A method for improving recovery of heavy oil reservoirs by foam-assisted steam flooding and application thereof

Abstract

The application provides a method for improving the recovery ratio of a heavy oil reservoir by using a foaming agent assisted steam drive and application, and relates to the technical field of oilfield development. The method comprises the following steps: injecting a steam pre-slug, injecting a nitrogen slug, injecting a foaming agent slug, and injecting a nitrogen mixed steam main slug. In the nitrogen mixed steam main slug, the injection speed ratio of nitrogen and steam is always kept at 1:(2-3), and the steam injection process maintains a slow injection in the early stage, a fast injection in the middle stage, and a slow injection in the late stage. The foaming agent comprises 8-15% of alpha-olefin sulfonate, 1-2% of sodium methyl cocoyl taurate, 12-18% of fatty alcohol polyoxyethylene ether, and 2-3% of lauryl hydroxyl sulfobetaine, and the rest is water. The method can greatly improve the sweep efficiency and displacement efficiency of the heavy oil steam drive, and improve the development effect of the heavy oil steam drive thermal recovery.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oilfield development, and particularly relates to a method for improving the recovery ratio of a heavy oil reservoir by using a foaming agent assisted steam flooding and application. BACKGROUND

[0002] Steam flooding is a thermal recovery technique for further improving the recovery ratio after steam stimulation in a heavy oil reservoir. Steam flooding technology can make high-pressure and low-pressure steam pulses act on the formation periodically, so that the steam enters low-permeability layers, low-permeability sections and low-permeability zones from high-permeability layers, high-permeability sections and high-permeability zones, thereby expanding the swept volume of the steam. Since steam is a hot fluid, it has small density and strong flowability, and the steam channeling phenomenon is serious in the formation pores, and the loss proportion is large, which limits the application of steam flooding. At present, the methods for improving the recovery efficiency of heavy oil steam flooding mainly include nitrogen injection, air injection, mixed gas injection and chemical agent injection. Although the gas injection method is relatively effective, steam channeling is serious between injection and production wells, and there is a safety hazard of oil and gas mixing explosion, while the chemical agent assisted steam flooding can avoid such problems.

[0003] The foaming agent, also known as a foaming agent, can reduce the surface tension of the liquid, produce a large amount of uniform and stable foam, and has a long history of application in oilfields. With the progress of surfactant technology, the types and properties of foaming agents will be more able to meet the needs of the actual field, and will play a more important role in the petroleum industry. However, since the steam flooding process can form a connection between the temperature fields of the wells, the temperature range of the steam swept zone is 100-300 DEG C, and therefore the foaming agent needs to be able to withstand high temperatures while maintaining good foaming properties. In addition, the conventional foaming agent is easily adsorbed by the formation after entering the formation, thereby affecting the foaming agent to play a role, and thereby affecting the recovery effect of steam flooding. Therefore, the development of a foaming agent that can withstand 100-300 DEG C high temperature, resist formation adsorption and have excellent foaming properties has great prospects in improving the recovery effect of steam flooding.

[0004] Patent CN107903886A discloses a high-temperature-resistant foaming agent for assisting steam flooding, which comprises 5-10 parts of a foaming agent, 10-30 parts of a foam stabilizer and 60-85 parts of water. The foaming agent is an imino-containing polyether sulfonate, which is the product of the reaction of N-alkyl polyethylene and butene ether polymer sulfonate. The foaming volume of the foaming agent at 300 DEG C is up to 468 mL, and the half-life is 91 min. Although the foaming agent can withstand 300 DEG C high temperature, the foaming performance needs to be improved. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a method for improving the recovery ratio of a heavy oil reservoir by using a foaming agent assisted steam flooding and application. The present application increases the steam swept volume, improves the displacement efficiency and increases the recovery of crude oil by using a foaming agent assisted steam flooding.

[0006] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0007] A method for improving the recovery ratio of a heavy oil reservoir by using a foaming agent assisted steam drive, comprising the following steps:

[0008] S1, injecting a steam pre-slug;

[0009] S2, injecting a nitrogen slug;

[0010] S3, injecting a foaming agent slug;

[0011] S4, injecting a nitrogen mixed steam main slug until the water content of the produced liquid is higher than 98%, and stopping production;

[0012] In the nitrogen mixed steam main slug, the injection speed ratio of nitrogen to steam is 1: (2-3), and the steam injection speed is divided into three stages:

[0013] Stage one: the steam injection speed is 3000-4000 m / d, and the injection time is 1 / 3-1 / 4 of the total injection time of the nitrogen mixed steam slug; 3

[0014] Stage two: the steam injection speed is 7000-8000 m / d, and the injection time is 1 / 2-1 / 3 of the total injection time of the nitrogen mixed steam slug; 3

[0015] Stage three: the steam injection speed is 4000-5000 m / d, and the injection time is 1 / 3-1 / 4 of the total injection time of the nitrogen mixed steam slug; 3

[0016] The foaming agent comprises, by mass percentage, 8-15% of alpha-olefin sulfonate, 1-2% of sodium methyl cocoyl taurate, 12-18% of fatty alcohol polyoxyethylene ether, and 2-3% of lauryl hydroxyl sulfobetaine, with the balance being water.

[0017] Preferably, the foaming agent comprises, by mass percentage, 12% of alpha-olefin sulfonate, 1% of sodium methyl cocoyl taurate, 15% of fatty alcohol polyoxyethylene ether, and 2.6% of lauryl hydroxyl sulfobetaine, with the balance being water.

[0018] Preferably, in the nitrogen mixed steam main slug, the steam injection speed is divided into three stages:

[0019] Stage one: the steam injection speed is 4000 m / d, and the injection time is 1 / 4 of the total injection time of the nitrogen mixed steam slug; 3

[0020] Stage two: the steam injection speed is 7600 m / d, and the injection time is 1 / 2 of the total injection time of the nitrogen mixed steam slug; 3 ​​​​ / d, the injection time is 1 / 2 of the total time of the steam injection mixed with the nitrogen gas slug;

[0021] Three stages: the steam injection rate is 4500m 3 / d, the injection time is 1 / 4 of the total time of the steam injection mixed with the nitrogen gas slug.

[0022] Further, in the steam injection pre-slug process, the steam injection rate is 3-5mL / min, the temperature is 250-300℃, the steam injection dryness is ≥95%, and the injection amount is 0.5-0.7PV.

[0023] Further, in the nitrogen gas injection slug process, the nitrogen gas injection rate is 3000-5000m 3 / d, when the production oil-gas ratio is >800m 3 / t, the next slug is performed.

[0024] Further, in the foam agent injection slug process, the foam agent injection amount is 0.1-0.15PV.

[0025] Further, the fatty alcohol polyoxyethylene ether in the foam agent satisfies that the alkyl carbon chain length is 12-16 and the oxyethylene polymerization degree is 9-14.

[0026] In a further aspect, the foam agent further contains 0-1% of modified nano-SiO2, preferably 0.5-1%, which is obtained by modifying nano-SiO2 with hexamethyldisilazane (HMDS) and polyether-modified heptamethyltrisiloxane. The polyether-modified heptamethyltrisiloxane can be purchased on the market or prepared by a method known to those skilled in the art, such as obtained by a silicon-hydrogen addition reaction of heptamethyltrisiloxane with an allyl polyether, without special limitation.

[0027] The preparation method of the modified nano-SiO2 described above includes the following steps:

[0028] (1) Disperse nano-SiO2 in an organic solvent, add HMDS, and react at 100-120℃ for 1-3h to obtain HMDS-modified nano-SiO2;

[0029] (2) Redisperse the HMDS-modified nano-SiO2 in an organic solvent, add polyether-modified heptamethyltrisiloxane, and react at 80-100℃ for 1-2h. After the reaction is complete, wash with anhydrous ethanol and dry to obtain the modified nano-silica.

[0030] Optionally, in step (1), in the modified nano-SiO2, the mass ratio of HMDS to nano-SiO2 is (10-18):100.

[0031] Optionally, in step (2), the mass ratio of polyether modified heptamethyltrisiloxane to nano-SiO2 in the modified nano-SiO2 is (5-8):100.

[0032] Optionally, the organic solvent is acetone, toluene, xylene, dichloromethane, etc., as long as it can be dissolved, and is not particularly limited; the amount of the organic solvent is generally more than 2 times the amount of the material.

[0033] According to another aspect of the present application, the application of the above-mentioned method for improving the recovery of heavy oil reservoirs by foam-assisted steam flooding in the development of heavy oil reservoirs is provided, and the application includes the development of heavy oil reservoirs with a reservoir burial depth of >1000m, a reservoir thickness of >5m, an oil saturation of >75%, a reservoir porosity of 30-40%, a permeability of <1000mD, and a crude oil viscosity of >10000mPa·s.

[0034] Compared with the prior art, the present application has the following beneficial effects:

[0035] 1. The steam flooding development method provided by the present application injects nitrogen and a foaming agent before injecting a nitrogen mixed steam main slug, and the foaming agent blocks high permeability layers or large pores after entering the formation, effectively inhibiting the entry of steam into high permeability zones and diverting to low permeability zones and other un-displaced zones, increasing the displacement volume, improving the steam sweep area, and effectively improving the recovery.

[0036] 2. The steam flooding development method provided by the present application uses a combination of alpha-olefin sulfonate, sodium methyl cocoyl taurate, fatty alcohol polyoxyethylene ether, and lauryl hydroxyl sultaine as the foaming agent, which has strong foaming capacity, good foam stability, maintains high foaming performance after 300℃ high temperature treatment, has good blocking effect, and good resistance to formation adsorption, can be used for steam flooding development, and improves the recovery.

[0037] 3. The steam flooding development method provided by the present application, during the process of injecting a nitrogen mixed steam main slug, nitrogen and steam are injected into the bottom layer at a slow-fast-slow injection rate, the initial injection rate is slow, the contact time of steam with the formation rock and crude oil is longer, the heat exchange is more sufficient, more heat energy can be transferred to the reservoir, and conditions can be created for subsequent crude oil flow; the middle period fast injection can cover more reservoir volume by increasing the steam injection amount and speed, and improve the sweep efficiency; the late slow injection can let the heat slowly penetrate to the low permeability area by prolonging the contact time of steam with these areas, heat and displace the remaining oil. Using the slow-fast-slow injection rate and controlling the injection rate can improve the heat utilization efficiency and improve the recovery. DETAILED DESCRIPTION

[0038] The following non-limiting examples can provide a more complete understanding of the application to those of ordinary skill in the art, but are not intended in any way to limit the application. The following description is merely exemplary of the application and is not intended to limit the scope, applicability, or claims of the application. Various modifications and changes can be made to the application as disclosed in the specification without departing from the scope of the application as recited in the claims.

[0039] The application is further described in the following detailed examples. The various chemical reagents used in the examples of the application are obtained from commercial sources unless otherwise specified.

[0040] Example 1

[0041] A method for improving the recovery of heavy oil reservoirs by foam assisted steam flooding and its application, characterized in that it comprises the following steps:

[0042] S1, injecting a steam pre-slug, the steam injection speed is 3 mL / min, the steam temperature is 250℃, the steam injection dryness is 95%, and the injection amount is 0.5 PV;

[0043] S2, injecting a nitrogen slug, the nitrogen injection speed is 3000 m 3 / d; when the production oil-gas ratio is >800 m 3 / t, the next slug is performed;

[0044] S3, injecting a foam agent slug, the foam agent injection amount is 0.1 PV;

[0045] S4, injecting a nitrogen mixed steam main slug;

[0046] S5, soaking well, and producing;

[0047] Among them, in the injection of the nitrogen mixed steam main slug, the injection speed ratio of nitrogen and steam is always kept at 1:2, and the steam injection speed is divided into three stages:

[0048] Stage one: the steam injection speed is 4000 m 3 / d, and the injection time is 1 / 4 of the total time of the nitrogen mixed steam slug injection;

[0049] Stage two: the steam injection speed is 8000 m 3 / d, and the injection time is 1 / 2 of the total time of the nitrogen mixed steam slug injection;

[0050] Stage three: the steam injection speed is 5000 m 3 / d, and the injection time is 1 / 4 of the total time of the nitrogen mixed steam slug injection;

[0051] The foam agent comprises, by mass percentage, alpha-olefin sulfonate 8%, sodium methyl cocoyl taurate 2%, fatty alcohol polyoxyethylene ether (alkyl carbon chain length 12, oxyethylene polymerization degree 9) 18%, and lauryl hydroxyl sulfobetaine 3%, with the balance being water.

[0052] Example 2

[0053] A method for improving the recovery of a heavy oil reservoir by a foam agent assisted steam drive and application, characterized in that it comprises the following steps:

[0054] S1, injecting a steam front slug, the steam injection speed is 5 mL / min, the steam temperature is 300 DEG C, the steam injection dryness is 95%, and the injection amount is 0.7 PV;

[0055] S2, injecting a nitrogen slug, the nitrogen injection speed is 5000 m 3 / d; when the production oil vapor ratio is greater than 800 m 3 / t, the next slug is performed;

[0056] S3, injecting a foam agent slug, the foam agent injection amount is 0.15 PV;

[0057] S4, injecting a nitrogen mixed steam main slug;

[0058] S5, hatching well, and opening well production;

[0059] Among them, in the injection of the nitrogen mixed steam main slug, the injection speed ratio of nitrogen and steam is always kept at 1:3, and the steam injection speed is divided into three stages:

[0060] Stage one: the steam injection speed is 4000 m 3 / d, and the injection time is 1 / 4 of the total time of the injection of the nitrogen mixed steam slug;

[0061] Stage two: the steam injection speed is 7600 m 3 / d, and the injection time is 1 / 2 of the total time of the injection of the nitrogen mixed steam slug;

[0062] Stage three: the steam injection speed is 4500 m 3 / d, and the injection time is 1 / 4 of the total time of the injection of the nitrogen mixed steam slug;

[0063] The foam agent comprises, by mass percentage, alpha-olefin sulfonate 8%, sodium methyl cocoyl taurate 2%, fatty alcohol polyoxyethylene ether (alkyl carbon chain length 12, oxyethylene polymerization degree 9) 18%, and lauryl hydroxyl sulfobetaine 3%, with the balance being water.

[0064] Example 3

[0065] A method for improving the recovery of heavy oil reservoirs by foam assisted steam flooding and application, characterized in that it comprises the following steps:

[0066] S1, injecting a steam pre-slug, the steam injection speed is 5 mL / min, the steam temperature is 300 DEG C, the steam injection dryness is 95%, and the injection amount is 0.7 PV;

[0067] S2, injecting a nitrogen slug, the nitrogen injection speed is 5000 m 3 / d; when the production oil vapor ratio is greater than 800 m 3 / t, the next slug is carried out;

[0068] S3, injecting a foam agent slug, the foam agent injection amount is 0.15 PV;

[0069] S4, injecting a nitrogen mixed steam main slug;

[0070] S5, soaking well, opening well and producing;

[0071] Among them, in the injection of the nitrogen mixed steam slug, the injection speed ratio of nitrogen and steam is always kept at 1:3, and the steam injection speed is divided into three stages:

[0072] Stage one: the steam injection speed is 3000 m 3 / d, and the injection time is 1 / 4 of the total time of the injection of the nitrogen mixed steam slug;

[0073] Stage two: the steam injection speed is 7000 m 3 / d, and the injection time is 1 / 2 of the total time of the injection of the nitrogen mixed steam slug;

[0074] Stage three: the steam injection speed is 4000 m 3 / d, and the injection time is 1 / 4 of the total time of the injection of the nitrogen mixed steam slug;

[0075] The foam agent contains, in terms of mass percentage, 15% of alpha-olefin sulfonate, 1% of sodium methyl cocoyl taurate, 12% of fatty alcohol polyoxyethylene ether (alkyl carbon chain length 16, oxyethylene polymerization degree 14), and 2% of lauryl hydroxyl sulfobetaine, and the balance is water.

[0076] Example 4

[0077] The difference from example 2 is that the foam agent further contains 0.5% of modified nano SiO2, and the preparation method of the modified nano SiO2 comprises the following steps:

[0078] (1) disperse nano SiO2 in sufficient dichloromethane, add HMDS, react at 100 DEG C for 3 h, and take out to obtain HMDS modified nano SiO2; the mass ratio of HMDS to nano SiO2 is 10:100;

[0079] (2) The HMDS modified nano-SiO2 is re-dispersed in sufficient dichloromethane, and polyether modified heptamethyltrisiloxane is added according to a mass ratio of polyether modified heptamethyltrisiloxane to nano-SiO2 of 5:100, and the reaction is carried out at 80°C for 2h. After the reaction is completed, the product is washed with anhydrous ethanol and dried to obtain the modified nano-SiO2.

[0080] Example 5

[0081] The difference from Example 2 is that the foaming agent further contains 1% of modified nano-SiO2, and the preparation method of the modified nano-SiO2 comprises the following steps:

[0082] (1) The nano-SiO2 is dispersed in sufficient dichloromethane, and HMDS is added, and the reaction is carried out at 120°C for 1h to obtain HMDS modified nano-SiO2; the mass ratio of HMDS to nano-SiO2 is 18:100;

[0083] (2) The HMDS modified nano-SiO2 is re-dispersed in sufficient dichloromethane, and polyether modified heptamethyltrisiloxane is added according to a mass ratio of polyether modified heptamethyltrisiloxane to nano-SiO2 of 8:100, and the reaction is carried out at 100°C for 1h. After the reaction is completed, the product is washed with anhydrous ethanol and dried to obtain the modified nano-SiO2.

[0084] Example 6

[0085] The difference from Example 5 is that in the preparation process of the modified nano-SiO2, the mass ratio of HMDS to nano-SiO2 is 25:100, and the mass ratio of polyether modified heptamethyltrisiloxane to nano-SiO2 is 10:100.

[0086] Example 7

[0087] The difference from Example 5 is that the foaming agent contains 2% of modified nano-SiO2, and the preparation method of the modified nano-SiO2 is the same as that of Example 5.

[0088] Comparative Example 1

[0089] The difference from Example 2 is that the foaming agent contains, according to mass percentage: α-olefin sulfonate 5%, sodium methyl cocoyl taurate 5%, fatty alcohol polyoxyethylene ether 20%, and lauryl hydroxyl sulfobetaine 5%, and the balance is water.

[0090] Comparative Example 2

[0091] The difference from Example 2 is that the foaming agent comprises, by mass percentage, a-olefin sulfonate 18%, sodium methyl cocoyl taurate 1%, fatty alcohol polyoxyethylene ether 10%, and lauryl hydroxyl sulfobetaine 1%, with the balance being water.

[0092] Comparative Example 3

[0093] The difference from Example 2 is that, during the injection of the main nitrogen- mixed steam slug, the steam injection rate is:

[0094] Stage 1: the steam injection rate is 2000 m 3 / d, and the injection time is 1 / 4 of the total time for the injection of the nitrogen-mixed steam slug;

[0095] Stage 2: the steam injection rate is 6000 m 3 / d, and the injection time is 1 / 2 of the total time for the injection of the nitrogen-mixed steam slug;

[0096] Stage 3: the steam injection rate is 3500 m 3 / d, and the injection time is 1 / 4 of the total time for the injection of the nitrogen-mixed steam slug.

[0097] Comparative Example 4

[0098] The difference from Example 2 is that, during the injection of the main nitrogen- mixed steam slug, the steam injection includes two stages,

[0099] Stage 1: the steam injection rate is 2 t / h, and the injection time is 1 / 2 of the total time for the injection of the nitrogen-mixed steam slug;

[0100] Stage 2: the steam injection rate is 4.5 t / h, and the injection time is 1 / 2 of the total time for the injection of the nitrogen-mixed steam slug.

[0101] Comparative Example 5

[0102] The difference from Example 2 is that, during the injection of the main nitrogen- mixed steam slug, the steam injection rate is kept at 4000 m 3 / d.

[0103] Test Example 1

[0104] Performance test of foaming agent

[0105] The foaming agents in Examples 1-7 and Comparative Examples 1 and 2 are configured into solutions with a mass concentration of 0.5%, and each group is divided into three parts, one of which is used to test the foam performance in a MRM-RI type Roesler foam instrument at 50°C, one of which is used to test the foam performance at 300°C, and one of which is placed in a high-temperature high-pressure reaction kettle for aging treatment at 300°C and 10 MPa for 72 h, and then the foam performance is tested in the foam instrument.

[0106] The measured results are shown in Table 1 below, and it can be seen that the foam agent provided in the application has high foaming volume and long half-life, and has good foam performance, and can maintain high foam volume and half-life after aging treatment at 300°C, and has good high-temperature resistance.

[0107] Table 1. Foam performance

[0108]

[0109] Test Example 2

[0110] Foam agent plugging performance

[0111] The inner diameter of the sandpack model is 25 mm, the length is 300 mm, the permeability is 3.00 μm 2 and the plugging performance of the foam is evaluated, and the specific steps are as follows:

[0112] (1) First, saturate the sandpack with water and measure the water phase permeability of the core;

[0113] (2) According to the gas-liquid ratio of 1:1, nitrogen and steam are simultaneously injected into the core. When the pressure difference between the two ends of the core reaches a steady state, the pressure difference between the two ends of the core at this time is recorded as the base pressure difference;

[0114] (3) According to the same gas-liquid ratio of 1:1, nitrogen and foam agent are simultaneously injected into the core. When the pressure difference between the two ends of the core reaches a steady state, the pressure difference between the two ends of the core at this time is recorded as the working pressure difference. Finally, the resistance factor of the foam system is calculated according to the formula: Fr = working pressure difference / base pressure difference.

[0115] The results are shown in Table 2 below, and the results show that the resistance factor of the foam agent provided in the application is above 40, and the plugging performance is excellent.

[0116] Table 2. Resistance factor

[0117]

[0118] Test Example 3

[0119] The oil displacement performance test is carried out by using a sand filling pipe model with an inner diameter of 400 mm, a length of 150 mm, a permeability of 680 mD, a reservoir porosity of 36.8%, an oil saturation of 85.8%, and a crude oil viscosity of 13600 mPa·s. Specifically: (1) saturate the sand filling pipe with water, then saturate it with crude oil at 50℃, and age for 24 hours; (2) inject 300℃ steam, and stop displacement when the water cut reaches 98%, and calculate the steam flooding recovery rate; (3) carry out displacement according to the method provided in the above examples and comparative examples, and end the displacement when the water cut of the produced liquid is greater than 98%, and calculate the final recovery rate; (4) the difference between the final recovery rate and the steam flooding recovery rate is the enhanced oil recovery.

[0120] The enhanced oil recovery is measured as shown in Table 3 below, and it can be seen that, compared with the traditional steam flooding, the steam flooding development method of the present application improves the recovery rate of crude oil.

[0121] Table 3. Oil displacement effect

[0122]

[0123] The above description of the examples is for the purpose of facilitating the understanding and use of the invention by those of ordinary skill in the art. Those skilled in the art can obviously make various modifications to these examples, and apply the general principles described herein to other examples without having to go through creative labor. Therefore, the present application is not limited to the above examples, and the improvements and modifications made by those skilled in the art according to the disclosure of the present application without departing from the scope of the present application should be within the protection scope of the present application.

Claims

1. A method for enhancing heavy oil recovery in a heavy oil reservoir by foam assisted steam flooding, characterized in that, It comprises the following steps: S1, injecting steam pre-pad; S2, injecting nitrogen pad; S3, injecting foam agent pad; S4, injecting nitrogen mixed steam main pad; In the nitrogen mixed steam main pad, the injection speed ratio of nitrogen and steam is always kept at 1:(2-3), and the injection speed of steam is divided into three stages: Stage 1: steam injection rate is 3000-4000 m 3 / d, and the injection time is 1 / 3-1 / 4 of the total time of the slug; Stage 2: steam injection rate is 7000-8000 m 3 / d, and the injection time is 1 / 2-1 / 3 of the total time of the slug; Three stages: steam injection rate is 4000-5000 m 3 / d, injection time is 1 / 3-1 / 4 of the total time of the slug The foam agent contains, in mass percentage, 8-15% of alpha-olefin sulfonate, 1-2% of sodium methyl cocoyl taurate, 12-18% of fatty alcohol polyoxyethylene ether, and 2-3% of lauryl hydroxyl sulfobetaine, with the balance being water; The fatty alcohol polyoxyethylene ether satisfies that the alkyl carbon chain length is 12-16, and the oxyethylene polymerization degree is 9-14.

2. The method of claim 1, wherein, In the process of injecting the steam pre-pad, the steam injection rate is 3-5 mL / min, the temperature is 250-300 DEG C, the steam injection dryness is greater than or equal to 95%, and the injection amount is 0.5-0.7 PV.

3. The method of claim 1, wherein, The nitrogen injection speed is 3000-5000 m 3 / d.

4. The method of claim 1, wherein, In the process of the foam agent pad, the foam agent injection amount is 0.1-0.15 PV.

5. The method of claim 1, wherein, The foam agent further contains 0-1% of modified nano-SiO2, which is obtained by modifying nano-SiO2 with hexamethyldisilazane (HMDS) and polyether modified heptamethyltrisiloxane.

6. The method of claim 5, wherein, In the modified nano-SiO2, the mass ratio of HMDS to nano-SiO2 is (10-18):

100.

7. The method of claim 6, wherein, In the modified nano-SiO2, the mass ratio of polyether modified heptamethyltrisiloxane to nano-SiO2 is (5-8):

100.

8. Use of the method according to any one of claims 1 to 7 for the development of a heavy oil reservoir, characterized in that, The application includes the development of heavy oil reservoirs with a burial depth of oil layer >1000 m, an oil layer thickness >5 m, an oil-bearing saturation >75%, a porosity of oil layer 30-40%, a permeability <1000 mD, and a crude oil viscosity >10000 mPa·s.

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