Process treatment method for gas well produced water

Abstract

The invention discloses a process treatment method for gas well produced water, which comprises the following steps: detecting the water quality of a liquid flow to be treated contained in a sedimentation tank, respectively adopting different treatment modes for high-water-quality and low-water-quality treated liquid flows, and if the treated liquid flows are high-water-quality treated liquid flows, the treated liquid flows are low-water-quality treated liquid flows and low-water-quality treated liquid flows are high-water-quality treated liquid flows. If yes, the rotating motor operates at the first rotating speed at the initial position in the height direction, then the rotating motor is controlled to move to the position below the sedimentation tank and operates at the lowest rotating speed, and therefore it can be guaranteed that a precipitant in the sedimentation tank is mixed with water produced by the gas well, and the situation that the rotating speed of the rotating motor is too large, and consequently impact of precipitates is caused is prevented; if the treated liquid flow is low in water quality, the rotating motor reciprocates between a first position and a second position in the height direction after rotating at a relatively high rotating speed, and the rotating speed is correspondingly changed in the middle stage of the moving process; the mixing performance can be improved through centrifugal operation generated by top rotational flow while mixing of the precipitant and water produced by drilling is improved.

Description

Technical Field

[0001] The present application relates to the technical field of treatment of produced water from a gas well, and in particular to a process treatment method for produced water from a gas well. Background Art

[0002] Gas well produced water refers to the water produced from the gas well along with the natural gas during the natural gas extraction process. Its main sources are: Formation water: native water in the natural gas reservoir, that is, when the natural gas is extracted, the water in the reservoir is also taken out. Fracturing fluid: During the fracturing operation of the gas well, a large amount of fracturing fluid is injected to create cracks to increase the permeability of the gas well. These fracturing fluids will mix with the formation water after fracturing and be produced together when the gas well produces gas. Rainwater and groundwater: During the extraction process of the gas well, rainwater may seep into the well or nearby groundwater may flow into the well.

[0003] The characteristics of gas well produced water are large changes in water quantity and quality. It usually contains high levels of salt, minerals, suspended solids, organic matter, and may even contain heavy metals and radioactive substances. These components can cause potential harm to the environment, so the produced water needs to be properly treated and disposed of. The treatment and reuse of gas well produced water is an important part of the natural gas extraction process. It is not only related to environmental protection, but also involves the effective use of resources and the stable production of gas wells.

[0004] At present, the treatment methods for gas well produced water include: 1. Physical treatment method: remove minerals and suspended solids through gravity separation, centrifugal separation, filtration and separation. 2. Chemical treatment method: use coagulation sedimentation, chemical oxidation and other methods to treat colloids and emulsified oil, and use oxidants to decompose the oil in the wastewater to purify the wastewater. 3. Biological treatment method: use the metabolism of microorganisms to degrade organic matter in wastewater, which is suitable for treating produced water containing a large amount of organic matter.

[0005] At present, in order to achieve effective treatment of gas well produced water, flocculants or precipitants are added to the sedimentation tank to react with the gas well produced water and produce precipitates. In order to achieve effective mixing of the flocculants or precipitants with the gas well produced water, a stirring device is set in the sedimentation tank to improve the mixing performance by stirring the liquid flow. However, at present, the operation mode of the stirring device in the mixing treatment process of gas well produced water is relatively single, and different mixing and stirring cannot be performed for gas well produced water of different water quality, thereby failing to effectively improve the treatment performance of gas well produced water. Summary of the invention

[0006] In an exemplary embodiment of the present application, a process treatment method for gas well produced water is provided, by rationally designing the working mode of the stirring unit according to gas well produced water of different water qualities, thereby improving the working performance of the gas well produced water in the sedimentation treatment process.

[0007] The present application provides a process treatment method for gas well produced water, comprising:

[0008] Testing the water quality of the treated liquid flow contained in the sedimentation tank to determine whether the water quality of the treated liquid flow is high water quality or low water quality;

[0009] If the water quality of the treated liquid flow is low, a precipitant is input into the sedimentation tank, the rotary motor is driven to move to an initial position and to operate at a first speed in a first time period, after the rotary motor operates in the first time period, the rotary motor is driven to move to the first position and to operate at a minimum speed in a second time period;

[0010] The output end of the rotating motor is connected to a driving shaft, a stirring blade is arranged on the driving shaft, and the stirring blade is driven by the rotating motor to rotate in the sedimentation tank, the first speed is greater than the minimum speed, and the first position is located below the initial position in the height direction of the sedimentation tank;

[0011] If the water quality of the treated liquid flow is high, a precipitant is input into the sedimentation tank, the rotary motor is driven to move to the initial position and operate at a second speed in a third time period, after the rotary motor operates in the third time period, the rotary motor is driven to move to the second position and reciprocate between the second position and the first position in a fourth time period and maintain operation, and when the rotary motor is driven to move from the first position to the second position in the fourth time period, the speed of the rotary motor is gradually reduced;

[0012] The second rotational speed is greater than the first rotational speed, and the second position is located above the initial position in the height direction of the sedimentation tank.

[0013] Further, when the rotating motor is driven to move from the second position toward the first position within the fourth time period, the rotation speed of the rotating motor gradually increases.

[0014] Further, the maximum rotational speed of the rotating electrical machine when operating in the fourth time period is the second rotational speed, and the minimum rotational speed of the rotating electrical machine when operating in the fourth time period is the minimum rotational speed.

[0015] Further, the first time period is greater than the second time period, and the third time period is less than the fourth time period.

[0016] Furthermore, the fourth time period is shorter than the second time period.

[0017] Furthermore, after driving the rotating motor to operate in the second time period, the rotating motor is controlled to stop operating.

[0018] Further, after driving the rotating electric machine to operate in the fourth time period, the rotating electric machine is controlled to stop operating.

[0019] Furthermore, the initial position is located between the first position and the second position and at a middle position along the height direction of the sedimentation tank.

[0020] The embodiments of the present application have the following beneficial effects: by detecting the water quality of the liquid flow to be treated in the sedimentation tank, different treatment methods are adopted for the treated liquid flow with high water quality and low water quality, respectively. If the treated liquid flow is of high water quality, the rotating motor is operated at a first speed at the initial position in the height direction, and then the rotating motor is controlled to move to the lower position of the sedimentation tank and operate at the lowest speed, thereby ensuring that the precipitant in the sedimentation tank is mixed with the produced water of the gas well and preventing the rotating motor from rotating too fast to cause the impact of the sediment. If the treated liquid flow is of low water quality, the rotating motor is operated at a higher speed. After operation, it reciprocates between the first position and the second position in the height direction, and the rotation speed changes accordingly during the movement process. While improving the mixing of the precipitant and the drilling produced water, the centrifugal operation generated by the top vortex can be used to improve the mixing performance. Therefore, by adjusting the working position and rotation speed of the rotating motor in the height direction, high-quality and low-quality gas well produced water can be efficiently mixed with the precipitant, and then the working mode of the stirring unit can be reasonably designed for gas well produced water with different water qualities to improve the working performance of the gas well produced water in the sedimentation treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 A schematic diagram of a process treatment method for produced water from a gas well provided in an embodiment of the present application is exemplarily shown;

[0023] Figure 2 The schematic diagram of the structure of a treatment device for produced water from a gas well provided in an embodiment of the present application is exemplarily shown. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0025] To further illustrate the technical solution provided by the embodiment of the present application, the following is a detailed description of this in conjunction with the accompanying drawings and specific implementation methods. Although the embodiment of the present application provides the operation steps of the composite processing system as shown in the following embodiments or drawings, more or fewer operation steps may be included in the composite processing system based on routine or no creative labor. In the steps where there is no necessary causal relationship logically, the execution order of these steps is not limited to the execution order provided by the embodiment of the present application.

[0026] refer to Figure 1 and 2 As shown, the present application provides a process treatment method for gas well produced water, comprising the following steps:

[0027] S1: Detect the water quality of the treated liquid flow contained in the sedimentation tank 11 to determine whether the water quality of the treated liquid flow is high or low. Specifically, the water quality of the treated liquid flow contained in the sedimentation tank 11 can be detected by a water quality detection device, that is, the water quality of the gas well produced water is detected, wherein the gas well produced water mainly includes calcium, magnesium, iron, sulfate, and chloride ions, and a precipitant needs to be added to precipitate the above ions and heavy metal ions and separate them from the gas well produced water. Among them, the optional precipitant is lime, sodium carbonate, etc.

[0028] Specifically, the water quality of the gas well produced water can be qualitatively judged and determined by setting the corresponding threshold value. If the water quality determined by the water quality detection device is higher than or equal to the threshold value, the water quality of the decapping liquid flow is high water quality. Correspondingly, if the water quality determined by the water quality detection device is lower than the threshold value, the water quality of the decapping liquid flow is low water quality. In addition, different treatment methods can be adopted for gas well produced water with different water qualities in the future.

[0029] S2: If the water quality of the treated liquid flow is low, a precipitant is input into the sedimentation tank 11, and the rotating motor 21 is driven to move to the initial position and operate at a first speed in a first time period. After the rotating motor 21 operates in the first time period, the rotating motor 21 is driven to move to the first position and operate at the lowest speed in a second time period.

[0030] The output end of the rotary motor 21 is connected to the driving shaft 22, and the driving shaft 22 is provided with a stirring blade 23, and the rotary motor 21 drives the stirring blade 23 to rotate in the sedimentation tank 11. The driving shaft 22 is used as a connecting device, one end of which is connected to the output shaft of the rotary motor 21, and the other end is provided with or connected to the stirring blade 23, and the rotary motor 21 drives the stirring blade 23 to rotate to achieve sufficient stirring and mixing of the liquid flow (including gas well produced water and precipitant) in the sedimentation tank 11.

[0031] Specifically, the moving device 24 driving the rotary motor 21 to move between the initial position, the first position or the second position can be a hydraulic cylinder, a pneumatic cylinder or a connection method of a gear rack or a worm gear to realize the movement of the rotary motor 21 in the height direction. This application does not make specific limitations here.

[0032] Specifically, when the rotating motor 21 is driven in the initial position, the first position or the second position, the corresponding stirring blades 23 connected thereto are also located in the middle, lower and upper areas of the sedimentation tank 11. By adjusting the position of the rotating motor 21, the position of the stirring blades 23 used for mixing and stirring in the height direction of the sedimentation tank 11 is adjusted accordingly.

[0033] Specifically, the initial position is located between the first position and the second position and at a middle position in the height direction of the sedimentation tank 11 .

[0034] The first rotation speed is greater than the minimum rotation speed, the first position is located below the initial position in the height direction of the sedimentation tank 11 , and the second position is located above the initial position in the height direction of the sedimentation tank 11 .

[0035] In this stage, the rotary motor 21 is first driven to be located at the initial position and operated at a relatively high or medium first speed, which helps the agent to diffuse rapidly in the water and fully contact with the pollutants, so that the precipitant can be fully mixed in the sedimentation tank 11, and then the initial precipitation can be achieved. After the first period of operation, at this time, the flocs that have been formed need a milder environment to continue to grow and condense, and the rotary motor 21 is driven to move downward to the first position, driving the stirring blade 23 to operate at the lowest speed. At this time, while fully ensuring the mixing of the precipitant and the gas well produced water, the flocs can be prevented from being destroyed, and at the same time, it is conducive to the precipitation of the flocs. The stirring blade 23 driven by the rotary motor 21 at the first position can achieve a slight disturbance of the liquid flow, and while preventing the precipitation flocs from being destroyed, it can also achieve a slight impact on the flocs to a certain extent, preventing the deposition or accumulation from being tight and affecting the subsequent discharge of the flocs or sediments.

[0036] S3: If the water quality of the treated liquid flow is high, a precipitant is input into the sedimentation tank 11, and the rotary motor 21 is driven to move to the initial position and operate at a second speed in a third time period, wherein the second speed is greater than the first speed. Thus, the precipitant can flow in the sedimentation tank 11 at a higher flow rate or in a moving state in the third time period, and effectively achieve mixing with the produced water of the gas well.

[0037] After the rotating motor 21 operates in the third time period, the rotating motor 21 is driven to move to the second position and reciprocates between the second position and the first position in a fourth time period and maintains operation. When the rotating motor 21 is driven to move from the first position toward the second position in the fourth time period, the rotation speed of the rotating motor 21 gradually decreases. When the rotating motor 21 is driven to move from the second position toward the first position in the fourth time period, the rotation speed of the rotating motor 21 gradually increases.

[0038] In this process, by adjusting the reciprocating movement of the rotating motor 21 in the height direction and the speed change adjustment of the rotating motor 21, it is possible to ensure that the stirring blade 23 rotates at a higher speed below the sedimentation tank 11, and generate a stronger centrifugal or cyclonic motion in the liquid flow contained in the sedimentation tank 11, thereby promoting the flow state of the precipitant and allowing it to be fully mixed with the gas well produced water. When the stirring blade 23 moves toward the second position above, the speed of the rotating motor 21 is reduced. While making full use of the centrifugal or cyclonic motion generated when it runs at a high speed in the first position, the mixing performance of the precipitant and the gas well produced water can be guaranteed and the speed of the rotating motor 21 can be reduced to reduce power consumption.

[0039] When the water quality of the gas well produced water is judged to be of high quality, the sediment that may be produced by adding the precipitant is relatively small. At this time, it is necessary to focus on the treatment efficiency of the gas well produced water. By changing the speed and working position of the rotating motor 21 in the shortest possible time, the flow state of the liquid flow in the sedimentation tank 11 can be enriched or greatly adjusted, thereby improving the treatment efficiency. If the water quality of the gas well produced water is judged to be low, the sediment that may be generated by adding the precipitant is relatively large. At this time, it is necessary to focus on the stability of the flocs or sediments generated in the treatment process of the gas well produced water and the subsequent discharge and treatment performance of the flocs or sediments. Therefore, in the technical solution provided in the present application, by driving the rotating motor 21 downward to the first position, the stirring blade 23 is driven to operate at the lowest speed. At this time, while fully ensuring the mixing of the precipitant and the gas well produced water, the flocs can be avoided from being destroyed, and at the same time, it is beneficial to the precipitation of the flocs. The stirring blade 23 driven by the rotating motor 21 in the first position can achieve a slight disturbance of the liquid flow. While preventing the precipitated flocs from being destroyed, it can also achieve a slight impact on the flocs to a certain extent, preventing deposition or accumulation from being tight and affecting the subsequent discharge of the flocs or sediments.

[0040] The maximum rotation speed of the rotating electrical machine 21 when operating in the fourth time period is the second rotation speed, and the minimum rotation speed of the rotating electrical machine 21 when operating in the fourth time period is the lowest rotation speed.

[0041] Further, the first time period is greater than the second time period, the third time period is less than the fourth time period, and the fourth time period is less than the second time period.

[0042] Furthermore, after driving the rotating motor 21 to operate in the second time period, the rotating motor 21 is controlled to stop operating, and after driving the rotating motor 21 to operate in the fourth time period, the rotating motor 21 is controlled to stop operating, thereby ensuring that the precipitant is fully mixed in the sedimentation tank 11 and then allowed to react statically to achieve stable generation of precipitates.

[0043] By detecting the water quality of the liquid flow to be treated in the sedimentation tank 11, different treatment methods are adopted for the treated liquid flow with high water quality and low water quality. If the treated liquid flow is of high water quality, the rotating motor 21 is operated at a first speed at the initial position in the height direction, and then the rotating motor 21 is controlled to move to the lower position of the sedimentation tank 11 and operate at the lowest speed, thereby ensuring that the precipitant in the sedimentation tank 11 is mixed with the gas well produced water and preventing the rotating motor 21 from rotating too fast to cause the impact of the sediment. If the treated liquid flow is of low water quality, the rotating motor 21 is operated at a higher speed. Afterwards, it reciprocates between the first position and the second position in the height direction, and the rotation speed changes accordingly during the movement process. While improving the mixing of the precipitant and the drilling produced water, the centrifugal operation generated by the top vortex can be used to improve the mixing performance. Therefore, by adjusting the working position and rotation speed of the rotating motor 21 in the height direction, high-quality and low-quality gas well produced water can be efficiently mixed with the precipitant, and then the working mode of the stirring unit can be reasonably designed for gas well produced water with different water qualities to improve the working performance of the gas well produced water in the sedimentation treatment process.

[0044] Those skilled in the art will appreciate that the embodiments of the present application can be provided as a composite processing system, system, or computer program product. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0045] The present application is described with reference to the flowcharts and / or block diagrams of the composite processing system, device (system), and computer program product according to the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0046] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0047] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0048] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A process treatment method for gas well produced water, characterized in that: include: Testing the water quality of the treated liquid flow contained in the sedimentation tank to determine whether the water quality of the treated liquid flow is high water quality or low water quality; If the water quality of the treated liquid flow is low, a precipitant is input into the sedimentation tank, the rotary motor is driven to move to an initial position and to operate at a first speed in a first time period, after the rotary motor operates in the first time period, the rotary motor is driven to move to the first position and to operate at a minimum speed in a second time period; The output end of the rotating motor is connected to a driving shaft, a stirring blade is arranged on the driving shaft, and the stirring blade is driven by the rotating motor to rotate in the sedimentation tank, the first speed is greater than the minimum speed, and the first position is located below the initial position in the height direction of the sedimentation tank; If the water quality of the treated liquid flow is high, a precipitant is input into the sedimentation tank, the rotary motor is driven to move to the initial position and operate at a second speed in a third time period, after the rotary motor operates in the third time period, the rotary motor is driven to move to the second position and reciprocate between the second position and the first position in a fourth time period and maintain operation, and when the rotary motor is driven to move from the first position to the second position in the fourth time period, the speed of the rotary motor is gradually reduced; The second rotational speed is greater than the first rotational speed, and the second position is located above the initial position in the height direction of the sedimentation tank.

2. The process treatment method for gas well produced water according to claim 1, characterized in that: When the rotating motor is driven to move from the second position toward the first position within the fourth time period, the rotation speed of the rotating motor gradually increases.

3. The process treatment method for gas well produced water according to claim 2, characterized in that: The maximum rotation speed of the rotating electric machine when operating in the fourth time period is the second rotation speed, and the minimum rotation speed of the rotating electric machine when operating in the fourth time period is the lowest rotation speed.

4. The process treatment method for gas well produced water according to claim 3, characterized in that: The first time period is greater than the second time period, and the third time period is less than the fourth time period.

5. The process treatment method for gas well produced water according to claim 4, characterized in that: The fourth time period is shorter than the second time period.

6. The process treatment method for gas well produced water according to claim 5, characterized in that: After driving the rotating electric machine to operate in the second time period, the rotating electric machine is controlled to stop operating.

7. The process treatment method for gas well produced water according to claim 1, characterized in that: After driving the rotating electric machine to operate in the fourth time period, the rotating electric machine is controlled to stop operating.

8. The process treatment method for gas well produced water according to claim 1, characterized in that: The initial position is located between the first position and the second position and at a middle position along the height direction of the sedimentation tank.

Images