A system for evaluating emulsification of a thickened oil composite flooding

Abstract

The application discloses a system for evaluating emulsification of thick oil composite flooding, which comprises an injection device for injecting one of crude oil, formation water, steam and oil displacement agent in different experimental stages; a production device for providing experimental pressure; a temperature control device for providing experimental temperature; a visual reaction kettle provided with a porous medium block at the bottom and communicated with the injection device; an experimental control device for carrying out emulsification and demulsification experiments, emulsion system manufacturing experiments, emulsion oil displacement agent displacement experiments and emulsion evaluation experiments based on a thermal chemical displacement front by controlling the injection device, the production device and the temperature control device according to different oil-water ratios, different temperatures, different pressures and different injection speeds, wherein the emulsification and demulsification experiments are formed by combination of steam flooding, and / or thermal chemical flooding, and / or thermal composite flooding, and / or multiple thick oil displacement; and an image acquisition device for capturing images in the visual reaction kettle in real time during the experiment implementation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of efficient development of heavy oil, and in particular to an experimental system for evaluating emulsification of heavy oil compound flooding. BACKGROUND

[0002] Steam huff and puff is the main way of heavy oil, but the steam huff and puff has limited scope, and there is a large amount of remaining oil between wells at the end of the huff and puff, and the recovery rate is low. Thermal compound flooding is an effective method for further improving the recovery rate of heavy oil after steam huff and puff. Emulsification to improve the flow capacity of heavy oil is one of the main mechanisms of thermal compound flooding, and the formation of emulsion flooding far from the well is the main mechanism to expand the swept volume. Evaluating the stability of emulsion has important significance for studying the displacement effect of thermal compound flooding and screening thermal chemicals.

[0003] At present, the heavy oil emulsion production device mainly adopts mechanical stirring, and the commonly used heavy oil emulsion preparation method also includes ultrasonic emulsification method, filter screen (membrane) method, pump replacement emulsifier and emulsification tube method. The emulsion used in the existing thermal compound flooding emulsion evaluation is still prepared by stirring according to the standard of chemical flooding. However, the emulsion prepared by this method is different from the emulsion formed by steam-heavy oil through porous medium, and the dispersed phase droplet is larger and the stability is poorer. The average droplet size of the emulsion formed by ultrasonic emulsification method is small, and the droplet size distribution range is narrow. However, ultrasonic itself can reduce the viscosity of heavy oil through ultrasonic cavitation, and the viscosity reduction through cavitation may be an irreversible process, thereby changing the properties of heavy oil. The filter screen (membrane) method is similar to the emulsification in the actual formation, but the water-in-oil emulsion produced by steam flooding is formed by condensation of steam bubbles, and the droplet size is smaller and more stable. The emulsification of pump replacement emulsifier is to generate strong shear force in high-speed rotation to realize emulsification, and the emulsification tube method is to realize emulsification by forming turbulent flow. These two methods are similar to mechanical stirring emulsification, and it is difficult to simulate the emulsification in the reservoir. In addition, there is another method that directly injects the dispersed phase into the flowing continuous phase through the emulsification tube to form emulsion droplets. This method is difficult to control and is only suitable for simulating emulsion in specific reservoirs. SUMMARY

[0004] The purpose of the present application is to provide a heavy oil thermal compound flooding emulsion evaluation system based on steam simulation, so that the thermal compound flooding simulation realized by the present application is the same as the emulsion principle of heavy oil thermal compound flooding, and the obtained emulsion is closer to the emulsion in the formation.

[0005] In order to solve the above technical problems, the embodiment of the present application provides a system for evaluating emulsification of thick oil composite flooding, comprising: an injection device for injecting one of experimental crude oil, formation water, steam and oil displacement agent in different experimental stages; a production device in communication with an internal space of a reaction kettle for providing experimental pressure meeting experimental requirements; a temperature control device arranged outside the reaction kettle for providing experimental temperature meeting experimental requirements; a visual reaction kettle with a porous medium block arranged at a bottom thereof and in communication with the injection device; an experimental control device for carrying out emulsification and demulsification experiments, various emulsion system manufacturing experiments, emulsion oil displacement agent displacement experiments and emulsion evaluation experiments based on a thermal chemical flooding displacement front by controlling the injection device, the production device and the temperature control device according to different oil-water ratios, different experimental temperatures, different experimental pressures and different injection speeds, wherein the emulsification and demulsification experiments are formed by combination of steam flooding, and / or thermal chemical flooding, and / or thermal composite flooding, and / or multiple thick oil displacement; and an image acquisition device for capturing images in the visual reaction kettle in real time during implementation of each experiment.

[0006] Preferably, the injection device comprises: a crude oil injection pump; a crude oil intermediate container with an inlet in communication with the crude oil injection pump, and an outlet connected with a first bottom inlet of the reaction kettle; a formation water intermediate container with an outlet on a pipeline between the outlet of the crude oil intermediate container and the first bottom inlet; a steam generator connected with a second bottom inlet of the reaction kettle; multiple-stage parallel oil displacement agent intermediate containers with outlets connected with an inlet of the steam generator; and a displacement pump as a power source connected with the formation water intermediate container, the steam generator and the oil displacement agent intermediate containers respectively.

[0007] Preferably, the visual reaction kettle comprises: a top end cover; a bottom end cover; multiple metal columns vertically penetrating through edges of the top end cover, and lower portions of the metal columns being fixed at edges of the bottom end cover; a glass tube reaction kettle arranged inside a space formed by the multiple metal columns, an upper end of the glass tube reaction kettle being inserted through a top piston at a lower portion of the top end cover, and a lower end of the glass tube reaction kettle being inserted through a bottom piston at an upper portion of the bottom end cover, wherein the porous medium block axially penetrates through a center of the bottom piston and is inserted into a center of the bottom end cover, and a bottom center of the porous medium block is provided with a first hole in communication with the first bottom inlet of the reaction kettle and a second hole in communication with the second bottom inlet of the reaction kettle.

[0008] Preferably, the center region of the top end cover is configured with a plurality of sampling holes axially penetrating through the center of the top end cover and the top piston, wherein each sampling hole corresponds to a sampling tube of different length inserted therein, and the sampling holes are in communication with the production device so that the production device is in communication with the reactor cavity, and the production device adopts a metal diaphragm back pressure valve.

[0009] Preferably, the top end cover is made of stainless steel, the glass tube reactor is made of sapphire, the side surface of the top piston and the side surface of the glass tube reactor are sealed by an O-ring, the side surface of the bottom piston and the side surface of the glass tube reactor are sealed by an O-ring, a polytetrafluoroethylene gasket is arranged between the annular bottom surface of the top end cover and the upper end surface of the glass tube reactor, and a polytetrafluoroethylene gasket is arranged between the annular top surface of the bottom end cover and the lower end surface of the glass tube reactor; and the porous medium block is tightly fitted into the groove of the bottom end cover.

[0010] Preferably, the experimental control device carries out the emulsification and demulsification experiments and the emulsified system manufacturing experiment according to the following steps: controlling the injection device to inject experimental crude oil into the porous medium block so as to saturate the porous medium block with oil; controlling the production device and the temperature control device so that the temperature and pressure in the reactor cavity reach the preset experimental temperature and the preset experimental pressure, respectively; according to a preset oil-water ratio, controlling the injection device to inject experimental crude oil and experimental steam into the reactor cavity, while controlling the image acquisition device to observe this step; according to the preset oil-water ratio, controlling the injection device to inject experimental crude oil and heated experimental oil displacement agent into the reactor cavity, while controlling the image acquisition device to observe this step; based on the collected images, evaluating the stability of the emulsion under the formation condition, analyzing the spontaneous blooming and demulsification characteristics under the combined conditions of different oil-water ratios, different experimental temperatures, different experimental pressures and different injection speeds, and sampling the formed emulsion to manufacture various emulsified systems of different oil-water ratios and analyze the influencing factors and rules of the emulsification performance.

[0011] Preferably, the experimental control device carries out the emulsion displacement experiment of the oil displacement agent according to the following step process: constructing oil sand configured according to the particle size distribution of the reservoir to be evaluated in the visualization reactor; controlling the injection device to inject experimental formation water into the reactor cavity until the cavity is filled with formation water to achieve pressure buildup, so as to calculate the porosity according to the pore volume of the obtained sandpack model; controlling the production device and the temperature control device so that the temperature and pressure in the reactor cavity reach the preset experimental temperature and the preset experimental pressure respectively, and controlling the injection device to inject gas-containing crude oil into the reactor cavity to establish the initial oil-water saturation, so as to obtain the water production and calculate the oil saturation; controlling the injection device to inject the heated oil displacement agent into the reactor cavity to carry out the thermal chemical displacement experiment, while controlling the image acquisition device to observe this step; at different times of the experiment, the emulsions formed at different positions are sampled, and the emulsification and rheological properties at different positions in the displacement process are analyzed, so as to clarify the oil displacement principle of the thermal chemical displacement of heavy oil.

[0012] Preferably, the experimental control device carries out the emulsion displacement experiment of the oil displacement agent according to the following step process: constructing oil sand configured according to the particle size distribution of the reservoir to be evaluated in the visualization reactor; controlling the injection device to inject experimental formation water into the reactor cavity until the cavity is filled with formation water to achieve pressure buildup, so as to calculate the porosity according to the pore volume of the obtained sandpack model; controlling the production device and the temperature control device so that the temperature and pressure in the reactor cavity reach the preset experimental temperature and the preset experimental pressure respectively, and controlling the injection device to inject gas-containing crude oil into the reactor cavity to establish the initial oil-water saturation, so as to obtain the water production and calculate the oil saturation; controlling the injection device to inject the heated oil displacement agent into the reactor cavity to carry out the thermal chemical displacement experiment, while controlling the image acquisition device to observe this step; at different times of the experiment, the emulsions formed at different positions are sampled, and the emulsification and rheological properties at different positions in the displacement process are analyzed, so as to clarify the oil displacement principle of the thermal chemical displacement of heavy oil.

[0013] Preferably, the experimental oil displacement agent includes but is not limited to chemical oil displacement agents and gas oil displacement agents, the chemical oil displacement agents include but are not limited to viscosity reducers, profile control agents, foaming agents and complex oil displacement agents, and the gas oil displacement agents include but are not limited to natural gas, N2 and CO2.

[0014] Preferably, the image acquisition device includes a camera and a background light source.

[0015] Compared with the prior art, one or more embodiments in the above scheme can have the following advantages or beneficial effects:

[0016] The present application provides a system for evaluating emulsification of thick oil composite flooding, which can study the spontaneous emulsification and demulsification process in the process of steam flooding, thermal chemical flooding, thermal composite flooding and combination of various thick oil flooding modes under different oil-water ratios, different temperatures, different pressures and different injection speeds, study the influence law of the conditions on the emulsification performance, simulate the emulsified liquid formed in the process of thick oil thermal composite flooding, and be used for evaluating the stability and rheological properties of the emulsified liquid of thick oil thermal composite flooding, and the emulsification characteristics of different positions. Meanwhile, the emulsified liquid prepared by the present application can be used for carrying out displacement experiment, and evaluating the emulsification characteristics and displacement characteristics of the emulsified liquid in different positions.

[0017] Additional features and advantages of the application will be set forth in the description that follows, and in part will be apparent from the description, or can be learned by practice of the application. The objectives and other advantages of the application will be realized and attained by the structure particularly pointed out in the description and claims. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0019] Figure 1 It is a whole structure schematic view of the system for evaluating emulsification of thick oil composite flooding of the embodiment of the present application.

[0020] Figure 2 It is a specific structure schematic view of the system for evaluating emulsification of thick oil composite flooding of the embodiment of the present application.

[0021] Figure 3 It is a structure schematic view of the visual reaction kettle in the system for evaluating emulsification of thick oil composite flooding of the embodiment of the present application. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be described in detail below with reference to the accompanying drawings and embodiments, so that how the present application applies technical means to solve technical problems and achieves technical effects can be fully understood and implemented. It should be noted that, as long as there is no conflict, each embodiment in the present application and each feature in each embodiment can be combined with each other, and the formed technical solutions are all within the protection scope of the present application.

[0023] In addition, the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a group of computer executable instructions. Moreover, although the logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0025] Steam huff and puff is the main way of heavy oil production, but the range of steam huff and puff is limited, and there is a large amount of remaining oil between wells at the end of steam huff and puff, and the recovery efficiency is low. Thermal combination flooding is an effective method for further improving the recovery efficiency of heavy oil after steam huff and puff. Emulsification to improve the flow capacity of heavy oil is one of the main mechanisms of thermal combination flooding, and the formation of emulsion flooding far from the well is the main mechanism to expand the swept volume. Evaluating the stability of emulsion is of great significance to the study of the displacement effect of thermal combination flooding and the screening of thermal chemicals.

[0026] At present, the mechanical stirring method is mainly used in the production device of heavy oil emulsion, and the commonly used heavy oil emulsion preparation method also includes ultrasonic emulsification method, filter (membrane) method, pump instead of emulsifier and emulsification tube method. The emulsion used in the existing evaluation of thermal combination flooding emulsion is still prepared by stirring according to the standard of chemical flooding. But the emulsion prepared by this method is different from the emulsion formed by steam-heavy oil through porous medium, its dispersed phase droplet is larger and its stability is poorer. The average droplet size of the emulsion formed by ultrasonic emulsification method is small, and the droplet size distribution range is narrow. But ultrasonic itself can reduce the viscosity of heavy oil through ultrasonic cavitation, and the viscosity reduction through cavitation may be an irreversible process, thereby changing the properties of heavy oil. The filter (membrane) method is similar to the emulsification in the actual formation, but the water-in-oil emulsion produced by steam flooding is formed by the condensation of steam bubbles, and the droplet size is smaller and more stable. The emulsification of pump instead of emulsifier is to generate strong shear force in high-speed rotation to realize emulsification, and the emulsification tube method is to realize emulsification by forming turbulent flow. These two methods are similar to mechanical stirring emulsification, and it is difficult to simulate the emulsification in the reservoir. In addition, there is another method that is to inject the dispersed phase into the flowing continuous phase directly through the emulsification tube to form emulsion droplets. This method is difficult to control and is only suitable for the simulation of emulsion in specific reservoirs.

[0027] Therefore, in order to clarify the oil displacement mechanism of heavy oil thermal combination flooding and study the emulsification characteristics in the process of thermal combination flooding, in order to solve one or more of the above technical problems, the present application provides a system for evaluating the emulsification of heavy oil combination flooding. The system can simulate the emulsion formed in the process of heavy oil thermal combination flooding, and can be used to evaluate the stability of the emulsion of heavy oil thermal combination flooding and the emulsification characteristics at different positions. The obtained emulsion can be used to carry out displacement experiment, so as to evaluate the emulsification characteristics and displacement characteristics of the emulsion at different positions.

[0028] Figure 1 The whole structure diagram of the system for evaluating emulsification of heavy oil compound flooding according to the embodiment of the present application is shown in the figure. As shown in the figure, the system for evaluating emulsification of heavy oil compound flooding according to the embodiment of the present application (hereinafter referred to as “evaluation system”) at least comprises injection device A, production device B, temperature control device C, visualized reactor D, experimental control device E and image acquisition device F. Figure 1

[0029] The injection device A is used to inject one of experimental crude oil, experimental formation water, experimental steam and experimental oil displacement agent (to be evaluated) in different experimental stages. The production device B is connected with the internal space of the visualized reactor D. The production device B is used to provide experimental pressure meeting the experimental requirements for the experimental reaction space. The temperature control device C is arranged outside the visualized reactor D. The temperature control device C is used to provide experimental temperature meeting the experimental requirements for the experimental reaction space. The bottom of the visualized reactor (pressure reactor) D is provided with a porous medium block 16. The porous medium block 16 is connected with the injection device A through the bottom of the reactor D. The experimental control device E is used to carry out emulsification and demulsification experiments, various emulsion system manufacturing experiments, emulsion oil displacement agent displacement experiments and emulsion evaluation experiments based on the displacement front of thermal chemical flooding by controlling the injection device A, the production device B and the temperature control device C according to different oil-water ratios, different experimental temperatures, different experimental pressures and different injection speeds, which are formed by the combination of steam flooding, and / or thermal chemical flooding, and / or thermal compound flooding, and / or various heavy oil displacement.

[0030] Figure 2 The specific structure diagram of the system for evaluating emulsification of heavy oil compound flooding according to the embodiment of the present application is shown in the figure. The specific structure of the evaluation system according to the embodiment of the present application is described below. Figure 2

[0031] As shown in the figure, the visualized reactor D is arranged inside the temperature control device C. The temperature control device C is provided with a heating table at the bottom and a transparent heat preservation cover made of glass. The lower part of the transparent heat preservation cover is provided with two pipeline inlets, and the top is left with a pipeline outlet. Figure 2

[0032] ​​​The injection device A comprises: a crude oil injection pump 1, a crude oil intermediate container 2, a formation water intermediate container 4, a steam generator 5, a flooding agent intermediate container (group) 6 and a displacement pump 3. The crude oil injection pump 1 is used to pump the experimental crude oil into the crude oil intermediate container 2 or pump the experimental crude oil from the crude oil intermediate container 2 into the reaction space of the reactor D under the control of the experimental control device E. The inlet of the crude oil intermediate container 2 is connected with the crude oil injection pump 1, and the outlet of the crude oil intermediate container 2 is connected with the first bottom inlet of the reactor D. The crude oil intermediate container 2 is used to contain the experimental crude oil, and the intermediate container 2 is provided with a heating jacket and can heat the crude oil, and the upper limit of the heating temperature is 150℃.

[0033] The outlet of the formation water intermediate container 4 is located on the pipeline between the outlet of the crude oil intermediate container 2 and the first bottom inlet. The crude oil injection pump 1 is connected with the bottom inlet of the crude oil intermediate container 2 and the bottom inlet of the formation water intermediate container 4 through valves and pipelines respectively.

[0034] In addition, the evaluation system described in the embodiment of the present application further comprises: a pressure sensor 9 located inside the pipeline between the outlet of the crude oil intermediate container 2 and the first bottom inlet. The pressure sensor 9 is used to monitor the dynamic pressure of the first bottom inlet in real time.

[0035] The steam generator 5 is connected with the second bottom inlet of the reactor D. The steam generator 5 can heat the deionized water to form steam, and the upper limit of the heating temperature is 350℃. The multi-stage parallel flooding agent intermediate containers constitute the flooding agent intermediate container group 6. The outlet of each flooding agent intermediate container is connected with the inlet of the steam generator 5. The flooding agent intermediate container group 6 is used to contain various types of flooding agents to be evaluated. The flooding agents include but are not limited to: chemical flooding agents and gas flooding agents. The chemical flooding agents include but are not limited to: viscosity reducers, profile control agents, foaming agents and complex flooding agents, etc. The gas flooding agents include but are not limited to: natural gas, N2 and CO2, etc.

[0036] The displacement pump 3 is connected with the corresponding formation water intermediate container 4, steam generator 5 and flooding agent intermediate container 6 as a power source. The displacement pump 3 is connected with the bottom inlet of the flooding agent intermediate container group 6 and the inlet of the steam generator 5 through valves and pipelines respectively. The steam outlet of the steam generator 5 passes through the pipeline inlet of the temperature control device C through the pipeline to be connected to the bottom steam inlet of the visual reactor D, and the top outlet of the crude oil intermediate container 2 and the formation water intermediate container 4 passes through another pipeline inlet of the temperature control device C through the pipeline to be connected to another bottom inlet of the visual reactor D.

[0037] In addition, the top outlet of the oil displacement agent intermediate container group 6 is connected to the inlet of the steam generator 5 through a valve and a pipeline. In the embodiment of the present application, by controlling the closing of the valve between the top outlet of the oil displacement agent intermediate container 6 and the visual reactor 7, and controlling the opening of the valve between the top outlet of the oil displacement agent intermediate container 6 and the steam generator 5, and the valve between the steam generator 5 and the steam inlet of the visual reactor 7, the thermal combination flooding can be realized.

[0038] The production device B is a bidirectional back pressure valve, which is communicated with the top sampling port of the visual reactor D through a pipeline. In one embodiment, the production device B adopts a metal diaphragm back pressure valve, which can control the visual reactor D to keep the pressure in the visual reactor D stable during discharging or injecting fluid.

[0039] With reference to the drawings, the present application will be further described. Figure 2 An image acquisition device F is arranged in the external space of the visual reactor D. The image acquisition device F includes a camera 10 and a background light source 11. Specifically, the camera 10 and the background light source 11 are arranged on the two sides of the visual reactor D, which can be used for dynamic observation of the emulsification process and demulsification process in the visual reactor D, so as to capture the image information about the emulsification segment.

[0040] Figure 3 The structural schematic diagram of the visual reactor in the system for evaluating the emulsification of the thickened oil combination flooding according to the embodiment of the present application is shown. As shown in Figure 3 The visual reactor D has a top end cover 13, a bottom end cover 17, a plurality of metal columns 15, a glass tube reactor 14 and a porous medium block 16.

[0041] The first end of the plurality of metal columns 15 penetrates through the edge of the top end cover 13 vertically, and the second end of the metal column 15 is fixed at the edge of the bottom end cover 17 vertically. The plurality of metal columns 15 are fixed to the top end cover 13 by nuts, and the lower part of the plurality of metal columns 15 are fixed to the bottom end cover 17 by threads.

[0042] The glass tube reactor 14 is arranged inside the space formed by the plurality of metal columns. The upper end of the glass tube reactor 14 is inserted into the interior of the glass tube reactor 14 through the top piston structure of the lower portion of the top end cap 13, so that the top end cap 13 integrated with the top piston seals the top of the glass tube reactor 14. The lower end of the glass tube reactor 14 is inserted into the interior of the glass tube reactor 14 through the bottom piston structure of the upper portion of the bottom end cap 17, so that the bottom end cap 17 integrated with the bottom piston seals the bottom of the glass tube reactor 14. The porous medium block 16 is axially inserted into the center of the bottom piston and the center of the bottom end cap. The bottom center of the porous medium block 16 is provided with a first hole in communication with the first bottom inlet of the reactor 7 and a second hole in communication with the second bottom inlet of the reactor 7.

[0043] In addition, the top end cap 13 is made of stainless steel. The glass tube reactor 14 is made of sapphire. The side surface of the top piston and the side surface of the glass tube reactor 14 are sealed by an O-ring, and the side surface of the bottom piston and the side surface of the glass tube reactor 14 are sealed by an O-ring. A polytetrafluoroethylene gasket is arranged between the annular bottom surface of the top end cap 13 and the upper end surface of the glass tube reactor 14, and a polytetrafluoroethylene gasket is arranged between the annular top surface of the bottom end cap 17 and the lower end surface of the glass tube reactor 14. The porous medium block 15 is tightly fitted into the groove of the bottom end cap 17.

[0044] Specifically, the lower portion of the top end cap 13 is provided with a piston structure, the end surface area of the top piston is smaller than the end surface area of the top end cap 13, the top piston is integrated with the top end cap 13, the top end cap 13 can be inserted into the sapphire glass tube 14, and the top piston and the sapphire glass tube 14 are sealed by an O-ring (for example, a fluoroether rubber O-ring). The fluoroether rubber O-ring can withstand a temperature of 320°C. An annular polytetrafluoroethylene gasket is arranged between the annular bottom surface of the top end cap 13 and the annular upper end surface of the sapphire glass tube 14, and the annular polytetrafluoroethylene gasket is used to protect the sapphire and prevent it from breaking due to uneven stress. The sapphire glass tube 14 is a transparent tube in the shape of a ring column made of artificial sapphire material.

[0045] The top of the bottom end cap 17 is provided with a piston structure, the end surface area of the bottom piston is smaller than that of the bottom end cap 17, the bottom piston is integrated with the bottom end cap 17, so that the bottom end cap 17 can be inserted into the other end of the sapphire glass tube 14, and the bottom piston and the sapphire glass tube 14 are sealed by an O-ring (for example, a fluoroether rubber O-ring). The fluoroether rubber O-ring can withstand a temperature of up to 320°C. The annular top surface of the bottom end cap 17 is in contact with the annular lower end surface of the sapphire glass tube 14 through an annular polytetrafluoroethylene gasket, which is used to protect the sapphire and prevent it from breaking due to uneven stress. When the nut on the upper part of the metal column 15 is fully tightened, the top end cap 13 and the bottom end cap 17 are fixed together, and at the same time, the annular polytetrafluoroethylene gaskets at the upper and lower ends of the sapphire glass tube 14 are not compressed, and the sapphire glass tube 14 does not bear axial pressure. The center of the bottom end cap 17 has a porous medium filter block 16 embedded in the groove of the bottom end cap 17, and the porous medium filter block 16 can be tightly fitted with the groove wall of the bottom end cap 17. The upper part of the porous medium filter block 16 is connected to the internal cavity of the visual pressure tank 7, and the lower part is connected to the outside of the temperature control device C through two tubes inside the bottom end cap 17.

[0046] Further, the central region of the top end cap 13 is configured with a plurality of sampling holes. The sampling holes axially penetrate the center of the top end cap and the top piston. Each sampling hole corresponds to a sampling tube of different length inserted therein. Each sampling hole is connected to the extraction device B, so that the extraction device B is connected to the internal cavity of the reaction tank. In this way, the top sampling port of the visual reaction tank D can adjust the sampling position in the visual reaction tank D by adjusting the length of the internal pipeline (sampling tube) of the visual pressure tank.

[0047] In actual application process, the evaluation system is formed based on the above-mentioned evaluation system, and the emulsion manufacturing, emulsification simulation and evaluation experiment scheme based on the heavy oil thermal complex flooding is formed. The scheme can carry out the emulsification and demulsification simulation experiment and the emulsion system manufacturing experiment by using the control of the experimental control device E. The experiment includes the following steps: first, the injection device A is controlled to inject the experimental crude oil into the porous medium block 15, so that the porous medium block is saturated with the crude oil; then, the production device B and the temperature control device C are controlled, so that the temperature and pressure in the reaction kettle cavity reach the preset experimental temperature and the preset experimental pressure respectively; then, according to the preset oil-water ratio, the injection device A is controlled to inject the experimental crude oil and the experimental steam into the reaction kettle cavity, and the image acquisition device F is controlled to observe this step; next, according to the preset oil-water ratio, the injection device A is controlled to inject the gas-containing crude oil and the heated experimental oil displacement agent into the reaction kettle cavity, and the image acquisition device F is controlled to observe this step; finally, according to the collected images, the stability of the emulsion under the formation condition is evaluated, the spontaneous emulsification and demulsification characteristics under the combination conditions of different oil-water ratios, different experimental temperatures, different experimental pressures and different injection speeds are analyzed, and the formed emulsion is sampled to manufacture various emulsion systems with different oil-water ratios and analyze the influencing factors and rules of the emulsification performance.

[0048] In one embodiment, taking a heavy oil region in Shengli Oilfield as an example, the provided emulsion system manufacturing and evaluation method includes the following steps:

[0049] Step 1, the degassed crude oil is pumped into the crude oil intermediate container 2, the oil displacement agent (such as viscosity reducer) to be evaluated is pumped into the oil displacement agent adding intermediate container 6, the air in the cavity of the visual pressure kettle 7 is pumped out through the two-way back pressure valve 8 at the top of the visual pressure kettle 7 by the vacuum pump, and then the crude oil in the crude oil intermediate container 2 is injected into the visual reaction kettle 7 by the crude oil injection pump 1 until the top of the porous medium filter block 16 is covered with crude oil, and then the two-way back pressure valve 8 is controlled to gradually suck the air back into the cavity of the visual pressure kettle 7, so that the crude oil fills the pores of the porous medium filter block 16, and the porous medium block reaches the saturated oil state;

[0050] Step 2, the pressure of the two-way back pressure valve 8 is set to the experimental pressure, N2 is injected into the cavity of the visual pressure kettle through the two-way back pressure valve to reach the experimental pressure, the temperature control device C is controlled to heat to the experimental temperature, and the back pressure is kept unchanged until the stable state is reached;

[0051] Step 3, according to a certain oil-water ratio, control the crude oil injection pump 1 to inject the crude oil in the crude oil intermediate container 2 into the cavity of the visualized pressure vessel 7, and then or simultaneously control the displacement pump 3 to inject steam into the cavity of the visualized pressure vessel 7 through the steam generator 5; after the experimental control device observes that the pressure of the pressure sensor 9 of the crude oil injection pump 1 starts to increase, adjust the pressure in the cavity of the visualized pressure vessel 7 through the bidirectional back pressure valve 8 according to the experimental needs, at this time, turn on the camera 10 and the background light source 11 to observe the spontaneous emulsification and demulsification process of the steam flooding in the visualized pressure vessel 7;

[0052] Step 4, repeat step 1 and step 2, according to a certain oil-water ratio, control the crude oil injection pump 1 to inject the crude oil in the crude oil intermediate container 2 into the cavity of the visualized pressure vessel 7, and then or simultaneously control the displacement pump 3 to inject the oil displacement agent (such as viscosity reducer) in the oil displacement agent intermediate container 6 into the cavity of the visualized pressure vessel 7 through the steam generator 5, at this time, turn on the camera 10 and the background light source 11 to observe the spontaneous emulsification and demulsification process of the thermal complex oil displacement agent flooding in the visualized pressure vessel 7, and after the generated emulsion reaches a certain volume, carry out emulsion stability evaluation based on image analysis;

[0053] Step 5, constantly repeat step 3 and step 4, study the spontaneous emulsification and demulsification process in the thermal complex oil displacement agent flooding under different oil-water ratios, different temperatures, different pressures, different injection speeds and other conditions, and at the same time, through sampling of the emulsion, study the influencing factors and rules of emulsification performance based on the rheometer;

[0054] Step 6, use step 5 to manufacture various emulsion systems of different oil-water ratios, and at the same time, it can also be used to carry out emulsion flooding experiments to study the displacement characteristics of the emulsion.

[0055] The evaluation system can also be used to form an injection well near-well region displacement rule evaluation scheme based on the heavy oil thermal chemical flooding, which can use the control of the experimental control device E to carry out the emulsion oil displacement experiment. The experiment includes the following steps: first, the oil sand is configured according to the particle size distribution of the reservoir to be evaluated in the visual reactor 7; second, the injection device A is controlled to inject experimental formation water into the reactor cavity until the cavity is filled with formation water to reach the pressure, so as to calculate the porosity according to the obtained pore volume of the sandpack model (since the total volume of the injected water when reaching the pressure is the pore volume of the sandpack model, the porosity = pore volume / model cavity volume); third, the production device B and the temperature control device C are controlled to make the temperature and pressure in the reactor cavity reach the preset experimental temperature and the preset experimental pressure respectively, and the injection device A is controlled to inject experimental crude oil into the reactor cavity to establish the initial oil-water saturation, so as to obtain the water production and calculate the oil saturation; fourth, the injection device A is controlled to inject the heated oil displacement agent (such as viscosity reducer) into the reactor cavity to carry out the thermal chemical flooding experiment, and the image acquisition device F is controlled to observe the step; fifth, the emulsion formed at different positions is sampled at different times of the experiment, and the emulsification and rheological properties of different positions in the displacement process are analyzed, so as to clarify the oil displacement principle of the heavy oil thermal chemical flooding.

[0056] In one embodiment, taking a heavy oil region in Shengli Oilfield as an example, the provided heavy oil thermal chemical flooding injection well near-well region displacement rule evaluation method includes the following steps:

[0057] Step S1, under the condition that the pressure is higher than the bubble point pressure of the crude oil, the gas-containing crude oil is pumped into the crude oil intermediate container 2, and the temperature of the crude oil intermediate container 2 is set to the formation temperature; the experimental formation water is pumped into the formation water intermediate container 4; the oil displacement agent (such as viscosity reducer) to be evaluated is pumped into the oil displacement agent intermediate container 6;

[0058] Step S2, the oil sand taken from the oilfield block to be evaluated is washed and sieved into sand particles of different sizes, and the oil sand is prepared according to the particle size distribution of the oilfield reservoir and filled into the sapphire glass tube 14. The top end cover 13 is fixed on the sapphire glass tube 14 by the nut and the metal column 15 screw.

[0059] Step S3, the air in the cavity of the visual pressure reactor 7 is pumped out to a certain vacuum degree by the vacuum pump through the top two-way back pressure valve 8 of the visual pressure reactor 7, the outlet valve of the two-way back pressure valve 8 and the vacuum pump are closed, the formation water in the formation water intermediate container 4 is pumped into the visual reactor 7 by the displacement pump 3, until the visual pressure reactor 7 is filled with formation water to reach the pressure, so as to calculate the porosity of the sandpack model.

[0060] Step S4, gradually increase the back pressure and displacement pressure through the bidirectional back pressure valve 8 and the displacement pump 3, until the back pressure increases to the formation pressure, set the temperature of the temperature control device C (see the component 12 in Figure 2 The temperature of the temperature control device C (see the component 12 in

[0061] Step S5, inject the oil displacement agent in the oil displacement agent intermediate container 6 into the visualization reactor 7 after heating through the steam generator 5, to carry out the thermal chemical flooding experiment, at this time, turn on the camera 10 and the background light source 11, and observe the displacement process of the thermal complex oil displacement agent in the visualization reactor 7. Among them, at different times of the experiment, sample from different positions in the visualization sandpack 7, and obtain the emulsification and rheological characteristics of different positions in the displacement process through stability and rheological analysis, to further clarify the oil displacement mechanism of the heavy oil thermal chemical flooding.

[0062] The embodiment of the present application can also form a emulsion displacement characteristic evaluation scheme based on the thermal chemical flooding displacement front based on the above-mentioned evaluation system, which can carry out the emulsion evaluation experiment based on the thermal chemical flooding displacement front by using the control of the experimental control device E. Among them, such experiment includes the following steps: step one, construct the oil sand in the visualization reactor 7 according to the particle size distribution of the reservoir to be evaluated; step two, control the injection device A to inject the experimental formation water into the reactor cavity until the cavity is filled with the formation water to reach the pressure, so as to calculate the porosity according to the obtained pore volume of the sandpack model (since the total volume of the injected water when reaching the pressure is the pore volume of the sandpack model, therefore, the porosity = pore volume / model cavity volume); step three, control the production device B and the temperature control device C, so that the temperature and pressure in the reactor cavity reach the preset experimental temperature and the preset experimental pressure respectively, and control the injection device A to inject the experimental crude oil into the reactor cavity to establish the initial oil-water saturation, so as to obtain the water production and calculate the oil saturation; step four, control the injection device A to inject the heated oil displacement agent (such as viscosity reducer) into the reactor cavity, while continuing to control the injection device A to inject the experimental crude oil into the reactor cavity, so as to carry out the emulsion displacement experiment of the thermal chemical flooding front, wherein the image acquisition device F is controlled to observe this step; step five, sample the emulsion formed at different positions at different times of the experiment, analyze the emulsification and rheological characteristics of different positions in the displacement process, so as to clarify the oil displacement principle of the heavy oil thermal chemical displacement front emulsion.

[0063] In one embodiment, taking a heavy oil region in Shengli Oilfield as an example, the emulsion displacement characteristic evaluation method based on the thermal chemical flooding displacement front provided includes the following steps:

[0064] Step T1, degassed crude oil is pumped into the crude oil intermediate container 2, and the temperature of the crude oil intermediate container 2 is set to the formation temperature, the formation water is pumped into the formation water intermediate container 4, the to-be-evaluated oil displacement agent (such as a viscosity reducer) is pumped into the oil displacement agent intermediate container 6, the oil sand after washing of the oil sand in the to-be-evaluated oilfield block is screened for sand particles of each size, and the oil sand is prepared according to the size distribution of the oilfield reservoir and filled into the sapphire glass tube 14, and the top end cover 13 is fixed on the sapphire glass tube 14 by means of the nut and the metal column 15 screw.

[0065] Step T2, the air in the cavity of the visual pressure vessel 7 is pumped out to a certain vacuum degree by means of the vacuum pump through the top two-way back pressure valve 8 of the visual pressure vessel 7, the outlet valve of the two-way back pressure valve 8 and the vacuum pump are closed, the formation water in the formation water intermediate container 4 is pumped into the visual pressure vessel 7 by means of the displacement pump 3, and the porosity of the sand filling model is calculated until the visual pressure vessel 7 is filled with the formation water to the pressure rise.

[0066] Step T3, the back pressure and the displacement pressure are gradually increased by means of the two-way back pressure valve 8 and the displacement pump 3, until the back pressure increases to the formation pressure, the temperature of the temperature control device 12 is set to the formation temperature, the back pressure is kept unchanged, and the stable state is waited until the back pressure is kept as the formation pressure, the crude oil in the crude oil intermediate container 2 is pumped into the visual pressure vessel 7 by means of the crude oil injection pump 1 to establish the initial oil-water saturation, the water production is measured, and the oil saturation is calculated.

[0067] Step T4, the viscosity-reducing oil displacement agent in the oil displacement agent intermediate container 6 is injected into the visual pressure vessel 7 after being heated by the steam generator 5 according to a certain oil-water ratio by means of the displacement pump 3, and the crude oil in the crude oil intermediate container 2 is pumped into the visual pressure vessel 7 by means of the crude oil injection pump 1 to carry out the emulsion flooding experiment of the thermal chemical flooding displacement front.

[0068] Step T5, the camera 10 and the background light source 11 are turned on, and the process of self-emulsification and demulsification of the steam flooding in the visual pressure vessel 7 is observed, wherein, at different times of the experiment, samples are taken from different positions in the visual sand filling tube 7, and the emulsification and rheological characteristics of different positions in the displacement process are obtained through stability and rheological analysis, and the oil displacement mechanism of the emulsion flooding of the thermal chemical flooding displacement front is further clarified.

[0069] In order to clarify the emulsification characteristics in the process of thickened oil thermal complex flooding, the application discloses an emulsification evaluation system based on thickened oil thermal complex flooding emulsification, which can study the spontaneous emulsification and demulsification process in the process of steam flooding, thermal chemical flooding, thermal complex flooding and various thickened oil displacement mode combination use under the conditions of different oil-water ratio, different temperature, different pressure and different injection speed, study the influence law of the research conditions on the emulsification performance, simulate the emulsified liquid formed in the process of thickened oil thermal complex flooding, and be used for evaluating the stability and rheological characteristics of the emulsion of thickened oil thermal complex flooding, and the emulsification characteristics of different positions.

[0070] The above merely describes preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope 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 subject to the protection scope of the claims.

[0071] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more; the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only for description purposes and cannot be understood as indicating or implying relative importance.

[0072] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrally connected; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0073] It should be understood that the embodiments disclosed in the present application are not limited to the specific structures, processing steps or materials disclosed herein, but should be extended to the equivalent alternatives of these features understood by those skilled in the related art. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments and do not mean limitation.

[0074] Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase "in one embodiment" or "an embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

[0075] Although the present application has been described with reference to the above embodiments, the contents described are merely adopted embodiments for facilitating the understanding of the present application, and are not intended to limit the present application. Any modification and change in the form and details of the embodiments can be made by any person skilled in the art without departing from the spirit and scope of the present application, and the patent protection scope of the present application shall be subject to the scope defined by the appended claims.

Claims

1. A system for evaluating emulsification of a thickened oil combination flooding, characterized by, The utility model relates to a kind of experimental device for emulsification and demulsification of heavy oil, which comprises: Injection device for injecting one of experimental crude oil, experimental formation water, experimental steam and experimental oil displacement agent in different experimental stages; Production device in communication with the internal space of the reactor for providing experimental pressure meeting experimental requirements; Temperature control device arranged outside the reactor for providing experimental temperature meeting experimental requirements; Visual reactor with a porous medium block arranged at the bottom thereof in communication with the injection device; Experimental control device for carrying out emulsification and demulsification experiment, various emulsion system manufacturing experiment, emulsion oil displacement agent displacement experiment and emulsion evaluation experiment based on thermal chemical displacement front by controlling the injection device, the production device and the temperature control device according to different oil-water ratio, different experimental temperature, different experimental pressure and different injection speed, which are combined in steam flooding, and / or thermal chemical flooding, and / or thermal complex flooding, and / or multiple heavy oil displacement; Image acquisition device for capturing images in the visual reactor in real time during the implementation of various experiments, The visual reactor comprises a top end cover, a bottom end cover, a plurality of metal columns and a glass tube reactor, wherein the plurality of metal columns vertically penetrate the edge of the top end cover, the lower part of the metal column is fixed at the edge of the bottom end cover, the glass tube reactor is arranged inside the space formed by the plurality of metal columns, the upper end of the glass tube reactor is inserted through the top piston at the lower part of the top end cover, the lower end of the glass tube reactor is inserted through the bottom piston at the upper part of the bottom end cover, the porous medium block axially penetrates the center of the bottom piston and is inserted into the center of the bottom end cover, the bottom center of the porous medium block is provided with a first hole in communication with the first bottom inlet of the visual reactor and a second hole in communication with the second bottom inlet of the visual reactor, the upper part of the porous medium block is in communication with the internal cavity of the visual reactor, and the lower part of the porous medium block is in communication with the outside of the temperature control device through two tubes inside the two bottom end covers, The center area of the top end cover is configured with a plurality of sampling holes axially penetrating the center of the top end cover and the top piston thereof, wherein each sampling hole is inserted with a sampling tube of different length, the sampling hole is in communication with the production device so that the production device is in communication with the cavity of the visual reactor, and the production device adopts a metal diaphragm back pressure valve.

2. The system of claim 1, wherein, The injection device comprises a crude oil injection pump, a crude oil intermediate container, a formation water intermediate container, a steam generator, a plurality of oil displacement agent intermediate containers connected in parallel, and a displacement pump, the inlet of the crude oil intermediate container is connected with the crude oil injection pump, the outlet of the crude oil intermediate container is connected with the first bottom inlet of the visualized reaction kettle, the outlet of the formation water intermediate container is located on the pipeline between the outlet of the crude oil intermediate container and the first bottom inlet, the steam generator is connected with the second bottom inlet of the visualized reaction kettle, the outlet of the oil displacement agent intermediate container is connected with the inlet of the steam generator, and the displacement pump is connected with the corresponding formation water intermediate container, steam generator and oil displacement agent intermediate container as a power source.

3. The system according to claim 1, wherein, the top end cover is made of stainless steel; the glass tube reaction kettle is made of sapphire, the side surface of the top piston is sealed with the side surface of the glass tube reaction kettle through an O-ring, the side surface of the bottom piston is sealed with the side surface of the glass tube reaction kettle through an O-ring, a polytetrafluoroethylene gasket is arranged between the annular bottom surface of the top end cover and the upper end surface of the glass tube reaction kettle, and a polytetrafluoroethylene gasket is arranged between the annular top surface of the bottom end cover and the lower end surface of the glass tube reaction kettle; the porous medium block is tightly embedded in the groove of the bottom end cover.

4. The system of any one of claims 1-3, wherein, The experimental control device carries out the emulsification and demulsification experiment and the emulsion system manufacturing experiment according to the following step process: The injection device is controlled to inject experimental crude oil into the porous medium block, so that the porous medium block is saturated with crude oil. The production device and the temperature control device are controlled, so that the temperature and pressure in the cavity of the visualized reaction kettle reach the preset experimental temperature and the preset experimental pressure respectively. According to the preset oil-water ratio, the injection device is controlled to inject experimental crude oil and experimental steam into the cavity of the visualized reaction kettle, and the image acquisition device is controlled to observe this step. According to the preset oil-water ratio, the injection device is controlled to inject experimental crude oil and heated experimental oil displacement agent into the cavity of the visualized reaction kettle, and the image acquisition device is controlled to observe this step. According to the collected images, the stability of the emulsion under the formation condition is evaluated, the spontaneous emulsification and demulsification characteristics under the combination conditions of different oil-water ratios, different experimental temperatures, different experimental pressures and different injection speeds are analyzed, and the formed emulsion is sampled to manufacture various emulsion systems with different oil-water ratios and analyze the influencing factors and rules of the emulsification performance.

5. The system of any one of claims 1-3, wherein, The experimental control device carries out the emulsion oil displacement agent displacement experiment according to the following step process: An oil sand is constructed in the visualized reaction kettle according to the particle size distribution of the reservoir to be evaluated; The injection device is controlled to inject experimental formation water into the cavity of the visualized reaction kettle until the cavity is filled with formation water to reach the pressure, so as to calculate the porosity according to the obtained pore volume of the sandpack model. The control device controls the temperature and pressure in the reactor chamber to reach the preset experimental temperature and pressure, respectively, and controls the injection device to inject the degassed crude oil into the chamber of the visualization reactor to establish the initial oil-water saturation, so as to obtain the water production and calculate the oil saturation; The control device controls the injection device to inject the heated oil displacement agent into the chamber of the visualization reactor, and controls the image acquisition device to observe the process. The emulsions formed at different positions are sampled at different times during the experiment, and the emulsification and rheological properties at different positions during the displacement process are analyzed, so as to determine the oil displacement principle of the thermal chemical displacement of heavy oil.

6. The system of any one of claims 1-3, wherein, The control device controls the temperature and pressure in the reactor chamber to reach the preset experimental temperature and pressure, respectively, and controls the injection device to inject the degassed crude oil into the chamber of the visualization reactor to establish the initial oil-water saturation, so as to obtain the water production and calculate the oil saturation; The control device controls the temperature and pressure in the reactor chamber to reach the preset experimental temperature and pressure, respectively, and controls the injection device to inject the degassed crude oil into the chamber of the visualization reactor to establish the initial oil-water saturation, so as to obtain the water production and calculate the oil saturation; The control device controls the temperature and pressure in the reactor chamber to reach the preset experimental temperature and pressure, respectively, and controls the injection device to inject the degassed crude oil into the chamber of the visualization reactor to establish the initial oil-water saturation, so as to obtain the water production and calculate the oil saturation; The control device controls the temperature and pressure in the reactor chamber to reach the preset experimental temperature and pressure, respectively, and controls the injection device to inject the degassed crude oil into the chamber of the visualization reactor to establish the initial oil-water saturation, so as to obtain the water production and calculate the oil saturation; 7. The system of any one of claims 1-3, wherein The experimental oil displacement agent includes but is not limited to a chemical oil displacement agent and a gas oil displacement agent, the chemical oil displacement agent includes but is not limited to a viscosity reducer, a profile control agent, a foaming agent and a composite oil displacement agent, and the gas oil displacement agent includes but is not limited to natural gas, N2 and CO2. ​ ​

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