Two-section double-gradient three-electric-field enhanced demulsification three-phase separator

Abstract

The utility model discloses a two-section double-gradient three-electric-field enhanced demulsification three-phase separator which comprises a tank body, a tubular distributor, a crude oil pipeline, a dosing pipeline, an oil outlet pipeline, a gas outlet pipeline, a multi-electric-field power supply device and heating equipment (optional), a first section, a second section, a crude oil collecting section and other crude oil treatment areas are arranged in the separator. The high-frequency / high-voltage insulated electrode is located in the oil-rich layer and the emulsion layer and located in the middle of the section; the ultrahigh-frequency / low-voltage bare electrode is positioned in the liquid phase layer of one section; the high-frequency / high-voltage bipolar bare electrode is positioned in the oil-rich layer of the second section; the existing thermochemical treatment process of the crude oil is simplified, the three electric fields can perform effective electric field demulsification and electrostatic coalescence dehydration on the crude oil with corresponding water content in the tank, the chemical demulsification process in the electric fields can be enhanced, the retention time of conventional high-frequency pulsed electric field treatment of the crude oil is shortened, and closed, efficient and low-cost treatment of the crude oil can be realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of three-phase separation technology, especially a kind of two-stage double-gradient three electric field enhanced demulsification three-phase separator, to carry out demulsification and dewatering treatment to crude oil, so that the crude oil after processing meets the related requirements of export standard in mine field or meets subsequent processing standard in oil refining workshop. BACKGROUND

[0002] Shale oil refers to the oil resources contained in shale series (mainly shale), mainly existing in rock pores, cracks and adjacent layers and interbeds of rock. Shale oil has the characteristics of high condensation point, high wax content, high wax precipitation point, small liquid drop particle size in emulsion and high emulsification degree, so there are problems such as demulsification and dewatering difficulty in the treatment process of shale oil produced liquid. In order to meet the needs of shale oil product metering in mine field, mine processing, commercial crude oil quality requirements, crude oil storage and pipeline (or other conveying mode) transportation, gas-liquid two-phase must be separated, crude oil and associated water in liquid phase must be separated, and three-phase separation treatment has thus become the primary treatment process of shale oil processing in mine field.

[0003] Oil, gas and water three-phase have different physical and chemical properties, such as density and viscosity, and oil, gas and water three-phase separator is to separate oil, gas and water to a certain extent by using the difference between three-phase properties in a certain way (such as gravity sedimentation method, centrifugal method, filler separation method, etc.). However, due to the different properties of produced liquid in each oil field, the separation degree of oil, gas and water three-phase required is also different, therefore, scholars and engineering and technical personnel at home and abroad continuously research, design and improve oil, gas and water three-phase separator according to production and exploitation environment requirements, so that it is more reasonable and effective, more economical and environmentally friendly.

[0004] Since 2017, Professor Chen Jiaqing's research group of Beijing Petroleum Chemical College has been committed to the localization application of the third generation VIEC technology and product. After more than two years of time, on the basis of fully digesting and absorbing the third generation VIEC electric field demulsification technology of foreign countries, a transformer non-embedded VIEC electrocoalescence module is independently developed, which is composed of metal electrode, insulating electrode, stainless steel pipe and wire collecting ball, wherein the insulating electrode plate is integrally molded by epoxy resin material. The technology was pilot tested in January 2019 in Zhanxi 106 transfer station of Shengli Oilfield, with three-phase separator inlet water content of 97.3%, crude oil density of 0.932 g / cm3 and viscosity of 328 mPa·s. The experimental results show that under the action of high-frequency / high-voltage pulse alternating current electric field, VIEC electric field demulsification technology can reduce the water content of oil well produced liquid with water content of 97% to about 4% or even lower after electrocoalescence dewatering, and the electric field demulsification effect is remarkable, which provides valuable experience for subsequent industrial field application experimental research.

[0005] In 2020, Liu Cunxin and others of Jintiao Intelligent Technology Co., Ltd. proposed a new type of high-frequency electrostatic coalescer, when working, the high water cut crude oil emulsion enters from the tangential inlet of the gas-liquid cyclone separator, after internal cyclone centrifugation, the gas is discharged from the upper exhaust pipe, the liquid flows into the electric field area from the lower part of the device, and the crude oil emulsion is subjected to electric field demulsification through the first high-frequency coalescing device, so that the high water cut crude oil emulsion realizes the purpose of oil-water separation: the second layer of coalescing device in the device can effectively cut the gas bubbles, improve the oxygen transfer rate and utilization efficiency, so that the organic matter in the water is effectively treated. In the same year, Sun Longlong and others of Shengli Oilfield Longxi Petroleum Engineering Service Co., Ltd. designed a high-frequency coalescing device for the problems of strong emulsification and difficult treatment of high water cut crude oil produced liquid. During the treatment process, the crude oil emulsion enters through the inlet and is uniformly dispersed in the tank through the oil hole distributor, flows through the electric field area, and under the action of the electrode mesh electric field, the oil and water phases are separated, and the oil phase is discharged from the oil outlet. The field experiment results show that the water content in the oil can be reduced to 5% after the treatment of the crude oil emulsion with water content of more than 90%, and the effect of electric field demulsification pre-water separation is remarkable.

[0006] In summary, in the existing crude oil three-phase separation process, the cost of thermochemical process is high, the treatment process is long, it is difficult to be sealed, so the oil and gas loss is large, the environmental problems are prominent, and the treated oil and water for external transport is difficult to meet the standard requirements. Objectively speaking, compared with the chemical demulsification, thermochemical demulsification and other oil-water emulsion treatment methods, the electric field demulsification has been highly concerned by domestic and foreign researchers in recent years due to high treatment efficiency and no side effects. At present, the electric field used in most in-service three-phase separators is still power frequency / high voltage alternating current electric field, and so far, a large number of engineering operation results show that the power frequency electric dehydration equipment is easy to produce electric breakdown, which leads to the damage of the electric field and the electrode, and the problems such as difficult to power on. At present, the residence time of the conventional high-frequency pulse electric field equipment for treating shale oil is more than twice that of the conventional crude oil treatment, so it is urgent to improve the effectiveness of the electric field used in the shale oil electric field separator.

[0007] Therefore, the utility model is provided. Utility model content

[0008] The utility model aims at providing a two-section double-gradient three-electric-field enhanced demulsification three-phase separator, so as to solve the above-mentioned technical problems in the prior art.

[0009] The utility model aims at realizing the following technical scheme:

[0010] The utility model discloses a two -segment double gradient three electric field enhanced demulsification three -phase separator, including separator jar body, the separator jar body is connected with crude oil pipeline 5, water injection pipeline 6, dosing pipeline 7, oil outlet pipeline 20, gas outlet pipeline 24, drainage pipeline 22, the drainage pipeline 22 side branch pipe is connected with the separator jar body through water pump and has the sand washing water pipeline 23 of mud,

[0011] The separator jar body is equipped with the tubular distributor 11 and is connected with the crude oil pipeline, and is sequentially divided into a section and a second section from the tubular distributor 11 to the oil outlet pipeline 20, and each section is respectively provided with a crude oil treatment area, and the first section and the second section are connected by a pipeline located outside the tank between the flange one 27 and the flange two 28.

[0012] Alternatively, the second section is further provided with a crude oil collection section.

[0013] The first section is sequentially provided with a gas phase layer 1, an oil-rich layer 2, an emulsion layer 3 and a water-rich layer 4 from top to bottom.

[0014] The second section is sequentially provided with the oil-rich layer 2 and the water-rich layer 4 from top to bottom.

[0015] The crude oil collection section is sequentially provided with the gas phase layer 1 and the oil-rich layer 2 from top to bottom.

[0016] Compared with the prior art, the two-section double-gradient three-electric-field enhanced demulsification three-phase separator provided by the utility model simplifies the existing thermal chemical treatment process of crude oil, the three electric fields can effectively demulsify and electrocoalesce and dewater the crude oil with corresponding water content in the tank, and can strengthen the chemical demulsification process in the electric field, shorten the residence time of the conventional high-frequency pulse electric field treatment of the crude oil, and realize closed, efficient and low-cost treatment of the crude oil. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The two-section double-gradient three-electric-field enhanced demulsification three-phase separator structure schematic diagram (not containing the crude oil collection section) provided by the utility model embodiment one is shown in the figure;

[0018] Figure 2 The two-section double-gradient three-electric-field enhanced demulsification three-phase separator structure schematic diagram provided by the utility model embodiment two is shown in the figure;

[0019] Figure 3 a、 Figure 3 b、 Figure 3 C is respectively the front view, top view and side view structure schematic diagram of the integrated installation electrode provided by the utility model embodiment;

[0020] Figure 4 The structure schematic diagram of the simple electrode plate provided by the utility model embodiment is shown in the figure;

[0021] The contents represented by each mark in the figure are as follows:

[0022] 1-gas phase layer, 2-oil-rich layer, 3-emulsion layer, 4-water-rich layer, 5-crude oil pipeline, 6-water injection pipeline, 7-dosing pipeline, 8-heat exchanger, 9-static mixer, 10-mixing valve, 11-pipe distributor, 12-ultra-high frequency / low-voltage bare electrode, 13-ground electrode (matched with the ultra-high frequency / low-voltage bare electrode), 14-high frequency / high-voltage insulated electrode, 15-ground electrode (matched with the high frequency / high-voltage insulated electrode), 16-high frequency / high-voltage bipolar bare electrode, 17-ground electrode (matched with the high frequency / high-voltage bipolar bare electrode), 18-power supply control cabinet, 19-transformer (matched with the separator), 20-oil outlet pipeline, 21-sediment flushing pipeline, 22-drainage pipeline, 23-sediment flushing water pipeline, 24-gas outlet pipeline, 25-weir plate one, 26-weir plate two, 27-flange one, 28-flange two;

[0023] 31-screw, 32-pole plate, 33-wiring terminal, 34-insulating ceramic ring, 35-nut;

[0024] 41-angle steel, 42-pole plate, 43-angle code. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, which does not constitute a limitation on the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0026] First, the terms that can be used in this paper are described as follows:

[0027] The term "and / or" means either one or both, for example, X and / or Y means three cases including "X" or "Y" and "X and Y".

[0028] The terms "include", "contain", "have", "possess" or other similar semantic descriptions should be interpreted as non-exclusive inclusion. For example: including a technical feature element (such as raw materials, components, ingredients, carriers, dosage forms, materials, sizes, parts, components, mechanisms, devices, steps, processes, methods, reaction conditions, processing conditions, parameters, algorithms, signals, data, products or articles, etc.) should be interpreted as not only including the explicitly listed technical feature element, but also including other technical feature elements that are not explicitly listed but are well known in the art.

[0029] The term "consisting of" denotes an exclusion of any element, not explicitly listed. If the term is used in the claims, the term shall make the claims closed and shall not be followed by any elements other than those explicitly listed. If the term is only used in a clause of the claims, it only restricts that clause and does not exclude any other elements from being present in the other clauses of the claims.

[0030] The contents not described in detail in the embodiments of the utility model belong to the prior art known to the person skilled in the art. The embodiments of the utility model are not marked with specific conditions, and are carried out according to the conventional conditions in the art or the conditions recommended by the manufacturer. The reagents or instruments used in the embodiments of the utility model are not marked with the manufacturer, and are all conventional products that can be obtained by market purchase.

[0031] The two-section double-gradient three-electric-field enhanced demulsification three-phase separator of the utility model, including separator tank body, the separator tank body is connected with crude oil pipeline 5, water injection pipeline 6, dosing pipeline 7, oil outlet pipeline 20, gas outlet pipeline 24, drainage pipeline 22, the drainage pipeline 22 side branch pipe is connected with the separator tank body through water pump and has mud sand flushing water pipeline 23;

[0032] The separator tank body is provided with a tubular distributor 11 connected with the crude oil pipeline, and is sequentially divided into a first section and a second section from the tubular distributor 11 to the oil outlet pipeline 20, each section is provided with a crude oil treatment area, and the first section and the second section are connected by a pipeline outside the tank between flange one 27 and flange two 28.

[0033] Alternatively, the second section is further provided with a crude oil collection section.

[0034] The first section is sequentially provided with a gas phase layer 1, an oil-rich layer 2, an emulsion layer 3, and a water-rich layer 4 from top to bottom.

[0035] The second section is sequentially provided with an oil-rich layer 2 and a water-rich layer 4 from top to bottom.

[0036] The crude oil collection section is sequentially provided with a gas phase layer 1 and an oil-rich layer 2 from top to bottom.

[0037] The separator tank body is provided with weir plate one 25 and weir plate two 26, the first section is arranged between the tubular distributor 11 and weir plate one 25, the second section is arranged in the area between weir plate two 26 and the oil outlet, and the crude oil collection section is arranged in the oil-rich layer 2 between weir plate one 25 and weir plate two 26.

[0038] The separator tank body is provided with a matching electric field power supply device, the electric field power supply device includes a power supply control cabinet 18 and a transformer 19.

[0039] The separator tank is provided with high-frequency / high-voltage insulated electrode 14, ultra-high-frequency / low-voltage bare electrode 12, high-frequency / high-voltage bipolar bare electrode 16, or is also provided with a heating device;

[0040] The high-frequency / high-voltage insulated electrode 14 is located in the middle of a section; the ultra-high-frequency / low-voltage bare electrode 12 is located in the liquid phase layer of a section, and is distributed in the liquid phase layer of a section under the condition of meeting the installation condition; the high-frequency / high-voltage bipolar bare electrode 16 is located in the oil-rich layer of a section;

[0041] The ultra-high-frequency / low-voltage bare electrode 12 in the separator tank is integrally installed, and the electrode plate is a longitudinal inclined plate, which has an inclined plate settling effect, and a plurality of pairs of electrodes are an integral whole, and installation supports of the electrodes are arranged at corresponding positions in the tank; electrodes of the same polarity are connected by cables, the ultra-high-frequency / low-voltage bare electrode 12 is connected to the ultra-high-frequency / low-voltage port of the transformer 19, the grounding electrode 17 is connected to the ground wire, and insulating materials are arranged between electrode plates of different polarities;

[0042] The ultra-high-frequency / low-voltage bare electrode 12 in the separator tank is also simply installed, four corners of each electrode plate in one group are connected by four angle steels, and the electrode plate and the angle steel are fixed by an angle code, installation supports of the electrodes are arranged at corresponding positions in the tank, two angle steels on one side of one group of electrode plates are connected to an ultra-high-frequency / low-voltage transformer, and the other two angle steels are connected to the ground, and the electrode plate in this mode is spliced by a metal electrode plate and an insulating material of appropriate size, so that the angle steel of the grounding side of the electrode plate is directly fixed, and the angle steel of the grounding side of the electrode plate is directly fixed.

[0043] The above-mentioned two-section double-gradient three-electric-field enhanced demulsification three-phase separator realizes the method for separating and treating crude oil, which comprises the following steps:

[0044] A. The crude oil mixed liquid enters from the inlet outside the tank body through the tubular distributor, is treated by the tubular distributor, is preliminarily separated from oil and gas, and changes the direction and speed of the fluid, and the liquid phase is distributed to the ultra-high-frequency / low-voltage electric field below the liquid surface;

[0045] B. In the working process of the separator, the one-section double-gradient electric field is a high-frequency / high-voltage pulse electric field in the oil-rich layer and the emulsion layer and an ultra-high-frequency / low-voltage electric field in the liquid phase layer, which respectively provide suitable electric field parameters for the electric field demulsification of the crude oil and the dehydration treatment;

[0046] C. In the working process of the separator, the high-water-content crude oil which is not fully demulsified and dehydrated in the one-section flows to the two-section through the pipeline between the flange one 27 and the flange two 28, the flange one 27 is located in the crude oil collecting section, and the high-frequency / high-voltage bipolar electric field is used for the electric field demulsification and electrostatic coalescence dehydration, so as to further reduce the water content in the crude oil.

[0047] In the step A, the crude oil mixture to be treated enters the tubular distributor from the crude oil pipeline, and after the crude oil mixture enters the tubular distributor, the gas overflows to the gas phase layer in the tank through the small holes on the side of the vertical tubular distributor, and the liquid phase is introduced into the ultrahigh frequency / low voltage electric field in the liquid phase in the first section of the tank by the action of gravity;

[0048] In the step B, the liquid phase after the oil-gas preliminary separation in the first section is stratified into the water-rich layer at the bottom, the oil-rich layer and the emulsion layer containing dispersed water beads at the upper part due to the density difference between the oil and water, so that the double gradient electric field is provided in the first section; the ultrahigh frequency / low voltage electric field is arranged in the liquid phase layer in the first section, and the electric field demulsification treatment and electrocoalescence dehydration can be effectively carried out on the high water content crude oil through the electric field, and the electric field is not collapsed; the high frequency / high voltage electric field is arranged in the oil-rich layer and the emulsion layer in the middle part of the first section, and the electric field demulsification treatment and electrocoalescence dehydration can be carried out on the oil-rich layer and the emulsion layer with low water content through the electric field.

[0049] In the step C, after the crude oil treated by the tubular distributor is discharged from the outlet thereof, the crude oil is firstly subjected to preliminary electrocoalescence dehydration through the ultrahigh frequency / low voltage electric field, the high water content crude oil is distributed downward, the low water content crude oil continues to pass through the high frequency / high voltage insulating electric field in the middle part of the upper part of the liquid phase in the first section, the high water content crude oil is subjected to targeted demulsification and dehydration treatment, and then the crude oil after the treatment of the front electric field is subjected to continuous dehydration treatment through the high frequency / high voltage bipolar electric field.

[0050] As can be seen from the above, the two-section double-gradient three-electric-field enhanced demulsification three-phase separator according to the embodiments of the present application can fully utilize the volume space of the separator, set two-section double-gradient three-electric-field, and improve the oil-water separation efficiency by combining the chemical demulsification of the demulsifier, so as to fully shorten the treatment time.

[0051] The two-section double-gradient three-electric-field intensified demulsification three-phase separator provided by the embodiment of the utility model, on the one hand, uses high-frequency / high-voltage electric field, ultrahigh-frequency / low-voltage electric field and high-frequency / high-voltage bipolar electric field to replace the conventional power frequency / high-voltage alternating current power supply system to carry out electric field demulsification and intensified chemical demulsification, thereby improving the single-body processing efficiency of the separator; on the other hand, the ultrahigh-frequency / low-voltage electric field is used to replace the conventional high-frequency / high-voltage electric field to process high-water-content crude oil emulsion, thereby realizing effective dehydration of the high-water-content emulsion and not collapsing the electric field; the three electric fields are used to replace the conventional single high-frequency / high-voltage electric field to process crude oil emulsion with different water contents, thereby fully processing the crude oil emulsion, further reducing the water content of the processed crude oil production fluid, ensuring that the quality of the exported crude oil meets the standards and reducing the oil concentration of the cut water, and simultaneously, the medicament cost and heating cost can also be greatly reduced.

[0052] In order to more clearly show the technical solutions provided by the utility model and the technical effects generated, the following will describe the in detail with specific embodiments.

[0053] The main equipment related to the utility model includes a separator tank, a tubular distributor, a crude oil pipeline, a medicament adding pipeline, an oil outlet pipeline, a gas outlet pipeline, an electric field power supply device and a heating device (optional). The crude oil production fluid to be processed, dilution water (optional) and demulsifier are heated by a heat exchanger, then fully mixed under the action of a static mixer and a mixing valve, and then enter the inlet of the tubular distributor in the separator. The dilution water (optional) extracts the salt in the crude oil in the mixing process, and the oil-water mixture enters the inlet outside the tank through the tubular distributor, is sprayed out from the outlet hole on the side of the adjacent head by the vertical pipe inside the tank, and then collides with the head. In this process, the oil and gas are preliminarily separated, and the direction and speed of the fluid are changed. Then the liquid phase is introduced below the liquid surface of the first section, and the oil and water are separated into layers due to the density difference. The bottom is the separated water-rich layer, and the upper part is the oil-rich layer and the emulsion layer containing dispersed water beads. Due to the characteristics of high freezing point, high wax content, high wax precipitation point, small liquid drop particle size in the emulsion and high emulsification degree of shale oil, and the easy emulsification of shale oil and dilution water (optional) under the action of mixing and shearing, part of the emulsion cannot be fully demulsified in the limited hydraulic retention time of the separator, and thus an emulsion layer is formed between the upper oil area and the lower water area. A single electric field cannot effectively process the emulsion in the shale oil, and part of the emulsion is also contained in the water layer. Therefore, an ultrahigh-frequency / low-voltage electrode is arranged in the liquid phase layer of the first section to effectively process the high-water-content emulsion in the water-rich layer of the first section, and a high-frequency / high-voltage bipolar bare electrode is arranged in the oil-rich layer of the second section to effectively process the low-water-content emulsion in the oil-rich layer of the first section. Through the above process, the emulsion in the separator can be effectively processed.

[0054] In order to improve the processing efficiency of the separator, the chemical demulsification of the electric field reinforced demulsifier is also used, namely, the demulsifier is added to the mixed inlet crude oil and dilution water (optional) at the same time, and the heat exchanger is passed before entering the external inlet of the tubular distributor to be heated, so that the electric field cooperates with the demulsifier to achieve higher demulsification efficiency under the coupling synergistic effect of a certain temperature.

[0055] The two-section double-gradient three-electric-field reinforced demulsification three-phase separator of the utility model, on the one hand, uses high-frequency / high-voltage electric field, ultrahigh-frequency / low-voltage electric field and high-frequency / high-voltage bipolar electric field instead of conventional single power frequency / high-voltage alternating current power supply system, strengthens the electric field effect, improves the single processing efficiency of the separator; on the other hand, the ultrahigh-frequency / low-voltage electric field is used instead of the conventional high-frequency / high-voltage electric field to process the high-water-content crude oil emulsion, the required field strength is lower, and the electric field can be realized without collapse, and stable dehydration; the three-electric-field segmented treatment of shale oil emulsion is used instead of the conventional single high-frequency / high-voltage electric field to process the crude oil, so that the water content of the treated shale oil is further reduced. The process can effectively remove the high-water-content emulsion and low-water-content emulsion dispersed in the tank caused by the conventional three-phase separation process, fully utilize the volume space of the separator, set two-section double-gradient three-electric-field, strengthen the chemical demulsification of the shale oil demulsifier, improve the oil-water separation efficiency, and fully shorten the processing time.

[0056] Example 1

[0057] As Figure 1 , Figure 2 and Figure 3 a, Figure 3 b, Figure 3As shown in the figure, the crude oil to be treated in the crude oil pipeline 5 is mixed with the dilution water (optional) in the water injection pipeline 6 through the static mixer 9 and the mixing valve 10, and at the same time, in order to ensure that the separator has relatively good demulsification effect, an appropriate amount of demulsifier is added to the mixed solution through the medicament pipeline 7, and the mixed solution is moderately heated through the heat exchange device 8. The mixed solution enters the inlet outside the tank body through the tubular distributor 11, is sprayed out from the outlet hole on the side of the adjacent head in the vertical pipe inside the tank body, and then collides with the head. In this process, the oil and gas are preliminarily separated, and the direction and speed of the fluid are changed, the gas floats to the top of the tank to form a gas phase layer 1, and then the liquid phase is introduced below the liquid level, and the oil and water are layered by relying on the density difference between the oil and water. The bottom is the separated water-rich layer 4, the upper part is the oil-rich layer 2 and the emulsion layer 3 containing dispersed water droplets, an ultrahigh frequency / low voltage electric field is arranged in the first-stage liquid phase layer, the chemical demulsification treatment and dehydration treatment of the high-water-content crude oil can be effectively strengthened through the electric field, and the electric field can be realized without collapse; a high-frequency / high-voltage electric field is arranged in the first-stage oil-rich layer and the emulsion layer, and the chemical demulsification treatment and dehydration treatment of the low-water-content oil-rich layer and the emulsion layer can be strengthened through the electric field; in order to prevent short circuit breakdown of adjacent high-frequency / high-voltage electrodes under the action of strong voltage, the high-voltage electrode 14 can be insulated, that is, a layer of insulating material is covered outside the high-voltage electrode 14. The insulating material can be selected from polytetrafluoroethylene (PTFE), polytetrafluoroethylene (FEP), fluororubber, ceramic and the like. The crude oil containing low-water-content emulsion after the first-stage treatment flows along the tank outside pipeline between the flange one 27 and the flange two 28, the liquid flows into the second-stage oil-rich layer, and the low-water-content emulsion is further demulsified in the electric field region formed between the high-frequency / high-voltage double bare electrodes 16 and the grounded bare electrode 17 of the separator. After the above treatment, the oil in the oil collecting section (optional) of the tank body is output through the external pipeline 20, and the water at the bottom is transported to the sewage treatment process through the pipeline 22, part of the water is circulated to the sand washing water pipeline 23 as a sand washing water source, and the sand at the bottom of the separator tank body is purged through the sand washing pipe manifold 21.

[0058] In order to further improve the treatment efficiency, the crude oil produced fluid is heated to a certain degree by the heating device or the heat exchanger before entering the tubular distributor of the separator, and an appropriate amount of demulsifier is added to the liquid by the medicament pipeline.

[0059] Compared with other process improvement schemes in the field, the utility model has the following advantages:

[0060] 1. For the treatment of oil-water emulsion in the separator, compared with the centrifugal method, chemical demulsification method, flash evaporation method and other treatment methods, the treatment unit required by the electric field demulsification is less, the treatment efficiency is higher, and a large amount of chemical agent is not needed. The treatment cost can be significantly saved, and the stable and efficient operation of the separator can be ensured on the basis of improving the treatment efficiency.

[0061] 2. Using high frequency / high voltage electric field, ultra-high frequency / low voltage electric field and high frequency / high voltage bipolar electric field instead of conventional power frequency / high voltage alternating current electric field, the effect of chemical agent is enhanced by electric field, and the efficiency of single treatment of the separator is improved;

[0062] 3. Using ultra-high frequency / low voltage electric field instead of conventional high frequency / high voltage electric field to effectively treat high water content crude oil emulsion, and realizing non-collapse electric field and stable dehydration;

[0063] 4. Using two-stage double gradient three electric fields instead of conventional single high frequency / high voltage electric field to treat crude oil emulsion, and treating various water content crude oil and emulsion in the separator, so that the water content of treated crude oil production fluid is further reduced, the two-stage three electric field treatment process ensures that the quality of outlet crude oil meets the standard, and the agent cost and heating cost are further reduced.

[0064] The above is only the preferred specific implementation manner of the present application, but the protection scope of the present application is not limited to this, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be limited by the protection scope of the claims. The information disclosed in the background section of the present application is only intended to deepen the understanding of the overall background technology of the present application, and should not be regarded as acknowledging or implying in any form that the information constitutes the prior art known by the skilled person in the art.

Claims

1. A two-stage, double-gradient, three-electric-field enhanced demulsification, three-phase separator, characterized in that, The separator tank is connected with a crude oil pipeline (5), a water injection pipeline (6), a chemical injection pipeline (7), an oil outlet pipeline (20), a gas outlet pipeline (24) and a drainage pipeline (22), and the drainage pipeline (22) is connected with a mud flushing water pipeline (23) through a water pump; The separator tank is provided with a tubular distributor (11) connected with the crude oil pipeline, and is divided into a first section and a second section in sequence from the tubular distributor (11) to the oil outlet pipeline (20), each of which is provided with a crude oil treatment area, and the first section and the second section are connected by a pipeline between flange one (27) and flange two (28) outside the tank; Alternatively, the second section is further provided with a crude oil collection section; The first section is sequentially provided with a gas phase layer (1), an oil-rich layer (2), an emulsion layer (3) and a water-rich layer (4) from top to bottom; The second section is sequentially provided with an oil-rich layer (2) and a water-rich layer (4) from top to bottom; The crude oil collection section is sequentially provided with a gas phase layer (1) and an oil-rich layer (2) from top to bottom.

2. The two-stage, double-gradient, three-electric-field intensified demulsifying three-phase separator of claim 1, wherein, The separator tank is provided with weir plate one (25) and weir plate two (26), the first section is arranged between the tubular distributor (11) and weir plate one (25), the second section is arranged in the area between weir plate two (26) and the oil outlet, and the crude oil collection section is arranged in the oil-rich layer (2) between weir plate one (25) and weir plate two (26).

3. The two-stage, double-gradient, three-electric-field intensified demulsifying three-phase separator of claim 2, wherein, The separator tank is provided with a matching electric field power supply device, which comprises a power supply control cabinet (18) and a transformer (19); The separator tank is provided with a high-frequency / high-voltage insulated electrode (14), an ultrahigh-frequency / low-voltage bare electrode (12) and a high-frequency / high-voltage bipolar bare electrode (16); or a heating device; The high-frequency / high-voltage insulated electrode (14) is located in the middle of the first section; the ultrahigh-frequency / low-voltage bare electrode (12) is located in the liquid phase layer of the first section and covers the liquid phase layer of the first section under the condition of meeting the installation condition; and the high-frequency / high-voltage bipolar bare electrode (16) is located in the oil-rich layer of the second section; The ultrahigh-frequency / low-voltage bare electrode (12) in the separator tank is integrally installed, and the electrode plate is a longitudinal inclined plate, which has an inclined plate settling effect, a plurality of pairs of electrodes form an integral whole, and a mounting bracket of the electrode is arranged at a corresponding position in the tank; electrodes of the same polarity are connected by a cable, the ultrahigh-frequency / low-voltage bare electrode (12) is connected to an ultrahigh-frequency / low-voltage port of the transformer (19), the grounding electrode (17) is connected to a ground wire, and an insulating material is arranged between electrode plates of different polarities. The ultra-high frequency / low voltage bare electrode (12) in the separator tank is also simple to install, wherein the four corners of each plate in a group are connected by four angle steels, and the plates and angle steels are fixed by angle brackets, and the installation support of the electrode is arranged at the corresponding position in the tank, and two angle steels on one side of the plate in the group are connected with the ultra-high frequency / low voltage transformer, and the other two angle steels are connected with the ground, and the plate in the mode is spliced by a metal plate and an appropriate size of insulating material, so that the angle steel on the insulating side of the ground plate is directly fixed with the power connection side, and the angle steel on the insulating side of the power connection plate is directly fixed with the ground side.

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