An automatic detection closed-loop control device for hydrogen sulfide content of associated gas of oil well produced fluid

Abstract

The utility model discloses a kind of oil well produced fluid associated gas hydrogen sulfide content automatic detection closed-loop control device, belong to oilfield safety production and gas detection technical field.The device includes pressure reducing valve, oil-water filter assembly, granular filter assembly, drying assembly, sampling pump, flowmeter and hydrogen sulfide gas detection probe connected in series sequentially.The utility model carries out pressure reduction, filtration and drying to high-pressure associated gas by multistage pretreatment unit, creates stable condition for detection, realizes remote real-time transmission of measurement data using wireless communication module, and finally through gas booster pump, after detection, waste gas is injected into oil gathering main line, realizes the full-process automation closed-loop control from sample gas processing, detection to waste gas recovery.The device effectively solves the problems of high risk of manual detection, poor adaptability of existing automated equipment and direct discharge of waste gas, significantly improves the safety, reliability and environmental protection of detection.

Description

Technical Field

[0001] This utility model relates to the field of associated gas detection technology in produced fluids, and provides an automatic closed-loop control device for detecting hydrogen sulfide content in associated gas from oil well produced fluids. Background Technology

[0002] Detecting hydrogen sulfide (H2S) content in associated gas from produced fluids is a crucial aspect of safe oilfield production. As a highly toxic and flammable gas, the concentration of hydrogen sulfide in the production environment directly impacts the safety of on-site personnel and the stable operation of production equipment. Currently, in most oilfields, the detection of hydrogen sulfide content in associated gas still relies on traditional manual sampling and laboratory analysis methods. This method typically requires two operators to collect gas samples from the wellhead or metering valve, extract them using a syringe, and inject them into a colorimetric tube. The concentration of hydrogen sulfide is then estimated by comparing the colorimetric reaction with a standard color chart. This method is not only cumbersome and inefficient, but also prone to leakage, gas escape, and valve closure issues due to the complex composition of produced fluids, high sand content, and large fluctuations in the gas-liquid ratio. These issues pose significant safety risks, including environmental pollution and personnel poisoning and asphyxiation. Especially in well areas with high hydrogen sulfide concentrations, manual sampling is no longer sufficient to meet the requirements of safe production and occupational health protection.

[0003] To overcome the drawbacks of manual detection, several automated or semi-automated hydrogen sulfide detection technologies and devices have emerged in recent years. For example, patent application CN202021696956.7 discloses a device for automatically monitoring the hydrogen sulfide content in biogas. This device integrates a robotic arm, a gas pump, a detection tube chamber, and an image recognition system, enabling automatic placement and removal of the detection tube, intake and detection of sample gas, and data processing and display via computer. While this device improves the automation level of detection and reduces manual intervention under certain conditions, its design is primarily aimed at biogas monitoring under normal or low pressure environments. It does not consider the harsh working conditions of oilfield wellheads, such as high pressure, explosiveness, and high impurities, and lacks structural design and explosion-proof measures suitable for pressure vessels. Furthermore, it does not achieve real-time remote transmission and platform integration of detection data, limiting its widespread application in oilfields.

[0004] Another related patent, CN202211475691.1, proposes a mobile hydrogen sulfide content detection device based on infrared detection technology. It features an adjustable-height gas collection assembly and a wheel structure, suitable for sampling and detecting gases around pipelines in industrial parks. While this device possesses a degree of mobility and adaptability, its detection method remains open-loop sampling, with the detected gas directly discharged into the atmosphere without considering the recovery and treatment of harmful gases. Furthermore, the device lacks pretreatment designs for the high pressure, high humidity, and high impurity content of associated gas from oilfields, such as gas path depressurization, filtration, and drying. The detection results are easily affected by operating conditions, resulting in insufficient stability and accuracy. Similarly, the device lacks data interface capabilities with production control systems (such as SCADA systems), making it impossible to remotely monitor, store, and analyze detection data, thus failing to meet the real-time data scheduling and intelligent decision-making needs of oilfield production command centers.

[0005] In summary, while existing hydrogen sulfide detection technologies have achieved some degree of automation in the detection process, they still suffer from several significant shortcomings: First, existing devices are mostly designed for atmospheric pressure or simple gas environments, failing to consider the high-pressure, high-risk conditions of associated gases in oilfields, lacking complete explosion-proof, pressure-reducing, and pretreatment units, resulting in poor adaptability. Second, detection data is isolated, lacking integration with remote transmission and a central monitoring platform, making real-time display and remote management of production data impossible, and exhibiting a low level of digitalization. Third, most devices employ an open-loop detection method, directly discharging the detected waste gas, which not only fails to meet environmental protection requirements but also poses secondary pollution and safety risks. Fourth, there is a lack of effective integration with existing oilfield production processes (such as oil quantification and gathering), failing to achieve closed-loop automated control throughout the entire process from sampling and detection to waste gas recovery. Therefore, oilfields urgently need an online automatic detection and control device for hydrogen sulfide that can adapt to high-pressure, flammable environments, achieve unmanned closed-loop operation, and possess data transmission and platform integration capabilities. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing an automatic closed-loop control device for detecting hydrogen sulfide content in associated gas from oil well produced fluids, solving the following technical problems: 1. Reliance on manual on-site sampling and testing exposes operators directly to a toxic gas environment, posing a risk of severe poisoning and asphyxiation; 2. Existing automated detection devices are generally not designed for harsh working conditions in oil fields, such as high pressure, flammability, and high levels of impurities, resulting in poor adaptability and insufficient detection stability; 3. Isolated detection data prevents remote real-time transmission and centralized monitoring, hindering production scheduling decisions; 4. The waste gas after detection is directly emitted into the atmosphere, failing to meet safety and environmental protection requirements and posing a pollution hazard.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: an automatic detection closed-loop control device for hydrogen sulfide content in associated gas from oil well produced fluid, comprising a pressure reducing valve, an oil-water filter assembly, a particle filter assembly, a drying assembly, a sampling pump, a flow meter, and a hydrogen sulfide gas detection probe connected in series, wherein the pressure reducing valve is provided with a sample gas inlet.

[0008] Preferably, the oil-water filtration assembly is mainly composed of multi-stage oil-water filters connected in series.

[0009] Preferably, the multi-stage oil-water filter is connected in parallel with an electric sewage pump.

[0010] Preferably, the drying assembly mainly consists of a series of multi-stage drying filters.

[0011] Preferably, the hydrogen sulfide gas detection probe is connected to a wireless communication module.

[0012] Preferably, the wireless communication module is a 4G communication module.

[0013] Preferably, the hydrogen sulfide gas detection probe is also connected to an exhaust gas outlet.

[0014] Preferably, it also includes a power supply, which is electrically connected to the wireless communication module, the hydrogen sulfide gas detection probe, the sampling pump, and the electric sewage pump.

[0015] Preferably, the power supply is a switching power supply with AC220V / DC24V output.

[0016] Preferably, the sample gas inlet and the exhaust gas outlet are made of stainless steel explosion-proof sealed glands.

[0017] The beneficial effects of this utility model are as follows: The online automatic detection closed-loop control device for hydrogen sulfide content in associated gas from oil well produced fluids provided by this utility model achieves significant advantages compared with the prior art described in the background section. This invention, by connecting a small oil-gas separator in series to the oil measurement process, realizes automatic, continuous, and closed-loop acquisition of the gas source, completely avoiding the risk of personnel directly contacting toxic gases and high-pressure fluids during manual sampling, fundamentally ensuring operational safety. Addressing the shortcomings of existing automated devices in adapting to the high-pressure, flammable, and multi-impurity conditions of oil fields, this device integrates multi-stage pretreatment units such as pressure reduction, filtration, and drying, along with an explosion-proof design, providing a safe and stable working environment for the detection probe and significantly improving the accuracy and reliability of detection. Through a built-in wireless remote transmission module, real-time remote transmission of measurement data and display on the PCS platform are achieved, overcoming the shortcomings of low digitalization and isolated data in existing technologies, and providing timely support for production decisions. Crucially, the innovative use of waste gas pressurization and reinjection technology pumps all the waste gas after testing into the oil collection trunk line, achieving closed-loop control throughout the entire process, eliminating the direct discharge of harmful gases, meeting environmental protection requirements, and achieving substantial progress in safety, adaptability, and environmental protection. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure; Figure 2 This is an implementation diagram; Figure 3 This is a schematic diagram of the principle. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0020] Example 1

[0021] Please refer to the closed-loop control device for automatic detection of hydrogen sulfide content in associated gas from oil well produced fluid. Figure 1 The device mainly includes the following components: the sample gas inlet 1 adopts an explosion-proof sealed gland made of stainless steel, which is directly connected to the gas sample outlet of the oil-gas separator to ensure safe connection in flammable and explosive environments.

[0022] The inlet of pressure reducing valve 2 is connected to the sample gas inlet 1 to reduce the pressure of the high-pressure associated gas from the wellhead to a safe range suitable for sensor detection.

[0023] The inlet of the oil-water filter assembly 3 is connected to the outlet of the pressure reducing valve 2. This assembly is usually composed of multiple oil-water filters connected in series. Its core function is to remove oil mist and droplets carried in the sample gas.

[0024] The inlet of the particulate filter assembly 4 is connected to the outlet of the oil-water filter assembly 3. It is mainly used to filter out fine solid particles that may be contained in the sample gas in order to protect downstream precision components.

[0025] The inlet of the drying component 5 is connected to the outlet of the particle filter component 4. It mainly consists of a filter filled with desiccant, which is used to deeply remove moisture from the sample gas and ensure that the gas entering the detection probe is dry and clean.

[0026] The sampling pump 6 is located after the drying component 5 and is used to provide power for the entire sample gas flow path, drawing the sample gas through the aforementioned pretreatment units and subsequent detection units in sequence to form a stable flow path.

[0027] The flow meter 7 is installed on the outlet pipeline of the sampling pump 6 to monitor and display the volumetric flow rate of the sample gas flowing through the sensor in real time, ensuring that the detection is carried out under the specified flow conditions.

[0028] The hydrogen sulfide gas detection probe 8 has its detection chamber inlet connected to the outlet pipe of the flow meter 7. It is the core measuring element used to accurately determine the concentration of hydrogen sulfide in the sample gas.

[0029] The exhaust outlet 9 is connected to the gas outlet of the detection probe 8, and it also uses a stainless steel explosion-proof sealed gland. It is connected to the inlet of the subsequent gas booster pump 24 through a pipeline.

[0030] The inlet of the electric sewage pump 10 is connected to the sewage outlet of the oil-water filter assembly 3 and the particulate filter assembly 4, and its outlet is connected to the waste liquid collection system 25, which can automatically discharge the filtered waste liquid according to the settings.

[0031] The device power supply 11 uses an AC220V to DC24V explosion-proof switching power supply to power all electrical units in the device, including the sampling pump 6, electric sewage pump 10, detection probe 8, wireless module 12, etc.

[0032] The wireless remote transmission module 12 is electrically connected to the signal output terminal of the hydrogen sulfide gas detection probe 8, and can use wireless communication methods such as 4G to upload the detected hydrogen sulfide concentration data to the remote monitoring platform in real time.

[0033] Example 2

[0034] Please see Figure 2 The application of this utility model also includes a front-end oil-gas separation device and a rear-end waste gas recovery unit.

[0035] The oil well produced fluid oil-gas separation device 14 is installed in series in the single-well oil metering manifold 22 within the metering station via its inlet quick valve 13 and outlet quick valve 19. After the produced fluid from the wellhead enters the device, it undergoes gas-liquid separation, and the associated gas after separation accumulates at the top of the device.

[0036] At the top of the separation device, a gas pressure detection and control valve 15 is provided to monitor the gas pressure. A gas sample collection control gate 16 is connected to the sample gas inlet 1 of the measurement unit of this utility model through a pressure-resistant pipeline. A gas flow rate control valve 17 is used to adjust the gas sample outflow rate. A drain valve 18 is also provided at the bottom to periodically clean the separated liquid and solid impurities.

[0037] The core of the waste gas recovery unit is the gas booster pump 24. Its inlet is connected to the waste gas outlet 9 of the measuring unit via a pipeline, and its outlet is connected to the oil collection trunk line 23 of the metering room via a pipeline equipped with a check valve. When the system detects that the waste gas storage pressure has reached the set value, the gas booster pump 24 automatically starts, pressurizing and reinjecting all the detected waste gas back into the production collection and transportation process, realizing true closed-loop control and preventing direct discharge of waste gas.

[0038] The waste liquid generated from filtration is discharged to a dedicated oil and gas waste liquid collection tank through the metering room venting pipeline 25.

[0039] like Figure 3 As shown, during operation, the produced fluid from the oil well undergoes gas-liquid separation in the oil-gas separation device 14. The separated associated gas is drawn out from the gas sample collection control gate 16 by the sampling pump 6 and enters the measurement unit through the sample gas inlet 1. The sample gas flows sequentially through the pressure reducing valve 2 for depressurization, the oil-water filter assembly 3 and the particle filter assembly 4 for purification, and the drying assembly 5 for dehydration, becoming a standard sample gas whose pressure, cleanliness, and dryness all meet the testing requirements. Subsequently, under the monitoring of the flow meter 7, the sample gas passes through the hydrogen sulfide gas detection probe 8 at a constant flow rate to complete the concentration measurement. The measurement data is transmitted to the remote monitoring center via the wireless transmission module 12. The waste gas after testing is led to the gas booster pump 24 through the waste gas outlet 9 and is finally safely reinjected into the oil collection trunk line 23. The waste liquid generated during the pretreatment process is automatically discharged into the waste liquid collection system 25 by the electric sewage pump 10.

[0040] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A closed-loop control device for automatic detection of hydrogen sulfide content in associated gas from oil well produced fluid, characterized in that, It includes a pressure reducing valve, an oil-water filter assembly, a particle filter assembly, a drying assembly, a sampling pump, a flow meter, and a hydrogen sulfide gas detection probe connected in series. The pressure reducing valve is equipped with a sample gas inlet.

2. The automatic detection closed-loop control device for hydrogen sulfide content in associated gas from oil well produced fluid according to claim 1, characterized in that, The oil-water filtration assembly is mainly composed of multi-stage oil-water filters connected in series.

3. The automatic detection closed-loop control device for hydrogen sulfide content in associated gas from oil well produced fluid according to claim 2, characterized in that, The multi-stage oil-water filter is connected in parallel with an electric sewage pump.

4. The automatic detection closed-loop control device for hydrogen sulfide content in associated gas from oil well produced fluid according to claim 3, characterized in that, The drying assembly mainly consists of a series of multi-stage drying filters.

5. The automatic detection closed-loop control device for hydrogen sulfide content in associated gas from oil well produced fluid according to claim 4, characterized in that, The hydrogen sulfide gas detection probe is connected to a wireless communication module.

6. The automatic detection closed-loop control device for hydrogen sulfide content in associated gas from oil well produced fluid according to claim 5, characterized in that, The wireless communication module is a 4G communication module.

7. The automatic detection closed-loop control device for hydrogen sulfide content in associated gas from oil well produced fluid according to claim 5, characterized in that, The hydrogen sulfide gas detection probe is also connected to an exhaust outlet.

8. The automatic detection closed-loop control device for hydrogen sulfide content in associated gas from oil well produced fluid according to any one of claims 1-7, characterized in that, It also includes a power supply, which is electrically connected to the wireless communication module, the hydrogen sulfide gas detection probe, the sampling pump, and the electric sewage pump.

9. The automatic detection closed-loop control device for hydrogen sulfide content in associated gas from oil well produced fluid according to claim 8, characterized in that, The power supply is a switching power supply with AC220V / DC24V output.

10. The automatic detection closed-loop control device for hydrogen sulfide content in associated gas from oil well produced fluid according to claim 9, characterized in that, The sample gas inlet and exhaust gas outlet are made of stainless steel explosion-proof sealed glands.

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