CN109209315B

CN109209315B - Device and method for improving thin-layer heavy oil reservoir recovery ratio based on foam flooding

Info

Publication number: CN109209315B
Application number: CN201811370471.6A
Authority: CN
Inventors: 周伟; 李荣西; 董明哲; 陈胜男
Original assignee: Changan University
Current assignee: Changan University
Priority date: 2018-11-17
Filing date: 2018-11-17
Publication date: 2020-05-12
Anticipated expiration: 2038-11-17
Also published as: CN109209315A

Abstract

The invention discloses a device for improving the recovery ratio of a thin-layer heavy oil reservoir based on polymer foam flooding. The invention also discloses a device for improving the recovery ratio of the thin-layer heavy oil reservoir based on the combination of the polymer foam flooding and the gel foam flooding. The invention also discloses a method for improving the thin-layer heavy oil reservoir recovery ratio based on polymer foam flooding. The invention discloses a method for improving the recovery ratio of a thin-layer heavy oil reservoir based on the combination of polymer foam flooding and gel foam flooding. The invention solves the problem that foaming liquid is easy to enter a foam generator and gas is difficult to enter during foam production, simultaneously solves the problems that the primary and secondary recovery rates of a thin-layer heavy oil reservoir are low and a thermal oil recovery mode cannot be applied by a cold oil recovery mode, and provides an important theoretical basis for scientifically utilizing foam flooding to improve the recovery rate of the thin-layer heavy oil reservoir and the specific field construction thereof.

Description

Device and method for improving thin-layer heavy oil reservoir recovery ratio based on foam flooding

Technical Field

The invention belongs to the technical field of improving the thin-layer heavy oil reservoir recovery ratio, and particularly relates to a device and a method for improving the thin-layer heavy oil reservoir recovery ratio based on foam flooding.

Background

The heavy oil resources are widely distributed around the world, and the crude oil in the heavy oil reservoir needs to be mined by an effective viscosity reduction technology due to high viscosity, and the conventional mining technologies mainly comprise thermal oil recovery technologies such as steam huff and puff, steam assisted gravity drive, steam flooding and in-situ combustion methods. However, for thin thick oil reservoirs (the effective thickness of the oil layer is less than 5m), the conventional thermal oil recovery method is greatly limited because the heat loss is very serious because the thickness of the oil layer is too thin, and the oil reservoirs cannot be economically and efficiently developed. And the crude oil in the thin-layer heavy oil reservoir has higher viscosity and poor flow capacity, so the primary recovery ratio of the oil reservoir is only about 6 percent. Moreover, because the flow capacities of crude oil and water in the thin-layer heavy oil reservoir are greatly different, and unfavorable water-oil flow rate ratio is caused, the water-drive recovery ratio (secondary oil recovery) of the thin-layer heavy oil reservoir can only reach about 8.5%. Therefore, in order to efficiently recover a large amount of heavy oil remaining in a thin heavy oil reservoir (85.5% of the crude oil remains underground after primary and secondary recovery), it is highly desirable to find an economical and efficient enhanced recovery method.

The polymer reinforced foam and the gel foam have the advantages of low cost, excellent injection performance, high-permeability stratum plugging and the like, and are applied to the field construction of thin oil reservoirs, so that the crude oil recovery rate is remarkably improved, and huge economic benefits are obtained. However, there has been little research on the application of polymer enhanced foam or a combination of polymer foam flooding and gel foam flooding in thin heavy oil reservoirs. Therefore, the device and the method for improving the thin-layer heavy oil reservoir recovery ratio based on foam flooding are simple in structure, convenient to operate and capable of accurately simulating foam flooding, the problem that the thin-layer heavy oil reservoir is low in recovery ratio in the existing exploitation technology is solved, the applicability of foam flooding to the thin-layer heavy oil reservoir is evaluated, and therefore efficient development of the thin-layer heavy oil reservoir is achieved, and the device and the method have important practical significance.

Disclosure of Invention

The invention aims to solve the technical problem that the prior art is insufficient, and provides a device for improving the thin-layer heavy oil reservoir recovery ratio based on polymer foam flooding, which is novel and reasonable in design, adopts a peristaltic pump to pre-mix polymer foam, and enables polymer foaming liquid and carbon dioxide gas to alternately enter a foam generator, so that the problem that only liquid enters the foam generator and gas is difficult to enter in the existing polymer foam production process is solved, and meanwhile, the problems that the thin-layer heavy oil reservoir is once low in secondary recovery ratio and cannot be applied in a thermal oil recovery mode are solved through a cold oil recovery mode, so that an important theoretical basis is provided for scientifically utilizing polymer reinforced carbon dioxide foam to improve the thin-layer heavy oil reservoir recovery ratio and the specific field construction thereof, and the device is convenient to popularize and use.

In order to solve the technical problems, the invention adopts the technical scheme that: the device for improving the thin-layer heavy oil reservoir recovery ratio based on polymer foam flooding is characterized in that: the device comprises a polymer foam generating mechanism for generating polymer foam, a sand filling pipe core simulating mechanism for simulating a thin-layer heavy oil reservoir core, a fluid injection mechanism for injecting saturated fluid into the polymer foam generating mechanism and the sand filling pipe core simulating mechanism, a produced fluid collecting mechanism for collecting produced fluid in the sand filling pipe core simulating mechanism, and a temperature control mechanism for controlling the temperature of the polymer foam generating mechanism and the temperature of the sand filling pipe core simulating mechanism; the polymer foam generating mechanism comprises a peristaltic pump and a foam generator communicated with the output end of the peristaltic pump, the sand filling pipe core simulation mechanism comprises a sand filling pipe communicated with the output end of the foam generator and quartz sand filled in the sand filling pipe, the input end of the sand filling pipe is provided with a fluid inflow valve, the fluid injection mechanism comprises a first pipeline communicated with the sand filling pipe, a second pipeline communicated with the peristaltic pump, a first intermediate container installed on the first pipeline in parallel and used for containing water, a second intermediate container used for containing thick oil, a third intermediate container installed on the second pipeline in parallel and used for containing polymer foaming liquid and a fourth intermediate container used for containing carbon dioxide gas, the liquid inlet ends of the first intermediate container, the second intermediate container and the third intermediate container are provided with first plunger pumps, the liquid inlet end of the fourth intermediate container is provided with a second plunger pump, the liquid outlet ends of the first intermediate container and the second intermediate container are communicated with the input end of the sand filling pipe, the liquid outlet end of the third intermediate container and the gas outlet end of the fourth intermediate container are communicated with the input end of the peristaltic pump.

The device for improving the recovery ratio of the thin-layer heavy oil reservoir based on polymer foam flooding is characterized in that: the produced fluid collecting mechanism comprises a measuring cylinder, a fluid outflow pipe and a fluid outflow valve, wherein the fluid outflow pipe is communicated with the output ends of the measuring cylinder and the sand filling pipe, and the fluid outflow valve is arranged on the fluid outflow pipe.

The device for improving the recovery ratio of the thin-layer heavy oil reservoir based on polymer foam flooding is characterized in that: the temperature control mechanism comprises a constant temperature box, and the peristaltic pump, the foam generator, the sand filling pipe and the fluid outflow pipe are all arranged in the constant temperature box.

The device for improving the recovery ratio of the thin-layer heavy oil reservoir based on polymer foam flooding is characterized in that: and the input end of the sand filling pipe is provided with a pressure sensor, and the pressure sensor is connected with a computer.

The device for improving the recovery ratio of the thin-layer heavy oil reservoir based on polymer foam flooding is characterized in that: and a water outlet valve is installed at the liquid outlet end of the first intermediate container, an oil outlet valve is installed at the liquid outlet end of the second intermediate container, a liquid outlet valve is installed at the liquid outlet end of the third intermediate container, and a gas outlet valve is installed at the gas outlet end of the fourth intermediate container.

The invention also provides a device for improving the thin-layer heavy oil reservoir recovery ratio based on the combination of the polymer foam flooding and the gel foam flooding. Further improving the thin layer heavy oil reservoir recovery ratio.

In order to realize the aim, the device for improving the thin-layer heavy oil reservoir recovery ratio based on the combination of the polymer foam flooding and the gel foam flooding adopts the technical scheme that: the device for improving the thin-layer heavy oil reservoir recovery ratio based on the combination of polymer foam flooding and gel foam flooding is characterized in that: the device comprises a third pipeline communicated with a foam generator and a fifth intermediate container arranged on the third pipeline and used for containing gel foaming liquid, wherein the third pipeline is used for improving the thin-layer heavy oil reservoir recovery ratio based on polymer foam flooding, a third plunger pump is arranged at the liquid inlet end of the fifth intermediate container, the liquid outlet end of the fifth intermediate container is communicated with the input end of the foam generator, a gel outlet valve is arranged at the liquid outlet end of the fifth intermediate container, the pipeline section of the peristaltic pump input end is communicated with one end of a fourth pipeline, the other end of the fourth pipeline is communicated with the pipeline section of the second pipeline, which is positioned at the output end of the peristaltic pump, a back pressure valve and a first safety valve are arranged on the fourth pipeline, and a second safety valve is arranged on the pipeline section of the second pipeline, which is positioned between the fourth pipelines.

Meanwhile, the invention also discloses a method for improving the thin-layer heavy oil reservoir recovery ratio based on polymer foam flooding, which is characterized by comprising the following steps:

step one, forming a sand filling pipe core simulation mechanism: filling dry quartz sand into a sand filling pipe by using a vibration filling method to form a sand filling pipe core simulation mechanism, wherein the mesh number of the quartz sand is 20-170 meshes;

step two, air tightness detection: sealing a fluid inflow valve and a fluid outflow valve, injecting high-pressure nitrogen into the sand filling pipe through the fluid inflow valve, and detecting the air tightness of the sand filling pipe;

step three, acquiring the porosity of the sand-filled pipe core simulation mechanism, wherein the process is as follows:

step 301, connecting a vacuum pump with a fluid inflow valve, and vacuumizing a sand filling pipe by using the vacuum pump;

step 302, closing the fluid inflow valve, opening the fluid outflow valve, and saturating the distilled water for the sand filling pipe by the measuring cylinder filled with the distilled water;

303, according to the formula

Calculating the porosity phi of the sand-filled pipe core simulation mechanism, wherein V₁The saturated distilled water output by the measuring cylinder is in unit of ml and V₂The volume of the sand filling pipe is ml;

step four, obtaining the absolute permeability of the sand-filled pipe core simulation mechanism, wherein the process is as follows:

step 401, installing a pressure sensor connected with a computer on an input end of a sand filling pipe, installing a water outlet valve on a liquid outlet end of a first intermediate container, opening the water outlet valve, a fluid inflow valve and a fluid outflow valve, setting n different displacement rates of a first plunger pump at room temperature, displacing a sand filling pipe core simulation mechanism by water in the first intermediate container through a first pipeline n times by using the first plunger pump, and recording pressure values acquired by the pressure sensor n times, wherein n is a positive integer not less than 3;

step 402, according to the formula

Calculating the absolute permeability k of the sand-filled pipe core simulation mechanism, wherein the unit is mum²Wherein k is_iSimulating the absolute permeability of the sand pack core mechanism for the first plunger pump at the ith displacement rate in step 401

Unit is mum²，Q_iFor the ith displacement of the first plunger pump in step 401Rate in cm³Mu is viscosity of water, expressed in mPa.s, L is length of sand-packed pipe, expressed in cm, A is cross-sectional area of sand-packed pipe, expressed in cm²，ΔP_i＝P_i-P₀The pressure difference between the two ends of the sand pack pipe of the first plunger pump at the ith displacement rate in step 401 is 10%^-1MPa，P_iPressure value in 10 units collected for the pressure sensor of the first plunger pump at the ith displacement rate^-1MPa，P₀Is at atmospheric pressure and has a unit of 10^-1MPa；

Step five, presetting the initial oil saturation of the sand filling pipe core simulation mechanism after saturated oil: installing an oil outlet valve at the liquid outlet end of the second intermediate container, opening the oil outlet valve, closing the water outlet valve, adjusting the temperature of the constant temperature box to be 60 ℃, driving the second intermediate container filled with the thick oil by using a first plunger pump at the temperature of 60 ℃, and saturating the thick oil in the sand-filled pipe core simulation mechanism until the initial crude oil saturation of the sand-filled pipe core simulation mechanism reaches a preset value; closing the fluid inflow valve and the fluid outflow valve and aging the sand filling pipe core simulation mechanism at a constant temperature for 3 days;

step six, simulating water drive to obtain water drive recovery ratio: adjusting the temperature of the constant temperature box to be 21 ℃, closing the oil outlet valve, opening the water outlet valve, the fluid inflow valve and the fluid outflow valve, injecting water in the first intermediate container into the sand filling pipe by using the first plunger pump to simulate a water drive process, closing the first plunger pump, the water outlet valve, the fluid inflow valve and the fluid outflow valve when the water content of the output end of the sand filling pipe reaches 99 percent, and according to a formula

Calculating water drive recovery factor gamma₁Wherein G is₂The amount of oil produced in the measuring cylinder is given in ml, G₁The unit of the thick oil output by the second intermediate container in the fifth step is ml;

step seven, forming polymer reinforced carbon dioxide foam, and the process is as follows:

701, installing a liquid outlet valve at the liquid outlet end of the third intermediate container, and installing a gas outlet valve at the gas outlet end of the fourth intermediate containerOpening the first plunger pump, the second plunger pump, the liquid outlet valve, the gas outlet valve and the peristaltic pump, and setting the displacement speed of the first plunger pump as v₁Driving a third intermediate container containing a polymer foaming liquid, v₁Is given in ml/min, the displacement speed of the second plunger pump is set to v₂Driving a fourth intermediate container containing carbon dioxide gas, v₂The unit of (a) is ml/min, the polymer foaming liquid and the carbon dioxide gas alternately enter a peristaltic pump to realize the premixing of the polymer foaming liquid and the carbon dioxide gas, wherein v₁<v₂；

Step 702, alternately feeding the polymer foaming liquid and the carbon dioxide gas into a peristaltic pump to sequentially feed the polymer foaming liquid and the carbon dioxide gas into a foam generator to form polymer reinforced carbon dioxide foam;

eighthly, reinforcing carbon dioxide foam flooding by using the polymer and obtaining the recovery ratio of the polymer foam flooding: opening the fluid inflow valve and the fluid outflow valve to enable the polymer reinforced carbon dioxide foam in the foam generator to enter the sand filling pipe, so that polymer reinforced carbon dioxide foam driving is carried out; when the injection amount of the polymer reinforced carbon dioxide foam reaches a set value, closing the first plunger pump, the second plunger pump, the liquid outlet valve, the gas outlet valve and the peristaltic pump, stopping the polymer reinforced carbon dioxide foam driving, and driving according to a formula

Calculating recovery factor gamma of polymer foam flooding₂，G₃Injecting polymer into the sand filling pipe to reinforce carbon dioxide foam, and then enabling the thickened oil and water produced at the output end of the sand filling pipe to enter a measuring cylinder, wherein the unit of oil production in the measuring cylinder is ml;

ninthly, acquiring the recovery ratio of the first subsequent water flooding by the first subsequent water flooding: opening a first plunger pump, a water outlet valve, a fluid inflow valve and a fluid outflow valve, driving a first intermediate container filled with water by using the first plunger pump to perform first subsequent water drive on the sand filling pipe, closing the first plunger pump, the water outlet valve, the fluid inflow valve and the fluid outflow valve when the water content of the output end of the sand filling pipe reaches 99%, stopping the first subsequent water drive, and performing water drive according to a formula

Calculating the first subsequent water drive recovery factor gamma₃Wherein G is₄The unit of the oil output in the measuring cylinder in the first subsequent water flooding is ml;

step ten, obtaining the recovery ratio of the sand filling pipe core simulation mechanism of the polymer foam flooding: according to the formula γ ═ γ₁+γ₂+γ₃And calculating the recovery rate gamma of the sand filling pipe core simulation mechanism of the polymer foam flooding.

The above method is characterized in that: displacement speed v of the first plunger pump in step 701₁And displacement speed v of the second plunger pump₂Satisfies the following conditions:

and step eight, setting the numerical value of the injection amount of the polymer reinforced carbon dioxide foam to be 0.1-5 times of the pore volume of the sand filling pipe core simulation mechanism.

Meanwhile, the invention also discloses a method for improving the thin-layer heavy oil reservoir recovery ratio based on the combination of polymer foam flooding and gel foam flooding, which comprises the steps from one to nine in the method for improving the thin-layer heavy oil reservoir recovery ratio based on the polymer foam flooding, and is characterized in that: the method further comprises the following steps:

step ten, formation of jelly foam: opening a second plunger pump, a third plunger pump, an air outlet valve, a glue outlet valve, a first safety valve and a back pressure valve, and setting the displacement speed of the third plunger pump as v₃Driving a fifth intermediate container filled with a gel foaming liquid, v₃In units of ml/min, wherein v₃<v₂(ii) a The pressure setting value of the back pressure valve is 2-3 times of the pressure of the outlet end of the sand filling pipe, when the gas pressure in the fourth intermediate container is greater than the pressure value set by the back pressure valve, the carbon dioxide gas flows out of the back pressure valve, so that the gas pressure at the outlet end of the back pressure valve is greater than the pressure of the jelly foaming liquid at the outlet end of the fifth intermediate container, and the carbon dioxide gas enters the foam generator; the pressure in the fourth intermediate container is continuously reduced as the gas flows out of the fourth intermediate container when the fourth intermediate container is usedWhen the gas pressure value is lower than the pressure set by the back pressure valve, the back pressure valve is closed, and then the gel foaming liquid enters the foam generator; when the gas pressure in the fourth intermediate container gradually recovers and rises and the pressure is larger than the pressure value set by the back pressure valve, repeating the process that carbon dioxide gas enters the foam generator, and enabling the jelly foaming liquid and the carbon dioxide gas to alternately enter the foam generator to form jelly foam;

eleven, gel foam flooding and obtaining the recovery ratio of the gel foam flooding: opening a fluid inflow valve and a fluid outflow valve to enable the jelly foam in the foam generator to enter a sand filling pipe, so that jelly foam is driven; when the injection amount of the jelly foam reaches a set value, closing the second plunger pump, the third plunger pump, the gas outlet valve, the jelly outlet valve, the first safety valve, the back pressure valve, the fluid inflow valve and the fluid outflow valve, stopping driving the jelly foam, placing the sand filling pipe for 4 days to enable the jelly liquid in the jelly foaming liquid to be frozen to form jelly, and according to a formula

Calculating recovery factor gamma of foam flooding₄，G₅The unit is the oil yield in the measuring cylinder in the gel foam flooding;

step twelve, acquiring the recovery ratio of the second follow-up water flooding by the second follow-up water flooding: opening a first plunger pump, a water outlet valve, a fluid inflow valve and a fluid outflow valve, driving a first intermediate container filled with water by using the first plunger pump to perform secondary subsequent water drive on the sand filling pipe, closing the first plunger pump, the water outlet valve, the fluid inflow valve and the fluid outflow valve when the water content of the output end of the sand filling pipe reaches 99%, stopping the secondary subsequent water drive, and performing the secondary subsequent water drive according to a formula

Calculating the recovery ratio gamma of the second subsequent water drive₅Wherein G is₆The unit of the oil output in the measuring cylinder in the second subsequent water flooding is ml;

thirteen, obtaining the recovery ratio of the sand filling pipe core simulation mechanism combining the polymer foam flooding and the gel foam flooding: according to the formula γ ═ γ₁+γ₂+γ₃+γ₄+γ₅And calculating the recovery ratio gamma' of the sand filling pipe core simulation mechanism combining the polymer foam flooding and the gel foam flooding.

The above method is characterized in that: displacement speed v of second plunger pump in step ten₂And displacement speed v of the third plunger pump₃Satisfies the following conditions:

in the step ten, the set numerical value of the injection amount of the jelly foam is 0.1-3 times of the pore volume of the sand filling pipe core simulation mechanism.

Compared with the prior art, the invention has the following advantages:

1. the device for improving the thin-layer heavy oil reservoir recovery ratio based on polymer foam flooding has the advantages that the first plunger pump is used for driving the liquid in the first intermediate container, the second intermediate container and the third intermediate container, the second plunger pump is used for driving the gas in the fourth intermediate container, the structure of the device is simplified, the connection is simple, the cost is saved, meanwhile, the polymer foaming liquid in the third intermediate container and the carbon dioxide gas in the fourth intermediate container are injected into the peristaltic pump through the second pipeline, the polymer foam with stable performance can be rapidly and continuously generated, and the popularization and the use are convenient.

2. The device for improving the thin-layer heavy oil reservoir recovery ratio based on polymer foam flooding solves the problem that only liquid enters a foam generator and gas is difficult to enter due to different compressibility of the liquid and the gas when polymer foam is prepared in an experimental process by arranging the peristaltic pump, the peristaltic pump can play a role in premixing polymer foaming liquid and carbon dioxide gas, so that the polymer foaming liquid and the carbon dioxide gas alternately enter the foam generator in a 'one-section liquid and one-section gas' form, the liquid and the gas enter the foam generator in a set volume ratio, and further stable polymer reinforced carbon dioxide foam is generated, and the use effect is good.

3. The invention relates to a device for improving the thin-layer heavy oil reservoir recovery ratio based on the combination of polymer foam flooding and gel foam flooding, which is characterized in that a gel foaming liquid and carbon dioxide gas alternately enter a foam generator in a 'one-section liquid one-section gas' mode by controlling a back pressure valve, so that the gel foaming liquid and the carbon dioxide gas enter the foam generator in a set volume ratio, and further stable gel foam is generated.

4. The method for improving the recovery ratio of the thin-layer heavy oil reservoir based on the polymer foam flooding has simple steps, simulates the thin-layer heavy oil reservoir with different permeability by changing the mesh number of quartz sand, prepares the polymer foam by using a peristaltic pump, leads polymer foaming liquid and carbon dioxide gas to alternately enter a foam generator in a 'one-section liquid and one-section gas' form, leads the liquid and the gas to enter the foam generator in a set volume ratio, further generates stable polymer reinforced carbon dioxide foam, carries out thin-layer heavy oil recovery by using the sequence of water flooding, polymer foam flooding and subsequent water flooding, avoids the low recovery ratio of the thin-layer heavy oil reservoir due to serious heat loss in the thin-layer heavy oil reservoir and cannot realize economic and efficient development of the reservoir in a cold oil recovery mode, reliable and stable, and is convenient for popularization and use.

5. The method for improving the thin-layer heavy oil reservoir recovery ratio based on the combination of the polymer foam flooding and the gel foam flooding has the advantages that the steps are simple, the gel foaming liquid and the carbon dioxide gas alternately enter the foam generator in a 'one-section liquid and one-section gas' mode on the basis of the method for improving the thin-layer heavy oil reservoir recovery ratio by the polymer foam flooding, the viscosity of the gel foaming liquid is far greater than that of the polymer, so that the gel foaming liquid and the carbon dioxide gas cannot be effectively mixed in advance by a peristaltic pump, and therefore, a back pressure valve is applied to the gel foam flooding and can be opened only when the back pressure valve is greater than a set pressure, the thin-layer heavy oil reservoir recovery ratio is further improved, the investment cost is low, and the use effect is good.

In conclusion, the invention has novel and reasonable design, adopts the peristaltic pump to carry out gas-liquid premixing, leads the polymer foaming liquid and the carbon dioxide gas to alternately enter the foam generator, solves the problem that only liquid enters the foam generator and gas is difficult to enter in the existing polymer foam manufacturing process, simultaneously solves the problems that the primary and secondary recovery rates of a thin-layer heavy oil reservoir are low and a thermal oil recovery mode cannot be effectively applied by a cold oil recovery mode, provides important theoretical basis for scientifically utilizing polymer reinforced carbon dioxide foam to improve the recovery rate of the thin-layer heavy oil reservoir and the specific field construction thereof, and is convenient for popularization and use.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

FIG. 1 is a schematic structural connection diagram of the device for improving the recovery ratio of a thin heavy oil reservoir based on polymer foam flooding.

FIG. 2 is a flow chart of the method for improving the recovery ratio of a thin heavy oil reservoir based on polymer foam flooding.

FIG. 3 is a schematic structural connection diagram of the device for improving the recovery ratio of a thin-layer heavy oil reservoir based on the combination of polymer foam flooding and gel foam flooding.

FIG. 4 is a flow chart of the method for improving the recovery ratio of a thin layer heavy oil reservoir based on the combination of polymer foam flooding and gel foam flooding.

Description of reference numerals:

1-a first plunger pump; 2-a second plunger pump; 3 — a first intermediate container;

4-a second intermediate container; 5-a third intermediate container; 6-a fourth intermediate container;

7-water outlet valve; 8, an oil outlet valve; 9-a liquid outlet valve;

10-air outlet valve; 11-a peristaltic pump; 12-a foam generator;

13-a fluid inflow valve; 14-sand filling pipe; 15-a fluid outflow valve;

16-measuring cylinder; 17-a thermostat; 18-a pressure sensor;

19-a computer; 20 — a first line; 21 — a second line;

22-a third plunger pump; 23 — a fifth intermediate container; 24-glue outlet valve;

25-a first safety valve; 26-a back pressure valve; 27 — a second safety valve;

28 — a third line; 29-fourth line.

Detailed Description

Example 1

As shown in fig. 1, the apparatus for improving the recovery ratio of a thin heavy oil reservoir based on polymer foam flooding of the present invention includes a polymer foam generating mechanism for generating polymer foam, a sand-packed pipe core simulation mechanism for simulating a thin heavy oil reservoir core, a fluid injection mechanism for injecting saturated fluid into the polymer foam generating mechanism and the sand-packed pipe core simulation mechanism, a produced fluid collecting mechanism for collecting produced fluid in the sand-packed pipe core simulation mechanism, and a temperature control mechanism for controlling the temperature of the polymer foam generating mechanism and the sand-packed pipe core simulation mechanism; the polymer foam generating mechanism comprises a peristaltic pump 11 and a foam generator 12 communicated with the output end of the peristaltic pump 11, the sand filling pipe core simulation mechanism comprises a sand filling pipe 14 communicated with the output end of the foam generator 12 and quartz sand filled in the sand filling pipe 14, a fluid inflow valve 13 is arranged at the input end of the sand filling pipe 14, the fluid injection mechanism comprises a first pipeline 20 communicated with the sand filling pipe 14, a second pipeline 21 communicated with the peristaltic pump 11, a first intermediate container 3 and a second intermediate container 4, a third intermediate container 5 and a fourth intermediate container 6, the first intermediate container 3, the second intermediate container 4 and the third intermediate container 5 are arranged on the first pipeline 20 in parallel and used for containing polymer foaming liquid and thick oil, the third intermediate container 5 and the fourth intermediate container 6 are arranged on the second pipeline 21 in parallel and used for containing carbon dioxide gas, a first plunger pump 1 is arranged at the liquid inlet ends of the first intermediate container 3, the second intermediate container 4 and the third intermediate container 5, the liquid inlet end of the fourth intermediate container 6 is provided with a second plunger pump 2, the liquid outlet ends of the first intermediate container 3 and the second intermediate container 4 are communicated with the input end of a sand filling pipe 14, and the liquid outlet end of the third intermediate container 5 and the gas outlet end of the fourth intermediate container 6 are communicated with the input end of a peristaltic pump 11.

It should be noted that the polymer foam generating mechanism is arranged to generate polymer foam for displacing the sand-filled pipe core simulation mechanism so as to generate oil, the polymer foam generating mechanism comprises a peristaltic pump 11 and a foam generator 12, the problem that only liquid enters the foam generator 12 and gas is difficult to enter due to different compressibility of liquid and gas when polymer foam is prepared in an experimental process is solved by using the peristaltic pump 11, the peristaltic pump 11 can play a role of premixing polymer foaming liquid and carbon dioxide gas, so that the polymer foaming liquid and the carbon dioxide gas alternately enter the foam generator in a 'one-section liquid and one-section gas' mode, so that the liquid and the gas enter the foam generator 12 in a set volume ratio, and further stable polymer reinforced carbon dioxide foam is generated, the using effect is good, and the fluid injection mechanism adopts a first plunger pump 1 to drive a first intermediate container 3 to generate oil, and the fluid injection mechanism adopts a second plunger pump 1 to drive a second intermediate container 3, The liquids in the second intermediate container 4 and the third intermediate container 5 drive the gas in the fourth intermediate container 6 by the second plunger pump 2, the structure of the device is simplified, the connection is simple, the cost is saved, and meanwhile, the polymer foaming liquid in the third intermediate container 5 and the carbon dioxide gas in the fourth intermediate container 6 are injected into the peristaltic pump 11 through the second pipeline 21 for premixing and then sent into the foam generator 12 to generate polymer foam, so that the polymer foam with stable performance can be rapidly and continuously generated.

In practical use, the polymer foaming liquid comprises a polymer, a surfactant and water, and the polymer is preferably partially hydrolyzed polyacrylamide.

In this embodiment, the produced fluid collecting mechanism includes a measuring cylinder 16, a fluid outflow pipe communicating the measuring cylinder 16 with the output end of the sand pack pipe 14, and a fluid outflow valve 15 provided on the fluid outflow pipe.

In this embodiment, the temperature control mechanism includes an incubator 17, and the peristaltic pump 11, the foam generator 12, the sand pack pipe 14, and the fluid outflow pipe are all disposed in the incubator 17.

In actual use, the peristaltic pump 11, the foam generator 12, the sand filling pipe 14 and the fluid outflow pipe are all arranged in the incubator 17 to keep the constant temperature environment of the experiment, so that the resistance brought by the temperature difference of the environment to the generation and the transportation of the polymer foam and the transportation of the thick oil is avoided, and a reliable environment is provided for the normal operation of the experiment.

In this embodiment, a pressure sensor 18 is installed at the input end of the sand filling pipe 14, and the pressure sensor 18 is connected to a computer 19.

In this embodiment, the mesh number of the quartz sand is 20 to 170 meshes.

In actual use, the thick oil reservoirs with different permeabilities are simulated by replacing quartz sand with different meshes.

In this embodiment, the liquid outlet end of the first intermediate container 3 is provided with a liquid outlet valve 7, the liquid outlet end of the second intermediate container 4 is provided with a liquid outlet valve 8, the liquid outlet end of the third intermediate container 5 is provided with a liquid outlet valve 9, and the gas outlet end of the fourth intermediate container 6 is provided with a gas outlet valve 10.

A method for improving the thin heavy oil reservoir recovery ratio based on polymer foam flooding, as shown in fig. 2, comprises the following steps:

step one, forming a sand filling pipe core simulation mechanism: filling dry quartz sand into the sand filling pipe 14 by using a vibration filling method to form a sand filling pipe core simulation mechanism, wherein the mesh number of the quartz sand is 20-170 meshes;

step two, air tightness detection: sealing a fluid inflow valve 13 and a fluid outflow valve 15, injecting high-pressure nitrogen into the sand filling pipe 14 through the fluid inflow valve 13, and detecting the air tightness of the sand filling pipe 14;

step 301, connecting a vacuum pump with the fluid inflow valve 13, and vacuumizing the sand filling pipe 14 by using the vacuum pump;

step 302, closing the fluid inflow valve 13, opening the fluid outflow valve 15, and saturating the sand filling pipe 14 with distilled water by the measuring cylinder 16 filled with distilled water;

303, according to the formula

Calculating the porosity phi of the sand-filled pipe core simulation mechanism, wherein V₁The saturated distilled water output by the measuring cylinder 16 is in unit of ml and V₂The volume of the sand-filled pipe 14 is ml;

step 401, installing a pressure sensor 18 connected with a computer 19 on an input end of a sand filling pipe 14, installing a water outlet valve 7 on a liquid outlet end of a first intermediate container 3, opening the water outlet valve 7, a fluid inflow valve 13 and a fluid outflow valve 15, setting n different displacement rates of a first plunger pump 1 at room temperature, displacing water in the first intermediate container 3 through a first pipeline 20 to a sand filling pipe core simulation mechanism n times by using the first plunger pump 1, and recording pressure values acquired by the pressure sensor 18 n times, wherein n is a positive integer not less than 3;

step 402, according to the formula

Calculating the absolute permeability k of the sand-filled pipe core simulation mechanism, wherein the unit is mum²Wherein k is_iThe absolute permeability of the sand-filled pipe core simulation mechanism at the ith displacement rate of the first plunger pump 1 in step 401 is calculated

Unit is mum²，Q_iIs the ith displacement rate of the first plunger pump 1 in step 401, in cm³μ is the viscosity of water in mPas, L is the length of the sand pack 14 in cm, A is the cross-sectional area of the sand pack 14 in cm²，ΔP_i＝P_i-P₀The pressure difference across the sand pack 14 at the ith displacement rate of the first plunger pump 1 in step 401 is 10%^-1MPa，P_iThe pressure value collected for the pressure sensor 18 of the first plunger pump 1 at the ith displacement rate is 10^-1MPa，P₀Is at atmospheric pressure and has a unit of 10^-1MPa；

Step five, presetting the initial oil saturation of the sand filling pipe core simulation mechanism after saturated oil: installing an oil outlet valve 8 at the liquid outlet end of the second intermediate container 4, opening the oil outlet valve 8, closing a water outlet valve 7, adjusting the temperature of a constant temperature box 17 to be 60 ℃, driving the second intermediate container 4 filled with thick oil by using a first plunger pump 1 at the temperature of 60 ℃, and enabling the thick oil saturation of the sand-packed pipe core simulation mechanism to reach a preset value until the initial crude oil saturation of the sand-packed pipe core simulation mechanism reaches the preset value; closing the fluid inflow valve 13 and the fluid outflow valve 15 and carrying out constant temperature aging on the sand filling pipe core simulation mechanism for 3 days;

step six, simulating water drive to obtain water drive recovery ratio: adjusting the temperature of the constant temperature box 17 to be 21 ℃, closing the oil outlet valve 8, opening the water outlet valve 7, the fluid inflow valve 13 and the fluid outflow valve 15, injecting water in the first intermediate container 3 into the sand filling pipe 14 by using the first plunger pump 1 to simulate a water drive process, closing the first plunger pump 1, the water outlet valve 7, the fluid inflow valve 13 and the fluid outflow valve 15 when the water content of the output end of the sand filling pipe 14 reaches 99%, and according to a formula

Calculating water drive recovery factor gamma₁Wherein G is₂Is the amount of oil produced in the measuring cylinder 16 in ml, G₁The unit of the thick oil output by the second intermediate container 4 in the fifth step is ml;

step 701, installing a liquid outlet valve 9 at the liquid outlet end of the third intermediate container 5, installing a gas outlet valve 10 at the gas outlet end of the fourth intermediate container 6, opening the first plunger pump 1, the second plunger pump 2, the liquid outlet valve 9, the gas outlet valve 10 and the peristaltic pump 11, and setting the displacement speed v of the first plunger pump 1 to be v₁Driving a third intermediate container 5, v containing a polymer foaming liquid₁Is given in ml/min, the displacement speed of the second plunger pump 2 is set to v₂Driving the fourth intermediate container 6, v filled with carbon dioxide gas₂Is ml/min, the polymer foaming liquid and the carbon dioxide gas alternately enter a peristaltic pump 11 to realize the pre-mixing of the polymer foaming liquid and the carbon dioxide gas, wherein v₁<v₂；

In this embodiment, the displacement speed v of the first plunger pump 1 in step 701₁And displacement speed v of the second plunger pump 2₂Satisfies the following conditions:

in actual use, the displacement speed v of the second plunger pump 2₂Greater than the displacement speed v of the first plunger pump 1₁The aim of the method is to meet the condition that the gas-liquid ratio of carbon dioxide gas to polymer foaming liquid is larger than 1, when the gas-liquid ratio of carbon dioxide gas to polymer foaming liquid is larger than 1, the plugging capability of polymer foam is stronger, the stability of polymer foam is also stronger, and the displacement speed v of the first plunger pump 1 is preferably selected in the embodiment₁And displacement speed v of the second plunger pump 2₂Satisfies the following conditions:

avoiding the problem of liquid only entering the foam generator 12 and gas being difficult to enter.

Step 702, alternately feeding the polymer foaming liquid and the carbon dioxide gas which enter the peristaltic pump 11 into the foam generator 12 in sequence to form polymer reinforced carbon dioxide foam;

eighthly, reinforcing carbon dioxide foam flooding by using the polymer and obtaining the recovery ratio of the polymer foam flooding: opening the fluid inflow valve 13 and the fluid outflow valve 15 to allow the polymer-reinforced carbon dioxide foam in the foam generator 12 to enter the sand pack pipe 14, thereby performing polymer-reinforced carbon dioxide foam flooding; when the injection amount of the polymer reinforced carbon dioxide foam reaches a set value, closing the first plunger pump 1, the second plunger pump 2, the liquid outlet valve 9, the gas outlet valve 10 and the peristaltic pump 11, stopping the polymer reinforced carbon dioxide foam driving, and performing foam driving according to a formula

Calculating recovery factor gamma of polymer foam flooding₂，G₃After polymer is injected into the sand filling pipe 14 to strengthen carbon dioxide foam, the thickened oil and water produced at the output end of the sand filling pipe enter a measuring cylinder 16, and the unit of oil production in the measuring cylinder 16 is ml;

in this embodiment, the set value of the injection amount of the polymer-reinforced carbon dioxide foam in the step eight is 0.1 to 5 times of the pore volume of the sand-packed pipe core simulation mechanism.

Step nine, firstObtaining the first subsequent water drive recovery ratio by the second subsequent water drive: opening the first plunger pump 1, the water outlet valve 7, the fluid inflow valve 13 and the fluid outflow valve 15, driving the first intermediate container 3 filled with water by using the first plunger pump 1 to perform first subsequent water drive on the sand filling pipe 14, closing the first plunger pump 1, the water outlet valve 7, the fluid inflow valve 13 and the fluid outflow valve 15 when the water content of the output end of the sand filling pipe 14 reaches 99%, stopping the first subsequent water drive, and performing water drive according to a formula

Calculating the first subsequent water drive recovery factor gamma₃Wherein G is₄The unit is ml of oil output in the measuring cylinder 16 in the first subsequent water flooding;

It should be noted that, in the sixth step to the ninth step, the heavy oil reservoir is recovered by sequentially utilizing the water drive, the polymer foam drive and the first subsequent water drive, and the thin-layer heavy oil reservoir is recovered in a cold oil recovery mode, so that the problems that the recovery of the heavy oil reservoir is greatly limited due to the fact that the thin-layer heavy oil reservoir is low in primary recovery rate and secondary recovery rate and the thermal loss of the thermal oil recovery mode in the thin-layer heavy oil reservoir is serious, economic and efficient development of the oil reservoir can not be realized, and the oil reservoir is reliable and stable are avoided.

When the polymer-reinforced carbon dioxide foam flooding system is used, quartz sand with 40-140 meshes is used for filling the sand filling pipe 14 to form a sand filling pipe core simulation mechanism, the absolute permeability of the sand filling pipe core simulation mechanism is 4.75 darcy, when the injection amount of the polymer-reinforced carbon dioxide foam is one time of the pore volume of the sand filling pipe core simulation mechanism in the polymer-reinforced carbon dioxide foam flooding process, the recovery rate values of water flooding, polymer-reinforced carbon dioxide foam flooding and first subsequent water flooding are respectively 28.0%, 7.0% and 3.3%, the total recovery rate of thickened oil is 38.3%, and the recovery rate is improved by 10.3% compared with that of water flooding;

when the injection amount of the polymer-enhanced carbon dioxide foam is twice of the pore volume of the sand-packed pipe core simulation mechanism, the recovery rate values of the water drive, the polymer-enhanced carbon dioxide foam drive and the first subsequent water drive are respectively 28.2%, 12.6% and 5.2%, and the total recovery rate of the thickened oil is 46% at the moment, which is 17.8% higher than the recovery rate of the water drive; therefore, the recovery of the heavy oil reservoir is effectively improved by using the cold oil recovery modes of water flooding, polymer foam flooding and first subsequent water flooding, and an important theoretical basis is provided for scientifically utilizing polymer reinforced carbon dioxide foam to improve the recovery of the thin-layer heavy oil reservoir and the specific field construction of the thin-layer heavy oil reservoir.

Example 2

As shown in fig. 3, the apparatus for improving the recovery ratio of a thin heavy oil reservoir based on a combination of a polymer foam flooding and a gel foam flooding of the present invention, unlike embodiment 1, further comprises a third pipeline 28 communicated with the foam generator 12 and a fifth intermediate container 23 installed on the third pipeline 28 for containing a gel foaming liquid, wherein a third plunger pump 22 is provided at an inlet end of the fifth intermediate container 23, an outlet end of the fifth intermediate container 23 is communicated with an input end of the foam generator 12, the glue outlet valve 24 is installed at the liquid outlet end of the fifth intermediate container 23, one end of a fourth pipeline 29 is communicated with a pipeline section, located at the input end of the peristaltic pump 11, of the second pipeline 21, the other end of the fourth pipeline 29 is communicated with a pipeline section, located at the output end of the peristaltic pump 11, of the second pipeline 21, a back pressure valve 26 and a first safety valve 25 are installed on the fourth pipeline 29, and a second safety valve 27 is installed on a pipeline section, located between the fourth pipelines 29, of the second pipeline 21.

It should be noted that, because the viscosity of the gel foaming liquid is much greater than that of the polymer, the peristaltic pump cannot effectively pre-mix the gel foaming liquid and the carbon dioxide gas, and cannot make the carbon dioxide gas and the gel foaming liquid enter the foam generator alternately, so the gel foam driver applies the back pressure valve 26, and utilizes the characteristic that the back pressure valve 26 can be opened only when the pressure is greater than the set pressure, so that the gel foaming liquid and the carbon dioxide gas enter the foam generator 12 alternately in a form of "one-section liquid and one-section gas", and further generate stable gel foam.

In practical use, the jelly foaming liquid comprises a jelly liquid, a surfactant and water, and preferably, the jelly liquid adopts cross-linked polymer type jelly such as organic chromium jelly, organic zirconium jelly and the like.

The method for improving the thin layer heavy oil reservoir recovery ratio based on the combination of the polymer foam flooding and the gel foam flooding as shown in fig. 4 comprises the steps one to nine of the method for improving the thin layer heavy oil reservoir recovery ratio based on the polymer foam flooding, and the method further comprises the following steps:

step ten, formation of jelly foam: the second plunger pump 2, the third plunger pump 22, the gas outlet valve 10, the glue outlet valve 24, the first safety valve 25 and the back pressure valve 26 are opened, and the displacement speed of the third plunger pump 22 is set to be v₃Driving a fifth intermediate container 23, v filled with a gel foaming liquid₃In units of ml/min, wherein v₃<v₂(ii) a The pressure setting value of the back-pressure valve 26 is 2-3 times of the pressure at the outlet end of the sand-filling pipe 14, when the gas pressure in the fourth intermediate container 6 is greater than the pressure value set by the back-pressure valve, the carbon dioxide gas flows out of the back-pressure valve, so that the gas pressure at the outlet end of the back-pressure valve 26 is greater than the pressure of the jelly foaming liquid at the outlet end of the fifth intermediate container 23, and the carbon dioxide gas enters the foam generator 12; as the gas flows out of the fourth intermediate container 6, the pressure in the fourth intermediate container 6 is continuously reduced, when the gas pressure value of the fourth intermediate container 6 is lower than the pressure set by the back pressure valve 26, the back pressure valve 26 is closed, and then the gel foaming liquid enters the foam generator 12; when the gas pressure in the fourth intermediate container 7 gradually recovers and rises and the pressure is greater than the pressure value set by the back pressure valve, the process that the carbon dioxide gas enters the foam generator 12 is repeated, so that the gel foaming liquid and the carbon dioxide gas alternately enter the foam generator 12 to form gel foam;

eleven, gel foam flooding and obtaining the recovery ratio of the gel foam flooding: opening the fluid inflow valve 13 and the fluid outflow valve 15 to make the jelly foam in the foam generator 12 enter the sand filling pipe 14, thereby performing jelly foam driving; when the injection amount of the jelly foam reaches a set value, the second plunger pump 2, the third plunger pump 22, the gas outlet valve 10, the gel outlet valve 24, the first safety valve 25, the back pressure valve 26, the fluid inlet valve 13 and the fluid are closedThe outflow valve 15 stops the gel foam driving, the sand filling pipe 14 is placed for 4 days to enable the gel liquid in the gel foaming liquid to be frozen to form gel, the gel foam driving is stopped, and the formula is adopted

Calculating recovery factor gamma of foam flooding₄，G₅The unit is ml of oil production in the measuring cylinder 16 in the gel foam flooding;

step twelve, acquiring the recovery ratio of the second follow-up water flooding by the second follow-up water flooding: opening the first plunger pump 1, the water outlet valve 7, the fluid inflow valve 13 and the fluid outflow valve 15, driving the first intermediate container 3 filled with water by using the first plunger pump 1 to perform secondary subsequent water drive on the sand filling pipe 14, closing the first plunger pump 1, the water outlet valve 7, the fluid inflow valve 13 and the fluid outflow valve 15 when the water content of the output end of the sand filling pipe 14 reaches 99%, stopping the secondary subsequent water drive, and performing the secondary subsequent water drive according to a formula

Calculating the recovery ratio gamma of the second subsequent water drive₅Wherein G is₆The oil yield in the measuring cylinder 16 in the second subsequent water flooding is expressed in ml;

In this embodiment, the displacement speed v of the second plunger pump 2 in step ten₂And the displacement speed v of the third plunger pump 22₃Satisfies the following conditions:

It should be noted that, in the method for improving the recovery efficiency of the thin-layer heavy oil reservoir based on the combination of the polymer foam flooding and the gel foam flooding, the water flooding, the polymer foam flooding, the first subsequent water flooding, the gel foam flooding and the second subsequent water flooding are sequentially utilized to recover the heavy oil reservoir in steps six to twelve, and the thin-layer heavy oil reservoir is recovered in a cold oil recovery mode, so that the problems that the thin-layer heavy oil reservoir is low in primary oil recovery efficiency and water flooding recovery efficiency, and the thermal oil recovery mode is serious in thermal loss in the thin-layer heavy oil reservoir, so that the heavy oil reservoir is greatly limited in exploitation, and the economic and efficient development of the oil reservoir can not be realized.

When the system is used, the injection amount of the polymer foam flooding and the injection amount of the gel foam flooding are both 1 time of pore volume, when the concentration of the polymer used in the gel foaming liquid is 3%, the recovery rate values of the water flooding, the polymer foam flooding, the first subsequent water flooding, the gel foam flooding and the second subsequent water flooding are respectively 28.0%, 7.0%, 3.3%, 4.7% and 6.4%, and at the moment, the total recovery rate of the thickened oil is 49.4%, which is 21.4% higher than the recovery rate of the water flooding;

when the concentration of the polymer used in the gel foaming liquid is 5%, the recovery rate values of the water drive, the polymer foam drive, the first subsequent water drive, the gel foam drive and the second subsequent water drive are respectively 28.2%, 12.6%, 5.2%, 7.6% and 10.1%, and the total recovery rate of the thickened oil is 63.7%, which is increased by 35.5% compared with the recovery rate of the water drive; therefore, the heavy oil reservoir is recovered by cold oil recovery modes of water drive, polymer foam drive, first follow-up water drive, gel foam drive and second follow-up water drive, the recovery ratio is effectively improved, and an important theoretical basis is provided for scientifically utilizing the gel foam to improve the recovery ratio of the thin-layer heavy oil reservoir and specific field construction of the thin-layer heavy oil reservoir.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. The device for improving the thin-layer heavy oil reservoir recovery ratio based on polymer foam flooding is characterized in that: the device comprises a polymer foam generating mechanism for generating polymer foam, a sand filling pipe core simulating mechanism for simulating a thin-layer heavy oil reservoir core, a fluid injection mechanism for injecting saturated fluid into the polymer foam generating mechanism and the sand filling pipe core simulating mechanism, a produced fluid collecting mechanism for collecting produced fluid in the sand filling pipe core simulating mechanism, and a temperature control mechanism for controlling the temperature of the polymer foam generating mechanism and the temperature of the sand filling pipe core simulating mechanism; the polymer foam generating mechanism comprises a peristaltic pump (11) and a foam generator (12) communicated with the output end of the peristaltic pump (11), the sand filling pipe core simulation mechanism comprises a sand filling pipe (14) communicated with the output end of the foam generator (12) and quartz sand filled in the sand filling pipe (14), a fluid inflow valve (13) is arranged at the input end of the sand filling pipe (14), the fluid injection mechanism comprises a first pipeline (20) communicated with the sand filling pipe (14), a second pipeline (21) communicated with the peristaltic pump (11), a first middle container (3) and a second middle container (4) which are arranged on the first pipeline (20) in a parallel mode and used for containing thick oil, a third middle container (5) and a fourth middle container (6) which are arranged on the second pipeline (21) in a parallel mode and used for containing polymer foaming liquid and carbon dioxide gas, and the first middle container (3), Liquid inlet ends of the second intermediate container (4) and the third intermediate container (5) are provided with a first plunger pump (1), a liquid inlet end of the fourth intermediate container (6) is provided with a second plunger pump (2), liquid outlet ends of the first intermediate container (3) and the second intermediate container (4) are communicated with an input end of a sand filling pipe (14), and a liquid outlet end of the third intermediate container (5) and a gas outlet end of the fourth intermediate container (6) are communicated with an input end of a peristaltic pump (11).

2. The apparatus for enhanced thin heavy oil reservoir recovery based on polymer foam flooding of claim 1, wherein: the produced fluid collecting mechanism comprises a measuring cylinder (16), a fluid outlet pipe for communicating the measuring cylinder (16) with the output end of the sand filling pipe (14), and a fluid outlet valve (15) arranged on the fluid outlet pipe.

3. The apparatus for enhanced thin heavy oil reservoir recovery based on polymer foam flooding of claim 2, wherein: the temperature control mechanism comprises a constant temperature box (17), a peristaltic pump (11), a foam generator (12), a sand filling pipe (14) and a fluid outflow pipe which are all arranged in the constant temperature box (17).

4. The apparatus for enhanced thin heavy oil reservoir recovery based on polymer foam flooding of claim 1, wherein: and the input end of the sand filling pipe (14) is provided with a pressure sensor (18), and the pressure sensor (18) is connected with a computer (19).

5. The apparatus for enhanced thin heavy oil reservoir recovery based on polymer foam flooding of claim 1, wherein: the liquid outlet end of the first intermediate container (3) is provided with a water outlet valve (7), the liquid outlet end of the second intermediate container (4) is provided with an oil outlet valve (8), the liquid outlet end of the third intermediate container (5) is provided with a liquid outlet valve (9), and the gas outlet end of the fourth intermediate container (6) is provided with a gas outlet valve (10).

6. The device for improving the thin-layer heavy oil reservoir recovery ratio based on the combination of polymer foam flooding and gel foam flooding is characterized in that: the device for improving the thin layer heavy oil reservoir recovery ratio based on polymer foam flooding according to any one of claims 1 to 5, a third pipeline (28) communicated with the foam generator (12) and a fifth intermediate container (23) arranged on the third pipeline (28) and used for containing gel foaming liquid, wherein a third plunger pump (22) is arranged at the liquid inlet end of the fifth intermediate container (23), the liquid outlet end of the fifth intermediate container (23) is communicated with the input end of the foam generator (12), a gel outlet valve (24) is arranged at the liquid outlet end of the fifth intermediate container (23), one end of a fourth pipeline (29) is communicated with a pipeline section on the second pipeline (21) and positioned at the input end of the peristaltic pump (11), the other end of the fourth pipeline (29) is communicated with a pipeline section on the second pipeline (21) and positioned at the output end of the peristaltic pump (11), a back pressure valve (26) and a first safety valve (25) are arranged on the fourth pipeline (29), a second relief valve (27) is mounted on a section of the second line (21) between the fourth lines (29).

7. A method for enhanced thin heavy oil reservoir recovery based on polymer foam flooding using the apparatus of claim 6, wherein: the method comprises the following steps:

step one, forming a sand filling pipe core simulation mechanism: filling dry quartz sand into a sand filling pipe (14) by using a vibration filling method to form a sand filling pipe core simulation mechanism, wherein the mesh number of the quartz sand is 20-170 meshes;

step two, air tightness detection: a sealing fluid inflow valve (13) and a fluid outflow valve (15), wherein high-pressure nitrogen is injected into the sand filling pipe (14) through the fluid inflow valve (13) to detect the air tightness of the sand filling pipe (14);

step 301, connecting a vacuum pump with a fluid inflow valve (13), and vacuumizing a sand filling pipe (14) by using the vacuum pump;

step 302, closing the fluid inflow valve (13), opening the fluid outflow valve (15), and saturating the distilled water in the sand filling pipe (14) by the measuring cylinder (16) filled with the distilled water;

303, according to the formula

Calculating the porosity phi of the sand-filled pipe core simulation mechanism, wherein V₁The saturated distilled water output by the measuring cylinder (16) has the unit of ml and V₂The volume of the sand filling pipe (14) is ml;

step 401, installing a pressure sensor (18) connected with a computer (19) on an input end of a sand filling pipe (14), installing a water outlet valve (7) on a liquid outlet end of a first intermediate container (3), opening the water outlet valve (7), a fluid inflow valve (13) and a fluid outflow valve (15), setting n different displacement rates of a first plunger pump (1) at room temperature, displacing a sand filling pipe core simulation mechanism by water in the first intermediate container (3) through a first pipeline (20) n times by using the first plunger pump (1), and recording pressure values acquired by the pressure sensor (18) n times, wherein n is a positive integer not less than 3;

step 402, according to the formula

Calculating the absolute permeability k of the sand-filled pipe core simulation mechanism, wherein the unit is mum²Wherein k is_iSimulating the absolute permeability of the sand-filled pipe core mechanism at the ith displacement rate for the first plunger pump (1) in step 401

Unit is mum²，Q_iIs the ith displacement rate of the first plunger pump (1) in step 401, in cm³Mu is viscosity of water in mPa.s, L is length of the sand-packed pipe (14) in cm, A is cross-sectional area of the sand-packed pipe (14) in cm²，ΔP_i＝P_i-P₀The pressure difference between the two ends of the sand filling pipe (14) of the first plunger pump (1) at the ith displacement rate in the step 401 is 10^-1MPa，P_iThe pressure value collected by the pressure sensor (18) of the first plunger pump (1) at the ith displacement rate is 10^-1MPa，P₀Is at atmospheric pressure and has a unit of 10^-1MPa；

Step five, presetting the initial oil saturation of the sand filling pipe core simulation mechanism after saturated oil: installing an oil outlet valve (8) at the liquid outlet end of the second intermediate container (4), opening the oil outlet valve (8), closing a water outlet valve (7), adjusting the temperature of a constant temperature box (17) to 60 ℃, driving the second intermediate container (4) filled with thick oil by using a first plunger pump (1) at the temperature of 60 ℃, and saturating the thick oil in the sand-filled pipe core simulation mechanism until the initial crude oil saturation of the sand-filled pipe core simulation mechanism reaches a preset value; closing the fluid inflow valve (13) and the fluid outflow valve (15) and aging the sand filling pipe core simulation mechanism at a constant temperature for 3 days;

step six, simulating water drive to obtain water drive recovery ratio: adjusting the temperature of the constant temperature box (17) to be 21 ℃, closing the oil outlet valve (8), opening the water outlet valve (7), the fluid inflow valve (13) and the fluid outflow valve (15), injecting water in the first intermediate container (3) into the sand filling pipe (14) by using the first plunger pump (1) to simulate the water drive process, and when the water content of the output end of the sand filling pipe (14) reaches the water contentWhen 99%, the first plunger pump (1), the water outlet valve (7), the fluid inflow valve (13) and the fluid outflow valve (15) are closed according to the formula

Calculating water drive recovery factor gamma₁Wherein G is₂Is the amount of oil produced in the measuring cylinder (16) in ml, G₁The unit of the thick oil output by the second intermediate container (4) in the fifth step is ml;

step 701, installing a liquid outlet valve (9) at the liquid outlet end of a third intermediate container (5), installing a gas outlet valve (10) at the gas outlet end of a fourth intermediate container (6), opening a first plunger pump (1), a second plunger pump (2), the liquid outlet valve (9), the gas outlet valve (10) and a peristaltic pump (11), and setting the displacement speed of the first plunger pump (1) to be v₁Driving a third intermediate container (5) containing a polymer foaming liquid, v₁Is set to the displacement speed v of the second plunger pump (2)₂Driving a fourth intermediate container (6) containing carbon dioxide gas, v₂Is ml/min, the polymer foaming liquid and the carbon dioxide gas are alternately led into a peristaltic pump (11) to realize the premixing of the polymer foaming liquid and the carbon dioxide gas, wherein v₁<v₂；

Step 702, alternately feeding the polymer foaming liquid and the carbon dioxide gas which enter the peristaltic pump (11) into a foam generator (12) in sequence to form polymer reinforced carbon dioxide foam;

eighthly, reinforcing carbon dioxide foam flooding by using the polymer and obtaining the recovery ratio of the polymer foam flooding: opening the fluid inflow valve (13) and the fluid outflow valve (15) to enable the polymer reinforced carbon dioxide foam in the foam generator (12) to enter the sand filling pipe (14), so that polymer reinforced carbon dioxide foam driving is performed; when the injection amount of the polymer reinforced carbon dioxide foam reaches a set value, closing the first plunger pump (1), the second plunger pump (2), the liquid outlet valve (9), the gas outlet valve (10) and the peristaltic pump (11), stopping the polymer reinforced carbon dioxide foam driving, and performing foam driving according to a formula

Calculating recovery factor gamma of polymer foam flooding₂，G₃Injecting polymer into the sand filling pipe (14) to reinforce carbon dioxide foam, and then enabling thick oil and water produced at the output end of the sand filling pipe to enter a measuring cylinder (16), wherein the unit of oil production in the measuring cylinder (16) is ml;

ninthly, acquiring the recovery ratio of the first subsequent water flooding by the first subsequent water flooding: opening a first plunger pump (1), a water outlet valve (7), a fluid inflow valve (13) and a fluid outflow valve (15), driving a first middle container (3) filled with water by using the first plunger pump (1) to perform first subsequent water drive on a sand filling pipe (14), closing the first plunger pump (1), the water outlet valve (7), the fluid inflow valve (13) and the fluid outflow valve (15) when the water content of the output end of the sand filling pipe (14) reaches 99%, stopping the first subsequent water drive, and performing the first subsequent water drive according to a formula

Calculating the first subsequent water drive recovery factor gamma₃Wherein G is₄The unit of the oil output in the measuring cylinder (16) in the first subsequent water flooding is ml;

8. The method of claim 7, wherein: displacement speed v of the first plunger pump (1) in step 701₁And the displacement speed v of the second plunger pump (2)₂Satisfies the following conditions:

9. A method for improving the recovery efficiency of a thin layer heavy oil reservoir based on a combination of a polymer foam flooding and a gel foam flooding, which comprises the steps one to nine as claimed in claim 7, wherein: the method further comprises the following steps:

step ten, formation of jelly foam: opening the second plunger pump (2), the third plunger pump (22), the gas outlet valve (10), the glue outlet valve (24), the first safety valve (25) and the back pressure valve (26), and setting the displacement speed of the third plunger pump (22) to be v₃V driving a fifth intermediate container (23) containing a gel foaming liquid₃In units of ml/min, wherein v₃<v₂(ii) a The pressure set value of the back pressure valve (26) is 2-3 times of the pressure of the outlet end of the sand filling pipe (14), when the gas pressure in the fourth intermediate container (6) is larger than the pressure value set by the back pressure valve, the carbon dioxide gas flows out of the back pressure valve, so that the gas pressure at the outlet end of the back pressure valve (26) is larger than the pressure of the jelly foaming liquid at the outlet end of the fifth intermediate container (23), and the carbon dioxide gas enters the foam generator (12); the pressure in the fourth intermediate container (6) is continuously reduced along with the outflow of the gas from the fourth intermediate container (6), when the gas pressure value of the fourth intermediate container (6) is lower than the pressure set by the back pressure valve (26), the back pressure valve (26) is closed, and then the jelly foaming liquid enters the foam generator (12); when the gas pressure in the fourth intermediate container (6) gradually recovers and rises and the pressure is larger than the pressure value set by the back pressure valve, the process that carbon dioxide gas enters the foam generator (12) is repeated, so that the jelly foaming liquid and the carbon dioxide gas alternately enter the foam generator (12) to form jelly foam;

eleven, gel foam flooding and obtaining the recovery ratio of the gel foam flooding: opening a fluid inflow valve (13) and a fluid outflow valve (15) to enable the jelly foam in the foam generator (12) to enter a sand filling pipe (14), so that jelly foam driving is performed; when the injection amount of the jelly foam reaches a set numerical value, closing the second plunger pump (2), the third plunger pump (22), the air outlet valve (10), the jelly outlet valve (24), the first safety valve (25), the back pressure valve (26), the fluid inflow valve (13) and the fluid outflow valve (15), stopping driving the jelly foam, placing the sand filling pipe (14) for 4 days to enable the jelly liquid in the jelly foaming liquid to be frozen to form jelly, and forming jelly according to a formula

Calculating recovery factor gamma of foam flooding₄，G₅The unit is ml of oil production in a measuring cylinder (16) in the gel foam flooding;

step twelve, acquiring the recovery ratio of the second follow-up water flooding by the second follow-up water flooding: opening a first plunger pump (1), a water outlet valve (7), a fluid inflow valve (13) and a fluid outflow valve (15), driving a first middle container (3) filled with water by using the first plunger pump (1) to perform secondary subsequent water drive on a sand filling pipe (14), closing the first plunger pump (1), the water outlet valve (7), the fluid inflow valve (13) and the fluid outflow valve (15) when the water content of the output end of the sand filling pipe (14) reaches 99%, stopping the secondary subsequent water drive, and performing the secondary subsequent water drive according to a formula

Calculating the recovery ratio gamma of the second subsequent water drive₅Wherein G is₆The unit of the oil output in the measuring cylinder (16) in the second subsequent water flooding is ml;

10. The method of claim 9, wherein: the displacement speed v of the second plunger pump (2) in step ten₂And the displacement speed v of the third plunger pump (22)₃Satisfies the following conditions: