CN210367068U - Fracturing flow-back fluid and oil field produced water solid-liquid separation system - Google Patents

Abstract

The utility model particularly relates to a flowing back and oil field extraction water solid-liquid separation system are returned to fracturing, this system is including adding medicine mixing unit, dissolve the air water unit, mix reaction unit and whirl air supporting unit, add medicine mixing unit and dissolve the play water end of air water unit all with the end intercommunication of intaking of mixing reaction unit, the play water end of mixing reaction unit and the end intercommunication of intaking of whirl air supporting unit, whirl air supporting unit includes the barrel, go up lid and the whirl air supporting subassembly of setting inside the barrel, the connection can be dismantled to barrel and last lid, whirl air supporting subassembly includes row oil pipe, the back taper shell, first cylinder shell, the second cylinder shell, the toper shell, arrange the miscellaneous pipe, first inlet tube, baffle under second inlet tube and the V-arrangement. The utility model discloses a flowing back and oil field extraction water solid-liquid separation system are returned in fracturing can improve the efficiency of getting rid of oil and suspended solid, and the unstable state of adaptation oil field site waste water quality of water yield is used.

Description

Fracturing flow-back fluid and oil field produced water solid-liquid separation system

Technical Field

The utility model belongs to the industrial wastewater treatment field, concretely relates to flowing back and oil field extraction water solid-liquid separation system are returned to fracturing.

Background

At present, most oil fields in China enter the middle stage and the later stage of oil exploitation, namely the second stage and the third stage of oil field produced water treatment, the water content of produced crude oil reaches 70% -80%, and the water content of some oil fields reaches 90%. Along with the annual improvement of the water content of crude oil in an oil field, the water content of associated oil field produced water is also increased continuously, and the oil field wastewater is treated and then re-injected up to the standard in consideration of environmental protection and resource conservation, so that the method is the main direction of energy conservation, emission reduction and clean production in the petrochemical industry.

Aiming at the difference of the sources and the compositions of the oil field wastewater and the difference of the treatment processes of the produced water, the main treatment methods comprise: physical, chemical, physicochemical, and the like.

The physical treatment method comprises the following steps: the gravity separation method has good treatment effect on floating oil and dispersed oil in water produced by an oil field, stable water production and lower operation cost, and has the defects of large occupied area of equipment, higher capital construction cost and unsatisfactory treatment effect on emulsified oil and dissolved oil. The centrifugal separation method is a method of separating phases having different masses by using a centrifugal force field generated by high-speed rotation. In the water produced in oil field, because of the different density of water and oil, the force applied on the centrifugal field is different, so as to achieve the separation purpose. The coarse granulation method has the advantages of simple equipment operation and low investment and construction cost, but has the defect that the conglomerate material is easy to block. The filtering method has the advantages of stable effluent quality, less investment and the like, but has the defect of higher requirement on backwashing operation. The membrane separation method has the advantages of simple operation, easy automation realization, good separation effect and the like, but has the defects of easy pollution of membrane materials, difficult cleaning and higher operation cost.

The chemical treatment method comprises the following steps: the coagulating sedimentation method has the advantages of good water outlet effect, mature process and the like, but has the defects of large occupied area of equipment, need of adding a large amount of medicament and difficulty in treating the generated sludge. The chemical oxidation method is to decompose and convert organic substances in the produced water into small molecular organic substances or inorganic substances by using an oxidizing substance, and is generally classified into an oxidizing agent method, an electrolytic oxidation method and a photochemical catalytic oxidation method.

The physical and chemical treatment method comprises the following steps: the adsorption method has the advantages of stable water quality, good water outlet effect, small occupied area and the like, but has the defects of difficult regeneration of the adsorbent, high investment cost and the like. The air floatation method has the advantages of mature process, good water outlet effect and the like, but has the defects of large occupied area, expensive air floatation medicament and the like.

Through on-site investigation of oil field wastewater treatment, the following problems are found in the treatment process of the oil field produced water and the fracturing flowback fluid: 1) the pretreatment equipment of the general process can only remove oil or suspended matters singly, and if the oil and the suspended matters are removed simultaneously, the equipment has the advantages of complex process, long flow, large volume and high manufacturing cost; 2) the removal rate of the equipment to the dissolved oil and the emulsified oil in water is low, and the water inlet requirement of the back-end processing equipment to the oil content cannot be met; 3) when the fluctuation of the water inflow amount is large, the treatment effect of general cyclone equipment often cannot reach the index in design, so that the water quality of the water outflow of the whole process is deteriorated, and particularly when the water inflow amount is small, the water inflow condition of the cyclone cannot be met; 4) the idea of 'moderate abundance and double-set flow' is not implemented, when the quality of inlet water is extremely deteriorated and oil or suspended matters seriously exceed the water inlet index, the rapid treatment cannot be realized, and the emergency treatment capability is not realized; 5) under the water injection requirement of an oil field on low-permeability and ultra-low-permeability oil reservoirs, no pretreatment or primary treatment equipment capable of meeting the requirement exists, and particularly, oil is separated and removed.

In summary, effective removal of suspended matter and crude oil is difficult to achieve with a single process, and a combination of multiple processes is generally used. However, as the amount of sewage generated in oil fields is increased, the complexity of water quality is increased, especially the content of oil in water is increased, which causes great impact on rear-end water treatment equipment and increases investment, operation and maintenance costs. In the face of the requirement of oil field wastewater treatment, the wastewater is either reinjected after treatment or discharged after reaching the standard. The demand for integration and multi-functionalization of processing equipment is not very slow.

SUMMERY OF THE UTILITY MODEL

In order to solve the above-mentioned problem that exists among the prior art, the utility model provides a flowing back and oil field extraction water solid-liquid separation system are returned to fracturing, this solid-liquid separation system not only can improve the efficiency of getting rid of oil and suspended solid, can adapt to the unstable state of oil field on-the-spot waste water quality of water yield moreover, guarantees the multi-functional whirl air supporting piece-rate system of equipment steady operation. The to-be-solved technical problem of the utility model is realized through following technical scheme:

the utility model provides a flowing back and oil field extraction water solid-liquid separation system are returned to fracturing, includes adds medicine mixing unit, dissolves gas water unit, mixed reaction unit and whirl air supporting unit, add medicine mixing unit and dissolve the play water end of gas water unit and all communicate with the end of intaking of mixed reaction unit, the play water end of mixed reaction unit and the end intercommunication of intaking of whirl air supporting unit.

Further, the rotational flow air flotation unit comprises a cylinder body, an upper cover body and a rotational flow air flotation assembly arranged in the cylinder body, wherein the cylinder body is detachably connected with the upper cover body;

the rotational flow air flotation assembly comprises an oil discharge pipe, an inverted conical shell, a first cylindrical shell, a second cylindrical shell, a conical shell, an impurity discharge pipe, a first water inlet pipe, a second water inlet pipe and a V-shaped lower baffle;

the top of the inverted cone-shaped shell is fixed and communicated with the bottom of the oil discharge pipe, the bottom of the inverted cone-shaped shell is fixedly connected with a first cylindrical shell, the top of the conical shell is fixedly connected with a second cylindrical shell, the bottom of the conical shell is fixed and communicated with the top of the impurity discharge pipe, and the first cylindrical shell is sleeved on the outer side of the second cylindrical shell;

the first water inlet pipe and the second water inlet pipe transversely penetrate through the first cylindrical shell and the second cylindrical shell, and the end parts of the first water inlet pipe and the second water inlet pipe are both in a spiral line type structure;

the bottom of the V-shaped lower baffle is provided with a slag discharge port, the side surface of the V-shaped lower baffle is provided with a sludge collecting hopper, and the bottom of the impurity discharge pipe penetrates through the slag discharge port to discharge impurities;

the top of oil extraction pipe passes the top of upper cover body and carries out the oil extraction, be provided with the outlet on the upper cover body.

Furthermore, an annular support frame is fixed outside the first cylindrical shell, an annular screen shell made of a screen mesh is fixed on the annular support frame, and a filter material is filled in the screen shell.

Further, the difference between the outer diameter and the inner diameter of the screen shell is equal to the distance between the inner wall of the cylinder and the outer wall of the first cylindrical shell.

Further, a feeding hole and a discharging hole are formed in the screen shell, and the feeding hole and the discharging hole penetrate through the side wall of the cylinder body.

Further, a partition plate for isolating fine impurities is fixed to the outside of the first cylindrical shell.

Further, the top of the oil discharge pipe is communicated with a pressure reducing valve.

Further, the upper cover body and the cylinder body are fixedly connected through screws.

The utility model has the advantages that:

the utility model discloses a flowing back and oil field produced water solid-liquid separation system are returned in fracturing, including adding medicine mixing unit, dissolved gas water unit and whirl air supporting unit, sewage is through adding medicine mixing, after introducing dissolved gas water, reentrant whirl air supporting unit realizes breakdown of emulsion, whirl, separation, filtration and deposit, finally realizes the separation of oil, sediment, water; the solid-liquid separation system can improve the removal efficiency of oil and suspended matters, can adapt to the unstable state of the quality and the quantity of wastewater in an oil field, and ensures the stable operation of equipment.

The present invention will be described in further detail with reference to the accompanying drawings and examples.

Drawings

FIG. 1 is a schematic view of a solid-liquid separation system according to the present embodiment.

FIG. 2 is a schematic structural diagram of a cyclone air-floating unit according to the present embodiment.

Fig. 3 is a bottom view of the structure of the cyclone air-floating unit of the embodiment.

In the figure: 1. a rotational flow air flotation unit; 21. an oil discharge pipe; 22. an inverted conical shell; 23. a first cylindrical shell; 24. a second cylindrical shell; 25. a conical shell; 26. a trash removal pipe; 27. a first water inlet pipe; 28. a second water inlet pipe; 29. a V-shaped lower baffle; 210. a slag discharge port; 212. a screen shell; 213. filtering the material; 214. a feed inlet; 215. a discharge port; 3. an upper cover body; 31. a water outlet; 4. a barrel; 5. a pressure reducing valve; 6. a screw; 7. a dosing and mixing unit; 8. a gas-water dissolving unit; 9. and (3) mixing the reaction unit.

Detailed Description

To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined purpose, the following detailed description of the embodiments, structural features and effects of the present invention will be made with reference to the accompanying drawings and examples.

In the description of the present embodiments, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to a number of indicated technical features. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the invention, the meaning of "a plurality" is two or more unless otherwise specified.

The terms "mounted," "connected," and "coupled" are to be construed broadly and may, for example, be fixedly coupled, detachably coupled, or integrally coupled; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the creation of the present invention can be understood by those of ordinary skill in the art through specific situations.

Referring to fig. 1, 2 and 3, the fracturing flow-back fluid and oilfield produced water solid-liquid separation system of the present embodiment includes a chemical-adding mixing unit 7, a gas-dissolved water unit 8, a mixing reaction unit 9 and a cyclone flotation unit 1, wherein water outlet ends of the chemical-adding mixing unit 7 and the gas-dissolved water unit 8 are both communicated with a water inlet end of the mixing reaction unit 9, and a water outlet end of the mixing reaction unit 9 is communicated with a water inlet end of the cyclone flotation unit 1.

Before the fracturing flow-back fluid and oilfield produced water with certain pressure and temperature enter the cyclone air flotation unit, the fracturing flow-back fluid and oilfield produced water are fully mixed with the medicament and the saturated dissolved air water, so that the separation time and space are saved. In the process, according to different water qualities, flocculating agents, coagulants, oxidants and other medicaments can be added to meet the requirements of demulsification, oxidation and the like of the wastewater. After the medicament and the wastewater are mixed and reacted, saturated dissolved gas water is introduced, and then the mixture is fully mixed through a mixing reaction unit. The generation of saturated dissolved gas water can select a pressurizing dissolved gas device or a multiphase flow dissolved gas pump according to field conditions. The reflux ratio is 15-30% of the treatment amount, the gas-water ratio is 10-20%, and the diameter of the formed bubbles is less than 30 μm. Before entering the cyclone air flotation unit, the small bubbles in the dissolved air water fully wrap the oil and the fine suspended matters in the water.

The cyclone air-floating unit 1 comprises a cylinder 4, an upper cover body 3 and a cyclone air-floating assembly arranged inside the cylinder 4, wherein the cylinder 4 and the upper cover body 3 are detachably connected. The cylinder 4 and the upper cover 3 of the present embodiment are made of stainless steel, and the upper cover 3 and the cylinder 4 are fixedly connected by screws 6.

The cyclone air flotation assembly comprises an oil discharge pipe 21, an inverted conical shell 22, a first cylindrical shell 23, a second cylindrical shell 24, a conical shell 25, an impurity discharge pipe 26, a first water inlet pipe 27, a second water inlet pipe 28 and a V-shaped lower baffle plate 29. The top of the inverted cone shell 22 is fixed and communicated with the bottom of the oil discharge pipe 21, the bottom of the inverted cone shell 22 is fixedly connected with the first cylindrical shell 23, the top of the conical shell 25 is fixedly connected with the second cylindrical shell 24, the bottom of the conical shell 25 is fixed and communicated with the top of the impurity discharge pipe 26, and the first cylindrical shell 23 is sleeved on the outer side of the second cylindrical shell 24. The rotational flow air flotation component is formed by processing stainless steel, so parts are fixed by welding.

The first water inlet pipe 27 and the second water inlet pipe 28 transversely penetrate through the first cylindrical shell 23 and the second cylindrical shell 24, the end parts of the first water inlet pipe 27 and the second water inlet pipe 28 are both in a spiral line type structure, and the turbulence and the disturbance degree of fluid at the water inlet can be weakened through the water inlet pipes with the sections, so that the energy loss in the cylinder body is reduced. The wastewater enters from the first water inlet pipe 27 and the second water inlet pipe 28 of the rotational flow air flotation unit at the same time, and the wastewater enters the rotational flow air flotation unit to generate rotational flow effect. The waste water enters the cylinder body along the tangential inlet at a certain speed, and rotates towards the center while moving downwards under the limit of the inner wall, namely, the waste water is subjected to outer rotational flow; due to the suction of the low pressure at the center of the cylinder and the space limitation of the conical section, the internal fluid rotates upwards to make a rotary motion, namely, an internal rotational flow. As the flow radius decreases, the pressure energy is gradually converted into fluid kinetic energy and energy loss. Oil, water or solid particles are subjected to centrifugal inertia force, centripetal buoyancy force and fluid resistance in the cylinder, and the 3 forces promote the ordered separation of substances with different densities in the cylinder.

Because the density difference of oil, water, gas, sediment etc. under the effect of centrifugal force, the material that density is bigger than water is got rid of on the inner wall of toper shell, discharges from row's miscellaneous mouthful at last, and oil, gas, water are compelled to central zone migration, and tiny bubble carries out oil, the flocculation in the migration in-process in aqueous to realize the enrichment in the central zone of back taper shell, at last through oil outlet pipe, with oil and floc discharge system. Because the oil and the floc are removed under the combined action of air flotation and rotational flow, the treatment time is greatly shortened, the treatment capacity of the equipment is increased, and particularly when the water quality is seriously deteriorated, the equipment can realize quick treatment, thereby achieving the purposes of moderate abundance and double processes.

After a large amount of oil and flocs are removed, the wastewater quickly flows into the upper area of the V-shaped lower baffle from the gap between the first cylindrical shell and the second cylindrical shell, and the water flow speed is quickly reduced due to the volume change of the area, so that the wastewater is very suitable for precipitation and filtration. Therefore, a filtering zone is designed in the upper part of this zone. The slag generated in the filtering area is discharged from the slag discharge port, and the treated water enters the inverted cone-shaped shell and the upper part of the filtering area to form a clear water area and is finally discharged from the water discharge port.

The ratio of the height of the rotational flow air flotation unit to the diameter of the cylinder body is 1.7, the diameters of the first water inlet pipe and the second water inlet pipe are 0.25-0.4 times of the diameter of the cylinder body, and the water inlet speed of the first water inlet pipe and the second water inlet pipe is generally 1-2 m/s.

The bottom of the V-shaped lower baffle plate 29 is provided with a slag discharge port 210, the side surface of the V-shaped lower baffle plate 29 is provided with a sludge collecting hopper, and the bottom of the impurity discharge pipe 26 penetrates through the slag discharge port 210 to discharge impurities. The top of the oil drain pipe 21 penetrates the top of the upper cover 3 to drain oil, and the upper cover 3 is provided with a water outlet 31. The top of the drain pipe 21 communicates with the pressure reducing valve 5.

In order to further improve the solid-liquid separation effect and separate fine impurities, an annular support frame is fixed outside the first cylindrical shell 23 of the solid-liquid separation system of the present embodiment, an annular screen shell 212 made of a screen mesh is fixed on the annular support frame, and the screen shell 212 is filled with a filter material 213. The difference between the outer diameter and the inner diameter of the screen shell 212 is equal to the distance between the inner wall of the cylinder 4 and the outer wall of the first cylindrical shell 23. The screen shell 212 is provided with a feed port 214 and a discharge port 215, and the feed port 214 and the discharge port 215 penetrate through the side wall of the cylinder 4.

In order to further improve the solid-liquid separation effect, the fine impurities can also be separated in the form of a partition plate. An annular support frame is fixed outside the first cylindrical shell 23, and a partition plate for isolating fine impurities is fixed on the annular support frame.

In order to improve the filtering effect, the filler can be flexibly selected according to the water quality of inlet water and the water outlet requirement. When the oil content in the inlet water is higher, the conglomerate filler with high-efficiency oil-removing effect is preferably selected, such as polypropylene corrugated plate, ceramic corrugation, ceramsite filler and the like; when the content of suspended matters in the inlet water is high, inclined plates, inclined tube fillers and the like for accelerating the sedimentation of the suspended matters can be selected; when the oil and suspended matters in the water are high, walnut shells, quartz sand and other filter materials can be selected to meet the water outlet requirement.

When the fluctuation of the inflow water is large, especially when the actual treatment capacity is less than the designed treatment capacity, the wastewater entering the rotational flow air flotation reactor cannot reach the flow rate required by the rotational flow or the amount of flocs in the effluent of the reactor is large, the buffer area has the functions of reducing the flow rate of the water body and increasing the settling time of the water body, and the outlet water quality of the system is still ensured by the principle of a shallow pool behind an inclined plate (pipe).

In the field operation process, the installation position of the rotational flow air flotation system in the whole process can be flexibly selected, and the property of the filler can be determined. When the composite material is used as a pretreatment device of a water treatment system, an inclined plate (pipe) or a coarse grained material can be selected to correspond to high-oil-content produced water and fracturing flow-back fluid, so that the rear-end load is reduced. When the filter material is used as a fine treatment device of a water treatment system, the walnut shell, the modified fiber balls, the quartz sand, the active filter material and other filter materials can be selected to correspond to the water quality of high suspended matters, so that the concentration of suspended matters in the water quality and the median of the particle size are reduced. The coarse grained material is an oleophilic material, the relative density is more than 1, and the grain size is preferably 3-5 mm, such as ceramsite and the like.

The foregoing is a more detailed description of the present invention, taken in conjunction with the specific preferred embodiments thereof, and it is not intended that the invention be limited to the specific embodiments shown and described. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.

Claims (8)

1. The utility model provides a flowing back and oil field extraction water solid-liquid separation system are returned to fracturing which characterized in that: the device comprises a dosing mixing unit (7), a gas water dissolving unit (8), a mixing reaction unit (9) and a rotational flow air flotation unit (1), wherein the water outlet ends of the dosing mixing unit (7) and the gas water dissolving unit (8) are communicated with the water inlet end of the mixing reaction unit (9), and the water outlet end of the mixing reaction unit (9) is communicated with the water inlet end of the rotational flow air flotation unit (1).

2. The fracturing flow-back fluid and oilfield produced water solid-liquid separation system according to claim 1, wherein the cyclone flotation unit (1) comprises a cylinder body (4), an upper cover body (3) and a cyclone flotation assembly arranged inside the cylinder body (4), and the cylinder body (4) and the upper cover body (3) are detachably connected;

the cyclone air floatation assembly comprises an oil discharge pipe (21), an inverted conical shell (22), a first cylindrical shell (23), a second cylindrical shell (24), a conical shell (25), an impurity discharge pipe (26), a first water inlet pipe (27), a second water inlet pipe (28) and a V-shaped lower baffle plate (29);

the top of the inverted cone-shaped shell (22) is fixed and communicated with the bottom of the oil discharge pipe (21), the bottom of the inverted cone-shaped shell (22) is fixedly connected with the first cylindrical shell (23), the top of the cone-shaped shell (25) is fixedly connected with the second cylindrical shell (24), the bottom of the cone-shaped shell (25) is fixed and communicated with the top of the impurity discharge pipe (26), and the first cylindrical shell (23) is sleeved on the outer side of the second cylindrical shell (24);

the first water inlet pipe (27) and the second water inlet pipe (28) transversely penetrate through the first cylindrical shell (23) and the second cylindrical shell (24), and the end parts of the first water inlet pipe (27) and the second water inlet pipe (28) are both in a spiral line type structure;

a slag discharge port (210) is formed in the bottom of the V-shaped lower baffle (29), and impurities are discharged from the bottom of the impurity discharge pipe (26) through the slag discharge port (210);

the top of the oil discharge pipe (21) penetrates through the top of the upper cover body (3) to discharge oil, and a water outlet (31) is formed in the upper cover body (3).

3. The fracturing flow-back fluid and oilfield produced water solid-liquid separation system according to claim 2, wherein an annular support frame is fixed to the outside of the first cylindrical shell (23), an annular screen shell (212) made of a screen mesh is fixed to the annular support frame, and a filter material (213) is filled in the screen shell (212).

4. The fracturing flow-back fluid and oilfield produced water solid-liquid separation system of claim 3, wherein the difference between the outer diameter and the inner diameter of the screen shell (212) is equal to the distance between the inner wall of the cylinder (4) and the outer wall of the first cylindrical shell (23).

5. The fracturing flow-back fluid and oilfield produced water solid-liquid separation system of claim 4, wherein the screen shell (212) is provided with a feed port (214) and a discharge port (215), and the feed port (214) and the discharge port (215) penetrate through the side wall of the cylinder (4).

6. The fracturing flow-back fluid and oilfield produced water solid-liquid separation system of claim 2, wherein an annular support frame is fixed outside the first cylindrical shell (23), and a partition plate for isolating fine impurities is fixed on the annular support frame.

7. The fracturing flow-back fluid and oilfield produced water solid-liquid separation system of claim 2, wherein the top of the oil drain pipe (21) is communicated with a pressure reducing valve (5).

8. The fracturing flow-back fluid and oilfield produced water solid-liquid separation system of claim 2, wherein the upper cover body (3) and the cylinder body (4) are fixedly connected through a screw (6).

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