed tightly. Clean the original sealant, clean the contact surface of the connection, and re-apply sealant or raw tape to seal.

[0013] Furthermore, when the pipeline flange is uneven or not coaxial in the pipeline flange reinstallation plan, the short section of the connecting pipe will be disassembled and transported to the designated hot work area for reprocessing; if it cannot be disassembled (the pipeline has no short section connection in the operating well) and the problem is serious, the oil tank will be transferred, cleaned, and filled with water. After checking that the oil and gas concentration is qualified and taking various safety measures, cutting and welding will be carried out in the operating well.

[0014] Furthermore, when the pipeline material or welding part leaks in the pipe leak repair scheme, the pipeline body has leakage points due to material problems, or the pipeline anti-corrosion is defective and causes pipeline corrosion and leakage, or there are rust leakage points in the weld, the pipeline with the leakage point will be replaced, and all the pipelines in the entire station will be checked and processed.

[0015] Furthermore, during the treatment operation, the steel guide tube of the oil tank metering operation well is prone to friction and collision with the oil tank mouth when entering and exiting the oil tank mouth, damaging the oil tank mouth and easily generating sparks, posing a major safety hazard. This treatment will lift the steel metering guide tube out of the oil tank, perform mechanical cutting on the lower part of the oil tank flange, and replace it with an aluminum guide tube.

[0016] Furthermore, the on-site operations include personnel inspection, material acceptance, equipment inspection, confirmation of operating conditions, oil and gas detection and ventilation of operating wells, pipeline opening, flange surface cleaning, gasket flange installation, equipment instrument installation, leakage testing, electrical connection and equipment debugging, and on-site cleaning.

[0017] Furthermore, the construction preparation includes the following steps:

[0018] Before construction, the construction unit shall prepare a construction plan to specify the construction materials, construction process quality control measures and construction safety control measures. The construction plan shall be approved by the construction unit;

[0019] Before construction, relevant work permits must be obtained as required, the work site must be isolated and fenced off, and a dedicated person must be assigned to guard the site. Unauthorized personnel are strictly prohibited from entering the work area.

[0020] Before on-site operations, the construction unit shall organize the contractor's personnel to carry out safety education and training and safety technology briefings, and the contractor shall carry out safety lesson training and plan, safety, and quality technology briefings for its on-site workers.

[0021] The advantages and positive effects of the present invention are:

[0022] The present invention solves the problems of oil and gas leakage and high oil and gas concentration in the oil tank operation well of a gas station due to poor sealing of the process system connection, while reducing the operating safety and environmental protection risks of the gas station. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it should be understood that these drawings are designed only for explanation purposes and are not intended to limit the scope of the present invention. In addition, unless otherwise specified, these drawings are intended only to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0024] Figure 1 A schematic flow chart of a method for treating oil and gas leakage in an oil tank operating well of a gas station provided by an embodiment of the present invention; DETAILED DESCRIPTION

[0025] First of all, it should be noted that the specific structure, features and advantages of the present invention will be specifically described below by way of example, but all descriptions are only for illustration and should not be understood as limiting the present invention in any way. In addition, any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature displayed or implied in the drawings, can still be combined or deleted between these technical features (or their equivalents) to obtain more other embodiments of the present invention that may not be directly mentioned in this document. In addition, in order to simplify the drawings, the same or similar technical features may be marked only in one place in the same drawing.

[0026] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0027] Example 1

[0028] The method for treating oil and gas leakage in the oil tank operating well of a gas station provided in this embodiment comprises the following steps:

[0029] Analyze the cause of the leakage and select a leakage control plan based on the analysis results. The leakage control plan can be selected individually or in multiple options;

[0030] Select contractors according to the leakage control plan and make construction preparations;

[0031] Carry out on-site operations according to the leakage control plan. After the operations are completed, make electrical connections and equipment commissioning, and check whether there are still oil and gas leaks;

[0032] The construction unit organizes the gas station and the contractor to jointly inspect the operating well process, electrical and grounding connections, and equipment commissioning; and the gas station should subsequently conduct continuous observation and inspection of the process pipelines in the operating well.

[0033] Among them, the leakage control plan includes flange bolt tightening plan, flange gasket replacement plan, electrical line interface sealing plan, pipeline flange reinstallation plan, and pipe leak repair plan.

[0034] Specifically: In the flange bolt tightening plan, the flange bolts are re-tightened in the bolt tightening sequence, and the bolt tightening condition is re-inspected after the bolts are tightened once; in the flange gasket replacement plan, if the flange gasket is not used as required by the design or the gasket is aged and not sealed tightly, the oil tank and pipeline flanges are opened, the original gaskets are removed, the flange surface is cleaned, the gaskets and flange bolts are re-installed, and the bolts are re-tightened in the bolt tightening sequence, and the bolt tightening condition is re-inspected after the bolts are tightened once; in the electrical circuit interface sealing plan, the electrical circuit interfaces of the submersible pump and the liquid level meter are not sealed tightly, the original sealant should be cleaned, the contact surface of the connection should be cleaned, and the sealant or fresh sealant should be re-applied. The material strip is sealed; when the pipeline flange is uneven or not coaxial in the pipeline flange reinstallation plan, the connecting pipe short section shall be disassembled and transported to the designated hot work area for reprocessing; if it cannot be disassembled (the pipeline has no short section connection in the operating well) and the problem is serious, the oil tank shall be transferred, cleaned, and filled with water. After checking that the oil and gas concentration is qualified and taking various safety measures, cutting and welding shall be carried out in the operating well; when the pipeline material or welding part leaks in the pipe fittings repair plan, the pipeline body has leakage points due to material problems, or the pipeline anti-corrosion is defective and causes pipeline corrosion and leakage, or there are rust leakage points in the weld, the pipeline with leakage points shall be replaced, and all pipelines of the entire station shall be checked and processed. During the treatment process, the steel guide pipe of the oil tank metering operation well is prone to friction and collision with the oil tank mouth when entering and exiting the oil tank mouth, which may damage the oil tank mouth and easily generate sparks, posing a major safety hazard. This treatment will lift the steel metering guide pipe out of the oil tank, perform mechanical cutting on the lower part of the oil tank flange, and replace it with an aluminum guide pipe.

[0035] Regarding material selection, the design pressure of the gas station process pipeline system is 0.4MPa, the design temperature is normal temperature, and the nominal pressure level of flanges and valves is 1.0MPa; the material selection for oil and gas leakage control of the gas station oil tank operation well is:

[0036] Bolt selection: hexagon head bolts, hexagon nuts, material: galvanized steel bolts, used when sealing with non-metallic gaskets.

[0037] Gasket selection: Polytetrafluoroethylene gasket, process pipeline flange gasket selection, oil tank manhole flange selection, oil tank gasket thickness 5mm, process pipeline gasket thickness 2mm; gasket should be flat, without warping and deformation, no slag inclusions, cracks, bubbles, foreign impurities and other defects that may affect the use are allowed, the edges should be cut neatly; gaskets should generally be made of a whole plate, and splicing is not allowed.

[0038] Grounding wire selection: 6 square millimeter special grounding wire, with copper special terminal blocks crimped on both ends.

[0039] Flange selection: The manhole flange of the gas station oil tank adopts flat-welded flat flange; the process pipeline flange of the gas station adopts raised face butt-welded flange with neck.

[0040] It should be noted that the on-site operations include personnel inspection, material acceptance, machine inspection, confirmation of operating conditions, oil and gas detection and ventilation of operating wells, pipeline opening, flange surface cleaning, gasket flange installation, equipment instrument installation, leakage test, electrical connection and equipment commissioning, and on-site cleaning, as follows:

[0041] (1) Personnel inspection: Gas stations should check whether contractors have received safety training and technical briefings, and verify special operation tickets (opening pipelines, entering confined spaces) and special personnel operation certificates;

[0042] (2) Material acceptance: Check whether the types, specifications and models of gaskets, bolts and electrostatic jumper wires used in construction are consistent with the scheme description, and whether the specifications and quantity of blind plates meet the construction requirements;

[0043] (3) Inspection of tools: The oil tank operation well is an explosion-hazardous area. The tools used should be made of copper or tools and utensils that do not produce sparks when they collide. The safety accessories of hand-held tools should be intact.

[0044] (4) Confirmation of operating conditions: Before opening the operating well for operation, the power supply and control lines of the equipment and instruments in the operating well should be disconnected. In particular, the operating well where the submersible pump is installed should stop responding to the refueling gun;

[0045] (5) Oil and gas detection and ventilation of the operating well: Open the operating well cover and detect the oil and gas concentration in the operating well. Two detection instruments of the same model should be used for the detection. If the oil and gas concentration is qualified, subsequent operations can be carried out. If the oil and gas concentration is unqualified, the operating well should be forced or naturally ventilated. When forced ventilation is used, the fan should be an explosion-proof fan;

[0046] (6) Pipeline opening: When opening the pipeline, the flange bolts should be loosened in sequence. For the oil pipeline, the bottom bolts should be loosened slowly first to facilitate the discharge of the oil in the pipeline. Before opening the oil pipeline, the oil receiving device should be prepared in advance. After the pipeline is opened, it should be immediately sealed with a blind plate to prevent the oil and oil gas from escaping to the operating well. Before removing the oil tank flange, it should be confirmed that all process pipelines in the operating well have been sealed with a blind plate. When replacing the oil pipe flange gasket, the submersible pump, leakage detection equipment and instruments should be removed in sequence for protection;

[0047] (7) Flange surface cleaning: A flange surface cleaning area should be set up outside the work site. Flanges that can be moved to the cleaning area for cleaning must be moved to the cleaning area for cleaning. After cleaning, the flange surface should be clean and free of floating rust, stains, floating dust and other attachments;

[0048] (8) Gasket flange installation: Before installing the gasket, check the cleanliness of the flange surface one by one, and verify whether the gasket type and specifications match the flange. Only when they meet the requirements can the gasket be installed; when installing the gasket, butter can be applied on both sides of the gasket to further improve its sealing; the gasket installation should be accurately positioned, and attention should be paid to positioning and centering of the bolt holes when installing the flange; the bolt tightening sequence and tightening force should meet the requirements. After the bolts are tightened, the personnel should be replaced for re-inspection. The order of tightening the horizontal and vertical flanges in the operating well is to tighten the horizontal flange first and then the vertical flange. After the bolts are tightened, the exposed length of the screw should be 2-3 threads. When installing the flange, the flange jumper (flange with less than 5 bolts) should be installed at the same time;

[0049] (9) Equipment and instrument installation: After the process pipeline flange in the operating well is installed, the submersible pump, liquid level meter and leakage detection equipment are installed in sequence; before installing the submersible pump, check that the thread of the submersible pump is well sealed, the threading hole of the liquid level meter flange is sealed, and the junction box is sealed (a conical sealing gasket should be installed). After the equipment is installed, the grounding wire should be led to the grounding terminal;

[0050] (10) Leakage test: After all flanges in the operating well are installed, a leakage test shall be carried out. The test medium shall be dry and clean nitrogen and the test pressure shall be the design pressure, i.e. 0.4Mpa. Before the test, the contractor shall prepare a test plan to specify the test method, test medium, test pressure, leak detection method, release point location, qualification standard, etc. Before the test, the conditions shall be confirmed to ensure that the test system is effectively isolated from the existing operating system. Business shall be suspended during the test. During the test, the pressure shall be increased slowly step by step to reach the test pressure. After stabilizing the pressure for 10 minutes, all sealing points such as flange seals and threads shall be checked by brushing with neutral foaming agent. No leakage at the sealing point is considered qualified. Test safety concerns: For old equipment, the current status of reduced pressure resistance of equipment and pipelines due to corrosion and thinning should be checked, and the test plan should be reasonably determined to avoid overpressure burst accidents; before the test, a test area should be set up, and unrelated personnel are prohibited from entering the test area during the test; before the test, an emergency plan should be prepared, and the possible dangers of the test should be accurately analyzed and a response plan should be formulated; during the test, when it is necessary to deal with defects in the test system, the pressure should be released first, and then the treatment should be carried out. It is strictly forbidden to operate under pressure when the system pressure is higher than the link pressure;

[0051] (11) Electrical connection and equipment commissioning: After the leakage pressure test is passed, the equipment shall be electrically connected and the power supply shall be restored. After the power supply is restored, the equipment shall be commissioned. The refueling guns corresponding to each submersible oil pump shall be commissioned one by one until the refueling guns discharge oil normally. During the commissioning, the contractor shall arrange special personnel to continuously observe the process pipelines and equipment operation conditions in the operating well, focusing on whether there is oil leakage at the outlet connection of the submersible oil pump and whether there is oil leakage at the threaded connection of the submersible oil pump body;

[0052] (12) Site cleaning: After the equipment is operating normally, the contractor shall clean up the site. The contractor’s personnel may leave the site only after the gas station has been inspected and found to be correct.

[0053] The construction preparation includes the following steps:

[0054] Before construction, the construction unit shall prepare a construction plan to specify the construction materials, construction process quality control measures and construction safety control measures. The construction plan shall be approved by the construction unit;

[0055] Before construction, relevant work permits must be obtained as required, the work site must be isolated and fenced off, and a dedicated person must be assigned to guard the site. Unauthorized personnel are strictly prohibited from entering the work area.

[0056] Before on-site operations, the construction unit shall organize the contractor's personnel to carry out safety education and training and safety technology briefings, and the contractor shall carry out safety lesson training and plan, safety, and quality technology briefings for its on-site workers.

[0057] During the completion acceptance, the construction unit should organize the gas station and the contractor to jointly inspect the operating well process, electrical and grounding connections, and equipment commissioning, and sign an acceptance form.

[0058] After the equipment is operating normally, the gas station should continuously observe the process pipelines in the operating well and conduct inspections four times a day to prevent the submersible pump from vibrating and causing bolts to loosen and pipelines to leak oil.

[0059] The above embodiments describe the present invention in detail, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for treating oil and gas leakage in an oil tank operating well of a gas station, characterized in that: The steps include: Analyze the cause of the leakage and select a leakage control plan based on the analysis results. The leakage control plan can be selected individually or in multiple options; Select contractors according to the leakage control plan and make construction preparations; Carry out on-site operations according to the leakage control plan. After the operations are completed, make electrical connections and equipment commissioning, and check whether there are still oil and gas leaks; The construction unit organizes the gas station and the contractor to jointly inspect the operating well process, electrical and grounding connections, and equipment commissioning; and the gas station should subsequently conduct continuous observation and inspection of the process pipelines in the operating well.

2. The method for treating oil and gas leakage in the oil tank operating well of a gas station according to claim 1, characterized in that: The leakage control plan includes flange bolt tightening plan, flange gasket replacement plan, electrical line interface sealing plan, pipeline flange reinstallation plan, and pipe leak repair plan.

3. The method for controlling oil and gas leakage in the oil tank operating well of a gas station according to claim 2, characterized in that: In the flange bolt tightening scheme, the flange bolts are retightened according to the bolt tightening sequence, and the tightening condition of the bolts is re-inspected after the bolts are tightened once.

4. The method for treating oil and gas leakage in the oil tank operating well of a gas station according to claim 2, characterized in that: In the flange gasket replacement plan, if the flange gasket does not use the gasket required by the design or the gasket is aged and not sealed tightly, open the oil tank and pipeline flanges, remove the original gaskets, clean the flange surface, reinstall the gaskets and flange bolts, and retighten them in the bolt tightening sequence. After the bolts are tightened once, recheck the tightening condition of the bolts.

5. The method for treating oil and gas leakage in the oil tank operating well of a gas station according to claim 3, characterized in that: In the sealing scheme of the electrical circuit interface, the electrical circuit interfaces of the submersible pump and the liquid level meter are not sealed tightly. Clean the original sealant, clean the contact surface of the connection, and re-apply sealant or raw tape to seal.

6. The method for treating oil and gas leakage in the oil tank operating well of a gas station according to claim 2, characterized in that: When the pipeline flange is uneven or out of axis in the pipeline flange reinstallation plan, the short section of the connecting pipe will be disassembled and transported to the designated hot work area for reprocessing; if it cannot be disassembled, the oil tank will be transferred, cleaned, and filled with water. After checking that the oil and gas concentration is qualified and taking safety measures, cutting and welding will be carried out in the operating well.

7. The method for treating oil and gas leakage in the oil tank operating well of a gas station according to claim 2, characterized in that: When the pipeline material or welding part leaks in the pipe leak repair plan, the pipeline body has leakage points due to material problems, or the pipeline anti-corrosion is defective and causes pipeline corrosion and leakage, or there are rust leakage points in the weld, the pipeline with the leakage point will be replaced, and all the pipelines in the entire station will be checked and processed.

8. The method for treating oil and gas leakage in a gas station oil tank operating well according to claim 1, characterized in that: The on-site operations include personnel inspection, material acceptance, machinery inspection, confirmation of operating conditions, oil and gas detection and ventilation of operating wells, pipeline opening, flange surface cleaning, gasket flange installation, equipment and instrument installation, leakage testing, electrical connection and equipment debugging, and on-site cleaning.

9. The method for treating oil and gas leakage in a gas station oil tank operating well according to claim 1, characterized in that: The construction preparation includes the following steps: Before construction, the construction unit shall prepare a construction plan to specify the construction materials, construction process quality control measures and construction safety control measures. The construction plan shall be approved by the construction unit; Before construction, relevant work permits must be obtained as required, the work site must be isolated and fenced off, and a dedicated person must be assigned to guard the site. Unauthorized personnel are strictly prohibited from entering the work area. Before on-site operations, the construction unit shall organize the contractor's personnel to carry out safety education and training and safety technology briefings, and the contractor shall carry out safety lesson training and plan, safety, and quality technology briefings for its on-site workers.

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