An integrated experimental device for condensation and oil displacement based on heavy oil steam extraction and its working method

Abstract

An integrated experimental device for condensation and oil recovery based on heavy oil steam recovery. It includes a steam generation injection pipeline, an auxiliary recovery fluid pipeline, a cooling water pipeline, a condensing device, a condensed fluid recovery pipeline, and a production fluid recovery pipeline. The core chamber is composed of an outer annular heating cylinder and an inner layer of heat insulation material; the condensation recovery pipeline contains a pressure control system; the production fluid recovery pipeline is provided with an independent pressure control system; the cooling cavity is a hemispherical cavity with the same diameter as the experimental core. The present invention takes into account the influence of the heat around the rock on the condensation effect, and simulates the steam condensation environment by adjusting the temperature of the cooling device and the pressure of the condensation cavity. After closing the cooling device outlet valve and the back pressure valve in the condensation recovery pipeline, various fluid-assisted steam oil recovery experiments can be carried out on the same core to ensure that the results of the oil recovery experiment match the measured steam condensation law, avoiding errors caused by core differences.

Description

Technical Field

[0001] The invention relates to a condensation and oil displacement integrated experimental device based on heavy oil steam recovery and a working method thereof, belonging to the technical field of steam injection thermal recovery of heavy oil reservoirs. Background Art

[0002] Heavy oil is a crucial component of oil and gas resources, boasting abundant reserves that account for over half of the world's total oil reserves. my country boasts relatively abundant heavy oil resources, distributed across numerous oil fields in eastern and western my country. Effectively utilizing these resources is crucial to my country's strategic energy security. To successfully utilize these resources, various heavy oil recovery technologies have been developed, including cold sand recovery, steam injection thermal recovery, and ignition.

[0003] Thermal recovery is a technology that significantly increases the recovery rate of heavy oil reservoirs. Currently, the main thermal recovery technologies include steam injection for viscosity reduction, underground combustion for thermal recovery, and thermal composite recovery. Water vapor is readily available, easy to transport, and has a large specific heat capacity, making it a suitable heat transfer medium. Steam huff-and-puff, steam flooding, and steam-assisted gravity drainage (SAGD), which heat the oil reservoir using the heat carried by steam, have become the primary methods for heavy oil recovery both domestically and internationally. Underground combustion for thermal recovery utilizes in-situ combustion for thermal flooding. This method has a complex mechanism and, in addition to thermal viscosity reduction, also includes miscible flooding and emulsion flooding. Thermal composite recovery combines chemical viscosity reduction with the synergistic effects of gases such as CO2 and N2, including energy enhancement, thermal insulation, and viscosity reduction assistance.

[0004] Understanding the condensation patterns of steam in oil reservoirs is crucial in steam injection thermal recovery. With the development of steam injection thermal recovery technology, the addition of other auxiliary non-condensable gases and chemical solutions during steam injection has further complicated the condensation patterns of these mixed steam in heavy oil reservoirs. Existing steam condensation experimental devices mostly use brass blocks, which are significantly different from the reservoir rock containing crude oil and formation water, and the condensation patterns of steam on them are also different.

[0005] Currently, most steam condensation experiments in China use brass blocks. The condensation patterns of steam on brass blocks do not accurately reflect the condensation patterns of steam in actual rock pores. Chinese patent document CN201810661459.4 discloses a device for testing the condensation patterns of steam in heavy oil reservoirs. This device can measure the condensation patterns of steam on rock cores, but it does not consider the impact of the heat around the core on the condensation patterns of steam. It also cannot conduct macro-scale oil recovery verification without replacing the core. Therefore, a device that can both test the condensation patterns of steam and perform displacement to simulate the steam recovery process is urgently needed. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides an integrated condensation and oil displacement experimental device based on heavy oil steam recovery.

[0007] The invention also discloses a working method of the experimental device.

[0008] The technical solutions of the present invention are as follows:

[0009] An integrated experimental device for condensation and oil displacement based on heavy oil steam recovery includes a steam generation and injection pipeline, an auxiliary recovery fluid pipeline, a cooling water pipeline, a condensation device, a condensate recovery pipeline, and a produced fluid recovery pipeline. The auxiliary recovery fluid is non-condensable gas such as nitrogen and carbon dioxide, as well as chemical solutions such as viscosity reducers and foaming agents.

[0010] The condensation device includes a core chamber, a condensation cavity and a cooling cavity, and a visual window is provided on the wall of the condensation cavity;

[0011] The core chamber is equipped with an experimental core saturated with formation water and heavy oil, and thermocouples are distributed on the experimental core;

[0012] The condensation recovery pipeline includes a pressure control system, and the pressure in the condensation chamber is adjusted by the pressure control system.

[0013] An independent pressure control system is provided in the produced fluid recovery pipeline. After the outlet valve of the cooling device is closed, the displacement pressure is adjusted by the pressure control system.

[0014] The core chamber is composed of an outer annular heating tube and an inner thermal insulation material. The inner thermal insulation material is tightly fitted to the experimental core, and only the two ends of the core are connected to the condensation chamber and the cooling chamber respectively.

[0015] The condensation chamber is a cylindrical cavity with the same diameter as the experimental core. The wall viewing window is a visible resin concentric glass with a heating device. The distance between the condensation chamber wall and the experimental core should be controlled between 15 and 20 mm. The volume of the condensation chamber controlled by this distance does not affect the observation and recording of steam condensation through the viewing window, and can meet the pressure holding requirements of the oil displacement experiment.

[0016] The cooling chamber is a hemispherical cavity with the same diameter as the experimental core. The hemispherical shape of the cooling chamber is conducive to displacing the produced fluid into the produced fluid recovery tank, avoiding the retention of fluid in the corners and affecting the experimental accuracy.

[0017] This integrated condensation and oil recovery experimental device for heavy oil steam recovery, after completing the steam condensation law experiment, adjusts the cooling chamber pressure through the pressure control system, closes the cooling device outlet valve and the back-pressure valve in the condensate recovery line, and then conducts the oil recovery experiment. The produced fluid is displaced into the produced fluid recovery tank, facilitating analysis of industrial characteristics and oil recovery effects. This design can meet the requirements of oil recovery without replacing the core, and the results of the oil recovery experiment match the measured steam condensation law.

[0018] An experimental device for testing the steam condensation law and displacement integration under heavy oil reservoir conditions works as follows:

[0019] The core to be tested is saturated with heavy oil and water and installed in the core chamber. The core is heated to the reservoir temperature to be simulated using an annular heating cylinder. The valve of the cooling water device and the back-pressure valve of the produced fluid recovery pipeline are opened. The back-pressure valve in the condensate recovery pipeline is set to the simulated reservoir pressure. Steam and auxiliary production fluid are injected into the condensation chamber at the ratio and rate set for the condensation experiment. The condensation phenomenon is observed and experimental data is collected.

[0020] Close the back-pressure valve in the condensate recovery line and the cooling device outlet valve, and adjust the back-pressure valves in the condensate recovery line and the produced fluid recovery line. Inject steam and auxiliary production fluid into the condensate chamber at the ratio and rate set for the oil displacement experiment, hold the pressure, and wait for the displaced produced fluid to be collected. Collect experimental data and analyze the state and properties of the produced fluid.

[0021] The technical advantages of the present invention are:

[0022] The core chamber consists of an outer annular heating cylinder bonded to an inner layer of insulation. The inner insulation adheres tightly to the experimental core, with only the core's ends connected to the condensation chamber and cooling chamber, respectively. The patent mentioned in the background art exposes the core within the condensation chamber, failing to consider the effect of the heat surrounding the core on steam condensation patterns. This design in the present invention effectively prevents injected steam from condensing around the core, resulting in more accurate test results for steam condensation experiments.

[0023] After completing the steam condensation law experiment, the cooling chamber pressure is adjusted through the pressure control system, and the cooling device outlet valve and the back-pressure valve in the condensate recovery line are closed. The oil displacement experiment is carried out by holding the pressure in the condensation chamber. The produced fluid is displaced into the produced fluid recovery tank, and the state and properties of the produced fluid can be analyzed. The integrated condensation and oil displacement design of the present invention can meet the requirements of conducting displacement experiments without replacing the core, ensuring that the results of the oil displacement experiment match the measured steam condensation law, and avoiding errors caused by core differences. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the device of the present invention

[0025] Among them: 1. ISCO pump-1; 2. ISCO pump-2; 3. On-off valve-1; 4. On-off valve-2; 5. Steam generator; 6. Intermediate container; 7. On-off valve-3; 8. On-off valve-4; 9. Sight window; 10. Condensation chamber; 11. Core chamber; 12. Thermocouple; 13. Insulation material; 14. Ring heating tube; 15. Cooling chamber; 16. Back pressure valve-1; 16-1, back pressure valve-1 with set pressure; 17. Back pressure valve-2; 18. Condensate recovery tank; 19. Produced fluid recovery tank; 20. Cooling device; 21. On-off valve-5. DETAILED DESCRIPTION

[0026] Example 1

[0027] like Figure 1 As shown in the figure, an integrated experimental device for condensation and oil displacement based on heavy oil steam extraction includes a steam generation injection pipeline, an auxiliary extraction fluid pipeline, a cooling water pipeline, a condensation device, a condensation recovery pipeline, and a production fluid recovery pipeline. Figure 1 The auxiliary production fluid is non-condensable gas such as nitrogen and carbon dioxide, as well as chemical solution such as viscosity reducer and foaming agent;

[0028] The condensation device includes a core chamber, a condensation cavity and a cooling cavity, and a visual window is provided on the wall of the condensation cavity;

[0029] The core chamber is equipped with an experimental core saturated with formation water and heavy oil, and thermocouples are distributed on the experimental core;

[0030] The condensation recovery pipeline includes a pressure control system, and the pressure in the condensation chamber is adjusted by the pressure control system.

[0031] An independent pressure control system is provided in the produced fluid recovery pipeline. After the outlet valve of the cooling device is closed, the displacement pressure is adjusted by the pressure control system.

[0032] The core chamber is composed of an outer annular heating tube and an inner thermal insulation material. The inner thermal insulation material is tightly fitted to the experimental core, and only the two ends of the core are connected to the condensation chamber and the cooling chamber respectively.

[0033] The condensation chamber is a cylindrical cavity with the same diameter as the experimental core. The wall viewing window is a visible resin concentric glass with a heating device. The distance between the condensation chamber wall and the experimental core should be controlled between 15 and 20 mm. The volume of the condensation chamber controlled by this distance does not affect the observation and recording of steam condensation through the viewing window, and can meet the pressure holding requirements of the oil displacement experiment.

[0034] The cooling chamber is a hemispherical cavity with the same diameter as the experimental core. The hemispherical shape of the cooling chamber is conducive to displacing the produced fluid into the produced fluid recovery tank, avoiding the retention of fluid in the corners and affecting the experimental accuracy.

[0035] This integrated condensation and oil recovery experimental device for heavy oil steam recovery, after completing the steam condensation law experiment, adjusts the cooling chamber pressure through the pressure control system, closes the cooling device outlet valve and the back-pressure valve in the condensate recovery line, and then conducts the oil recovery experiment. The produced fluid is displaced into the produced fluid recovery tank, facilitating analysis of industrial characteristics and oil recovery effects. This design can meet the requirements of oil recovery without replacing the core, and the results of the oil recovery experiment match the measured steam condensation law.

[0036] Example 2

[0037] (1) The experimental device is Figure 1 Installation connection;

[0038] (2) The core to be tested was dried in a constant temperature oven at 80°C for 12 h, and then mounted on a core holder. The vacuum pump was turned on and extracted at a pressure of -0.1 MPa for 4-5 h. Water with the same salinity as the simulated formation water was prepared and pressurized at 1 mL / min to saturate the core with water. The permeability was measured at three flow rates: 1 mL / min, 2 mL / min, and 3 mL / min. The average value was taken if the difference was not large.

[0039] (3) Connect the core holder to the intermediate container containing heavy oil and saturate the core with heavy oil at a rate of 0.1 mL / min.

[0040] (4) aging the core for 12 h;

[0041] (5) Drill four small holes in the experimental core to install four thermocouples, and the spacing between the four thermocouples is the same, all 5 mm;

[0042] (6) Install the experimental core into the core chamber and heat the core to 53°C using a ring heating tube;

[0043] (7) Open valve-5 in the cooling water pipeline, back pressure valve-1 in the condensate recovery pipeline, and back pressure valve-2 in the output fluid recovery pipeline, and control the condensate chamber pressure at 8 MPa through the pressure control system;

[0044] (8) When the steam generator is fully preheated, open valve-1 and turn on ISCO pump-1 to inject water into the steam generator at a rate of 5 mL / min;

[0045] (9) Open valve-2 and start ISCO pump-2 to inject water into the intermediate container containing N2 at 2.5 ml / min;

[0046] (10) Open valve-3 and valve-4 simultaneously, and inject steam and N2 into the condensation chamber at a ratio of 2:1;

[0047] (11) Adjust the injection rate and ratio of steam and N2;

[0048] (12) Observe and record the condensation phenomenon through the visual window on the wall of the visual condensation chamber, collect the temperature data detected by the thermocouple, and analyze the condensation law of the mixed steam;

[0049] (13) After completing the steam condensation experiment, drain the liquid in the condensation chamber and the cooling chamber and close all valves;

[0050] (14) Reheat the core to 53°C;

[0051] (15) Open the back pressure valve-2 of the output fluid recovery pipeline and control the cooling chamber pressure at 8 MPa through the pressure control system;

[0052] (16) Open valve-1, turn on ISCO pump-1 to inject water into the steam generator at a rate of 5 mL / min, open valve-2, turn on ISCO pump-2 to inject water into the intermediate container containing N2 at a rate of 2.5 mL / min;

[0053] (17) Open valve-3 and valve-4 simultaneously, and inject steam and N2 into the condensation chamber at a ratio of 2:1;

[0054] (18) Record the temperature of the thermocouple;

[0055] (19) Analyze the state and properties of the produced fluid.

Claims

1. An integrated experimental device for condensation and oil displacement based on heavy oil steam recovery, including a steam generator, an intermediate container, a cooling device, a condensing device, a condensate recovery tank, and a production fluid recovery tank; The condensation device includes a cooling chamber, a core chamber, and a condensation chamber connected in sequence from left to right, and a visual window is provided on the wall of the condensation chamber; the core chamber is installed with an experimental core saturated with formation water and heavy oil, and thermocouples are distributed on the experimental core, and the two ends of the experimental core are respectively connected to the condensation chamber and the cooling chamber; The steam generator and the intermediate container are connected to the condensing chamber respectively, and the cooling device is connected to the cooling chamber; a switch valve-3 is provided between the steam generator and the condensing chamber, a switch valve-4 is provided between the intermediate container and the condensing chamber; and a switch valve-5 is provided between the cooling device and the cooling chamber; The condensate recovery tank is connected to the condensing chamber, and the output fluid recovery tank is connected to the cooling chamber. The output fluid recovery tank is used to collect the fluid produced by displacement; a back pressure valve-1 is provided between the condensate recovery tank and the condensing chamber, and a back pressure valve-2 is provided between the output fluid recovery tank and the cooling chamber; The intermediate container is used to contain non-condensable gas and / or chemical solution.

2. The condensation and oil displacement integrated experimental device according to claim 1, characterized in that: The core chamber is composed of an outer annular heating tube and an inner layer of thermal insulation material, and the thermal insulation material fits tightly to the experimental core.

3. The condensation and oil displacement integrated experimental device according to claim 1, characterized in that: The condensation chamber is a cylindrical cavity with the same diameter as the experimental core. The viewing window is a visible resin concentric glass with a heating device. The distance between the viewing window and the experimental core is 15mm-20mm.

4. The condensation and oil displacement integrated experimental device according to claim 1, characterized in that: The cooling cavity is a hemispherical cavity with the same diameter as the experimental core.

5. A working method of the integrated condensation and oil displacement experimental device based on heavy oil steam recovery according to any one of claims 1 to 4, characterized in that: The steps include: Install the experimental core saturated with formation water and heavy oil into the core chamber. After heating the experimental core, open on-off valve 5 to cool it. Open back-pressure valves 1 and 2 to control the pressure in the condensation chamber. Open on-off valves 3 and 4 to inject steam, non-condensable gas, and / or chemical solution into the condensation chamber. Observe and record the condensation phenomenon through the viewing window, collect temperature data measured by thermocouples, analyze the steam condensation pattern, and complete the condensation experiment. After draining the condensation chamber and cooling chamber liquids, close the valves and reheat the experimental core. Open back-pressure valve-2 to control the cooling chamber pressure. Open on-off valves-3 and -4 to inject steam, non-condensable gas, and / or chemical solution into the condensation chamber. Record the thermocouple temperature. Collect the fluid produced by the displacement in the production fluid recovery tank. Analyze the state and properties of the produced fluid to complete the displacement experiment.

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