CN110242272B - Separation device for extracting reinjection water from high-water-content oil well production liquid - Google Patents

Abstract

The invention relates to a separation device for extracting reinjection water from high-water-content oil well production fluid, which comprises a rotary drum and a shell. The rotary drum can be driven by a motor and a rotating shaft to rotate in the shell, and is provided with an impeller, a main separation wheel, an oil drain disc, a guide wheel, a water blocking wheel and a drain disc, wherein the rotary drum is divided into a liquid inlet rotary acceleration section, a main separation section, an oil drain section, an oil-in-water emulsion secondary separation section and a drain section; after oil well produced liquid entering the rotary drum from the shell is separated, water is discharged into the drainage pipeline from the drainage disc through the shell and can be directly input into the reinjection pipeline, separated oil or oil-water mixture with high oil content is input into the oil discharge pipeline from the oil discharge disc through the shell, and separated gas is input into the exhaust pipeline through the shell. The scheme of the invention can meet the requirements of oil delivery pipelines, and extracts a part of water with better water quality index from high-content aquatic product liquid to be used for on-site reinjection, thereby realizing on-site treatment and on-site reinjection of the oil well produced liquid.

Description

Separation device for extracting reinjection water from high-water-content oil well production liquid

Technical Field

The invention relates to on-site treatment equipment for oil well production liquid in petroleum industry, in particular to a separation device for extracting reinjection water from high-water-content oil well production liquid.

Background

As oilfield exploitation enters a high water content period, the water content of the produced liquid continuously rises, and the water content reaches 80% -98% at present. On the one hand, the burden of a liquid production conveying system and downstream treatment equipment is increased, on the other hand, because a large amount of water injection is needed for the oil reservoir, water intensively treated by the downstream combined station is conveyed to the water injection well through a long-distance pipe network, a long-distance water roaming circulation is formed unintentionally, a large amount of heat energy and electric energy are consumed, and the problem of poor compatibility of reinjection water and the oil reservoir is also generated. Obviously, if the in-situ treatment of the produced liquid and in-situ reinjection can be realized, the production cost can be obviously reduced, and the water injection effect can be improved. The traditional gravity sedimentation method is difficult to achieve due to overlarge occupied area, high investment efficiency and low efficiency. At present, the centrifugal separator has the highest separation capacity and separation efficiency, the centrifugal acceleration can reach thousands to tens of thousands times of gravity acceleration, and certain application and development in emergency treatment of crude oil leakage on water and sewage treatment are started, for example, chinese patent application number CN201611000394.6, U.S. Pat. No. 9731223, U.S. Pat. No. 5582724,US 5484521 and the like respectively disclose the oil-water centrifugal separation device and method. According to the on-site skimming separation experiment TURBYLEC: DEVELOPMENT AND EXPERIMENTAL VALIDATION OF AN INNOVATIVE CENTRIFUGAL OIL – WATER SEPARATOR,2014 INTERNATIONAL OIL SPILL CONFERENCE, of YLEC Consultants company, the daily processing capacity of a prototype with a diameter of 380mm has reached the level of 64.8 m ³/d, the oil content in the effluent has been approaching the environmental protection index of 15ppm, and the final goal is to be able to process crude oils of various properties, including heavy oils with an oil-to-water density ratio approaching 0.98, The daily treatment capacity is up to 172.8 m ³/d, and the oil content of the drainage accords with the environmental protection standard. The centrifuge is therefore well suited for application on wellheads and production transfer lines. However, unlike the emergency treatment of crude oil leakage on water, during the production of crude oil production liquid, serious emulsification phenomenon often occurs due to the action of valves, elbows and other pipe fittings in a pumping unit and a pipeline and various chemical injection objects, and the crude oil production liquid is still an oil-water mixture as a whole, but contains a large amount of water-in-oil and oil-in-water emulsion, wherein the oil-in-water emulsion has the greatest influence on the water quality of the effluent of the separator. By oil-in-water emulsion is meant an emulsion of very fine oil droplets uniformly dispersed in water, which physically corresponds to a homogeneous single-phase fluid having a density close to that of water and slightly less than that of water. While many measures have been taken in the prior art to enhance the separation of emulsions, virtually every separator has a limit on the separation of fine droplets, known as the critical separation diameter, and fine droplets having diameters below this value are not well separated. This is because as the diameter of the fine droplets decreases, the volume of the droplets decreases dramatically relative to their surface area, and the volumetric force to which they are subjected, here centrifugal force, is less dominant than the force of the fluid surrounding the surface force on the droplets, where the fine droplets are substantially unaffected by the centrifugal force in the water and flow with the water or do brownian motion in the water. The critical separation diameter of a typical separator is currently on the order of 100 microns to tens of microns. While the critical separation diameter can be further reduced by increasing the centrifugal force, such as increasing the rotational speed or increasing the diameter of the separation drum, it is likely not economically viable. Therefore, the existing centrifugal separator cannot realize complete separation of oil and water due to the existence of emulsion. According to the centrifuge separation principle, the oil-in-water emulsion is generally always located on the water side of the oil-water interface in the separation cylinder, and the closer to the oil-water interface, the greater the oil content of the oil-in-water emulsion. Because the existing separator is not provided with a special separation mechanism for oil-in-water emulsion, the emulsion with more oil cannot cross an oil-water interface to enter an oil diversion channel, and can be discharged out of the separator along with the oil and can be accumulated in situ until the emulsion is diffused into a water body, so that the oil content in the effluent is increased, and the requirement of water injection quality of an oil field cannot be met.

Disclosure of Invention

The invention aims to provide a separation device for extracting reinjection water from high-water-content oil well production fluid based on the problems in the prior art, so that the in-situ treatment of the oil well production fluid is realized, and the oil content of the separated water meets the oilfield water injection standard.

The invention realizes the aim through the following technical scheme:

the separating device for extracting reinjection water from the high-water-content oil well produced liquid comprises a rotary drum and a shell, wherein the rotary drum can be driven by a motor and a rotating shaft to rotate in the shell, an impeller, a main separating wheel, an oil drain disc, a guide wheel, a water blocking wheel and a drain disc are arranged in the rotary drum, and the rotary drum is divided into a liquid inlet rotation accelerating section, a main separating section, an oil discharging section, an oil-in-water emulsion secondary separating section and a drain section; the impeller, the main separation wheel, the guide wheel, the water blocking wheel, the oil drain disc and the water drain disc are all connected with the rotary drum, and the guide wheel and the water blocking wheel are arranged in the oil-in-water emulsion secondary separation section and are positioned between the oil drain disc and the water drain disc; after oil well produced liquid entering the rotary drum from the shell is separated, water is discharged into the drainage pipeline from the drainage disc through the shell and can be directly input into the reinjection pipeline, separated oil or oil-water mixture with high oil content is input into the oil discharge pipeline from the oil discharge disc through the shell, and separated gas is input into the exhaust pipeline through the shell.

The oil discharge disc is fixed with the rotary drum through a hollow screw I and is communicated with the shell; the water draining disc is provided with a water overflow weir, a water pool and a hollow screw II, and is fixed with the rotary drum through the hollow screw II and communicated with the shell.

The front part of the shell is provided with an inlet vortex chamber through a partition board, one side of the shell is communicated with a liquid inlet connecting pipe, and oil well liquid can be tangentially introduced into the vortex chamber from the side surface of the shell; the front end of the rotary drum is provided with an impeller, an impeller hub of the impeller is connected with a rotary shaft key groove, the front end of the rotary drum is arranged in a center hole of the partition plate and forms an impeller inlet channel with the impeller hub, and a liquid flow hole is arranged on an impeller end cover of the impeller.

Compared with the prior art, the invention has the remarkable use effects that: the invention is provided with an impeller, a main separation wheel, an oil drain disc, a guide wheel, a water blocking wheel and a drain disc, and can divide the rotary drum into a liquid inlet accelerating section, a main separation section, an oil drain section, an oil-in-water emulsion secondary separation section and a drain section. The oil discharge section is internally provided with an oil discharge disc, the secondary separation section of the oil-in-water emulsion is internally provided with a guide wheel and a water blocking wheel, after the high-content aquatic product liquid entering the rotary drum from the shell is separated, water is input into the water discharge pipeline from the water discharge disc through the shell and can directly enter the reinjection water pipeline, the separated oil is input into the oil discharge pipeline from the oil discharge disc through the shell, and the separated gas is input into the exhaust pipeline through the shell. The guide wheel and the water retaining wheel in the oil-in-water emulsion secondary separation section carry out secondary separation on the oil-in-water emulsion entering the separation section, so that the quality of separated water is ensured, and the quality of reinjection water is ensured.

The reason for the arrangement of the oil-in-water emulsion secondary separation section is that the prior researches prove that even if an emulsion diversion port is arranged in the device, the effect of primary centrifugal separation has a great relationship with the water content of crude oil, and the higher the water content is, the higher the separation efficiency is and the better the water quality is. Only when the water content is higher than 98%, the water quality obtained by one-time separation is close to the environmental protection index of 15mg/L, and when the water content is lower than 80%, the oil content of the water obtained by one-time separation is more than 50ppm and even more than 200ppm, and the conclusion also accords with the general mass transfer rule. Therefore, the invention is provided with the secondary separation section, one is the main separation section, and the other is the oil-in-water emulsion secondary separation section, which is equivalent to greatly improving the water content of the liquid in the oil-in-water emulsion secondary separation section, thereby effectively improving the separation efficiency of the device.

The water entering the secondary separation section of the oil-in-water emulsion of the present invention, although having a very low oil content, is all of a few dispersed fine oil droplets, which should be strictly referred to as oil-in-water emulsion, but in the central region of the drum, the separation is difficult. In order to improve the separation capability of the fine oil drops and the emulsion, a flow guiding wheel is arranged in the section, and the surface of the flow guiding blade is coated with an oleophilic material, so that short circuit of partial fluid is avoided, and the sufficient separation time of each partial fluid is ensured. The small amount of oil droplets separated in this section and the emulsion having a high oil content are discharged into the oil discharge pan 1-5 through the oil-in-water emulsion overflow weir 1-52 on the downstream side of the oil discharge pan 1-5. The purified water enters the drainage section through a water retaining channel at the lower part of the water retaining wheel, and is discharged into a drainage volute on the shell through a water overflow weir and a hollow screw II on the drainage disc, so as to be discharged into a drainage pipeline. The separated gas flows into the exhaust line through the exhaust vent of the housing downstream end cap.

The quality of the water discharged and the ratio of the water taken can be comprehensively adjusted by changing the flow area of the oil-in-water emulsion discharge hole, or changing the height of the hole of the oil-in-water emulsion discharge hole on the overflow weir, or changing the height of the oil-in-water emulsion overflow weir, or changing the height of the overflow weir in the drain pan. In order to avoid secondary pollution caused by oil channeling into the waterway after separation, sealing rings are arranged at the connection parts of the oil discharge volute and the shell, and meanwhile, the height of a hollow screw I in the oil discharge disc is lower than that of a hollow screw II in the water discharge disc, so that the pressure of the waterway is ensured to be slightly higher than that of the oil path.

According to the technical scheme, the fluid can be prevented from rotating at a low speed by the aid of the pre-rotation of the inlet vortex chamber before entering the rotary drum, and shear stress and oil emulsification degree in the fluid can be reduced. Through set up oil extraction dish and the drain pan of relative independence in the device to and set up special oil-in-water emulsion discharge port and oil-in-water emulsion overflow weir on the oil extraction dish, solved the drainage problem of oil-in-water emulsion and quality of water and the regulation problem of water dividing the proportion, through setting up oil-in-water emulsion secondary separation section, further improved separation efficiency, ensured quality of water. The scheme of the invention can meet the requirements of oil delivery pipelines, and extracts a part of water with better water quality index from the high-content aquatic product liquid for on-site reinjection, so that the on-site treatment and on-site reinjection of the oil well produced liquid are realized, the oil content of the produced water can be ensured to meet the oilfield water injection standard, and meanwhile, a part of water content in the original produced liquid is reserved according to the requirement, so that the flow resistance of the delivery pipeline is reduced.

Drawings

For a better description of the embodiments of the present invention, the drawings that are used in the following description of the embodiments will be briefly described, which are to be construed as merely illustrative, and not limitative of the present invention.

FIG. 1 is an overall longitudinal cross-sectional view of the present invention;

fig. 2 is a partial enlarged view of the oil drain pan;

FIG. 3 is an enlarged view of a portion of the drain pan;

FIG. 4 is a cross-sectional view taken along the direction A-A in FIG. 1;

FIG. 5 is a cross-sectional view taken along the direction B-B in FIG. 1;

FIG. 6 is a cross-sectional view taken along the direction C-C in FIG. 1;

FIG. 7 is a cross-sectional view taken along the direction D-D in FIG. 1;

FIG. 8 is a cross-sectional view taken along the direction E-E in FIG. 1;

fig. 9 is a cross-sectional view taken along the direction F-F in fig. 1.

Detailed Description

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown.

As shown in fig. 1 to 9, a separation device for extracting reinjection water from high-water-content oil well production fluid comprises a rotary drum 1 and a shell 2, wherein the rotary drum 1 can be driven by a motor 3-5 and a rotating shaft 3 to rotate in the shell 2; the rotary drum 1 is provided with an impeller 1-2, a main separating wheel, an oil drain disc 1-5, a guide wheel 1-6, a water blocking wheel 1-7 and a drain disc 1-8, and the rotary drum 1 is divided into a liquid inlet rotary accelerating section 01, a main separating section 02, an oil drain section 03, an oil-in-water emulsion secondary separating section 04 and a drain section 05; the impeller 1-2, the main separating wheel, the guide wheel 1-6, the water blocking wheel 1-7, the oil drain disc 1-5 and the drain disc 1-8 are all connected with the rotary drum 1, and the guide wheel 1-6 and the water blocking wheel 1-7 are arranged in the oil-in-water emulsion secondary separating section 04 and positioned between the oil drain disc 1-5 and the drain disc 1-8; after the oil well produced liquid entering the rotary drum 1 from the shell 2 is separated, water is discharged into a drainage pipeline 6 from a drainage disc 1-8 through the shell 2 and can be directly input into a reinjection water pipeline, separated oil or oil-water mixture with high oil content is input into an oil discharge pipeline 5 from an oil discharge disc 1-5 through the shell 2, and separated gas is input into an exhaust pipeline 7 through the shell 2.

The rotary drum 1 and the rotary shaft 3 are coaxial, and the rotary drum 1 is connected with the rotary shaft 3 through end covers at two ends of the rotary drum 1; the drum 1 is located in the housing 2 and can freely rotate in the housing 2 via a shaft 3. The two ends of the rotating shaft 3 extend out of the rotary drum 1 and the shell 2 and are fixed on the shell 2 through the bearing 3-1 and the bracket 3-3, one end of the rotating shaft 3 extends out of the bearing 3-1 and is connected with the motor 3-5 through the coupler 3-4, and the rotating shaft can be driven to rotate by the motor 3-5. The rotary shaft 3 and the shell 2 are sealed by a shaft seal 3-2.

Referring to fig. 1, 2, 3 and 7, an oil pool 1-56, an oil overflow weir 1-55, an oil-in-water emulsion discharge hole 1-51, an oil-in-water emulsion overflow weir 1-52 and a water channel 1-53 are arranged in the oil drain pan 1-5, and the oil drain pan 1-5 is fixed with the rotary drum 1 and communicated with the shell 2 through a hollow screw 1-54; the drain pan 1-8 is provided with a water overflow weir 1-82, a water pool 1-83 and a hollow screw II 1-81, and the drain pan 1-8 is fixed with the rotary drum 1 through the hollow screw II 1-81 and communicated with the shell 2.

Referring to fig. 1,4 and 5, the front part of the shell 2 is provided with an inlet vortex chamber 2-1 through a partition board, one side of the shell 2 is communicated with a liquid inlet connecting pipe 2-7, and oil well liquid can be tangentially imported into the vortex chamber 2-1 from the side surface of the shell 2; the front end of the rotary drum 1 is provided with an impeller 1-2, an impeller hub 1-21 of the impeller 1-2 is connected with a key groove of a rotary shaft 3, the front end of the rotary drum 1 is arranged in a center hole of a partition plate, an impeller inlet channel 1-1 is formed between the impeller hub 1-21, so that high-water-content oil well production liquid can enter a liquid inlet rotary acceleration section 01, a liquid flow hole 1-3 is arranged on an impeller end cover 1-22 of the impeller 1-2, and the high-water-content oil well production liquid can enter a main separation section 02 from the liquid flow hole 1-3.

Referring to fig. 1, 5 and6, the main separating wheel is arranged between an impeller end cover 1-22 of an impeller 1-2 and an oil discharge disc 1-5, the main separating wheel is provided with a wheel sheet 1-4, and the wheel sheet 1-4 divides a main separating section 02 in a rotary drum 1 into a fan-shaped oil-water channel 1-41 with a small center and a large periphery; the sheet bodies of the wheel sheets 1-4 are corrugated in the longitudinal direction, and the wheel sheets 1-4 of the main separating wheel are fixed with the rotary drum 1. The wheel piece 1-4 can be welded with the inner wall of the rotary drum 1, the wheel piece 1-4 and the barrel of the rotary drum 1 can be fixed together by using screws, and the structures of the outer edge of the wheel piece 1-4 and the inner wall of the rotary drum 1 can be changed, so that the wheel piece 1-4 and the barrel are mutually spliced or connected together.

The oil drain device is characterized in that an oil drain volute 2-3 and a drain volute 2-6 are respectively arranged on the shell 2 and at the installation positions of the oil drain disc 1-5 and the drain disc 1-8, and the outer walls of the oil drain volute 2-3 and the drain volute 2-6 are protruded out of the shell 2 and are respectively connected with an oil drain connecting pipe 2-8 and a drain connecting pipe 2-9.

The oil drain disc 1-5 is arranged at the downstream of the main separation section 02, the oil drain disc 1-5 is in the shape of a circular short cylinder, a circular oil pool 1-56 is contained in the oil drain disc, an oil overflow weir 1-55 is arranged in the pool wall at the upstream side of the oil pool 1-56, and oil-in-water emulsion drain holes 1-51 are uniformly arranged above the oil overflow weir 1-55 along the circumferential direction; the weir mouth of the oil overflow weir 1-55 is arranged on one side of the rotating shaft 3, and the distance between the weir roof of the oil overflow weir 1-55 and the inner wall of the rotating drum 1 is larger than the height of the oil-in-water emulsion discharge hole 1-51 arranged above the oil overflow weir 1-55; the tank wall at the downstream side of the oil tank 1-56 is provided with an oil-in-water emulsion overflow weir 1-52, and the distance between the weir top of the oil-in-water emulsion overflow weir 1-52 and the inner wall of the rotary drum 1 is smaller than the distance between the weir top of the oil overflow weir 1-55 and the inner wall of the rotary drum 1. The height of the overflow weir 1-52 is smaller than that of the overflow weir 1-55, so that the oil-in-water emulsion can flow to the next separation section before the oil or oil-water mixture with high oil content.

Referring to fig. 7, water channels 1-53 are uniformly formed on the outer edge of the oil drain pan 1-5, and the water channels 1-53 are opened at one side of the rotary drum 1 and are staggered with the hollow screws 1-54; the hollow screw 1-54 is arranged at the bottom of the oil pool 1-56, the center hole of the hollow screw 1-54 is respectively communicated with the shell 2 and the oil pool 1-56, the wing edge of the screw head of the hollow screw 1-54 is fixed between the rotary drum 1 and the shell 2, and the wing edge surrounding the screw head of the hollow screw 1-54 is also padded with the sealing ring 2-4 so as to ensure the sealing performance. The oil drain disc 1-5 is not only provided with an oil overflow weir 1-55, but also is specially provided with an oil-in-water emulsion drain hole 1-51, so that oil in the centrifugal force direction and a part of oil-in-water emulsion with higher oil content in the central area of the rotary drum 1 can be introduced into the oil drain disc 1-5 through the oil overflow weir 1-55 and the oil-in-water emulsion drain hole 1-51, oil or high-oil-in-water mixture is drained into the shell 2 through the hollow screw 1-54 and is drained through the oil drain volute 2-3 and the oil drain pipeline 5, and the oil-in-water emulsion enters the oil-in-water emulsion secondary separation section 04 through the oil-in-water emulsion overflow weir 1-52. The hollow screw 1-54 has two functions, namely oil discharge, namely the oil tank 1-56 can be communicated with the oil discharge volute 2-3 through the central through hole, more importantly, the oil is further accelerated by means of rotation, and the pressure of the oil is increased, namely the effect similar to a blade is achieved; and secondly, the connection function is realized, the rotary drum 1 and the oil drain disc 1-5 are connected into a whole, and part of centrifugal force on the rotary drum 1 can be transmitted to the oil drain disc 1-5 to support the rotary drum 1. And the liquid with more water enters the oil-in-water emulsion secondary separation section 04 through the water channels 1-53 at the outer edge of the oil drain disc 1-5. Thus, mutual interference and secondary mixing between the oil and the water are avoided, and the water quality is guaranteed. After the oil or oil-water mixture with high oil content entering the oil discharge volute 2-3 rotates in the oil discharge volute 2-3 to reduce the speed, the pressure is further improved, and finally the oil enters the oil discharge pipeline 5 from the oil discharge connecting pipe 2-8 along the tangential direction, and then enters the crude oil outer conveying pipeline, so that the flow resistance of the crude oil outer conveying pipeline is reduced while the part of the oil or oil-water mixture with high oil content is conveyed through the crude oil outer conveying pipeline of an oil well.

Referring to fig. 1 and 8, the guide wheel 1-6 is provided with guide vanes 1-61, the guide vanes 1-61 form secondary separation channels 1-62 in the oil-in-water emulsion secondary separation section 04 of the rotary drum 1, and the guide vanes 1-61 are fixed with the rotary drum 1. The fixation between the guide vanes 1-61 and the drum 1 is the same as the fixation between the wheel pieces 1-4 of the main separating wheel and the drum 1.

The surface of the guide vane 1-61 is also coated with an oleophilic material, which can be polypropylene, polyurethane foam, alkyl vinyl polymer, etc.

Referring to fig. 1 and 8, the water blocking wheels 1-7 are provided with water blocking blades, water blocking channels 1-71 are arranged in the water blocking blades, and the water blocking blades are fixed with the rotary drum 1. The fixing manner between the water blocking blades and the rotary drum 1 is the same as the fixing manner between the wheel pieces 1-4 of the main separating wheel and the rotary drum 1.

The water blocking wheel 1-7 is arranged on one side of the downstream of the guide wheel 1-6, the outer diameter of the water blocking blade is larger than that of the guide blade 1-61, and the water blocking channel 1-71 is arranged on the outer edge of the water blocking blade.

Referring to fig. 1, 3 and 9, the drain pan 1-8 is arranged on the downstream side of the water blocking wheel 1-7, the distance from the weir crest of the overflow weir 1-82 in the drain pan 1-8 to the inner wall of the rotary drum 1 is smaller than the distance from the weir crest of the overflow weir 1-55 to the inner wall of the rotary drum 1, the wing edge of the screw head of the hollow screw II 1-81 is fixed between the rotary drum 1 and the shell 2, the wing edge surrounding the screw head of the hollow screw II 1-81 is provided with a sealing ring 2-4, and the central hole of the hollow screw II 1-81 is communicated with the water pool 1-83 and the drain volute 2-6.

The screw heads of the hollow screws II 1-81 outwards protrude from the shell 2 to a height greater than the height of the hollow screws I1-54 outwards protrude from the shell 2; the outer diameter of the drain volute 2-6 formed on the shell 2 is larger than the outer diameter of the drain volute 2-3 formed on the shell 2, the drain volute 2-6 is connected with the drain pipeline 6 through a drain connecting pipe 2-9, and the drain volute 2-3 is connected with the drain pipeline 5 through a drain connecting pipe 2-8. The radial distance from the outer end face of the screw head of the hollow screw I1-54 to the central line of the rotating shaft 3 is smaller than the radial distance from the outer end face of the screw head of the hollow screw II 1-81 to the central line of the rotating shaft 3, and the outer diameter of the drain volute 2-6 is larger than the outer diameter of the drain volute 2-3, so that the drain pressure is larger than the drain pressure.

The rotary drum 1 is characterized in that vent holes 1-91 are arranged on the rotary drum downstream end cover 1-9, the vent holes 1-91 are arranged on the periphery of a central hole of the rotary drum downstream end cover 1-9, the radial distance between the vent holes 1-91 and a rotating shaft 3 is smaller than the radial distance between an exhaust hole 7-1 in the downstream end cover of the shell 2 and the rotating shaft 3, and the exhaust hole 7-1 is connected with an exhaust pipeline 7. The vent holes 1-91 are staggered with the vent holes 7-1, so that the gas can be buffered effectively.

The invention can be connected with a production pipeline of a wellhead of an oil production well and a crude oil output pipeline to realize on-site treatment and on-site reinjection of the produced liquid, so that the oil content of separated water meets the oilfield water injection standard, and meanwhile, according to the requirement, a part of water content in the produced liquid of the crude oil well is reserved in oil or oil-water mixture with high oil content entering the crude oil output pipeline after separation, so that the flow resistance of the crude oil output pipeline is reduced.

As shown in fig. 1, the oil-water mixture from the liquid inlet line 4 enters the gas-liquid coarse separator 4-2 through the liquid inlet control valve 4-1, and the carried free gas is separated out and discharged to the gas line 4-5. The gas-liquid coarse separator 4-2 can be a simple cyclone separator, can separate free gas carried in the original high-water-content oil well production liquid, and can reduce the influence of high-flow gas on the separation device. The deaerated oil-water mixture then enters a filter 4-3, solid impurities are filtered out, and then enters an inlet vortex chamber 2-1 on the shell 2 tangentially by a liquid inlet connecting pipe 2-7. The liquid inlet pipeline 4 is also connected with a liquid inlet sensor assembly 4-4, the liquid inlet sensor assembly 4-4 and the liquid inlet control valve 4-1 are connected with a controller 8 through cables, and the controller 8 is a programmable logic controller. The inlet swirl chamber 2-1 is a cylindrical chamber upstream of the housing 2 into which chamber the oil-water mixture, after entering tangentially from the inlet nipple 2-7, will flow in a spiral around the rotor 3 and then from the impeller inlet channel 1-1 in the central region into the inlet spin-up section 01 of the rotor 1. This pre-rotation acceleration movement is a transition of the oil-water mixture before it enters the high-speed rotation movement, with the aim of reducing the speed difference between it and the impeller 1-2, in order to reduce the shear stresses in the fluid and the resulting emulsification phenomena.

As shown in fig. 1 and 5, the oil-water mixture is subjected to the tangential velocity of high-speed rotation by the blades of the impeller 1-2, and then enters the main separation section 02 through the liquid flow holes 1-3 in the impeller end cover 1-22.

As shown in fig. 1, 5 and 6, the main separation section 02 is uniformly divided into a plurality of sector-shaped oil-water passages 1-41 by the wheel disc 1-4, and simultaneously, the oil-water mixture is uniformly distributed into the respective sector-shaped oil-water passages 1-41 due to the flow equalizing effect of the liquid flow holes 1-3. Under the action of centrifugal force, the oil-gas-water three-phase mixture is separated and layered, gas is gathered in the central area of the rotary drum 1, and the distribution of liquid is sequentially layered according to the order of oil, oil-in-water emulsion and water along the direction of radius centrifugal force according to the density.

According to this layered arrangement of liquids, as shown in fig. 1,2, 6 and 7, an oil drain pan 1-5 is provided downstream of the main separation section 02. The oil drain pan 1-5 has a short cylindrical shape in the shape of a circular ring, and comprises an oil pool 1-56 therein, wherein the side of the oil pool 1-56 facing the rotating shaft 3 is in the direction opposite to the direction of centrifugal force, so that liquid can pass through. The wall of the upstream side of the oil pool 1-56 forms an oil overflow weir 1-55, and the oil overflow weir 1-55 is provided with oil-in-water emulsion discharge holes 1-51 which are uniformly distributed along the circumferential direction. The wall of the oil tank 1-56 at the downstream side forms an oil-in-water emulsion overflow weir 1-52, and a plurality of water channels 1-53 are uniformly arranged at the outer edge of the oil discharge disc 1-5. Therefore, the oil drain disc 1-5 is not only provided with the oil overflow weir 1-55, but also is specially provided with the oil-in-water emulsion drain hole 1-51, so that oil in the reverse centrifugal force direction in the central area of the rotary drum 1 and a part of oil-in-water emulsion with higher oil content can be drained from the oil drain section 03 through the hollow screw 1-54. The hollow screw 1-54 connects the rotary drum 1 and the oil drain pan 1-5 integrally, and water enters the oil-in-water emulsion secondary separation section 04 from the periphery through the water channel 1-53 at the outer edge of the oil drain pan 1-5. Thus, mutual interference and secondary mixing between oil and water are avoided, and the water quality is guaranteed. After the oil body entering the oil discharge volute 2-3 rotates in the oil discharge volute 2-3 to reduce the speed, the pressure is further improved, and finally the oil enters the oil discharge pipeline 5 from the oil discharge connecting pipe 2-8 in the tangential direction, and then enters the crude oil output pipeline.

As shown in fig. 1 and 8, the water entering the oil-in-water emulsion secondary separation section 04 can further remove residual droplets and higher oil emulsions therein. In order to improve the separation capacity of the fine oil droplets, a plurality of guide wheels 1-6 are arranged in the separation section, wherein the guide wheels are uniformly distributed with guide vanes 1-61 along the circumferential direction. On one hand, the guide vanes 1-61 divide the whole oil-in-water emulsion secondary separation section 04 into secondary separation channels 1-62, so that the uniformity of flow is improved, the turbulence of water is reduced, and the separation of fine liquid drops is facilitated; in addition, the surfaces of the guide vanes 1-61 are coated with a lipophilic material such as polypropylene or polyurethane, etc., which can further promote the separation of fine oil droplets. The flow guide wheels 1-6 and the water blocking wheels 1-7 arranged in the axial direction can further improve the uniformity of a flow field, avoid the short circuit of partial water bodies and ensure that the whole water body has enough separation time. The separated oil-in-water emulsion with less oil and more oil is discharged into the oil pool 1-56 through the emulsion overflow weir 1-52 at the downstream side of the oil drain pan 1-5, and the water enters the drainage section 05 through the water retaining channel 1-71 at the outer edge of the water retaining wheel 1-7.

As shown in fig. 1,3, 8 and 9, after being purified by the oil-in-water emulsion secondary separation section 04, water enters the drainage section 05 from the water retaining channels 1-71 at the outer edges of the water retaining wheels 1-7. A drain pan 1-8 is provided in the drain section 05. The inside of the drain pan 1-8 is provided with a water pool 1-83, one surface of the water pool 1-83 facing the rotating shaft 3 is a weir top of the overflow weir 1-82 against the direction of centrifugal force, water is discharged into the water pool 1-83 in the drain pan 1-8 from the weir top of the overflow weir 1-82, and a plurality of hollow screws II 1-81 are uniformly arranged at the bottom of the water pool 1-83 along the circumferential direction. The hollow screw II 1-81 has two functions, namely, a drainage function, not only can communicate the water tank 1-83 with the drainage volute 2-6 through the center hole of the hollow screw II, but also can further accelerate water flow by means of rotation function, and the pressure of the water flow is improved, namely, the hollow screw II has the function similar to a blade; and secondly, the connection function is realized, the rotary drum 1 and the drain discs 1-8 are connected into a whole, and part of centrifugal force on the rotary drum 1 can be transmitted to the drain discs 1-8 to support the rotary drum 1. After the water flow entering the drain volute 2-6 rotates in the water flow to reduce speed, the pressure is further increased, and finally the water flow enters the drain pipeline 6 from the drain connecting pipe 2-9 in the tangential direction and then enters the reinjection pipeline.

The gas separated in the above separation sections is continuously collected in the central region of the drum 1, and finally flows into the exhaust line 7 through the vent holes 1-91 at the end of the drum 1 and the exhaust hole 7-1 at the end of the housing 2, and finally merges into the gas outlet line.

In the separation process, the controller 8 can timely adjust the opening of the oil discharge control valve 5-1, the opening of the water discharge control valve 6-1 and the opening of the air discharge control valve 7-2 and the opening of the motor 3-5 according to the measurement results of the liquid inlet sensor assembly 4-4, the oil liquid sensor assembly 5-2, the water sensor assembly 6-2 and the air path sensor assembly 7-3 on the liquid inlet pipeline 4, the oil discharge pipeline 5, the water discharge pipeline 6 and the air discharge pipeline 7, so as to ensure the normal operation of the device.

In the use process, according to the properties of crude oil and the requirements of water quality and water taking proportion, oil discharge discs 1-5 with different specifications and sizes, such as oil overflow weirs 1-55 with different heights, oil-in-water emulsion overflow weirs 1-52 and oil-in-water emulsion discharge holes 1-51 with different apertures, can be filled to meet the requirements.

When the water quality needs to be improved, the oil-in-water emulsion discharge hole 1-51 can be increased by increasing the flow area of the oil-in-water emulsion discharge hole 1-51 and reducing the height of the oil-in-water emulsion discharge hole 1-51 and the oil-in-water emulsion overflow weir 1-52 in the oil discharge disc 1-51; it can also be achieved by raising the weir height of the weirs 1-82 in the drainage tray 1-8.

In order to prevent secondary pollution caused by oil flowing into the waterway during operation, sealing rings 2-4 are arranged at the connection part of the oil discharge volute 2-3 and the shell 2 and the connection part of the water discharge volute 2-6 and the shell 2. Meanwhile, the radial distance from the outer end face of the screw head of the hollow screw II 1-81 in the drain pan 1-8 to the central line of the rotating shaft 3 is ensured to be larger than the radial distance from the outer end face of the screw head of the hollow screw I1-54 in the drain pan 1-5 to the central line of the rotating shaft 3, so that the pressure of the waterway is slightly higher than that of the oil way.

The specific working process is that the motor 3-5 is started by the controller 8 to drive the rotary drum 1 to rotate at a high speed, then the liquid inlet control valve 4-1 on the liquid inlet pipeline 4 is opened, the oil well liquid can sequentially pass through the gas-liquid coarse separator 4-2 and the filter 4-3, and the separated gas is input into the gas output pipeline. The oil well produced liquid after the carried free gas and solid impurities are removed enters an inlet vortex chamber 2-1 in a shell 2 through a liquid inlet connecting pipe 2-7 in a tangential direction, and enters a liquid inlet rotary accelerating section 01, a main separating section 02, an oil discharging section 03, an oil-in-water emulsion secondary separating section 04 and a water discharging section 05 of the rotary drum 1 in sequence after a certain pre-rotation is generated. Under the action of centrifugal force, the oil-gas-water three-phase mixture is separated and layered, and gas, oil-in-water emulsion and water are layered in sequence along the radial direction from the center of the rotary drum 1, wherein the separated oil or oil-water mixture with high oil content is discharged into a crude oil output pipeline through an oil discharge pipeline 5 and an oil discharge control valve 5-1; the separated water can directly enter a reinjection water pipeline through a drainage pipeline 6 and a drainage control valve 6-1 and be directly utilized by a water injection well; the separated gas is inputted into the gas output line through the gas discharge line 7 and the gas discharge control valve 7-2.

The embodiments described above are only exemplary embodiments, but the present invention is not limited to these embodiments, and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Many variations, combinations, and modifications of the arrangements disclosed herein are possible and are within the scope of the invention, and therefore, the scope of protection is not limited solely by the description set forth above.

Claims (14)

1. The separating device for extracting reinjection water from high-water-content oil well produced liquid comprises a rotary drum (1) and a shell (2), wherein the rotary drum (1) can be driven by a motor (3-5) and a rotating shaft (3) to rotate in the shell (2), and is characterized in that an impeller (1-2), a main separating wheel, an oil discharging disc (1-5), a guide wheel (1-6), a water retaining wheel (1-7) and a water discharging disc (1-8) are arranged in the rotary drum (1), and the rotary drum (1) is divided into a liquid inlet rotation accelerating section (01), a main separating section (02), an oil discharging section (03), an oil-in-water emulsion secondary separating section (04) and a water discharging section (05) by the impeller (1-2), the main separating wheel, the oil discharging disc (1-5), the guide wheel (1-6), the water discharging disc (1-7) and the water discharging disc (1-8); the impeller (1-2), the main separating wheel, the guide wheel (1-6), the water retaining wheel (1-7), the oil discharge disc (1-5) and the water discharge disc (1-8) are all connected with the rotary drum (1), and the guide wheel (1-6) and the water retaining wheel (1-7) are arranged in the oil-in-water emulsion secondary separating section (04) and positioned between the oil discharge disc (1-5) and the water discharge disc (1-8); after oil well produced liquid entering the rotary drum (1) from the shell (2) is separated, water is discharged into the drain pipeline (6) from the drain pan (1-8) through the shell (2) and can be directly input into the reinjection water pipeline, separated oil or oil-water mixture with high oil content is input into the oil discharge pipeline (5) from the oil discharge pan (1-5) through the shell (2), and separated gas is input into the exhaust pipeline (7) through the shell (2); an oil tank (1-56), an oil overflow weir (1-55), an oil-in-water emulsion discharge hole (1-51), an oil-in-water emulsion overflow weir (1-52) and a water channel (1-53) are arranged in the oil discharge disc (1-5), and the oil discharge disc (1-5) is fixed with the rotary drum (1) and communicated with the shell (2); the water draining disc (1-8) is internally provided with a water overflow weir (1-82) and a water pool (1-83), and the water draining disc (1-8) is fixed with the rotary drum (1) and communicated with the shell (2); the front part of the shell (2) is provided with an inlet vortex chamber (2-1) through a partition board, the front end of the rotary drum (1) is provided with an impeller (1-2), an impeller hub (1-21) of the impeller (1-2) is connected with a key slot of the rotary shaft (3), and the front end of the rotary drum (1) is arranged in a central hole of the partition board and forms an impeller inlet channel (1-1) with the impeller hub (1-21); the main separation wheel is arranged between an impeller end cover (1-22) of the impeller (1-2) and the oil discharge disc (1-5), the main separation wheel is provided with a wheel sheet (1-4), and the wheel sheet (1-4) separates a main separation section (02) in the rotary drum (1) into a fan-shaped oil-water channel (1-41) with a small center and a large periphery; an oil drain volute (2-3) and a drain volute (2-6) are respectively arranged on the shell (2) at the installation positions of the oil drain disc (1-5) and the drain disc (1-8), and can be respectively connected with the oil drain connecting pipe (2-8) and the drain connecting pipe (2-9); the oil drain disc (1-5) is arranged at the downstream of the main separation section (02) and internally comprises an annular oil pool (1-56).

2. A separation device for extracting reinjection water from high-water-content oil well production fluid according to claim 1, characterized in that the oil-discharging disc (1-5) is fixed with the rotary drum (1) and communicated with the shell (2) through a hollow screw one (1-54); the drain pan (1-8) is fixed with the rotary drum (1) through a hollow screw II (1-81) and is communicated with the shell (2).

3. A separation device for extracting reinjection water from high water content oil well production fluid according to claim 1 or 2, characterized in that one side of the housing (2) is in communication with the intake nipple (2-7) enabling the oil well production fluid to be tangentially imported into the swirl chamber (2-1) from the side of the housing (2); the impeller comprises an impeller (1-2) and an impeller end cover (1-22), wherein a liquid flow hole (1-3) is arranged on the impeller end cover.

4. A separation device for extraction of reinjection water from high water content oil well production fluid according to claim 3, characterized in that the sheet body of the wheel sheet (1-4) is corrugated in longitudinal direction, the wheel sheet (1-4) of the main separation wheel being fixed to the drum (1).

5. A separation device for extracting reinjection water from high-water-content oil well production fluid according to claim 2, characterized in that the outer walls of the oil discharge volute (2-3) and the water discharge volute (2-6) are both protruded out of the shell (2) and are respectively connected with the oil discharge connecting pipe (2-8) and the water discharge connecting pipe (2-9).

6. A separation device for extracting reinjection water from high-water-content oil well production fluid according to claim 5, characterized in that the oil discharge disc (1-5) is arranged at the downstream of the main separation section (02), the oil discharge disc (1-5) is in the shape of a circular short cylinder, the inside of the oil discharge disc comprises a circular oil tank (1-56), the oil overflow weir (1-55) is arranged in the tank wall at the upstream side of the oil tank (1-56), and the oil-in-water emulsion discharge holes (1-51) are uniformly arranged above the oil overflow weir (1-55) along the circumferential direction; the weir mouth of the oil spilling weir (1-55) is arranged at one side of the rotating shaft (3), and the distance between the weir roof of the oil spilling weir (1-55) and the inner wall of the rotating drum (1) is larger than the height of the oil in water emulsion discharging hole (1-51) arranged above the oil spilling weir (1-55); the wall of the downstream side of the oil tank (1-56) is provided with an oil-in-water emulsion overflow weir (1-52), and the distance from the weir top of the oil-in-water emulsion overflow weir (1-52) to the inner wall of the rotary drum (1) is smaller than the distance from the weir top of the oil overflow weir (1-55) to the inner wall of the rotary drum (1).

7. The separation device for extracting reinjection water from high-water-content oil well production fluid according to claim 6, wherein the outer edge of the oil discharge disc (1-5) is uniformly provided with water channels (1-53), and the water channels (1-53) are opened at one side of the rotary drum (1) and are staggered with the hollow screws (1-54); the hollow screw I (1-54) is arranged at the bottom of the oil pool (1-56), the central hole of the hollow screw I (1-54) is respectively communicated with the shell (2) and the oil pool (1-56), the wing edge of the screw head of the hollow screw I (1-54) is fixed between the rotary drum (1) and the shell (2), and the sealing ring (2-4) is also arranged around the wing edge of the screw head of the hollow screw I (1-54).

8. A separation device for extracting reinjection water from a high water-containing well production fluid according to claim 2, characterized in that the inducer (1-6) is provided with guide vanes (1-61), the guide vanes (1-61) forming secondary separation channels (1-62) in the oil-in-water emulsion secondary separation section (04) of the rotor (1), the guide vanes (1-61) being fixed to the rotor (1).

9. A separation device for extraction of reinjection water from high water content oil well production fluid according to claim 8, characterized in that the surface of the guide vane (1-61) is also coated with an oleophilic material.

10. A separation device for extracting reinjection water from high water content oil well production fluid according to claim 8, characterized in that the water retaining wheel (1-7) is provided with water retaining blades, in which water retaining channels (1-71) are provided, which are fixed with the drum (1).

11. A separation device for extracting reinjection water from high-water-content oil well production fluid according to claim 10, characterized in that the water retaining wheel (1-7) is arranged at the downstream side of the guide wheel (1-6), the outer diameter of the water retaining blade is larger than that of the guide blade (1-61), and the water retaining channel (1-71) is arranged at the outer edge of the water retaining blade.

12. A separation device for extracting reinjection water from high water content oil well production fluid according to claim 5, characterized in that the drain pan (1-8) is arranged at the downstream side of the water retaining wheel (1-7), the distance from the weir top of the weir (1-82) in the drain pan (1-8) to the inner wall of the drum (1) is smaller than the distance from the weir top of the weir (1-55) to the inner wall of the drum (1), the wing edge of the screw head of the hollow screw two (1-81) is fixed between the drum (1) and the shell (2), the sealing ring (2-4) is arranged around the wing edge of the screw head of the hollow screw two (1-81), and the central hole of the hollow screw two (1-81) is communicated with the water pool (1-83) and the drain volute (2-6).

13. A separation device for extracting reinjection water from high water-containing oil well production fluid according to claim 12, wherein the height of the screw head of the hollow screw II (1-81) protruding outwards from the shell (2) is larger than the height of the hollow screw I (1-54) protruding outwards from the shell (2); the outer diameter of the drain volute (2-6) formed on the shell (2) is larger than the outer diameter of the drain volute (2-3) formed on the shell (2), the drain volute (2-6) is connected with the drain pipeline (6) through a drain connecting pipe (2-9), and the drain volute (2-3) is connected with the drain pipeline (5) through a drain connecting pipe (2-8).

14. A separation device for extracting reinjection water from a high water content oil well production fluid according to claim 3, characterized in that the rotor (1) is provided with a vent hole (1-91) on the rotor downstream end cap (1-9), the vent hole (1-91) is arranged on the periphery of the center hole of the rotor downstream end cap (1-9), the radial distance from the vent hole (1-91) to the rotating shaft (3) is smaller than the radial distance from the vent hole (7-1) in the housing (2) downstream end cap to the rotating shaft (3), and the vent hole (7-1) is connected with the vent line (7).