Supercritical carbon dioxide oil displacement and two-phase fluid separation system and method

Abstract

The application discloses a supercritical carbon dioxide oil displacement and two-phase fluid separation system and a method thereof. The supercritical carbon dioxide oil displacement and two-phase fluid separation system comprises a generating assembly, a displacement assembly, a separation assembly and a detection assembly, the generating assembly is used for preparing supercritical carbon dioxide, the displacement assembly is used for displacing a core by using the supercritical carbon dioxide to produce a mixed fluid, a separation layer is arranged in a separation cavity of the separation assembly, and the separation layer is used for mechanically puncturing foam in the mixed fluid to realize separation of tight oil and the supercritical carbon dioxide, and the detection assembly is used for detecting the content of organic matter in the separated fluid. The application realizes efficient foam breaking in a physical mode, improves the separation efficiency and recovery rate of the tight oil, simultaneously ensures the thoroughness of the separation through quantitative monitoring, and thus improves the accuracy and reliability of experimental data.

Description

Technical Field

[0001] This invention relates to the field of crude oil recovery technology, and in particular to a supercritical carbon dioxide flooding and two-phase fluid separation system and method. Background Technology

[0002] Due to its low viscosity, high diffusivity, and excellent solubility, supercritical carbon dioxide can effectively reduce crude oil viscosity and improve the oil-water mobility ratio during displacement, thereby effectively displacing crude oil from the formation. In laboratory studies, to accurately evaluate the oil displacement effect, core displacement simulation experiments are usually required, and the resulting mixed fluids after displacement must be precisely separated and measured.

[0003] In laboratory supercritical carbon dioxide displacement experiments, the resulting fluid mixture typically contains supercritical carbon dioxide, displaced tight oil, core debris, and a large amount of stable foam formed from gas and liquid. In related technologies, separation methods rely on physical differentiation principles such as gravity settling. However, due to the high stability of the foam and the large amount of tight oil it encapsulates, this method struggles to quickly and thoroughly destroy the foam layer, resulting in low efficiency in separating the oil and gas phases.

[0004] More importantly, during subsequent processing, supercritical carbon dioxide undergoes a phase transition as system pressure and temperature change. This phase transition process carries away the tight oil, which is not yet fully separated and exists in the form of microdroplets, and it is discharged along with the carbon dioxide gas. This results in the final amount of tight oil collected being less than the amount of oil actually displaced from the core, causing errors in the experimental measurement data and making it impossible to truly reflect the oil displacement efficiency. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] Therefore, embodiments of the present invention propose a supercritical carbon dioxide flooding and two-phase fluid separation system and method, which realizes efficient and accurate separation and recovery of tight oil in the product liquid after supercritical carbon dioxide displacement.

[0007] The supercritical carbon dioxide flooding and two-phase fluid separation system of this invention includes:

[0008] Generating component, the generating component being used to produce supercritical carbon dioxide;

[0009] Displacement assembly, the inlet of which is connected to the outlet of the generating assembly, the displacement assembly being used to contain the core and receive supercritical carbon dioxide delivered by the generating assembly to produce a mixed fluid;

[0010] A separation component, the inlet of which is connected to the outlet of the displacement component, the separation component having a separation chamber, the separation chamber having a separation layer, the separation layer being used to puncture foam in the mixed fluid to separate supercritical carbon dioxide and tight oil;

[0011] A detection component, the inlet of which is connected to the outlet of the separation component, is used to detect the organic matter content in the separated supercritical carbon dioxide.

[0012] In some embodiments, the separation chamber is inverted conical in shape, and the separation layer is disposed at the top of the separation chamber so that the separated dense oil falls and collects at the bottom of the separation chamber.

[0013] In some embodiments, the separation layer includes a screen arranged horizontally, the screen having a mesh size smaller than that of the lithological debris in the mixed fluid, and the screen having a plurality of spikes on both its upper and lower surfaces.

[0014] In some embodiments, the separation assembly includes an inverted conical shell and a cover disposed on the top of the shell. The inner cavity of the shell forms the separation chamber. The cover has a guide portion protruding toward the screen. The guide portion and the inner wall of the shell together form an annular guide channel. The cross-sectional area of ​​the guide channel gradually increases toward the screen. The separation assembly also includes a vibration device connected to the screen. The vibration device is used to drive the screen to vibrate.

[0015] In some embodiments, the generating component includes a carbon dioxide cylinder, a first storage tank, a booster pump, and a second storage tank connected in sequence via pipelines. The generating component also includes a heating device connected to the first storage tank, so that the gaseous carbon dioxide delivered from the carbon dioxide cylinder to the first storage tank is heated by the heating device, and the heated carbon dioxide is pressurized by the booster pump and delivered to the second storage tank, thereby converting the carbon dioxide in the second storage tank into a supercritical state.

[0016] In some embodiments, the displacement assembly includes a clamp and a core displacement tank, the clamp being detachably connected to the core displacement tank, the core displacement tank being connected via a pipeline to a second storage tank to receive supercritical carbon dioxide from the second storage tank, and a control valve and a metering device being provided on the pipeline between the core displacement tank and the second storage tank to quantitatively control the injection of supercritical carbon dioxide into the core displacement tank.

[0017] In some embodiments, the detection assembly includes a detection tank and a detector disposed within the detection tank.

[0018] In some embodiments, the supercritical carbon dioxide flooding and two-phase fluid separation system further includes an exhaust gas treatment component, the inlet of which is connected to the outlet of the detection component, and the exhaust gas treatment component is used to treat supercritical carbon dioxide that has passed the detection.

[0019] The supercritical carbon dioxide flooding and two-phase fluid separation method of this invention is applicable to the supercritical carbon dioxide flooding and two-phase fluid separation system described in the above embodiments.

[0020] The supercritical carbon dioxide flooding and two-phase fluid separation method of this invention includes:

[0021] Preparation of supercritical carbon dioxide;

[0022] Supercritical carbon dioxide is injected into a displacement assembly containing a core, producing a mixed fluid containing tight oil, core fragments, and foam.

[0023] The mixed fluid is introduced into the separation chamber, and the mixed fluid passes through the separation layer in the separation chamber. The separation layer mechanically punctures the foam to achieve the separation of tight oil and supercritical carbon dioxide.

[0024] The organic matter content of the supercritical carbon dioxide effluent after separation was detected.

[0025] Supercritical carbon dioxide that has passed the test is then processed.

[0026] In some embodiments, when the organic matter content detection result is higher than a predetermined threshold, the residence time of the mixed fluid in the separation layer is extended or the separation is repeated.

[0027] In the embodiments of the present invention, the problem of low oil-water separation efficiency is solved by efficiently puncturing stable foam through the separation layer; real-time monitoring of the separation effect provides a quantitative means to prevent the loss of tight oil with gas entrainment, thereby reducing the measurement error that plagues the experiment and ensuring that the collected oil volume can truly reflect the displacement efficiency; through the integrated system of generation, displacement, separation, detection and exhaust gas treatment components, not only is the experimental process automated and systematized, but also the accuracy, reliability and overall safety of supercritical carbon dioxide oil displacement experimental data are improved through the synergy of structure and control logic. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a supercritical carbon dioxide flooding and two-phase fluid separation system according to an embodiment of the present invention.

[0029] Figure 2 This is a top view of the separation component according to an embodiment of the present invention.

[0030] Figure 3This is a schematic diagram of the internal structure of the separation component according to an embodiment of the present invention.

[0031] Figure label:

[0032] 1-Generating component; 11-Carbon dioxide cylinder; 12-First storage tank; 13-Booster pump; 14-Second storage tank; 15-Heating device;

[0033] 2-Displacement assembly; 21-Holder; 22-Core displacement tank; 23-Control valve; 24-Meter;

[0034] 3-Separation component; 31-Housing shell; 311-Separation chamber; 32-Cover; 321-Flow guide; 33-Screen; 34-Vibration device;

[0035] 4-Detection component; 41-Detection tank; 42-Detector;

[0036] 5-Exhaust gas treatment components. Detailed Implementation

[0037] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0038] The supercritical carbon dioxide flooding and two-phase fluid separation system of the present invention is described below with reference to the accompanying drawings.

[0039] like Figure 1 As shown, the supercritical carbon dioxide flooding and two-phase fluid separation system of this invention includes a generation component 1, a displacement component 2, a separation component 3, and a detection component 4.

[0040] Generating component 1 is used to produce supercritical carbon dioxide. Optionally, generating component 1 includes a carbon dioxide cylinder 11, a first storage tank 12, a booster pump 13, a second storage tank 14, and a heating device 15. The high-pressure carbon dioxide cylinder 11 serves as the gas source, and its outlet is connected to the inlet of the first storage tank 12 via a pipeline equipped with a one-way valve to control the gas flow direction. The outlet of the first storage tank 12 is connected to the inlet of the booster pump 13 via a pipeline, and the outlet of the booster pump 13 is connected to the inlet of the second storage tank 14. Pressure gauges and thermometers are installed on the second storage tank 14 for real-time monitoring of the carbon dioxide's state parameters within the tank.

[0041] The heating device 15 is arranged around the first storage tank 12. The heating device 15 can be a water bath heating system, specifically including a temperature control cavity, a thermocouple disposed in the cavity, and a heating controller electrically connected to the thermocouple.

[0042] The operating process of component 1 is as follows: Carbon dioxide cylinder 11 is opened, and carbon dioxide gas enters the first storage tank 12. The temperature controller is activated, and the water bath inside the temperature control chamber is heated via a thermocouple, thereby indirectly heating the carbon dioxide in the first storage tank 12 to a preset temperature close to but below the critical temperature. Subsequently, the booster pump 13 is activated, pressurizing the heated carbon dioxide gas to above the critical pressure. The high-temperature, high-pressure carbon dioxide enters the second storage tank 14, ultimately transforming into a supercritical state and being stored for later use.

[0043] The inlet of the displacement component 2 is connected to the outlet of the generator component 1. The displacement component 2 is used to contain the core and receive the supercritical carbon dioxide delivered by the generator component 1 to produce a mixed fluid.

[0044] Optionally, the displacement assembly 2 includes a clamp 21 and a core displacement tank 22. The clamp 21 is detachably connected to the core displacement tank 22, the size of which can be changed according to the size of the experimental core. The core displacement tank 22 is connected to a second storage tank 14 via a pipeline to receive supercritical carbon dioxide from the second storage tank 14. A control valve 23 and a metering device 24 are provided on the pipeline between the core displacement tank 22 and the second storage tank 14 for precisely controlling and metering the flow rate and velocity of the injected supercritical carbon dioxide.

[0045] Before the experiment, a core column saturated with crude oil was placed into the core displacement tank 22 and fixed and sealed by the core displacement clamp 21. The control valve 23 was opened, and supercritical carbon dioxide stored in the second storage tank 14 was injected into the core displacement tank 22 at a preset flow rate. The displacement process was simulated under high temperature and high pressure to displace the tight oil in the core, forming a mixed fluid containing supercritical carbon dioxide, tight oil, core fragments and a large amount of stable foam.

[0046] The inlet of the separation component 3 is connected to the outlet of the core displacement tank 22 via a fluid inlet valve. The interior of the separation component 3 forms a separation chamber 311, which contains a separation layer. The separation layer punctures the foam in the mixed fluid to separate supercritical carbon dioxide and tight oil.

[0047] The displaced fluid mixture enters the separation chamber 311 of the separation assembly 3 through the fluid inlet valve. Under pressure, the fluid is forced through the separation layer. The separation layer, through its special physical structure (e.g., sharp protrusions), effectively punctures stable foams in the mixture. Upon foam rupture, the trapped dense oil is released, while supercritical carbon dioxide gas is separated out.

[0048] The outlet of separation component 3 is connected to the inlet of detection component 4 via a fluid outlet valve and a conduit. Detection component 4 is used to detect the organic matter content in the separated supercritical carbon dioxide. Optionally, detection component 4 includes a detection tank 41 and a detector 42 disposed within the detection tank 41. The conduit at the outlet of separation component 3 is inserted into the bottom of detection component 4. The ultraviolet line of detector 42 is aligned with the outlet of the conduit. The signal output terminal of detector 42 is connected to a data processing device such as a computer.

[0049] The gas discharged from the separation component 3 enters the bottom of the detection tank 41. The detector 42 irradiates the flowing gas in real time, and determines whether the gas contains organic matter (i.e., dense oil droplets or oil vapor) and the amount contained by detecting the absorption spectrum of ultraviolet light at a specific wavelength. The detection results are displayed in real time on the connected computer, providing the operator with direct evidence to determine whether the separation is complete.

[0050] The supercritical carbon dioxide flooding and two-phase fluid separation system of this invention forms an integrated displacement, separation, and detection system through the sequential connection of the generation component 1, displacement component 2, separation component 3, and detection component 4, realizing a streamlined operation of supercritical carbon dioxide displacement experiments. The entire system architecture allows for the continuous execution of supercritical fluid generation, core displacement, produced fluid separation, and separation effect verification within a single closed system, reducing material transfer and environmental interference between different operational stages, thereby ensuring the stability of experimental parameters and the reliability of experimental data.

[0051] By precisely controlling the temperature and pressure of supercritical carbon dioxide using the generating component 1, and combining this with the metering control of the injection flow rate using the displacement component 2, the displacement process is precisely controllable, ensuring a high degree of reproducibility of experimental conditions. This allows for consistency of initial conditions between different experimental batches or when verifying the effects of different displacement parameters, thereby enhancing the scientific comparative value of the experimental results.

[0052] The separation layer within the separation chamber 311 of the separation component 3 enables the mechanical removal of foam in the mixed fluid and the two-phase separation of oil and gas. Specifically, when a mixed fluid containing stable foam passes through the separation layer, the separation layer punctures the foam through its physical structure, releasing the encapsulated dense oil. This overcomes the technical deficiency of relying on gravity separation to effectively handle stable foam and improves the oil phase recovery rate.

[0053] By using detection component 4 to monitor the organic matter content in the separated fluid in real time, the effectiveness of the separation process can be quantitatively monitored. Detection component 4 can identify and quantify trace amounts of organic matter entrained in the supercritical carbon dioxide gas stream after separation, thereby determining the degree of separation thoroughness. This allows operators to adjust separation parameters (such as separation time or fluid flow rate) based on the detection results until the results meet the standards, ensuring maximum tight oil collection and solving the problem of experimental measurement errors caused by incomplete separation.

[0054] In some embodiments, such as Figure 3 As shown, the separation chamber 311 is inverted conical in shape, and the separation layer is located at the top of the separation chamber 311 so that the separated dense oil falls and collects at the bottom of the separation chamber 311.

[0055] When the mixed fluid enters through the inlet of the separation component 3, the fluid first contacts the separation layer located at the top. The separation layer punctures the foam, and the separated dense oil droplets drip downwards under the influence of gravity. Since the separation chamber 311 is inverted conical in shape, its inclined inner wall guides the falling oil droplets, which slide down the inner wall and collect in the bottom area of ​​the separation chamber 311 for subsequent discharge.

[0056] In some embodiments, such as Figure 3 As shown, the separation layer includes a screen 33, which is arranged horizontally. The mesh size of the screen 33 is smaller than the size of the lithological debris in the mixed fluid. The upper and lower surfaces of the screen 33 are provided with multiple spikes.

[0057] In other words, the separation layer is specifically embodied in a screen 33. This screen 33 is horizontally arranged at the top of the inverted conical separation chamber 311 to ensure that the fluid can pass uniformly through the entire separation layer. The mesh size (or mesh count) of the screen 33 is precisely selected, its key feature being that it is smaller than the typical size of the lithological debris contained in the mixed fluid, so that the screen 33 can effectively block the passage of solid particles (lithological debris) generated during core displacement. The spikes of the screen 33 can be integrally formed with the screen 33 or fixed as independent components on the surface of the screen 33, with the spikes protruding in the direction of fluid flow.

[0058] The mixed fluid passes through screen 33 from top to bottom for the first time. During this process, larger lithological debris is directly intercepted on the upper surface of screen 33, physically isolated from the subsequently separated tight oil, and will not mix. At the same time, the foam layer in the fluid first comes into contact with the spikes on the upper surface of screen 33, is mechanically punctured for the first time, and some of the foam is destroyed, releasing the tight oil.

[0059] The fluid passing through screen 33 (containing released tight oil, supercritical carbon dioxide, and remaining foam) briefly accumulates in the central space of separation chamber 311 or continues to fall. Subsequently, guided by the structural design of separation chamber 311, this fluid passes through screen 33 a second time from bottom to top, eventually flowing to the gas outlet located at the top of separation assembly 3. During this process, the remaining foam layer comes into contact with the spikes on the lower surface of screen 33 and is mechanically punctured a second time.

[0060] After being punctured on both sides, most of the foam is destroyed, the dense oil is fully released, and eventually settles to the bottom of the inverted conical separation chamber 311 under the action of gravity. The supercritical carbon dioxide gas is discharged through the gas outlet.

[0061] The mixed fluid intercepts lithological debris on sieve 33 during the first pass through the screen, preventing solid impurities from mixing with the separated pure tight oil. This ensures the purity of the collected tight oil sample, simplifies subsequent oil purification steps, and provides a high-quality sample for subsequent analysis.

[0062] By having the mixed fluid pass through the screen 33 twice, the foam layer is punctured in both directions. This method can handle highly stable foam systems and ensures that the dense oil is released from the foam to the maximum extent, thereby improving the oil phase recovery rate.

[0063] In some embodiments, such as Figure 2 and Figure 3 As shown, the separation component 3 includes an inverted conical shell 31 and a cover 32 detachably mounted on the top of the shell 31. The hollow part inside the shell 31 forms an inverted conical separation cavity 311, and the screen 33 is horizontally arranged at the top opening of the shell 31.

[0064] The cover 32 is not a plane. Its central part has a guide portion 321 protruding towards the screen 33. The guide portion 321 can be designed as conical, hemispherical or streamlined. The guide portion 321 and the inner wall of the shell 31 together form an annular guide channel. The cross-sectional area of ​​the guide channel gradually increases towards the screen 33.

[0065] The inlet and outlet of the separation component 3 are located on opposite sides of the annular flow channel. For example, the inlet is located on one side of the flow channel, while the outlet is located on the opposite side. The screen 33 is horizontally positioned below the flow channel.

[0066] The mixed fluid from displacement component 2 enters the annular guide channel through the inlet of separation component 3. The fluid then passes through screen 33 from top to bottom for the first time. During this process, lithological debris is intercepted on the upper surface of screen 33, and some foam is punctured by the spikes on the upper surface. The fluid passing through screen 33 (containing released tight oil, supercritical CO2, and remaining foam) collects at the bottom of the inverted conical shell 31.

[0067] Subsequently, propelled by the following fluid, the collected fluid passes through the screen 33 a second time from bottom to top, entering the space above the screen 33. During this process, any remaining foam is punctured by the spikes on the lower surface of the screen 33. After passing through the screen twice, the gas rich in supercritical carbon dioxide enters the annular guide channel and flows along it, eventually exiting from the outlet located on the other side.

[0068] When the separated gas enters the guide channel from above the screen 33, the cross-sectional area of ​​the guide channel gradually increases towards the screen 33, allowing the gas to achieve a smooth and low-resistance transition when entering the channel from the screen 33 surface. This avoids pressure changes and turbulence, and guides the gas to flow smoothly to the outlet.

[0069] By setting the inlet and outlet on both sides of the flow channel and limiting the fluid to pass through the mesh twice, a U-shaped separation flow path is formed, realizing a complete cycle of bubble breaking, sedimentation and venting within the same separation component 3.

[0070] Furthermore, the separation component 3 also includes a vibration device 34, which is connected to the screen 33. During the separation process, the vibration device 34 drives the screen 33 to generate mechanical vibration to prevent the mesh from being blocked by the foam film or oil film.

[0071] For example, the vibration device 34 can be composed of electromagnetic coils and an elastic suspension system. Specifically, multiple electromagnetic coils are fixedly mounted on the housing 31 of the separation assembly 3, located to the side of the screen 33. The edge of the screen 33 is connected to the housing 31 by multiple metal springs (or other elastic connectors), keeping it suspended.

[0072] The screen 33 itself or its fixed frame is made of magnetically conductive material. When an external controller supplies alternating current to the electromagnetic coil, the resulting alternating magnetic field exerts periodic attractive and repulsive forces on the screen 33, thereby driving the screen 33 to reciprocate at a high frequency and small amplitude. The elastic suspension system provides restoring force and also serves as electrical isolation and vibration damping.

[0073] In some embodiments, such as Figure 1As shown, the supercritical carbon dioxide flooding and two-phase fluid separation system also includes an exhaust gas treatment component 5. The inlet of the exhaust gas treatment component 5 is connected to the outlet of the detection component 4. The exhaust gas treatment component 5 is used to treat the supercritical carbon dioxide that has passed the detection. That is, the gas is only allowed to enter the exhaust gas treatment component 5 after the detection component 4 confirms that the organic matter content in the gas is qualified (i.e., below a predetermined threshold).

[0074] The exhaust gas treatment component 5 chemically absorbs or neutralizes supercritical carbon dioxide to eliminate the potential impacts of its direct emission (such as increased carbon dioxide concentration in the laboratory environment, pressure fluctuations, etc.) and achieves safe final disposal or recycling.

[0075] Optionally, the exhaust gas treatment component 5 can be an exhaust gas treatment cylinder. The cylinder contains an absorbent that can chemically react with carbon dioxide, such as limewater. The inlet of the cylinder is located at the bottom, and the outlet is located at the top or side. Gas enters from the bottom, reacts fully with the limewater, and the purified gas exits from the top. Furthermore, the limewater in the exhaust gas treatment cylinder is not completely filled, ensuring that the pressure within the cylinder is maintained within a controllable range.

[0076] The supercritical carbon dioxide flooding and two-phase fluid separation method of this invention is applicable to the supercritical carbon dioxide flooding and two-phase fluid separation system described in the above embodiments.

[0077] The supercritical carbon dioxide flooding and two-phase fluid separation method of this invention includes:

[0078] S1. Preparation of supercritical carbon dioxide. This step corresponds to generating component 1 in the system. The carbon dioxide cylinder 11 is started, allowing carbon dioxide gas to enter the first storage tank 12. The water bath inside the temperature-controlled chamber is heated using a temperature controller and thermocouples, thereby heating the carbon dioxide in the first storage tank 12 to a preset temperature. Once the temperature is reached, the booster pump 13 is started to pressurize the heated carbon dioxide to a preset pressure, ultimately forming and storing supercritical carbon dioxide that meets the experimental conditions in the second storage tank 14. This provides a high-quality displacing agent with controllable pressure, temperature, and flow rate for subsequent displacement.

[0079] S2. Inject supercritical carbon dioxide into the displacement assembly 2 containing the core, producing a mixed fluid containing tight oil, core fragments, and foam. This step corresponds to displacement assembly 2 in the system. A core sample saturated with crude oil is loaded into the core displacement chamber and sealed. The control valve 23 on the pipeline connecting the second storage tank 14 and the core displacement tank 22 is opened, and the injection flow rate and velocity of supercritical carbon dioxide are precisely controlled by the meter 24. After entering the core displacement tank 22, the supercritical carbon dioxide interacts with the core, displacing the crude oil and producing a mixed fluid containing tight oil, core fragments, and a large amount of stable foam, thereby simulating the formation environment and obtaining the target fluid for the separation experiment.

[0080] S3. The mixed fluid is introduced into the separation chamber 311, allowing it to pass through the separation layer within the chamber. The separation layer mechanically punctures the foam, thus separating the tight oil from the supercritical carbon dioxide. This step corresponds to the separation component 3 in the system. The mixed fluid produced in the previous step is guided into the separation chamber 311 of the separation component 3 through a fluid inlet valve. The fluid flows within the separation chamber 311 and passes through the separation layer inside. The separation layer mechanically punctures the foam in the fluid through its physical structure, releasing the trapped tight oil. The denser tight oil settles, while the less dense supercritical carbon dioxide gas separates, achieving effective oil-gas separation and solving the problem of low separation efficiency in related technologies.

[0081] S4. Detect the organic matter content of the supercritical carbon dioxide flowing out after separation. This step corresponds to detection component 4 in the system. The supercritical carbon dioxide gas flowing out from separation component 3 is introduced into detection component 4 through the fluid outlet valve. Specifically, the gas enters the bottom of detection tank 41, where the organic matter content is detected in real time by ultraviolet detector 42. The detection results can be displayed in real time, enabling quantitative evaluation of the separation effect, ensuring the thoroughness of separation, preventing the loss of tight oil due to gas entrainment caused by incomplete separation, and thus solving the problem of measurement error.

[0082] S5. Treat the qualified supercritical carbon dioxide. This step corresponds to exhaust gas treatment component 5 in the system. When the test results from the previous step show that the organic matter content is lower than the preset qualified threshold, the operator (or the automatic control system) opens the valve leading to exhaust gas treatment component 5. At this time, the qualified supercritical carbon dioxide gas is introduced into the exhaust gas treatment cylinder. The lime water contained in the cylinder reacts chemically with the carbon dioxide, absorbing and fixing it, thereby completing the harmless treatment.

[0083] Furthermore, when the organic matter content test result is higher than the predetermined threshold, the residence time of the mixed fluid in the separation layer is extended or the separation is repeated. In other words, if the test result is unqualified, the gas will continue to be temporarily stored or recycled back to the separation component 3 for further separation until the test result is qualified, thereby achieving safe and environmentally friendly final disposal of experimental waste gas and ensuring that only the completely separated gas is emitted, thus forming a complete, safe, and environmentally friendly closed-loop process.

[0084] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0085] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0086] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0087] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0088] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0089] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A supercritical carbon dioxide flooding and two-phase fluid separation system, characterized in that, include: Generating component, the generating component being used to produce supercritical carbon dioxide; Displacement assembly, the inlet of which is connected to the outlet of the generating assembly, the displacement assembly being used to contain the core and receive supercritical carbon dioxide delivered by the generating assembly to produce a mixed fluid; A separation assembly, the inlet of which is connected to the outlet of the displacement assembly, is provided with a separation chamber containing a separation layer. This separation layer punctures foam in the mixed fluid to separate supercritical carbon dioxide and tight oil. The separation layer includes a screen. The separation assembly comprises an inverted conical shell and a cover at the top of the shell. The inner cavity of the shell forms the separation chamber, which is inverted conical. The cover has a guide portion protruding towards the screen. This guide portion and the inner wall of the shell together form an annular guide channel. The cross-sectional area of ​​the guide channel is oriented towards the screen. The direction of the screen gradually increases; the mixed fluid from the displacement component enters the annular guide channel through the inlet of the separation component, and the fluid passes through the screen from top to bottom for the first time. The fluid containing released tight oil, supercritical CO2 and residual foam that passes through the screen gathers at the bottom of the inverted conical shell. The gathered fluid, driven by the subsequent fluid, turns and passes through the screen from bottom to top for the second time. After passing through the screen twice, the gas rich in supercritical carbon dioxide enters the annular guide channel and flows along the annular guide channel, and finally exits from the outlet located on the other side of the separation component. A detection component, the inlet of which is connected to the outlet of the separation component, is used to detect the organic matter content in the separated supercritical carbon dioxide.

2. The supercritical carbon dioxide flooding and two-phase fluid separation system according to claim 1, characterized in that, The separation layer is located at the top of the separation chamber so that the separated dense oil falls and collects at the bottom of the separation chamber.

3. The supercritical carbon dioxide flooding and two-phase fluid separation system according to claim 2, characterized in that, The screen is arranged horizontally, and the mesh size of the screen is smaller than the size of the lithological debris in the mixed fluid. The upper and lower surfaces of the screen are provided with multiple spikes.

4. The supercritical carbon dioxide flooding and two-phase fluid separation system according to claim 3, characterized in that, The separation assembly also includes a vibration device connected to the screen, which drives the screen to vibrate.

5. The supercritical carbon dioxide flooding and two-phase fluid separation system according to claim 1, characterized in that, The generating assembly includes a carbon dioxide cylinder, a first storage tank, a booster pump, and a second storage tank connected in sequence via pipelines. The generating assembly also includes a heating device connected to the first storage tank, which heats the gaseous carbon dioxide delivered from the carbon dioxide cylinder to the first storage tank. The heated carbon dioxide is then pressurized by the booster pump and delivered to the second storage tank, thereby converting the carbon dioxide in the second storage tank into a supercritical state.

6. The supercritical carbon dioxide flooding and two-phase fluid separation system according to claim 5, characterized in that, The displacement assembly includes a clamp and a core displacement tank. The clamp is detachably connected to the core displacement tank. The core displacement tank is connected to a second storage tank via a pipeline to receive supercritical carbon dioxide from the second storage tank. A control valve and a meter are provided on the pipeline between the core displacement tank and the second storage tank to quantitatively control the injection of supercritical carbon dioxide into the core displacement tank.

7. The supercritical carbon dioxide flooding and two-phase fluid separation system according to claim 6, characterized in that, The detection assembly includes a detection tank and a detection instrument disposed inside the detection tank.

8. The supercritical carbon dioxide flooding and two-phase fluid separation system according to any one of claims 1-7, characterized in that, It also includes an exhaust gas treatment component, the inlet of which is connected to the outlet of the detection component, and the exhaust gas treatment component is used to treat supercritical carbon dioxide that has passed the detection.

9. A method for supercritical carbon dioxide flooding and two-phase fluid separation, characterized in that, The supercritical carbon dioxide flooding and two-phase fluid separation method is applicable to the supercritical carbon dioxide flooding and two-phase fluid separation system according to any one of claims 1-8, and the supercritical carbon dioxide flooding and two-phase fluid separation method includes: Preparation of supercritical carbon dioxide; Supercritical carbon dioxide is injected into a displacement assembly containing a core, producing a mixed fluid containing tight oil, core fragments, and foam. The mixed fluid is introduced into the separation chamber, and the mixed fluid passes through the separation layer in the separation chamber. The separation layer mechanically punctures the foam to achieve the separation of tight oil and supercritical carbon dioxide. The organic matter content of the supercritical carbon dioxide effluent after separation was detected. Supercritical carbon dioxide that has passed the test is then processed.

10. The supercritical carbon dioxide flooding and two-phase fluid separation method according to claim 9, characterized in that, When the organic matter content test result is higher than the predetermined threshold, the residence time of the mixed fluid in the separation layer is extended or the separation is repeated.

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