System and method for testing rheological property of whole process of carbon dioxide flooding

Abstract

The invention relates to a carbon dioxide oil displacement full-flow rheological property test system and method, and the system comprises a carbon dioxide oil displacement fluid circulation system which is used for the circulation flow of fluid; the liquid dynamic rheological testing unit is used for receiving a fluid medium which is in a liquid state and does not reach a steady state in the oil displacement process; the liquid steady-state rheological testing unit is used for receiving a fluid medium which is in a liquid state and reaches a steady state in the oil displacement process; the supercritical dynamic rheological testing unit is used for receiving a fluid medium which is in a supercritical phase state and does not reach a steady state in the oil displacement process; the supercritical steady-state rheological testing unit is used for receiving a fluid medium which is in a supercritical phase state and reaches a steady state in the oil displacement process; the gaseous dynamic rheological testing unit is used for receiving a fluid medium which is in a gaseous phase state and does not reach a steady state in the oil displacement process; the gaseous steady-state rheological testing unit is used for receiving a fluid medium which is in a gaseous phase state and reaches a steady state in the oil displacement process, and the device and the method can be widely applied to the technical field of rheological property testing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon sequestration and oil exploitation and rheological property testing, and particularly to a carbon dioxide flooding whole-process rheological property testing system and method. BACKGROUND

[0002] Carbon dioxide has the characteristics of easy miscibility with crude oil and low viscosity, so it has good flowability in reinjection and reservoirs. Based on these characteristics of carbon dioxide, the carbon dioxide flooding method is currently widely used in the field of carbon sequestration and is one of the relatively mature methods for improving oil recovery. Generally, high carbon dioxide content oil and gas fields produce high carbon dioxide content natural gas which needs to be carbon removed to meet the national natural gas pipeline transportation standards and anticorrosion requirements. Therefore, high carbon dioxide content natural gas needs to be separated by membrane separation method or amine method. At present, in offshore or onshore oil and gas field exploitation, the separated carbon dioxide is used for oil displacement by direct reinjection or reinjection after mixing with natural gas, which can improve the oil and gas field recovery rate and achieve effective recovery of carbon dioxide.

[0003] However, after carbon dioxide reinjection and mixing with crude oil, the rheological property of the mixed fluid changes, and with the change of temperature and pressure during the reinjection process and after reinjection into the underground, the phase state of the mixed fluid also changes. The change of rheological property affects the pressure drop and other parameters in the fluid transportation process, and has a certain influence on the design of the process.

[0004] However, the traditional rheological testing equipment or system can only detect the rheological properties of single-phase or stable-state fluid. Therefore, for the carbon dioxide reinjection process, it is necessary to design a device capable of detecting the rheological properties of the whole process of carbon dioxide flooding, so as to understand the rheological law of carbon dioxide mixed oil and guide the design of the process in the oil and gas field development process. SUMMARY

[0005] To solve the above problems, the present application provides a carbon dioxide flooding whole-process rheological property testing system and method, which can understand the rheological law of carbon dioxide mixed oil.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: on the one hand, a carbon dioxide flooding whole-process rheological property testing system is provided, which comprises: a carbon dioxide flooding fluid circulation system for circulating flow of the measured fluid medium; a liquid dynamic rheological testing unit for receiving fluid medium in a liquid state and not reaching a steady state in the oil displacement process of the carbon dioxide flooding fluid circulation system; a liquid steady-state rheological testing unit for receiving fluid medium in a liquid state and reaching a steady state in the oil displacement process. a supercritical dynamic rheological test unit for receiving fluid medium in a supercritical phase and not reaching a steady state during the oil displacement process; a supercritical steady-state rheological test unit for receiving fluid medium in a supercritical phase and reaching a steady state during the oil displacement process; a gaseous dynamic rheological test unit for receiving fluid medium in a gaseous phase and not reaching a steady state during the oil displacement process; a gaseous steady-state rheological test unit for receiving fluid medium in a gaseous phase and reaching a steady state during the oil displacement process.

[0007] Further, the system further comprises: a temperature and pressure test point arranged in each test unit for monitoring the temperature and pressure of the corresponding measured fluid medium in real time; a host computer for receiving the temperature and pressure monitored by each temperature and pressure test point and determining the phase of the measured fluid medium based on a fluid phase diagram.

[0008] Further, one end of the carbon dioxide oil displacement fluid circulation system is connected to the other end of the carbon dioxide oil displacement fluid circulation system in sequence through the circulation pipeline via the corresponding first valve, connecting the liquid dynamic rheological test unit, the liquid steady-state rheological test unit, the supercritical dynamic rheological test unit, the supercritical steady-state rheological test unit, the gaseous dynamic rheological test unit and the gaseous steady-state rheological test unit.

[0009] Further, the carbon dioxide oil displacement fluid circulation system comprises a buffer tank, a circulation pump, a fluid mixer and a microscopic visualization window; One end of the buffer tank is connected to the liquid dynamic rheological test unit in sequence through the circulation pump, the fluid mixer and the microscopic visualization window, and the other end of the buffer tank is connected to the gaseous steady-state rheological test unit; the buffer tank is used to store the measured fluid medium; the circulation pump is used for the circulation flow of the measured fluid medium; the fluid mixer is used for fully stirring and mixing the measured fluid medium; and the microscopic visualization window is used for observing and recording the flow state of the measured fluid medium before entering the test unit.

[0010] Further, each test unit comprises a shell, a water bath, a rheological test tube, a second valve and a visualization window; The shell is provided with the water bath and two rheological test tubes, the two rheological test tubes are immersed in the water bath, one end of the two rheological test tubes is connected to the circulation pipeline via the corresponding temperature and pressure test point and second valve; the other end of the two rheological test tubes is connected to each other, and the corresponding first valve is arranged on the circulation pipeline between the pipelines of the two rheological test tubes; and the rheological test tube is used for testing the performance parameters of the measured fluid medium.

[0011] Further, the control temperature of the water bath of the liquid dynamic rheological test unit and the liquid steady-state rheological test unit is in a liquid temperature range; the control temperature of the water bath of the supercritical dynamic rheological test unit and the supercritical steady-state rheological test unit is in a supercritical temperature range; and the control temperature of the water bath of the gaseous dynamic rheological test unit and the gaseous steady-state rheological test unit is in a gaseous temperature range.

[0012] In another aspect, a method for testing rheological properties of a whole process of carbon dioxide flooding oil is provided, comprising: setting the system for testing rheological properties of a whole process of carbon dioxide flooding oil; according to actual needs, observing and testing rheological properties of carbon dioxide in different flow states and phase states of the measured fluid medium.

[0013] Further, the method further comprises: the temperature and pressure test points of each test unit monitor the temperature and pressure of the corresponding measured fluid medium in real time and send the temperature and pressure to the upper computer; the upper computer determines the phase state of the measured fluid medium based on the temperature and pressure monitored by the temperature and pressure test points according to a fluid phase state diagram.

[0014] Further, the method according to actual needs, observing and testing rheological properties of carbon dioxide in different flow states and phase states of the measured fluid medium comprises: if the measured fluid medium is in a liquid state, observing and testing rheological properties of carbon dioxide in the liquid state through the liquid dynamic rheological test unit and the liquid steady-state rheological test unit; if the measured fluid medium is in a supercritical state, observing and testing rheological properties of carbon dioxide in the supercritical state through the supercritical dynamic rheological test unit and the supercritical steady-state rheological test unit; if the measured fluid medium is in a gaseous state, observing and testing rheological properties of carbon dioxide in the gaseous state through the gaseous dynamic rheological test unit and the gaseous steady-state rheological test unit.

[0015] The present application has the following advantages due to the above technical solutions: 1. Each test unit of the present application is visualized, and can complete observation and rheological testing of carbon dioxide in different flow states and phase states, thereby understanding rheological rules in different flow states and phase states in the whole process of carbon dioxide flooding oil.

[0016] 2. The present application adopts a combination of dynamic test units and steady-state test units, which can detect dynamic changes in rheological rules and states during the conversion of carbon dioxide fluid from one phase state to another phase state, and can also detect rheological rules and states of fluid in a stable liquid state or gaseous state or supercritical state.

[0017] In summary, the present application can be widely applied in the fields of carbon sequestration, oil exploitation and rheological property testing. BRIEF DESCRIPTION OF DRAWINGS

[0018] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The detailed description is made with reference to the accompanying drawings. The drawings are for purposes of illustration only and are not intended to be limiting. Like reference numerals designate corresponding parts throughout the several views. In the drawings: Figure 1 is a schematic diagram of a system structure according to an embodiment of the present application.

[0019] Reference numerals in the drawings are as follows: 1: carbon dioxide flooding fluid circulation system; 2: liquid dynamic rheological test unit; 3: liquid steady-state rheological test unit; 4: supercritical dynamic rheological test unit; 5: supercritical steady-state rheological test unit; 6: gaseous dynamic rheological test unit; 7: gaseous steady-state rheological test unit; 8: first valve; 9: temperature and pressure test point; 1-1: buffer tank; 1-2: circulation pump; 1-3: fluid mixer; 1-4: microscopic visualization window; 10-1: housing; 10-2: water bath; 10-3: rheological test tube; 10-4: second valve; 10-5: visualization window. DETAILED DESCRIPTION

[0020] Example embodiments of the present application will be described herein below with reference to the accompanying drawings. While example embodiments of the present application are illustrated, it is to be understood that the present application is not limited to the embodiments described herein, but can be practiced with variation of them. Rather, these embodiments are included to more fully describe the present application and to convey the scope of the present application to those skilled in the art.

[0021] It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. 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. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described, unless specifically identified as an order dependent step. It is also to be understood that additional or alternative steps can be employed.

[0022] Although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can be only used to distinguish one element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms when used in the singular or plural herein do not imply a sequence or order unless the context clearly indicates otherwise. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0023] For ease of description, spatial relative terms can be used herein to describe the relationship of one element or feature to another element or feature as shown in the figures, such as "inner", "outer", "inside", "outside", "lower", "upper", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures.

[0024] At present, the conventional rheological test device or system can only detect the rheological characteristics of the fluid in single phase or steady state. Therefore, for the carbon dioxide reinjection process, it is necessary to design a device capable of detecting the rheological performance of the whole process in the carbon dioxide oil displacement process, so as to understand the rheological law of the carbon dioxide mixed oil, and guide the process flow design work in the oil and gas field development process. The embodiment of the present application provides a carbon dioxide oil displacement whole process rheological performance test system, which comprises: a carbon dioxide oil displacement fluid circulation system for circulating flow of the measured fluid medium; a liquid dynamic rheological test unit for receiving the fluid medium in the oil displacement process which is in liquid phase and has not reached a steady state; a liquid steady-state rheological test unit for receiving the fluid medium in the oil displacement process which is in liquid phase and has reached a steady state; a supercritical dynamic rheological test unit for receiving the fluid medium in the oil displacement process which is in supercritical state and has not reached a steady state; a supercritical steady-state rheological test unit for receiving the fluid medium in the oil displacement process which is in supercritical state and has reached a steady state; a gaseous dynamic rheological test unit for receiving the fluid medium in the oil displacement process which is in gaseous state and has not reached a steady state; and a gaseous steady-state rheological test unit for receiving the fluid medium in the oil displacement process which is in gaseous state and has reached a steady state. The present application can test the rheological properties of the medium in liquid state, supercritical state and gaseous state. At the same time, the present application has simple structure and convenient operation, and can provide a theoretical basis for the rheological law and process flow design and construction in the carbon dioxide oil displacement process.

[0025] Example 1 As Figure 1As shown, the embodiment provides a carbon dioxide flooding oil full-process rheological property testing system, which comprises a carbon dioxide flooding oil fluid circulation system 1, a liquid dynamic rheological testing unit 2, a liquid steady-state rheological testing unit 3, a supercritical dynamic rheological testing unit 4, a supercritical steady-state rheological testing unit 5, a gaseous dynamic rheological testing unit 6, a gaseous steady-state rheological testing unit 7 and a host computer.

[0026] One end of the carbon dioxide flooding oil fluid circulation system 1 is connected to the other end of the carbon dioxide flooding oil fluid circulation system 1 through the circulation pipeline and the corresponding first valve 8 in sequence, and is connected to the liquid dynamic rheological testing unit 2, the liquid steady-state rheological testing unit 3, the supercritical dynamic rheological testing unit 4, the supercritical steady-state rheological testing unit 5, the gaseous dynamic rheological testing unit 6 and the gaseous steady-state rheological testing unit 7 in sequence. The carbon dioxide flooding oil fluid circulation system 1 is used for circulating flow of the measured fluid medium. The liquid dynamic rheological testing unit 2 is used for receiving the fluid medium in the liquid state and not reaching the steady state in the oil displacement process of the carbon dioxide flooding oil fluid circulation system 1. When the testing unit works, the temperature of the water bath 10-2 makes the fluid change into the liquid state, and the rheological characteristics of the fluid in the process of changing from the non-liquid state to the liquid state are recorded. The liquid steady-state rheological testing unit 3 is used for receiving the fluid medium in the liquid state and reaching the steady state in the oil displacement process. The testing unit receives the fluid that has changed into the liquid state, and records the rheological characteristics of the fluid in the stable liquid state. The supercritical dynamic rheological testing unit 4 is used for receiving the fluid medium in the supercritical state and not reaching the steady state in the oil displacement process. The supercritical steady-state rheological testing unit 5 is used for receiving the fluid medium in the supercritical state and reaching the steady state in the oil displacement process. The gaseous dynamic rheological testing unit 6 is used for receiving the fluid medium in the gaseous state and not reaching the steady state in the oil displacement process. The gaseous steady-state rheological testing unit 7 is used for receiving the fluid medium in the gaseous state and reaching the steady state in the oil displacement process.

[0027] Temperature and pressure test points 9 are arranged in the liquid dynamic rheological testing unit 2, the liquid steady-state rheological testing unit 3, the supercritical dynamic rheological testing unit 4, the supercritical steady-state rheological testing unit 5, the gaseous dynamic rheological testing unit 6 and the gaseous steady-state rheological testing unit 7, and the host computer is electrically connected to each temperature and pressure test point 9. The temperature and pressure test points 9 are used for real-time monitoring of the temperature and pressure of the corresponding measured fluid medium. The host computer is used for receiving the temperature and pressure monitored by each temperature and pressure test point 9, and determining the phase state of the measured fluid medium based on the fluid phase state diagram.

[0028] In a preferred embodiment, the carbon dioxide recovery fluid circulation system 1 includes a buffer tank 1-1, a circulation pump 1-2, a fluid mixer 1-3 and a microscopic visualization window 1-4. One end of the buffer tank 1-1 is connected to the liquid dynamic rheology test unit 2 through the circulation pump 1-2, the fluid mixer 1-3 and the microscopic visualization window 1-4 in sequence, and the other end of the buffer tank 1-1 is connected to the gaseous steady-state rheology test unit 7. The buffer tank 1-1 is used to store the fluid medium to be measured. The circulation pump 1-2 is used for the circulation flow of the fluid medium to be measured. The fluid mixer 1-3 is used to fully stir and mix the fluid medium to be measured. The microscopic visualization window 1-4 is used to observe and record the flow state of the fluid medium to be measured before entering the test unit.

[0029] In a preferred embodiment, each test unit comprises a housing 10-1, a water bath 10-2, a rheological test tube 10-3, a second valve 10-4, and a visualization window 10-5. Housing 10-1 houses a water bath 10-2 and two rheological test tubes 10-3. The two rheological test tubes 10-3 are immersed in the water bath 10-2. One end of each rheological test tube 10-3 is connected to a circulation pipeline via a corresponding temperature and pressure test point 9 and a second valve 10-4. The other ends of the two rheological test tubes 10-3 are interconnected. A corresponding first valve 8 is located on the circulation pipeline between the two rheological test tubes 10-3. The rheological test tubes 10-3 are used to test the performance parameters (including apparent viscosity, friction coefficient, and rheological parameters) of the fluid being tested. The temperature and pressure test point 9 is used to obtain the temperature and pressure of the fluid being tested and transmit them to a host computer. The host computer determines the phase state of the fluid being tested based on the monitored temperature and pressure values ​​and the fluid phase diagram. A visualization window 10-5 is provided on the housing 10-1, and the visualization window is used to observe the flow state of the fluid and assist in determining the phase state of the fluid.

[0030] In a preferred embodiment, the controlled temperature of the water bath 10-2 of the liquid dynamic rheology test unit 2 and the liquid steady-state rheology test unit 3 is within the liquid temperature range; the controlled temperature of the water bath 10-2 of the supercritical dynamic rheology test unit 4 and the supercritical steady-state rheology test unit 5 is within the supercritical temperature range; and the controlled temperature of the water bath 10-2 of the gas dynamic rheology test unit 6 and the gas steady-state rheology test unit 7 is within the gaseous temperature range.

[0031] Example 2 This embodiment provides a method for testing rheological properties of the entire carbon dioxide flooding process, comprising the following steps: 1) Setting up the rheological properties testing system for the full process of carbon dioxide flooding in Example 1.

[0032] 2) According to actual needs, observe and perform rheological tests on the measured fluid medium under different flow states and phases of carbon dioxide.

[0033] Specifically, if the measured fluid medium is liquid, observation and rheological test are performed by the liquid dynamic rheological test unit 2 and the liquid steady-state rheological test unit 3; if the measured fluid medium is supercritical, observation and rheological test are performed by the supercritical dynamic rheological test unit 4 and the supercritical steady-state rheological test unit 5; if the measured fluid medium is gaseous, observation and rheological test are performed by the gaseous dynamic rheological test unit 6 and the gaseous steady-state rheological test unit 7.

[0034] 3) The temperature and pressure test points 9 of each test unit monitor the temperature and pressure of the corresponding measured fluid medium in real time and send them to the upper computer.

[0035] 4) The upper computer determines the phase state of the measured fluid medium based on the fluid phase diagram and the temperature and pressure monitored by each temperature and pressure test point 9.

[0036] The above embodiments are only used to illustrate the present application, wherein the structure, connection mode and manufacturing process of each component can be changed, and any equivalent transformation and improvement based on the technical scheme of the present application should not be excluded from the protection scope of the present application.

Claims

1. A rheological properties testing system for the entire process of carbon dioxide flooding, characterized in that: include: CO2 flooding fluid circulation system, used for the circulation of the measured fluid medium; A liquid dynamic rheology testing unit, configured to receive a fluid medium that is in a liquid phase and has not yet reached a steady state during the oil displacement process of the carbon dioxide oil displacement fluid circulation system; Liquid steady-state rheological test unit, used to receive fluid medium that is in liquid phase and has reached steady state during oil displacement; Supercritical dynamic rheological test unit, used to receive fluid medium that is in supercritical phase and has not reached steady state during oil displacement; Supercritical steady-state rheological test unit, used to receive fluid media that is supercritical and has reached a steady state during oil displacement; The gas dynamic rheological test unit is used to receive the fluid medium that is in gas phase and has not reached steady state during the oil displacement process; The gaseous steady-state rheological test unit is used to receive fluid media that is in a gaseous phase and has reached a steady state during the oil displacement process.

2. A carbon dioxide flooding full process rheological properties testing system according to claim 1, characterized in that: Also includes: Temperature and pressure test points are set in each test unit to monitor the temperature and pressure of the corresponding measured fluid medium in real time; The host computer is used to receive the temperature and pressure monitored by each of the temperature and pressure test points, and determine the phase state of the measured fluid medium based on the fluid phase diagram.

3. A carbon dioxide flooding full process rheological properties testing system according to claim 1, characterized in that: One end of the carbon dioxide flooding fluid circulation system is connected to the liquid dynamic rheology test unit, the liquid steady-state rheology test unit, the supercritical dynamic rheology test unit, the supercritical steady-state rheology test unit, the gas dynamic rheology test unit and the gas steady-state rheology test unit in sequence through a circulation pipeline and a corresponding first valve, and is connected to the other end of the carbon dioxide flooding fluid circulation system.

4. A carbon dioxide flooding full process rheological properties testing system according to claim 3, characterized in that: The carbon dioxide flooding fluid circulation system includes a buffer tank, a circulation pump, a fluid mixer and a microscopic visualization window; One end of the buffer tank is connected to the liquid dynamic rheology test unit through the circulation pump, the fluid mixer and the microscopic visualization window in sequence, and the other end of the buffer tank is connected to the gaseous steady-state rheology test unit; the buffer tank is used to store the measured fluid medium; the circulation pump is used for the circulation flow of the measured fluid medium; the fluid mixer is used to fully stir and mix the measured fluid medium; the microscopic visualization window is used to observe and record the flow state of the measured fluid medium before entering the test unit.

5. A carbon dioxide flooding full process rheological properties testing system according to claim 1, characterized in that: Each test unit includes a housing, a water bath, a rheological test tube, a second valve, and a visualization window; The water bath and the two rheological test tubes are disposed in the housing. The two rheological test tubes are immersed in the water bath. One end of each of the two rheological test tubes is connected to the circulation pipeline via the corresponding temperature and pressure test point and the second valve. The other ends of the two rheological test tubes are connected to each other. The corresponding first valve is disposed on the circulation pipeline between the pipelines of the two rheological test tubes. The rheological test tubes are used to test the performance parameters of the measured fluid medium.

6. A carbon dioxide flooding full process rheological properties testing system according to claim 5, characterized in that: The controlled temperature of the water bath of the liquid dynamic rheology test unit and the liquid steady-state rheology test unit is within the liquid temperature range; the controlled temperature of the water bath of the supercritical dynamic rheology test unit and the supercritical steady-state rheology test unit is within the supercritical temperature range; the controlled temperature of the water bath of the gas dynamic rheology test unit and the gas steady-state rheology test unit is within the gaseous temperature range.

7. A method for testing rheological properties of the entire process of carbon dioxide flooding, characterized in that: include: A rheological properties testing system for the entire process of carbon dioxide flooding according to any one of claims 1 to 6 is provided; According to actual needs, observation and rheological tests of carbon dioxide in different flow states and phases are carried out on the measured fluid medium.

8. A method for testing rheological properties of a full-process carbon dioxide flooding as claimed in claim 7, characterized in that: Also includes: The temperature and pressure test points of each test unit monitor the temperature and pressure of the corresponding measured fluid medium in real time and send them to the host computer; Based on the fluid phase diagram, the host computer determines the phase state of the measured fluid medium according to the temperature and pressure monitored at each temperature and pressure test point.

9. A method for testing rheological properties of a full-process carbon dioxide flooding as claimed in claim 7, characterized in that: According to actual needs, the measured fluid medium is subjected to observation and rheological testing of carbon dioxide under different flow states and phases, including: If the fluid medium being measured is liquid, observation and rheological testing are performed using the liquid dynamic rheological testing unit and the liquid steady-state rheological testing unit; If the fluid medium being measured is supercritical, observation and rheological testing are performed using a supercritical dynamic rheological test unit and a supercritical steady-state rheological test unit; If the fluid medium being measured is gaseous, observation and rheological testing are performed using a gas dynamic rheological testing unit and a gas steady-state rheological testing unit.

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