Oil field fracturing flow-back fluid purification system

Abstract

The utility model is suitable for the field of oil field equipment, and provides an oil field fracturing flow-back fluid purification system which comprises a liquid guide pipe, a reaction kettle, a centrifugal pump, a liquid feeding system and a catalysis system, wherein the reaction kettle is provided with a liquid inlet pipe, a white cement feed opening and a gas phase emptying opening, the outer wall of the reaction kettle is provided with a thermal insulation layer, the liquid inlet pipe is communicated with the liquid guide pipe, the liquid inlet pipe is provided with a flow meter, a discharge opening of the reaction kettle is communicated with an input opening of the centrifugal pump, and the centrifugal pump is connected with the liquid guide pipe. A liquid phase output port of the centrifugal pump is communicated with a liquid inlet of the liquid feeding system, and a liquid outlet of the liquid feeding system is communicated with a liquid inlet of the catalysis system. The oil field fracturing flow-back fluid purification system has the advantages of being low in cost, high in purification efficiency, environmentally friendly, low in energy consumption and easy to operate.

Description

Technical Field

[0001] The utility model belongs to the technical field of oil field equipment, and in particular relates to an oil field fracturing return fluid purification system. Background Art

[0002] Fracturing technology refers to the process of using hydraulic force to create cracks in the oil layer during oil production, also known as hydraulic fracturing of the oil layer. After cracks appear in the oil layer, proppants are added to fill the cracks, improve the permeability of the oil layer, and increase oil production.

[0003] Fracturing fluid is a working fluid used for fracturing oil and gas reservoirs. It is an unstable chemical substance mixed with different types of additives in a specific proportion. According to different design process requirements and different fracturing stages, the fracturing fluid should have a certain fracture-making ability, the fractures should have good conductivity, and it should have the characteristics of small filtration loss, low residue, easy flowback, and strong sand suspension capacity to facilitate efficient reservoir development. Surfactants give fracturing fluids many advantages and properties that conventional fracturing fluids do not have. Since surfactants are soluble in water and can effectively reduce the surface energy of water, different types of surfactants are selected depending on the required properties and actual usage. Surfactants as additives to fracturing fluids can make fracturing fluids have key characteristics such as good flowback effect and little damage to formations and reservoirs, which can improve the entire drilling and production process.

[0004] Fracturing fluid flowback means that after the fracturing fluid is injected into the ground, the remaining material of the fracturing fluid must be returned to the ground for treatment or reuse. During the reuse of the flowback fluid, because the flowback fluid contains a large amount of Ca 2+ Mg 2+ , Fe 2+ The presence of divalent ions has a great impact on the viscosity and temperature resistance of the thickener. Because the fracturing flowback fluid contains a large amount of calcium, magnesium ions and carbonate and sulfate ions, it is very easy to precipitate in the form of scale at a certain concentration and temperature. Therefore, directly using the fracturing flowback fluid to make fracturing fluid and injecting it into the ground again will easily cause scaling to block the supporting fracture diversion channel, greatly reducing the fracturing production increase effect, resulting in production reduction or even shutdown. The fracturing fluid will change the microorganisms contained in it after experiencing the ground process, and it needs to be sterilized before it can be reinjected.

[0005] However, the existing method of treating oilfield fracturing return fluid has not been able to effectively remove the substances that are prone to scaling and precipitation. As the number of cycles accumulates and the formation deviates from the stable state, it eventually becomes scaling and ineffective, and cannot meet the reinjection standards. Utility Model Content

[0006] In order to solve the above problems existing in the related technologies, the utility model provides an oilfield fracturing flowback fluid purification system. The technical problems to be solved by the utility model are achieved through the following technical solutions:

[0007] An oilfield fracturing flowback fluid purification system comprises: a liquid guide pipe, a reactor, a centrifugal pump, a liquid feeding system and a catalytic system; wherein the reactor is provided with a liquid inlet pipe, a white cement discharge port and a gas phase venting port, and an outer wall of the reactor is provided with a thermal insulation layer, the liquid inlet pipe is connected with the liquid guide pipe, a flow meter is provided on the liquid inlet pipe, the discharge port of the reactor is connected with the input port of the centrifugal pump, the liquid phase output port of the centrifugal pump is connected with the liquid inlet of the liquid feeding system, and the liquid outlet of the liquid feeding system is connected with the liquid inlet of the catalytic system.

[0008] In some embodiments, the liquid feeding system includes: a first liquid storage tank and a clear liquid pump; wherein, the liquid inlet of the first liquid storage tank is connected to the liquid phase output port of the centrifugal pump, the liquid outlet of the first liquid storage tank is connected to the liquid inlet of the clear liquid pump, and the liquid outlet of the clear liquid pump is connected to the liquid inlet of the catalytic system.

[0009] In some embodiments, the catalytic system includes: a pipeline mixer, an ozone generator and an oxidation tower; wherein the liquid inlet of the pipeline mixer is connected to the liquid outlet of the liquid feeding system, the output port of the ozone generator is connected to the air inlet of the pipeline mixer, and the liquid outlet of the pipeline mixer is connected to the liquid inlet of the oxidation tower.

[0010] In some embodiments, the oxidation tower is a vertical tower structure, a liquid inlet is provided at the bottom of the tower body of the oxidation tower, a liquid outlet is provided at the top of the tower body, an exhaust port is provided at the top of the tower body, and a catalytic filler is provided in the middle of the tower body.

[0011] In some embodiments, the oilfield fracturing flowback fluid purification system further includes: a second liquid storage tank; the liquid inlet of the second liquid storage tank is connected to the liquid outlet of the oxidation tower.

[0012] In some embodiments, the oilfield fracturing flowback fluid purification system further includes: a slurry delivery pump; the liquid inlet of the slurry delivery pump is connected to the discharge port of the reactor, and the output port of the slurry delivery pump is connected to the input port of the centrifugal pump.

[0013] In some embodiments, the reactor is provided with an exhaust port.

[0014] In some embodiments, the centrifugal pump further comprises a solid phase output port.

[0015] In some embodiments, a radar level gauge is disposed on the top of the reactor.

[0016] In some embodiments, a glass window is provided on the top of the reactor.

[0017] The utility model has the following beneficial technical effects: the utility model first uses a liquid guide pipe and a reactor to fully mix and react white cement with oilfield fracturing return fluid in the reactor, so as to promote the supersaturation precipitation of easily scale-forming precipitates in the oilfield fracturing return fluid, actively flocculate and scale, and entrain and adsorb other organic impurities, and then use a centrifugal pump to separate the solid-liquid phase of the mixture containing impurities, and then oxidize the liquid separated by the centrifugal pump through a liquid feeding system and a catalytic system to deeply sterilize, thereby obtaining a fracturing fluid that meets the reinjection standard. The oilfield fracturing return fluid purification system provided by the utility model has the characteristics of low cost, high purification efficiency, green environmental protection, low energy consumption and simple operation.

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The utility model is a structural schematic diagram of an oilfield fracturing flowback fluid purification system.

[0020] Description of Figure Numbers:

[0021] 1-reactor, 2-slurry delivery pump, 3-centrifugal pump, 4-first clear liquid tank, 5-clear liquid pump, 6-pipeline mixer, 7-ozone generator, 8-oxidation tower, 81-catalytic filler. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with specific embodiments, but the implementation methods of the present invention are not limited thereto.

[0023] The existing method of treating oilfield fracturing flowback fluid fails to effectively remove the easily scaled precipitates, and there is a problem that the scale becomes ineffective as the number of cycles accumulates and the formation deviates from the stable state, and the problem that the re-injection standard cannot be met is solved. The utility model provides an oilfield fracturing flowback fluid purification system, which first uses a liquid guide pipe and a reactor to fully mix and react white cement with the oilfield fracturing flowback fluid in the reactor, so as to promote the supersaturation precipitation of the easily scaled precipitates in the oilfield fracturing flowback fluid, actively flocculate and scale, and entrain and adsorb other organic impurities, and then use a centrifugal pump to separate the solid-liquid phase of the mixture containing impurities, and then oxidize the liquid separated by the centrifugal pump through a liquid feeding system and a catalytic system for deep sterilization, so as to obtain a fracturing fluid that meets the re-injection standard. The oilfield fracturing flowback fluid purification system provided by the utility model has the characteristics of low cost, high purification efficiency, green environmental protection, low energy consumption and simple operation.

[0024] The utility model provides an oilfield fracturing flowback liquid purification system, comprising: a liquid guide pipe, a reactor, a centrifugal pump, a liquid feeding system and a catalytic system; wherein, the reactor is provided with a liquid inlet pipe, a white cement discharge port and a gas phase venting port, and an insulation layer is provided on the outer wall of the reactor, the liquid inlet pipe is connected with the liquid guide pipe, a flow meter is provided on the liquid inlet pipe, the discharge port of the reactor is connected with the input port of the centrifugal pump, the liquid phase output port of the centrifugal pump is connected with the liquid inlet of the liquid feeding system, and the liquid outlet of the liquid feeding system is connected with the liquid inlet of the catalytic system.

[0025] See also Figure 1 As shown, Figure 1 The utility model is a structural schematic diagram of an oilfield fracturing flowback fluid purification system.

[0026] Here, the centrifugal pump 3 is a horizontal centrifugal pump, and the reactor 1 is a normal pressure jacketed enamel reactor, and a white cement discharge port is arranged on the top thereof, and the white cement discharge port is connected to the discharge port of the white cement storage bin, and a star-shaped discharger is arranged at the discharge port of the white cement storage bin. The star-shaped discharger is used to control the rotation of the star-shaped blades in the star-shaped discharger to push the white cement to be discharged from the discharge port of the white cement storage bin. The white cement storage bin is a closed structure to prevent dust leakage.

[0027] Here, in order to prevent the liquid temperature from being too low and freezing, the insulation layer provided on the outer wall of the reactor 1 is a heat supplement jacket.

[0028] Here, white cement is white silicate cement, which can react chemically with the oilfield fracturing flowback fluid in the reactor 1 to replace the Ca in the oilfield fracturing flowback fluid. 2+ Mg 2+ , Fe 2+ The displaced substances flocculate and scale and entrain and absorb other impurities mixed in the liquid. Among them, in the reactor 1, the mass ratio of white cement and oilfield fracturing return fluid is 0.1% to 1%, and the time for the reactor 1 to stir the white cement and oilfield fracturing return fluid is 15min to 30min. After the stirring is completed, the generated solid-liquid mixture is transported to the horizontal centrifugal pump, the solid impurities are precipitated, and the liquid wastewater is extracted by the liquid feeding system and transported to the catalytic unit for secondary sterilization and purification. The method of using white cement and oilfield fracturing return fluid for chemical reaction does not rely on scale inhibitors, and the purification of fracturing return fluid can be completed in a short time. It is extremely efficient and has a high degree of purification, and there is no scaling risk during subsequent use. In addition, the purification device used is simple and easy to use, and does not require the use of expensive and sophisticated instruments, which can effectively save cost investment.

[0029] In a possible implementation, a radar level gauge is provided on the top of the reactor 1. Electric control valves are provided on the liquid inlet pipe and the white cement discharge port. When the radar level gauge monitors that the liquid level of the solid-liquid mixture in the reactor 1 reaches the highest liquid level, the electric control valve closes the liquid inlet pipe and the white cement discharge port.

[0030] In another possible implementation, a glass window is provided on the top of the reactor 1. The technician directly observes the liquid level in the reactor 1 through the glass window, and when the liquid level is about to reach the highest liquid level, the inlet pipe of the oilfield fracturing return fluid and the white cement discharge port are manually closed.

[0031] Please continue to see Figure 1 As shown, the oilfield fracturing flowback fluid purification system also includes: a slurry delivery pump 2; the liquid inlet of the slurry delivery pump 2 is connected to the discharge port of the reactor 1, and the output port of the slurry delivery pump is connected to the input port of the centrifugal pump 3. The slurry delivery pump 2 is used to extract the solid-liquid mixture to deliver the solid-liquid mixture to the centrifugal pump 3. Here, the slurry delivery pump 2 is a screw pump.

[0032] Please continue to see Figure 1 As shown, the centrifugal pump 3 also includes a solid phase output port. The solid phase output port is used to discharge solid phase impurities, and the solid phase impurities are transported out of the slurry cement by tank trucks. The solid phase impurities are slurry cement in a sludge state. The used white cement paste can be calcined and powdered again for recycling, or delivered for cement production. The sanitary landfill gradually solidifies into a concrete rock state without subsequent pollution.

[0033] Please continue to see Figure 1 As shown, in the oilfield fracturing flowback fluid purification system provided by the utility model, the liquid feeding system includes: a first liquid storage tank and a clean liquid pump 5; wherein, the liquid inlet of the first liquid storage tank is connected to the liquid phase output port of the centrifugal pump 3, the liquid outlet of the first liquid storage tank is connected to the liquid inlet of the clean liquid pump 5, and the liquid outlet of the clean liquid pump 5 is connected to the liquid inlet of the catalytic system.

[0034] Here, the clear liquid pump 5 is a self-priming centrifugal pump. The first liquid storage tank stores the separated liquid wastewater.

[0035] Please continue to see Figure 1 As shown, the catalytic system includes: a pipeline mixer 6, an ozone generator 7 and an oxidation tower 8; wherein the liquid inlet of the pipeline mixer 6 is connected to the liquid outlet of the liquid feeding system, the output port of the ozone generator 7 is connected to the air inlet of the pipeline mixer 6, and the liquid outlet of the pipeline mixer 6 is connected to the liquid inlet of the oxidation tower 8.

[0036] Here, the ozone generator 7 is a PSA pressure swing adsorption pure oxygen ozone generator, and the generated ozone has an oxygen purity of ≥90% and an ozone concentration of ≥125 mg / L.

[0037] Here, the oxidation tower 8 is a vertical tower structure, the bottom of the tower body of the oxidation tower is provided with a liquid inlet, the upper part of the tower body is provided with a liquid outlet, the top of the tower body is provided with an exhaust port, and the middle part of the tower body is provided with a catalytic filler. Among them, the catalytic filler 81 can be a mixture of activated carbon and aluminum oxide, and the catalytic filler 81 has the effect of adsorbing residual ozone and residual pollutants and promoting ozone oxidation and degradation of liquid wastewater. Among them, before being put into actual use, the catalytic filler 81 is pre-installed in the processing plant. After the installation is completed, the tower body is subjected to pressure resistance test and non-destructive testing to make it comply with relevant regulations and exit standards.

[0038] Here, the pipeline mixer 6 dissolves ozone in the liquid wastewater by fully stirring, and then pours the mixed liquid of the two into the oxidation tower 8. In the oxidation tower 8, the mixed liquid is catalyzed by the catalytic filler 81, so that the ozone and the liquid wastewater are further emulsified and fused, thereby achieving a deep sterilization effect; when the air pressure in the oxidation tower 8 exceeds the preset air pressure, the gas is discharged from the top exhaust port into the torch or boiler air intake system to ensure the internal air pressure balance.

[0039] Here, the oilfield fracturing return fluid purification system also includes: a second liquid storage tank; wherein the liquid inlet of the second liquid storage tank is connected to the liquid outlet of the oxidation tower 8. In one possible implementation, the liquid after deep sterilization, that is, the liquid level of the fracturing fluid that meets the reinjection standard, overflows from the liquid outlet after reaching the position where the liquid outlet is set, enters the second liquid storage tank or the water reservoir, is pumped away by an automatically controlled water pump, and is recycled. In another possible implementation, the device also includes a return water pump. A return water pump is set to extract the liquid in the oxidation tower 8, and the liquid is transported to the second liquid storage tank or the water reservoir, and is pumped away by an automatically controlled water pump for recycling. Here, the return water pump is a self-priming centrifugal pump.

[0040] Please continue to see Figure 1 As shown, an exhaust port is provided on the reactor 1. The reactor 1, the first clear liquid tank 4 and the oxidation tower 8 are gas-connected, and the volatile gas is discharged into the flare or boiler air intake system through the exhaust ports provided on the reactor 1 and the oxidation tower 8 to ensure internal pressure balance.

[0041] In the present invention, in order to avoid ion contamination, all equipment, pipelines, instruments and valves are not made of carbon steel, copper or zinc. The main body of the static equipment and pipeline materials (including the reactor 1, the first clear liquid tank 4, the oxidation tower 8, the second liquid storage tank and the pipeline mixer 6) are all made of 304 stainless steel, and the centrifugal pump 3, the return water pump, the slurry delivery pump 2 and the clear liquid pump 5 are made of 316 stainless steel, and lining with fluoroplastics or ceramics is allowed.

[0042] In the utility model, the installation and use of all electrical equipment meet the explosion-proof and communication protocol requirements of the use environment.

[0043] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0044] The above description shows and describes several preferred embodiments of the utility model, but as before, it should be understood that the utility model is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the utility model concept of this article through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the utility model, and should be within the scope of protection of the claims attached to the utility model.

Claims

1. An oilfield fracturing flowback fluid purification system, characterized in that: include: A liquid guide pipe, a reactor, a centrifugal pump, a liquid feeding system and a catalytic system; wherein the reactor is provided with a liquid inlet pipe, a white cement discharge port and a gas phase vent, and an outer wall of the reactor is provided with a thermal insulation layer, the liquid inlet pipe is connected with the liquid guide pipe, a flow meter is provided on the liquid inlet pipe, the discharge port of the reactor is connected with the input port of the centrifugal pump, the liquid phase output port of the centrifugal pump is connected with the liquid inlet of the liquid feeding system, and the liquid outlet of the liquid feeding system is connected with the liquid inlet of the catalytic system.

2. The oilfield fracturing flowback fluid purification system according to claim 1, characterized in that: The liquid feeding system includes: a first liquid storage tank and a clear liquid pump; wherein, the liquid inlet of the first liquid storage tank is connected to the liquid phase output port of the centrifugal pump, the liquid outlet of the first liquid storage tank is connected to the liquid inlet of the clear liquid pump, and the liquid outlet of the clear liquid pump is connected to the liquid inlet of the catalytic system.

3. The oilfield fracturing flowback fluid purification system according to claim 1, characterized in that: The catalytic system includes: a pipeline mixer, an ozone generator and an oxidation tower; wherein the liquid inlet of the pipeline mixer is connected to the liquid outlet of the liquid feeding system, the output port of the ozone generator is connected to the air inlet of the pipeline mixer, and the liquid outlet of the pipeline mixer is connected to the liquid inlet of the oxidation tower.

4. The oilfield fracturing flowback fluid purification system according to claim 3, characterized in that: The oxidation tower is a vertical tower structure, the bottom of the tower body of the oxidation tower is provided with a liquid inlet, the upper part of the tower body is provided with a liquid outlet, the top of the tower body is provided with an exhaust port, and the middle part of the tower body is provided with a catalytic filler.

5. The oilfield fracturing flowback fluid purification system according to claim 3, characterized in that: The oilfield fracturing flowback fluid purification system further comprises: a second liquid storage tank; the liquid inlet of the second liquid storage tank is connected to the liquid outlet of the oxidation tower.

6. The oilfield fracturing flowback fluid purification system according to claim 1, characterized in that: The oilfield fracturing flowback fluid purification system also includes: a slurry delivery pump; the liquid inlet of the slurry delivery pump is connected to the discharge port of the reactor, and the output port of the slurry delivery pump is connected to the input port of the centrifugal pump.

7. The oilfield fracturing flowback fluid purification system according to claim 3, characterized in that: The reactor is provided with an exhaust port.

8. The oilfield fracturing flowback fluid purification system according to claim 1, characterized in that: The centrifugal pump also includes a solid phase output port.

9. The oilfield fracturing flowback fluid purification system according to claim 1, characterized in that: A radar level gauge is arranged on the top of the reactor.

10. The oilfield fracturing flowback fluid purification system according to claim 1, characterized in that: A glass window is arranged on the top of the reactor.

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