Oil and gas field treatment waste liquid treatment equipment and process

Abstract

The application provides an oil and gas field measure waste liquid treatment equipment and process, and relates to the field of waste liquid treatment. The oil and gas field measure waste liquid treatment equipment comprises a multi-stage waste liquid treatment system connected at the head and tail, a pneumatic system, a blowdown system and a water distribution system. The waste liquid treatment system comprises a sedimentation tank and a purification tank, the sedimentation tank is installed in the purification tank, the purification tanks of the waste liquid treatment system are connected, and waste water in the previous purification tank can be moved into the next purification tank for transmission. The oil and gas field measure waste liquid treatment equipment and process can realize sludge reduction, sludge fishing, waste liquid homogenization and other effects, has higher integration, can be used modularly, can flexibly adjust the number of treatment units according to different waste liquid scales, does not need additional civil construction, and is more convenient to carry and install, and can be adapted to the oil and gas field mobile operation scene.

Description

Technical Field

[0001] This invention relates to the field of waste liquid treatment, specifically to a waste liquid treatment equipment and process for oil and gas field operations. Background Technology

[0002] During the exploration, development, and production processes of oil and gas fields, operations such as acidizing, fracturing, well washing, and water shut-off / profile modification generate a large amount of waste fluid, mainly including fracturing flowback fluid, acidizing waste fluid, and well washing waste fluid. This type of waste fluid is characterized by complex composition, high suspended solids content, strong colloidal particle stability, large viscosity fluctuations, high pollutant concentrations, and unstable water quality. It contains not only large amounts of solid impurities such as silt, formation debris, and flocculated sediments, but also contaminants such as crude oil, chemical additives, and polymers. If discharged or reinjected directly without effective treatment, it can easily cause reservoir blockage, pipeline corrosion, and pollution of surface soil and water bodies, seriously affecting safe production and environmental compliance management in oil and gas fields. Therefore, efficient, stable, and harmless treatment of this waste fluid is one of the core aspects of oil and gas field production and operation.

[0003] On the one hand, existing treatment equipment cannot achieve repeated removal of settled sludge, resulting in poor sludge treatment thoroughness and low precision in wastewater treatment. Conventional sedimentation tanks can only achieve the settling and separation of solid sludge through a single static sedimentation process. The settled sludge accumulates directly at the bottom of the tank and can only be discharged through periodic manual sludge removal or a single mechanical suction. In actual operation, fine colloidal particles and tiny silt particles in the wastewater are difficult to completely separate through a single sedimentation, leaving a large amount of fine suspended impurities in the wastewater after a single treatment. At the same time, the sludge deposited at the bottom carries some incompletely separated wastewater and light impurities. Existing equipment lacks a secondary, multi-stage sludge recycling structure, making it impossible to perform secondary flocculation, stratification, and re-sedimentation treatment on the settled sludge. This leads to the re-mixing of pollutants from the sludge into the wastewater, causing substandard wastewater treatment and large fluctuations in effluent quality. In addition, single-time sludge cleaning methods are prone to sludge residue and incomplete dredging. Long-term sludge residue will harden and breed dirt in the tank, block the flow channel and filter structure, significantly reduce the continuous processing capacity of the equipment, and increase the equipment failure rate and operation and maintenance costs.

[0004] In addition, existing split-type equipment has limited functionality, possessing only simple sedimentation and filtration capabilities, lacking supporting functions such as sludge recycling and purification, multi-stage fine treatment of waste liquid, and integrated temperature and pressure control. Its capacity to treat complex waste liquids with high viscosity and high impurity concentrations is insufficient, making it difficult to meet current oil and gas field environmental emission standards and waste liquid reinjection water quality requirements. In summary, existing oil and gas field waste liquid treatment equipment suffers from numerous technical shortcomings, including the inability to repeatedly remove sludge, incomplete sludge treatment, low equipment integration, large footprint, cumbersome operation and maintenance, low automation, and poor treatment effect stability. These shortcomings severely restrict the efficient, integrated, and intelligent development of oil and gas field waste liquid treatment. Therefore, there is an urgent need to develop an oil and gas field waste liquid treatment equipment that can achieve multi-stage repeated sludge removal, high integration, high treatment precision, and strong adaptability to address the pain points of existing technologies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an equipment and process for treating waste liquid from oil and gas field operations, which solves the problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: an oil and gas field waste liquid treatment device, comprising a multi-stage waste liquid treatment system, a pneumatic system, a sewage discharge system and a water distribution system connected end to end. The waste liquid treatment system includes a sedimentation tank and a purification tank. The sedimentation tank is installed in the purification tank. The purification tanks of the waste liquid treatment system are connected to each other, and the wastewater in the previous purification tank can be transferred to the next purification tank for transfer. The waste liquid treatment system also includes a movable pool bottom and a sludge scraping assembly. The movable pool bottom [1][2] is installed in the sedimentation tank and can move up and down in the sedimentation tank. The sludge scraping assembly is installed above the purification tank and is used to scrape off the sludge on the surface of the movable pool bottom after it is moved out of the sedimentation tank [3][4]. The sewage system connects to all waste liquid treatment systems and is used to transfer oil film and sludge. The pneumatic system connects the sedimentation tank and the purification tank, and can realize the aeration of the purification tank, control the position of the movable bottom in the sedimentation tank, and pressurize the wastewater in the purification tank into the sedimentation tank. The water distribution system is connected to the beginning waste liquid treatment system and the end waste liquid treatment system respectively, and is used to pump wastewater and treated waste liquid.

[0007] Preferably, the upper end of the purification tank is a sealed structure, and two sets of one-way valves are installed between the purification tank and the sedimentation tank. The two sets of one-way valves are located at the upper and lower ends of the sedimentation tank, respectively. The upper one-way valve can only allow wastewater in the sedimentation tank to move into the purification tank, and the lower one-way valve can only allow wastewater in the purification tank to move into the sedimentation tank. An overflow pipe is also installed on the other side of the purification tank. The overflow pipe is connected to the purification tank of the next waste liquid treatment system. The overflow pipe connected to the purification tank of the waste liquid treatment system at the end is connected to the water distribution system. The sedimentation tank and purification tank have a notch on the side facing the sewage system, and a diversion plate is installed on the notch. The sludge scraping assembly can block the notch.

[0008] Preferably, the movable pool bottom includes a heating base plate, a piston ring, and a rubber extension sleeve. The rubber extension sleeve is fitted onto the bottom of the outer ring of the heating base plate, and the outer ring of the rubber extension sleeve is fixed to the piston ring. The four bottom corners of the heating base plate are connected to the piston ring by elastic rods. The piston ring is located in the sedimentation tank and is slidably and sealed to the inner wall of the sedimentation tank.

[0009] Preferably, the sludge scraping assembly includes a scraper, a slide rail, and a mover. There are two sets of slide rails, both fixed to the upper end of the purification tank. There are two movers, which are installed on the two slide rails respectively. The two ends of the scraper are connected to the movers. The movers can drive the scraper to move when they move on the slide rails. The movers can adjust the angle of the scraper. When the scraper is in the notch position, its lower end can abut against the diversion plate.

[0010] Preferably, the pneumatic system includes a central distributor and air pipes A, B, and C connected to the central distributor. The bottom of the purification tank is provided with aeration holes. Air pipe A is connected to the aeration holes for aeration. Air pipe B is connected to the bottom of the sedimentation tank for moving the piston ring. Air pipe C is connected to the top of the purification tank for discharging wastewater from the purification tank into the sedimentation tank.

[0011] Preferably, the sewage system includes sewage pipes, which are fixed to the outside of all the purification tanks and correspond to the diversion plates.

[0012] Preferably, the water distribution system includes a water tank, a partition is fixedly installed inside the water tank, the end of the water tank is connected to a purification tank at the end, the front end of the water tank is guided to a sedimentation tank at the beginning, and the partition is used to separate wastewater.

[0013] An equipment and process for treating waste liquid from oil and gas field operations, comprising the following steps: S1: Wastewater is drawn from the water tank and released into the first set of sedimentation tanks, where it undergoes flocculation and sedimentation after chemical dosing; S2: Push the movable pool bottom upwards [5][6] so that the oil film above overflows from the position of the diversion plate. Continuing to push the movable pool bottom can allow wastewater to enter the purification tank for aeration treatment. Then scrape off the sludge on the movable pool bottom. S3: After compressed air treatment, the wastewater can be returned to the sedimentation tank for further sedimentation, and then the oil film removal and sludge scraping work can be carried out in step S2. S4: After treatment, the wastewater can overflow into the next waste liquid treatment system and then continue to perform oil film removal and sludge removal. S5: The purified wastewater will be moved to a water tank for further treatment.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The waste liquid treatment equipment and process for this oil and gas field measure, through the setting of a waste liquid treatment system, allows the waste liquid to be repeatedly circulated for sedimentation and aeration treatment. During the repeated sedimentation process, sludge can be centrally dried, and the waste liquid can also be treated in stages. Compared with existing technologies, it can achieve multiple effects such as sludge reduction, sludge removal, and waste liquid homogenization. The single waste liquid treatment system with centralized functions has a higher degree of integration and can be used modularly. The number of treatment units can be flexibly adjusted according to different waste liquid scales. No additional civil construction is required, and transportation and installation are more convenient. It can be adapted to the mobile field operation scenarios of oil and gas fields.

[0015] 2. The wastewater treatment equipment and process of this oil and gas field measure, through the combination of multi-stage wastewater treatment system with reciprocating sedimentation and aeration treatment, can remove oil and suspended solids from the wastewater step by step. It has stronger resistance to water quality fluctuations, more stable effluent quality after treatment, higher reagent utilization rate, and less reagent dosage. At the same time, through the closed-loop treatment process, it realizes a complete treatment system of wastewater pretreatment, deep purification, sludge reduction, and water resource reuse, with higher resource utilization rate and lower overall operating cost.

[0016] 3. The wastewater treatment equipment and process for this oil and gas field measures, by setting up a pneumatic system, allows the wastewater to flow driven by gas, and the effect of the gas can make the combination between the chemical solution and the wastewater more uniform.

[0017] 4. The waste liquid treatment equipment and process of this oil and gas field measure, by setting up a movable pool bottom and a sludge scraping component, can directly lift out the settled sludge and scrape it off, without the need for additional dredging into the pool. The sludge treatment efficiency is higher. In addition, the heating structure of the movable pool bottom can also dry and reduce the volume of sludge, thereby reducing the cost of subsequent sludge transportation and treatment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a top view of the structure of the present invention; Figure 3 This is a side view of the structure of the present invention; Figure 4 This is a top view of the water distribution system of the present invention; Figure 5 This is a connection diagram of multiple waste liquid treatment systems of the present invention; Figure 6This is a schematic diagram of the structure of a single waste liquid treatment system of the present invention; Figure 7 This is a structural diagram of the pneumatic system of the present invention; Figure 8 This is an internal structural diagram of the waste liquid treatment system of the present invention; Figure 9 This is a top view of the waste liquid treatment system of the present invention; Figure 10 This is a schematic diagram of the bottom structure of the movable pool bottom of the present invention; Figure 11 This is a top structural diagram of the movable pool bottom of the present invention; Figure 12 This is a bottom structural diagram of the purification tank of the present invention.

[0019] In the diagram: 1. Wastewater treatment system; 101. Sedimentation tank; 102. Purification tank; 103. Movable tank bottom; 1031. Heating base plate; 1032. Piston ring; 1033. Rubber extension sleeve; 1034. Elastic rod; 104. Sludge scraper assembly; 1041. Scraper; 1042. Slide rail; 1043. Movers; 105. Overflow pipe; 106. Drainage plate; 2. Pneumatic system; 201. Central distributor; 202. Air pipe A; 203. Air pipe B; 204. Air pipe C; 205. Aeration hole; 3. Sewage system; 301. Sewage pipe; 4. Water distribution system; 401. Water tank; 402. Baffle. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] It should be noted that all directional indications in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0022] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0024] like Figure 1-12 As shown, an oil and gas field wastewater treatment device and process includes a multi-stage wastewater treatment system 1, a pneumatic system 2, a sewage discharge system 3, and a water separation system 4 connected end-to-end. The wastewater treatment system 1 includes a sedimentation tank 101 and a purification tank 102. The sedimentation tank 101 is installed in the purification tank 102, and the purification tanks 102 of the wastewater treatment system 1 are connected to each other, allowing wastewater from one purification tank 102 to be transferred to the next. The wastewater treatment system 1 also includes a movable tank bottom 103 and a sludge scraper assembly 104. The movable tank bottom 103 is installed inside the sedimentation tank 101 and can move up and down within the sedimentation tank 101. The sludge scraper assembly 104 is installed above the purification tank 102 and is used to scrape off the sludge on the surface of the movable tank bottom 103 after it is moved upward out of the sedimentation tank 101. The sewage system 3 connects to all wastewater treatment systems 1 and is used to transfer oil film and sludge. The pneumatic system 2 connects to the sedimentation tank 101 and the purification tank 102, enabling aeration of the purification tank 102, control of the position of the movable bottom 103 in the sedimentation tank 101, and pumping wastewater from the purification tank 102 into the sedimentation tank 101. The water distribution system 4 connects to the beginning and end of the wastewater treatment system 1 and is used to pump wastewater and treated wastewater.

[0025] Oil and gas field treatment waste fluids include fracturing flowback fluid, acidizing waste fluid, well workover and washing waste fluid, and gas testing waste fluid. Common characteristics include high oil content, high suspended solids, high viscosity, high salinity, guar gum / slickwater polymers, heavy metals, and persistent COD. The equipment is mainly skid-mounted / vehicle-mounted / container integrated, suitable for dispersed well sites, intermittent operations, and rapid relocation. The treatment targets are divided into three categories: formation reinjection, compound fracturing fluid reuse, and compliant discharge / zero-discharge salt separation.

[0026] This application utilizes a modular, multi-stage treatment unit series structure, allowing for flexible adjustment of the number of treatment stages based on the influent water quality and treatment objectives. For reinjection needs, the number of treatment units can be reduced to control treatment costs; for reuse or compliant discharge requirements, advanced treatment units can be added to improve effluent quality, adapting to different treatment requirements. Each treatment unit internally completes a cyclical treatment process of sedimentation-oil skimming-aeration-re-sedimentation through pneumatic control. The overall equipment structure is simpler, with fewer potential failure points, making it more adaptable to complex field operating environments.

[0027] Unlike existing technologies, each treatment unit in this application can independently separate and remove oil and suspended solids. The entire treatment process is completed by gas power, eliminating the need for large pumping mechanisms, resulting in lower energy consumption. Furthermore, the movable pool bottom 103 is raised in conjunction with the sludge scraping assembly 104 to directly dry and scrape off sludge, eliminating the need for additional sludge thickening tanks and sludge pumps. This approach offers higher integration and is more suitable for mobile operations. Through multiple cycles of sedimentation and aeration, the flocculation reaction is more complete, and the separation of oil and suspended solids is more thorough. Each treatment unit can achieve water quality homogenization, and the stability of the effluent quality is significantly improved after multi-stage treatment. This forms a complete closed-loop treatment system from pretreatment and step-by-step purification to sludge reduction and wastewater reuse. This solves the problems of poor versatility, low integration, unstable effluent, and high operating costs of existing equipment, and can better meet the wastewater treatment needs of decentralized operations in oil and gas fields.

[0028] Sedimentation tank 101 is a small sedimentation tank, generally with an effective volume of a few cubic meters (0.5-5 m³). 3 This is a square integrated sedimentation unit, and its load capacity is completely different from that of a large municipal sedimentation tank. A narrow gap is left between the movable tank bottom 103 and the tank wall, and a wear-resistant sliding seal (EPDM / fluororubber lip seal + wear-resistant slider) is installed. An annular sand collection trough and flushing nozzle are set on the outer edge of the bottom plate to flush the sealing area before each raising and lowering to prevent solid particles from embedding into the sealing pair. The small movable tank bottom 103 does not require a very thick bottom plate; reinforced steel plate is sufficient. The load is not large, and deformation is easily controlled.

[0029] In an optional embodiment, the upper end of the purification tank 102 is a sealed structure. Two sets of one-way valves are installed between the purification tank 102 and the sedimentation tank 101. The two sets of one-way valves are located at the upper and lower ends of the sedimentation tank 101, respectively. The upper one-way valve can only allow wastewater in the sedimentation tank 101 to move into the purification tank 102, while the lower one-way valve can only allow wastewater in the purification tank 102 to move into the sedimentation tank 101. An overflow pipe 105 is also installed on the other side of the purification tank 102. The overflow pipe 105 is connected to the purification tank 102 of the next wastewater treatment system 1. The overflow pipe 105 connected to the purification tank 102 of the wastewater treatment system 1 at the end is connected to the water distribution system 4. The sedimentation tank 101 and the purification tank 102 have a notch on the side facing the sewage discharge system 3. A diversion plate 106 is installed on the notch, and the sludge scraper assembly 104 can block the notch.

[0030] In this embodiment, the upper one-way valve is a sliding opening valve. Once the water level exceeds the one-way valve, it can flow naturally. After the movable tank bottom 103 is raised to increase the water level, the supernatant after sedimentation can automatically flow into the purification tank 102 through the upper one-way valve without additional pumping. The lower one-way valve opens when the pneumatic system 2 pressurizes the purification tank 102, allowing the aerated wastewater to flow back to the sedimentation tank 101 for further sedimentation. The circulation of wastewater between the sedimentation tank 101 and the purification tank 102 is achieved using pneumatic power, resulting in a simple and reliable power structure. When the movable tank bottom 103 continues to rise and the water level is higher than the diversion plate 106, the oil film floating on the wastewater surface will flow directly into the sewage system 3 along the diversion plate 106, automatically completing the collection and removal of the surface oil film.

[0031] In an optional embodiment, the movable pool bottom 103 includes a heating base plate 1031, a piston ring 1032, and a rubber extension sleeve 1033. The rubber extension sleeve 1033 is fitted onto the bottom of the outer ring of the heating base plate 1031. The outer ring of the rubber extension sleeve 1033 is fixed to the piston ring 1032. The four bottom corners of the heating base plate 1031 are connected to the piston ring 1032 by elastic rods 1034. The piston ring 1032 is located in the sedimentation tank 101 and is slidably and sealed to the inner wall of the sedimentation tank 101.

[0032] In this embodiment, the heating base plate 1031 is equipped with an electric heating component, such as a resistance heating tube. After the sludge settles onto the surface of the heating base plate 1031, the water in the sludge is evaporated by heating, thereby achieving sludge drying and volume reduction. With the buffer connection structure of the elastic rod 1034, the heating base plate 1031 can always remain horizontal, ensuring the stability of the liquid surface during the lifting process and preventing the oil film and wastewater from shaking and mixing. The rubber extension sleeve 1033 can adaptively extend and contract with the movement of the heating base plate 1031, always maintaining a sealed structure and preventing wastewater from leaking from the gaps to below the piston ring 1032.

[0033] In an optional embodiment, the sludge scraping assembly 104 includes a scraper 1041, a slide rail 1042, and a mover 1043. There are two sets of slide rails 1042, both of which are fixed to the upper end of the purification tank 102. There are two movers 1043, which are respectively installed on the two slide rails 1042. The two ends of the scraper 1041 are connected to the movers 1043. The movers 1043 can move the scraper 1041 by moving on the slide rails 1042. The movers 1043 can adjust the angle of the scraper 1041. When the scraper 1041 is in the notch position, its lower end can abut against the diversion plate 106.

[0034] In this embodiment, the servo motor and gear are installed inside the mover 1043, and a rack is installed on the inner side of the slide rail 1042. The gear meshes with the rack. When the servo motor is working, it can drive the scraper 1041 to move along the slide rail 1042. When adjusting the angle of the scraper 1041, another rotating motor can drive the scraper 1041 to rotate relative to the mover 1043. After the sludge is dried, the movable tank bottom 103 is lifted out of the sedimentation tank 101. The scraper 1041 is rotated to an inclined state. Moving the scraper 1041 can scrape the dried sludge directly from the surface of the movable tank bottom 103 into the notch. The sludge enters the sewage system 3 along the diversion plate 106 to complete the sludge discharge. After scraping the sludge, the scraper 1041 can be reset. After the scraper 1041 is reset, the notch can be closed. The operation is highly automated and no manual entry into the tank is required for cleaning.

[0035] In an optional embodiment, the pneumatic system 2 includes a central distributor 201 and air pipes A202, B203, and C204 connected to the central distributor 201. The bottom of the purification tank 102 is provided with aeration holes 205. Air pipe A202 is connected to the aeration holes 205 for aeration. Air pipe B203 is connected to the bottom of the sedimentation tank 101 for moving the piston ring 1032. Air pipe C204 is connected to the top of the purification tank 102 for discharging wastewater from the purification tank 102 into the sedimentation tank 101.

[0036] In this embodiment, the central distributor 201 disperses the directly supplied gas using electromagnetic valves, controlling the opening and closing of the three gas pipes respectively. Gas is supplied and pressurized to the bottom of the sedimentation tank 101 through gas pipe B203, which pushes the piston ring 1032 and the movable tank bottom 103 to rise as a whole. After the gas is released, the pressure decreases, and the movable tank bottom 103 automatically falls back down, eliminating the need for an additional lifting drive mechanism and further simplifying the equipment structure. Gas pipe A202 supplies gas to the aeration holes 205, which generates fine bubbles in the purification tank 102, aerating and stirring the wastewater to ensure that the reagents and wastewater are fully mixed and reacted, improving the flocculation and sedimentation effect. After the gas pipe C204 pressurizes the top of the purification tank 102, the aerated wastewater is pushed back to the sedimentation tank 101 through the one-way valve below, completing the sedimentation cycle. The entire process is achieved through pneumatic control, with centralized power, simple control logic, and a lower failure rate.

[0037] In an optional embodiment, the sewage system 3 includes a sewage pipe 301, which is fixed to the outside of all the purification tanks 102 and corresponds to the diversion plate 106.

[0038] In this embodiment, the oil film and dried sludge separated from all waste liquid treatment units are directly discharged into the sewage pipe 301 through the corresponding diversion plate 106 for unified collection and transportation. This eliminates the need for each unit to have a separate sewage collection device, simplifies the overall structure, facilitates subsequent centralized treatment of oil and sludge, and reduces the cost of supporting facilities.

[0039] In an optional embodiment, the water separation system 4 includes a water tank 401, a partition 402 is fixedly installed inside the water tank 401, the end of the water tank 401 is connected to the end purification tank 102, the front end of the water tank 401 is guided to the beginning sedimentation tank 101, and the partition 402 is used to separate wastewater.

[0040] In this embodiment, the untreated high-concentration waste liquid and the treated purified waste liquid are separated on both sides of the water tank 401 by the partition 402, which further simplifies the equipment structure.

[0041] An equipment and process for treating waste liquid from oil and gas field operations, comprising the following steps: S1: Wastewater is drawn from water tank 401 and released into the first set of sedimentation tanks 101, where it undergoes flocculation and sedimentation after chemical dosing; S2: Push the movable pool bottom 103 upward so that the oil film above overflows from the position of the diversion plate 106. Continuously push the movable pool bottom 103 so that the wastewater can enter the purification tank 102 for aeration treatment. Then scrape off the sludge on the movable pool bottom 103. S3: After compressed air treatment, the wastewater can be returned to sedimentation tank 101 for further sedimentation, and then oil film removal and sludge scraping can be carried out in step S2. S4: After treatment, the wastewater can overflow into the next waste liquid treatment system 1, and then continue to perform oil film removal and sludge removal. S5: The purified wastewater will be moved to water tank 401 for further treatment.

[0042] In use, first, adjust the number of connected wastewater treatment system 1 units according to the scale of the wastewater to be treated. After assembling each unit with the pneumatic system 2, sewage system 3, and water distribution system 4 through pipelines, it can be put into use. The wastewater from oil and gas field operations to be treated is introduced into the water tank 401 of the water distribution system 4. The partition 402 in the water tank 401 separates the wastewater to be treated from the treated clean water. The wastewater is transported to the sedimentation tank 101 of the first wastewater treatment system 1. Flocculation agents are added to the sedimentation tank 101. The suspended solids and oil impurities in the wastewater flocculate and settle on the heating base plate 1031 of the movable tank bottom 103. After the initial sedimentation is completed, the pneumatic system 2 connects to the system via air pipes. B203 introduces compressed air into the bottom of sedimentation tank 101. The air pressure pushes piston ring 1032 upward along the inner wall of sedimentation tank 101. Piston ring 1032 drives heating base plate 1031 to rise synchronously. As the movable tank bottom 103 rises, the liquid level in sedimentation tank 101 rises. The oil film floating on the liquid surface overflows from the notch along the guide plate 106 and flows into the sewage pipe 301 of sewage system 3 for discharge. After the movable tank bottom 103 continues to rise, the wastewater in sedimentation tank 101 exceeds the position of the upper one-way valve and flows into purification tank 102 through the upper one-way valve. At this time, the movable tank bottom 103 is raised to the notch position, and the settled sludge is fully exposed. The angle of scraper 1041 is adjusted to tilt it. The scraper 1041, driven by the mover 1043, moves along the slide rail 1042 to scrape the sludge from the surface of the heating base plate 1031 into the sewage pipe 301 to complete the cleaning. After cleaning, the scraper 1041 returns to its original position. At the same time, the central distributor 201 supplies air to the air pipe A202, and compressed air is discharged from the aeration hole 205 at the bottom of the purification tank 102 to aerate the wastewater in the purification tank 102, allowing the chemicals to mix fully with the wastewater and improving the treatment effect. After aeration, the central distributor 201 supplies air to the air pipe C204, and compressed air enters the sealed top of the purification tank 102, pressurizing the wastewater in the purification tank 102 through the one-way valve below. The wastewater is returned to the sedimentation tank 101 for sedimentation again. The above steps of oil film overflow and sludge scraping are repeated. After multiple cycles, the wastewater flows into the next stage of waste liquid treatment system 1 through the overflow pipe 105 to repeat the treatment process. After all treatment units are completed, the qualified effluent flows back to the water tank 401 clean water area of ​​the water distribution system 4 through the overflow pipe 105 of the terminal purification tank 102, which can be reused later. During the sludge scraping process, the heating base plate 1031 can be activated to heat and dry the surface sludge, reduce the sludge moisture content, and reduce the subsequent transportation and treatment costs. The entire treatment process does not require civil engineering. The modular units can be flexibly combined to meet different scale treatment needs and are suitable for mobile operations in oil and gas fields.

[0043] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0044] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A waste liquid treatment device for oil and gas field operations, characterized in that: The system includes a multi-stage wastewater treatment system (1), a pneumatic system (2), a sewage discharge system (3), and a water distribution system (4). The wastewater treatment system (1) includes a sedimentation tank (101) and a purification tank (102). The sedimentation tank (101) is installed in the purification tank (102). The purification tanks (102) of the wastewater treatment system (1) are connected to each other. Wastewater in the previous purification tank (102) can be transferred to the next purification tank (102) for transfer. The waste liquid treatment system (1) also includes a movable tank bottom (103) and a sludge scraping assembly (104). The movable tank bottom (103) is installed in the sedimentation tank (101) and can move up and down in the sedimentation tank (101). The sludge scraping assembly (104) is installed above the purification tank (102) and is used to scrape off the sludge on its surface after the movable tank bottom (103) moves upward out of the sedimentation tank (101). The sewage system (3) connects to all waste liquid treatment systems (1) and is used to transfer oil film and sludge. The pneumatic system (2) connects the sedimentation tank (101) and the purification tank (102) and can aerate the purification tank (102), control the position of the movable bottom (103) in the sedimentation tank (101), and pressurize the wastewater in the purification tank (102) into the sedimentation tank (101). The water distribution system (4) is connected to the waste liquid treatment system (1) at the beginning and the waste liquid treatment system (1) at the end, respectively, for pumping wastewater and treated waste liquid.

2. The oil and gas field wastewater treatment equipment according to claim 1, characterized in that: The upper end of the purification tank (102) is a sealed structure. Two sets of one-way valves are installed between the purification tank (102) and the sedimentation tank (101). The two sets of one-way valves are located at the upper and lower ends of the sedimentation tank (101). The upper one-way valve can only allow wastewater in the sedimentation tank (101) to move into the purification tank (102), and the lower one-way valve can only allow wastewater in the purification tank (102) to move into the sedimentation tank (101). An overflow pipe (105) is also installed on the other side of the purification tank (102). The overflow pipe (105) is connected to the purification tank (102) of the next waste liquid treatment system (1). The overflow pipe (105) connected to the purification tank (102) of the waste liquid treatment system (1) at the end is connected to the water distribution system (4). The sedimentation tank (101) and the purification tank (102) have a notch on the side facing the sewage system (3), and a diversion plate (106) is installed on the notch. The sludge scraping assembly (104) can block the notch.

3. The oil and gas field wastewater treatment equipment according to claim 2, characterized in that: The movable pool bottom (103) includes a heating base plate (1031), a piston ring (1032), and a rubber extension sleeve (1033). The rubber extension sleeve (1033) is fitted onto the bottom of the outer ring of the heating base plate (1031). The outer ring of the rubber extension sleeve (1033) is fixed to the piston ring (1032). The four bottom corners of the heating base plate (1031) are connected to the piston ring (1032) by elastic rods (1034). The piston ring (1032) is located in the sedimentation tank (101) and is slidably and sealed to the inner wall of the sedimentation tank (101).

4. The oil and gas field wastewater treatment equipment according to claim 3, characterized in that: The sludge scraping assembly (104) includes a scraper (1041), a slide rail (1042), and a mover (1043). There are two sets of slide rails (1042), both of which are fixed to the upper end of the purification tank (102). There are two movers (1043), which are installed on the two slide rails (1042) respectively. The two ends of the scraper (1041) are connected to the movers (1043). The movers (1043) can drive the scraper (1041) to move when they move on the slide rails (1042). The movers (1043) can adjust the angle of the scraper (1041). When the scraper (1041) is in the notch position, its lower end can abut against the diversion plate (106).

5. The oil and gas field wastewater treatment equipment according to claim 4, characterized in that: The pneumatic system (2) includes a central distributor (201) and air pipes A (202), B (203) and C (204) connected to the central distributor (201). The bottom of the purification tank (102) is provided with aeration holes (205). Air pipe A (202) is connected to the aeration holes (205) to realize aeration. Air pipe B (203) is connected to the bottom of the sedimentation tank (101) to realize the movement of piston ring (1032). Air pipe C (204) is connected to the top of the purification tank (102) to press out the wastewater in the purification tank (102) into the sedimentation tank (101).

6. The oil and gas field wastewater treatment equipment according to claim 5, characterized in that: The sewage system (3) includes a sewage pipe (301), which is fixed on the outside of all the purification tanks (102) and corresponds to the diversion plate (106).

7. The oil and gas field wastewater treatment equipment according to claim 6, characterized in that: The water separation system (4) includes a water tank (401), a partition (402) is fixedly installed inside the water tank (401), the end of the water tank (401) is connected to the end purification pool (102), the front end of the water tank (401) is guided to the beginning sedimentation pool (101), and the partition (402) is used to separate wastewater.

8. An oil and gas field treatment waste liquid treatment device and process, utilizing the oil and gas field treatment waste liquid treatment device as described in claim 7, characterized in that: Includes the following steps: S1: Wastewater is drawn from the water tank (401) and released into the first set of sedimentation tanks (101), where it undergoes flocculation and sedimentation after chemical dosing; S2: Push the movable pool bottom (103) upward so that the oil film above overflows from the position of the diversion plate (106). Continuing to push the movable pool bottom (103) can allow the wastewater to enter the purification tank (102) for aeration treatment. Then scrape off the sludge on the movable pool bottom (103). S3: After compressed air treatment, the wastewater can be returned to the sedimentation tank (101) for further sedimentation, and then the oil film removal and sludge scraping work can be carried out in step S2. S4: After treatment, the wastewater can overflow into the next waste liquid treatment system (1) and then continue to perform oil film removal and sludge removal work; S5: The purified wastewater will be moved to the water tank (401) for further treatment.

Images