Method and equipment for continuously producing reservoir modification heating aid for SAGD (Steam Assisted Gravity Drainage) technology

Abstract

The invention provides a method and equipment for continuously producing a reservoir modification heating aid for an SAGD (Steam Assisted Gravity Drainage) technology. The method comprises the following steps: step 1, pumping out the SAGD output liquid from a production well, and separating the SAGD output liquid to obtain output water, associated gas, thickened oil and crude oil; 2, CO2 and CH4 in the associated gas are separated, collected and cached; removing impurities in the produced water to obtain a heating aid solvent and a steam water source; and step 3, adding heat-assisting minerals into the heat-assisting agent solvent, and fully mixing to obtain the heat-assisting agent. In the invention, by improving the production efficiency of the reservoir modification heating aid, the production cost of the reservoir modification heating aid is greatly reduced, the oil extraction efficiency and convenience of crude oil are ensured, and the production process is more energy-saving and environment-friendly.

Description

Technical Field

[0001] The present invention belongs to the technical field of steam-assisted gravity drainage (SAGD) oil production, and more particularly relates to a method for continuously producing a reservoir modification thermal aid used in the SAGD technology. Background Art

[0002] Reservoir modification thermal additives are chemical additives used in heavy oil thermal recovery (such as SAGD, steam flooding, and oil layer combustion). They aim to improve reservoir properties, increase heat transfer efficiency, and reduce heavy oil viscosity through physical or chemical effects, thereby increasing recovery rates and reducing energy consumption.

[0003] In order to ensure the thermal performance of the current reservoir modification thermal aids, the production and preparation often requires complex production processes to ensure production. However, due to factors such as production raw materials and production environment, its production method cannot achieve the purpose of continuous production. This also leads to the inability to meet the demand for the use of thermal aids in the SAGD oil production process. Summary of the Invention

[0004] In response to the problems existing in the prior art, the purpose of the present invention is to provide a continuous production method for reservoir modification thermal aids for SAGD technology, which can improve the production efficiency of reservoir modification thermal aids while reducing the production cost of reservoir modification thermal aids.

[0005] To achieve the above objectives, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for continuous production of a thermal agent for reservoir modification using the SAGD technology. The method comprises the following steps: step 1, extracting SAGD produced fluid from a production well, separating the SAGD produced fluid to obtain produced water, associated gas, heavy oil and crude oil; step 2, separating CO2 and CH4 in the associated gas and collecting and buffering them; removing impurities in the produced water to obtain a thermal agent solvent and a steam water source; step 3, adding a thermal mineral to the thermal agent solvent and fully mixing them to obtain a thermal agent.

[0007] Furthermore, step one specifically includes: extracting SAGD produced fluid from the production well, separating the SAGD produced fluid using a high-pressure separator in the three-phase separation system to obtain associated gas, heavy oil, and an oil-water mixture; further separating the oil-water mixture using a medium-pressure separator in the three-phase separation system to obtain associated gas and an oil-water emulsion; and further separating the oil-water emulsion using an oil-liquid separator in the three-phase separation system to obtain crude oil, produced water, and residual associated gas. It should be explained that both heavy oil and crude oil are essentially petroleum. Heavy oil is the product separated by the high-pressure separator, but it is indeed untreated petroleum with high viscosity and density. Crude oil is petroleum that has been separated and dehydrated. Although both are petroleum, they are in different states, have different physical properties, and are in different processing stages. Therefore, heavy oil and crude oil are used to distinguish. Similarly, produced water may contain other substances, while recycled water is treated water.

[0008] Furthermore, the working pressure for separating the SAGD output fluid is 1-3 MPa, and the working temperature is 150-200°C; the working pressure for separating the oil-water mixture is 0.5-1 MPa, and the working temperature is 100-150°C; the working pressure for separating the oil-water emulsion is normal pressure-0.3 MPa, and the working temperature is 80-100°C.

[0009] Furthermore, step 2 specifically includes: absorbing CO2 and H2S by amine liquid to obtain rich amine liquid; and then heating the rich amine liquid to release CO2, with the heating temperature being 120°C.

[0010] Furthermore, the method also includes: Step 4, reinjecting the thermal agent and CO2 into the production well; and using CH4 as a heat source to heat a steam water source to form steam, which is injected into the production well. The thermal agent and steam are used to cooperate with the electric heating cable to reduce the viscosity of the crude oil. It should be noted that the thermal agent produced in this application is a liquid, wherein CO2 is a gaseous thermal agent, and CO2 is a by-product of the production of this application. It is used in conjunction with the thermal agent produced in this application to form a composite thermal fluid to increase the economic efficiency of this production method. The thermal agent cannot generate heat independently; its purpose is to facilitate the increase and transfer of heat to reduce the viscosity of the oil, so it is necessary to install an electric heating cable in the production well.

[0011] The present invention also provides a device for continuous production of a reservoir modification thermal agent for SAGD technology, which is used in the above-mentioned method for continuous production of a reservoir modification thermal agent for SAGD technology;

[0012] The equipment includes: a three-phase separation system connected to the SAGD production liquid discharge port of the production well, wherein the three-phase discharge ports of the three-phase separation system are respectively connected to an associated gas tank, a produced water tank and a heavy oil tank, and the associated gas tank, the produced water tank and the heavy oil tank are used to store produced water, associated gas and heavy oil respectively;

[0013] The associated gas tank is connected to an absorption tower, which is used to absorb CO2 and H2S through amine liquid to obtain rich amine liquid; the absorption tower is also connected to a CH4 storage tank and a regeneration tower, and the regeneration tower is also connected to a CO2 storage tank; the CH4 storage tank is used to collect CH4 in the associated gas; the regeneration tower is used to heat the rich amine liquid and release CO2; the CO2 storage tank is used to collect CO2;

[0014] The produced water tank is connected to a high-speed centrifuge, which is used to separate the oil and water in the emulsion, and store the separated oil and water in the emulsion storage tank and the recycled water storage tank respectively;

[0015] The recycled water storage tank is connected to a high-temperature steam generator and a reactor respectively. The high-temperature steam generator is used to heat the steam water source using CH4 as a heat source to form steam; the reactor is provided with a drug addition port for adding a thermal aid and montmorillonite powder.

[0016] Furthermore, the three-phase separation system includes a high-pressure separator, a medium-pressure separator and an oil-liquid separator. The high-pressure separator is used to separate associated gas from oil-water mixture, the medium-pressure separator is used to separate associated gas from oil-water emulsion, and the oil-liquid separator is used to separate produced water from oil.

[0017] Furthermore, a SAGD thermal agent pipeline is provided between the reactor and the production well, and the SAGD thermal agent pipeline is used to pump the thermal agent into the production well; a SAGD steam pipeline is provided between the CO2 storage tank, the high-temperature steam generator and the production well, and the SAGD steam pipeline is used to pump steam and CO2 into the production well.

[0018] Furthermore, the high-temperature steam generator is also used to output the generated high-temperature steam to the regeneration tower; and the recycled water storage tank is provided with a water supply port.

[0019] Furthermore, the CH4 storage tank and the CO2 storage tank are respectively provided with air pressure sensors, and the recycled water storage tank is provided with a liquid level sensor.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] (1) This solution processes the SAGD output fluid to obtain raw materials and auxiliary materials for preparing the reservoir modification thermal aid, which not only improves the production efficiency of the reservoir modification thermal aid, but also reduces the production cost of the reservoir modification thermal aid, and the production process is more energy-saving and environmentally friendly.

[0022] (2) This solution forms a cycle by adding the thermal agent and extracting the SAGD output fluid with the continuous production process of the present invention, thereby greatly reducing the production cost of the reservoir modification thermal agent and ensuring the efficiency and convenience of crude oil recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the continuous production process of the reservoir modification thermal aid of the present invention;

[0024] Figure 2 This is a schematic diagram of the continuous production principle of the reservoir modification thermal aid of the present invention;

[0025] Figure 3 Schematic diagram of the separation principle of the three-phase separation system of the present invention.

[0026] Description of the numbers in the figure:

[0027] 1. Three-phase separation system; 101. High-pressure separator; 102. Medium-pressure separator; 103. Oil-liquid separator; 2. Associated gas tank; 3. Produced water tank; 4. Heavy oil tank; 5. Absorption tower; 6. Regeneration tower; 7. CH4 storage tank; 8. CO2 storage tank; 9. High-speed centrifuge; 10. Emulsion storage tank; 11. Recycled water storage tank; 12. High-temperature steam generator; 13. Reactor. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention;

[0029] See also Figure 1 、 Figure 2 and Figure 3 , the present invention provides the following embodiments:

[0030] The present invention provides an apparatus for the continuous production of a reservoir modification thermal agent using the SAGD technology. The apparatus comprises: a three-phase separation system 1 connected to a SAGD produced fluid discharge port of a production well, and utilizing the three-phase separation system 1 to separate the extracted SAGD produced fluid; the three-phase discharge ports of the three-phase separation system 1 are respectively connected to an associated gas tank 2, a produced water tank 3, and a heavy oil tank 4, for respectively storing the associated gas, produced water, and heavy oil separated by the three-phase separation system 1;

[0031] The gas outlet of the associated gas tank 2 is connected to the absorption tower 5. An amine liquid spray head is provided in the absorption tower. After the associated gas enters the absorption tower 5, it contacts the amine liquid in reverse. The amine liquid absorbs the CO2 and H2S in the associated gas, leaving relatively pure CH4. The exhaust port of the absorption tower 5 is connected to the CH4 storage tank 7. The filtered CH4 is then collected in the CH4 storage tank 7. The liquid discharge port of the absorption tower 5 is connected to the regeneration tower 6. The regeneration tower 6 is provided with heating steam for heating the rich amine liquid to release CO2, thereby extracting the CO2 and collecting the CO2 in the CO2 storage tank 8.

[0032] The outlet of the produced water tank 3 is connected to a high-speed centrifuge 9 to separate the oil and water in the emulsion, and the oil and water are stored in an emulsion storage tank 10 and a recycled water storage tank 11 respectively; the outlet of the recycled water storage tank 11 is connected to a high-temperature steam generator 12 and a reactor 13, so that the recycled water is used as a steam raw material and a thermal aid solvent. The heat source of the high-temperature steam generator 12 adopts the CH4 in the CH4 storage tank 7. The reactor 13 is provided with a drug addition port for adding a thermal aid and montmorillonite powder, through which a thermal aid mineral can be added to the thermal aid solvent.

[0033] The present invention utilizes the continuous SAGD output fluid produced during the SAGD oil production process, processes the SAGD output fluid, obtains raw materials and auxiliary materials for preparing a reservoir modification thermal agent, and fully utilizes the CH4 generated during the treatment process as energy to achieve the purpose of processing and production, thereby improving the production efficiency of the reservoir modification thermal agent and reducing the production cost of the reservoir modification thermal agent, and the production process is more energy-saving and environmentally friendly.

[0034] The three-phase separation system 1 includes a high-pressure separator 101, a medium-pressure separator 102 and an oil-liquid separator 103. The high-pressure separator 101 is used to separate associated gas from oil-water mixture, the medium-pressure separator 102 is used to separate associated gas from oil-water emulsion, and the oil-liquid separator 103 is used to separate produced water from oil.

[0035] The working pressure of the high-pressure separator 101 is 1-3 MPa and the working temperature is 150-200°C. The working pressure of the medium-pressure separator 102 is 0.5-1 MPa and the working temperature is 100-150°C. The working pressure of the oil-liquid separator 103 is between normal pressure and 0.3 MPa and the working temperature is 80-100°C. The working pressure and temperature for separating the heavy oil are maintained to prevent the precipitation and solidification of asphaltene in the heavy oil, which affects the collection of the heavy oil, and avoid clogging of the separation system.

[0036] The temperature of high-temperature steam in regeneration tower 6 is 120°C, which is used to release CO2 from rich amine liquid. The temperature of CO2 released from rich amine liquid is 120°C. Maintaining the steam temperature in regeneration tower 6 at 120°C facilitates the collection of CO2.

[0037] The high-temperature steam generated by the high-temperature steam generator 12 is output and connected to the regeneration tower 6. A water supply port is provided on the recycled water storage tank 11, which fully utilizes the high-temperature steam generated by the recycled water by the high-temperature steam generator 12, thereby further reducing energy consumption. At the same time, the recycled water consumed in continuous production can be replenished through the water supply port.

[0038] The CH4 storage tank 7 and the CO2 storage tank 8 are provided with air pressure sensors, and the recycled water storage tank 11 is provided with a liquid level sensor. The air pressure sensors and liquid level sensors are used to conveniently understand the reserves of CH4, CO2 and recycled water, which is conducive to timely replenishment and maintaining continuous production conditions.

[0039] The present invention also provides a method for continuous production of a reservoir modification thermal agent for SAGD technology, which is further described in detail. Figure 1 , including the following steps:

[0040] Step 1: The SAGD produced fluid extracted from the production well is separated through a three-phase separation system 1 to obtain produced water, associated gas, heavy oil and crude oil;

[0041] Step 2: Separate CO2 and CH4 from the associated gas and collect them for buffering, remove impurities from the produced water and use it as a heating agent solvent and steam water source;

[0042] Step 3: Add montmorillonite powder to the thermal agent solvent and mix thoroughly, then inject the thermal agent and CO2 back into the production well;

[0043] Step 4: CH4 is used as a heat source to heat the steam water source to form steam and inject it into the production well. The thermal agent and steam cooperate with the electric heating cable to reduce the viscosity of the crude oil.

[0044] In steps 3 and 4, the thermal agent is pumped in through the SAGD thermal agent pipeline, and steam and CO2 are pumped in through the SAGD steam pipeline.

[0045] By adding the thermal agent and extracting the SAGD produced fluid, a cycle is formed with the continuous production process of the present invention, thereby greatly reducing the production cost of the reservoir modification thermal agent and ensuring the efficiency and convenience of crude oil recovery.

[0046] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any person skilled in the art who, within the technical scope disclosed by the present invention, makes equivalent substitutions or modifications based on the technical solutions and improved concepts of the present invention shall be covered by the scope of protection of the present invention.

Claims

1. A method for continuous production of a reservoir modification thermal agent for SAGD technology, characterized in that: The method comprises the following steps: Step 1: extracting SAGD produced fluid from the production well and separating the SAGD produced fluid to obtain produced water, associated gas, heavy oil and crude oil; Step 2: Separate CO2 and CH4 in the associated gas and collect and cache them; remove impurities from the produced water to obtain a heating agent solvent and steam water source; Step 3: Add the heat-assisting mineral to the heat-assisting agent solvent and mix thoroughly to obtain the heat-assisting agent.

2. The method for continuous production of a reservoir modification thermal agent for SAGD technology according to claim 1, characterized in that: Step one specifically includes: extracting SAGD produced fluid from the production well, separating the SAGD produced fluid by a high-pressure separator in a three-phase separation system to obtain associated gas, heavy oil and an oil-water mixture; continuing to separate the oil-water mixture by a medium-pressure separator in the three-phase separation system to obtain associated gas and an oil-water emulsion; and further separating the oil-water emulsion by an oil-liquid separator in the three-phase separation system to obtain crude oil, produced water and residual associated gas.

3. The method for continuous production of a reservoir modification thermal agent for SAGD technology according to claim 2, characterized in that: The working pressure for separating the SAGD output liquid is 1-3 MPa, and the working temperature is 150-200°C; the working pressure for separating the oil-water mixture is 0.5-1 MPa, and the working temperature is 100-150°C; the working pressure for separating the oil-water emulsion is normal pressure-0.3 MPa, and the working temperature is 80-100°C.

4. The method for continuous production of a reservoir modification thermal agent for SAGD technology according to claim 1, characterized in that: Step 2 specifically includes: absorbing CO2 and H2S through amine liquid to obtain rich amine liquid; and then heating the rich amine liquid to release CO2, with the heating temperature being 120°C.

5. The method for continuous production of reservoir modification thermal aid for SAGD technology according to claim 1, characterized in that: The method further includes: Step 4: Reinject the thermal agent and CO2 into the production well; use CH4 as a heat source to heat the steam water source to form steam and inject it into the production well. The thermal agent and steam are used to cooperate with the electric heating cable to reduce the viscosity of the crude oil.

6. A device for continuous production of reservoir modification thermal aids for SAGD technology, characterized in that: The device is used in the method for continuous production of reservoir modification thermal aid for SAGD technology as described in claims 1 to 5; The equipment comprises: a three-phase separation system (1) connected to a SAGD produced liquid discharge port of a production well; the three-phase discharge ports of the three-phase separation system (1) are respectively connected to an associated gas tank (2), a produced water tank (3) and a heavy oil tank (4); the associated gas tank (2), the produced water tank (3) and the heavy oil tank (4) are respectively used to store produced water, associated gas and heavy oil; The associated gas tank (2) is connected to an absorption tower (5), and the absorption tower (5) is used to absorb CO2 and H2S through amine liquid to obtain rich amine liquid; the absorption tower (5) is also connected to a CH4 storage tank (7) and a regeneration tower (6), and the regeneration tower (6) is also connected to a CO2 storage tank (8); the CH4 storage tank (7) is used to collect CH4 in the associated gas; the regeneration tower (6) is used to heat the rich amine liquid and release CO2; the CO2 storage tank (8) is used to collect CO2; The produced water tank (3) is connected to a high-speed centrifuge (9), which is used to separate oil and water in the emulsion, and store the separated oil and water in an emulsion storage tank (10) and a recycled water storage tank (11), respectively; The recycled water storage tank (11) is respectively connected to a high-temperature steam generator (12) and a reactor (13). The high-temperature steam generator (12) is used to heat a steam water source using CH4 as a heat source to form steam. The reactor (13) is provided with a drug addition port for adding a thermal aid and montmorillonite powder.

7. The equipment for continuous production of reservoir modification thermal aid for SAGD technology according to claim 6, characterized in that: The three-phase separation system (1) comprises a high-pressure separator (101), a medium-pressure separator (102) and an oil-liquid separator (103); the high-pressure separator (101) is used to separate associated gas from an oil-water mixture; the medium-pressure separator (102) is used to separate associated gas from an oil-water emulsion; and the oil-liquid separator (103) is used to separate produced water from oil.

8. The equipment for continuous production of reservoir modification thermal aid for SAGD technology according to claim 6, characterized in that: A SAGD thermal agent pipeline is provided between the reactor (13) and the production well, and the SAGD thermal agent pipeline is used to pump the thermal agent into the production well; a SAGD steam pipeline is provided between the CO2 storage tank (8), the high-temperature steam generator (12) and the production well, and the SAGD steam pipeline is used to pump steam and CO2 into the production well.

9. The equipment for continuous production of reservoir modification thermal aid for SAGD technology according to claim 6, characterized in that: The high-temperature steam generator (12) is also used to output the generated high-temperature steam and connect it to the regeneration tower (6); the recycled water storage tank (11) is provided with a water supply port.

10. The equipment for continuous production of reservoir modification thermal aid for SAGD technology according to claim 6, characterized in that: The CH4 storage tank (7) and the CO2 storage tank (8) are respectively provided with air pressure sensors, and the recycled water storage tank (11) is provided with a liquid level sensor.

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