Safety control system and method for high-temperature and high-sulfur-content wellhead

Abstract

The invention provides a high-temperature and high-sulfur-content wellhead safety control system and method. An incinerator is arranged at a wellhead, and a high-pressure release valve and a low-pressure release valve are arranged on a wellhead extract pipeline; a cut-off valve is arranged on a pipeline between a wellhead produced product pipeline and a treatment station, wellhead produced products flow to the treatment station through the wellhead produced product pipeline under the normal production condition, when the pressure exceeds an initial set value, a low-pressure release valve is opened for torch emptying, and when the pressure reaches a high set value, the cut-off valve is automatically closed to cut off the pipeline, so that the wellhead produced products flow to the treatment station through the low-pressure release valve. And meanwhile, the high-pressure release valve is opened until the torch is released for combustion, and when the pressure continues to be increased and the torch cannot be absorbed, poisonous gas at the well mouth enters the incinerator for incineration. The pressure can be effectively controlled within a safe and reasonable range by adopting a multi-stage safety control mode, so that the overpressure relief treatment of toxic gas is realized, and the requirement of shale oil in-situ conversion wellhead safety control is met.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field surface engineering, and relates to a high-temperature and high-sulfur wellhead safety control system and method. Background Art

[0002] The underground in-situ conversion of shale oil is a physical and chemical process that uses horizontal well electric heating to convert heavy oil, asphalt and various organic matter in shale at a depth of 300 to 3000 meters into light oil and natural gas on a large scale. It can be called an "underground refinery". Due to the particularity of the in-situ conversion mining process and the characteristics of the produced materials, the toxicity and corrosion problems of the produced materials are more prominent. According to the test simulation data results, Chang 7 3 The produced material temperature generated by in-situ conversion of shale oil is as high as 300°C, and the normal production wellhead pressure is about 1MPa. 2 S(9.25%), CO 2 The content is very high (5.16%), and it contains a large amount of water vapor (32.41%) and a certain amount of H 2 (6.06%) is a typical high-sulfur, high-temperature substance with strong corrosiveness. The safety of ground engineering is particularly important. There is currently no corresponding supporting ground process, and once the electric heating well is heated, the production wellhead cannot be closed for a long time in an emergency.

[0003] Wellheads with high temperature and high sulfur content use pressure relief methods to ensure wellhead safety, or use methods such as shutting in the well to achieve wellhead safety under abnormal conditions. The gas field wellhead uses a safety valve method for release. According to the patent query "Unattended Wellhead Safety Control System" CN202122658818.0, this invention patent uses an unattended wellhead safety control system, including production pipelines, downhole safety valves, pipeline safety valves and hydraulic control systems, which meet the wellhead safety control and its own anti-destruction and anti-theft functions, and can achieve oil well closure in emergency conditions without supervision.

[0004] This patent is used to achieve unattended wellhead safety control to avoid major safety accidents. It is necessary to completely shut down the well or wellhead through automatic control. Since the underground heating body of shale oil in-situ conversion cannot be urgently cooled, the wellhead cannot be closed for a long time. Therefore, it is necessary to develop a process that can adapt to the safety control of the heating wellhead. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a high-temperature and high-sulfur wellhead safety control system and method, which adopts multi-level safety control and safety pressure relief to achieve overpressure release and disposal of toxic gases and meet the requirements of shale oil in-situ conversion wellhead safety control.

[0006] The present invention is achieved through the following technical solutions:

[0007] A high-temperature and high-sulfur wellhead safety control system, comprising:

[0008] Incinerators, flares, and treatment stations;

[0009] The incinerator is arranged at a high-temperature and high-sulfur wellhead, one line of the wellhead produced material pipeline of the high-temperature and high-sulfur wellhead is connected to the flare, and another line of the wellhead produced material pipeline of the high-temperature and high-sulfur wellhead is connected to the processing station; a high-pressure relief valve is arranged on the high-pressure pipeline between the wellhead produced material pipeline and the flare, and a low-pressure relief valve is arranged on the low-pressure pipeline between the wellhead produced material pipeline and the flare; a shut-off valve is arranged on the pipeline between the wellhead produced material pipeline and the processing station.

[0010] Preferably, an incineration control valve is provided between the high-temperature and high-sulfur wellhead and the incinerator.

[0011] Preferably, a throttle valve is provided on the wellhead production pipeline of the high-temperature and high-sulfur wellhead.

[0012] A high-temperature and high-sulfur wellhead safety control method, comprising:

[0013] Under normal production conditions, the wellhead produced material flows to the processing station through the wellhead produced material pipeline. When the pressure exceeds the initial set value, the low-pressure relief valve is opened to vent the flare. When the pressure reaches the high set value, the pipeline is cut off by automatically closing the shut-off valve, and the high-pressure relief valve is opened at the same time to vent the flare and burn. When the pressure continues to increase and the flare cannot absorb it, the toxic gas at the wellhead is sent to the incinerator for combustion.

[0014] Preferably, when the wellhead produced material pressure is between 0.2MPa and 1.2MPa, it is the normal production stage, the incinerator, the high-pressure relief valve and the low-pressure relief valve are all closed, the shut-off valve is opened, and the wellhead produced material is transported to the processing station through a pipeline for processing.

[0015] Preferably, when the wellhead produced material pressure is below 0.2 MPa, it is the low-pressure production stage, the heating well does not meet the heating requirements, the shut-off valve, high-pressure relief valve and low-pressure relief valve are all closed, and the wellhead pressure is held down.

[0016] Preferably, when the wellhead production pressure is between 1.2MPa and 1.4MPa, it is the overpressure production stage, the incinerator and the high-pressure relief valve are closed, and the low-pressure relief valve and the shut-off valve are opened. Part of the wellhead production is released to the flare, and the remaining part of the wellhead production is transported to the processing station through a pipeline for processing.

[0017] Preferably, when the wellhead produced pressure is above 1.4 MPa, it is the high-pressure production stage, the incinerator is closed, the high-pressure relief valve and the shut-off valve are opened, the low-pressure relief valve is closed, and the wellhead produced is discharged to the flare.

[0018] Preferably, when the pressure of the wellhead produced material remains above 1.4MPa after being released through the high-pressure relief valve, it is in an out-of-control state, the incinerator is opened, the high-pressure relief valve, the shut-off valve, and the low-pressure relief valve are closed, and the wellhead produced material is incinerated through the incinerator.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] The present invention provides a high-temperature and high-sulfur wellhead safety control system and method. An incinerator is arranged at the wellhead, a high-pressure relief valve is arranged on the high-pressure pipeline between the wellhead produced pipeline and the flare, and a low-pressure relief valve is arranged on the low-pressure pipeline between the wellhead produced pipeline and the flare; a cut-off valve is arranged on the pipeline between the wellhead produced pipeline and the processing station, and the high-pressure control valve and the low-pressure control valve are interlocked for venting and the cut-off valve is cut off. Under normal production conditions, the wellhead produced flows to the processing station through the wellhead produced pipeline. When the pressure exceeds the initial set value, the low-pressure relief valve is opened to vent the flare. When the pressure reaches the high set value, the cut-off valve is automatically closed to cut off the pipeline, and the high-pressure relief valve is opened to vent the flare for combustion. When the pressure continues to increase and the flare cannot absorb it, the toxic gas at the wellhead enters the incinerator for combustion. The present invention converts shale oil in situ into a high-temperature, high-sulfur and other toxic gas mixture at the wellhead production site, and the wellhead pressure cannot be reduced rapidly. A multi-level safety control method is used to effectively control the pressure within a safe and reasonable range. After overpressure, flare combustion or incineration in an incinerator is used to effectively avoid the diffusion of toxic gases and reduce safety risks, thereby achieving overpressure discharge and disposal of toxic gases and meeting the requirements for wellhead safety control of shale oil in situ conversion.

[0021] Furthermore, the pipeline corresponding to the low-pressure discharge of the present invention realizes normal transportation at the same time, which meets the normal production under the condition of low accuracy of the wellhead production volume, has certain adaptability, meets the production operation of the test station, and has certain economic effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of a high-temperature and high-sulfur wellhead safety control system;

[0023] Figure 2 It is a partial diagram of the connection between the incinerator and the inlet;

[0024] Figure 3 It is a partial diagram of the connection between the throttle valve and the high-pressure relief valve;

[0025] Figure 4It is a partial diagram of the connection between the high-pressure relief valve and the low-pressure relief valve;

[0026] Figure 5 This is a partial structural diagram of the flare and treatment station;

[0027] In the figure: 1. Wellhead; 2. Incinerator; 3. Throttle valve; 4. High-pressure relief valve; 5. Low-pressure relief valve; 6. Shut-off valve; 7. Flare; 8. Control valve; 9. Processing station. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0029] A high temperature and high sulfur content wellhead safety control system, such as Figure 1 As shown, including,

[0030] Incinerator 2, flare 7 and treatment station 9;

[0031] The incinerator 2 is arranged at a high-temperature and high-sulfur wellhead 1, one line of the wellhead production pipeline of the high-temperature and high-sulfur wellhead 1 is connected to a flare 7, and the other line of the wellhead production pipeline of the high-temperature and high-sulfur wellhead 1 is connected to a processing station 9;

[0032] like Figure 3 and Figure 4 As shown, a high-pressure relief valve 4 is provided on the high-pressure pipeline between the wellhead produced product pipeline and the flare 7, and a low-pressure relief valve 5 is provided on the low-pressure pipeline between the wellhead produced product pipeline and the flare 7;

[0033] like Figure 5 As shown, a cut-off valve 6 is provided on the pipeline between the wellhead production pipeline and the processing station 9. An incineration control valve 8 is provided between the high-temperature and high-sulfur wellhead 1 and the incinerator 2.

[0034] like Figure 2 As shown, a throttle valve 3 is provided on the wellhead production pipeline of the high-temperature and high-sulfur wellhead 1. The present invention converts the shale oil in-situ into a high-temperature, high-sulfur and other toxic gas mixture from the wellhead production, and the wellhead pressure cannot be reduced quickly. The multi-level safety control method can effectively control the pressure within a safe and reasonable range. After overpressure, the flare combustion or incinerator combustion method can effectively avoid the diffusion of toxic gases and reduce safety risks, thereby realizing the overpressure discharge and disposal of toxic gases and meeting the requirements of shale oil in-situ conversion wellhead safety control.

[0035] Furthermore, the pipeline corresponding to the low-pressure discharge of the present invention realizes normal transportation at the same time, which meets the normal production under the condition of low accuracy of the wellhead production volume, has certain adaptability, meets the production operation of the test station, and has certain economic effects.

[0036] A high-temperature and high-sulfur wellhead safety control method, comprising:

[0037] An incinerator 2 is provided at the high-temperature and high-sulfur wellhead 1. After the wellhead produced material passes through the throttle valve 3, it is interlocked and vented by the high-pressure control valve 4 and the low-pressure control valve 5 and cut-off valve 6 cuts off. Under normal production conditions, the wellhead produced material flows to the processing station 9 through the wellhead produced material pipeline. When the pressure exceeds the initial set value, the low-pressure relief valve 5 is opened to vent the flare 7. When the pressure reaches the high set value, the pipeline is cut off by automatically closing the cut-off valve 6, and the high-pressure relief valve 4 is opened to vent and burn to the flare 7. When the pressure continues to increase and the flare cannot absorb it, the toxic gas at the wellhead enters the incinerator 2 for incineration.

[0038] The high-temperature and high-sulfur well is provided with a pressure detection device including a pressure gauge PG, a pressure indicator PI and a pressure transmitter PT which can be remotely transmitted to the control unit.

[0039] The wellhead produced material pipeline is also equipped with a pressure gauge PG, a pressure indicator PI and a pressure transmitter PT;

[0040] A PN40-PN250 pressure level dividing line is set at the throttle valve 3, a PN16-PN40 pressure level dividing line is set near the high-pressure relief valve 4, a PN16-PN40 pressure level dividing line is set near the low-pressure relief valve 5; a PN25-PN40 pressure level dividing line is set near the cut-off valve 6;

[0041] 1. Normal production process

[0042] When the wellhead produced material pressure is between 0.2MPa and 1.2MPa, it is the normal production stage, the incinerator 2, the high-pressure relief valve 4 and the low-pressure relief valve 5 are all closed, the shut-off valve 6 is opened, and the wellhead produced material is transported to the processing station 9 through a pipeline for processing.

[0043] 2. Low-pressure production process

[0044] When the wellhead produced material pressure is below 0.2MPa, it is the low-pressure production stage. The heating well does not meet the heating requirements. The shut-off valve 6, high-pressure relief valve 4 and low-pressure relief valve 5 are all closed to hold the wellhead pressure.

[0045] 3. Overpressure production process

[0046] When the wellhead produced material pressure is between 1.2MPa and 1.4MPa, it is the overpressure production stage, the incinerator 2 and the high-pressure relief valve 4 are closed, the low-pressure relief valve 5 and the shut-off valve 6 are opened, part of the wellhead produced material is discharged to the flare 7, and the remaining part of the wellhead produced material is transported to the processing station 9 through a pipeline for processing.

[0047] 4. High-pressure production process

[0048] When the pressure of the wellhead produced material is above 1.4 MPa, it is the high-pressure production stage, the incinerator 2 is closed, the high-pressure relief valve 4 and the shut-off valve 6 are opened, the low-pressure relief valve 5 is closed, and the wellhead produced material is discharged to the flare 7.

[0049] 5. Out-of-control process

[0050] When the pressure of the wellhead produced material remains above 1.4 MPa after being released through the high-pressure relief valve 4, it is in an out-of-control state, the incinerator 2 is opened, the high-pressure relief valve 4, the shut-off valve 6, and the low-pressure relief valve 5 are closed, and the wellhead produced material is incinerated through the incinerator 2.

[0051] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0052] It should be noted that the terms "high", "low", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0053] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0055] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A high temperature and high sulfur content wellhead safety control system, It is characterized in that include, Incinerator (2), flare (7) and treatment station (9); The incinerator (2) is arranged at a high-temperature and high-sulfur wellhead (1); one wellhead produced material pipeline of the high-temperature and high-sulfur wellhead (1) is connected to a flare (7), and another wellhead produced material pipeline of the high-temperature and high-sulfur wellhead (1) is connected to a processing station (9); a high-pressure relief valve (4) is arranged on the high-pressure pipeline between the wellhead produced material pipeline and the flare (7), and a low-pressure relief valve (5) is arranged on the low-pressure pipeline between the wellhead produced material pipeline and the flare (7); and a shut-off valve (6) is arranged on the pipeline between the wellhead produced material pipeline and the processing station (9).

2. A high temperature and high sulfur content wellhead safety control system according to claim 1, It is characterized in that An incineration control valve (8) is provided between the high-temperature and high-sulfur wellhead (1) and the incinerator (2).

3. A high-temperature and high-sulfur wellhead safety control system according to claim 1, It is characterized in that A throttle valve (3) is provided on the wellhead production pipeline of the high-temperature and high-sulfur wellhead (1).

4. A high-temperature and high-sulfur wellhead safety control method, based on the high-temperature and high-sulfur wellhead safety control system according to any one of claims 1 to 3, It is characterized in that include, Under normal production conditions, the wellhead produced material flows to the processing station (9) through the wellhead produced material pipeline. When the pressure exceeds the initial set value, the low-pressure relief valve (5) is opened to vent the flare (7). When the pressure reaches the high set value, the pipeline is cut off by automatically closing the shut-off valve (6), and the high-pressure relief valve (4) is opened to vent and burn the flare (7). When the pressure continues to increase and the flare cannot absorb it, the toxic gas at the wellhead enters the incinerator (2) for incineration.

5. A high temperature and high sulfur content wellhead safety control method according to claim 4, It is characterized in that When the wellhead produced material pressure is between 0.2MPa and 1.2MPa, it is the normal production stage, the incinerator (2), the high-pressure relief valve (4) and the low-pressure relief valve (5) are all closed, the shut-off valve (6) is opened, and the wellhead produced material is transported to the processing station (9) through a pipeline for processing.

6. A high temperature and high sulfur content wellhead safety control method according to claim 4, It is characterized in that When the wellhead produced material pressure is below 0.2 MPa, it is the low-pressure production stage. The heating well does not meet the heating requirements. The shut-off valve (6), the high-pressure relief valve (4) and the low-pressure relief valve (5) are all closed to hold the wellhead pressure.

7. A high temperature and high sulfur content wellhead safety control method according to claim 4, It is characterized in that When the wellhead production pressure is between 1.2MPa and 1.4MPa, it is the overpressure production stage. The incinerator (2) and the high-pressure relief valve (4) are closed, and the low-pressure relief valve (5) and the shut-off valve (6) are opened. When the wellhead production pressure is opened, part of the wellhead production is discharged to the flare (7), and the remaining part of the wellhead production is transported to the processing station (9) through a pipeline for processing.

8. A high temperature and high sulfur content wellhead safety control method according to claim 4, It is characterized in that When the pressure of the produced material at the wellhead is above 1.4 MPa, it is the high-pressure production stage, the incinerator (2) is closed, the high-pressure relief valve (4) and the shut-off valve (6) are opened, the low-pressure relief valve (5) is closed, and the produced material at the wellhead is discharged to the flare (7).

9. A high temperature and high sulfur content wellhead safety control method according to claim 4, It is characterized in that When the pressure of the wellhead produced material remains above 1.4 MPa after being released through the high-pressure relief valve (4), it is an out-of-control state, the incinerator (2) is opened, the high-pressure relief valve (4), the shut-off valve (6), and the low-pressure relief valve (5) are closed, and the wellhead produced material is incinerated through the incinerator (2).

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