A method for determining technical parameters of nitrogen foam-viscosity reducer alternating profile control in heavy oil reservoirs with strong edge and bottom water

Abstract

The application discloses a method for determining technical parameters of nitrogen foam-viscosity reducer alternating profile control in heavy oil reservoirs with strong edge and bottom water, and belongs to the technical field of heavy oil water flooding development. The method adopts nitrogen foam-viscosity reducer collaborative profile control, and comprehensively utilizes the oil displacement and plugging characteristics of the three, and the process is relatively simple. The method has better injection and oil washing efficiency in the reservoir, can significantly reduce the remaining oil saturation, and can guide the formulation of the field profile control scheme, so as to achieve the effects of inhibiting edge and bottom water breakthrough, plugging water channeling, adjusting the displacement plane heterogeneity breakthrough, expanding the displacement area and displacement efficiency, and improving the heavy oil recovery.

Description

Technical Field

[0001] This invention belongs to the field of heavy oil waterflooding development technology, specifically involving a method for determining the technical parameters of alternating nitrogen foam-viscosity reducer regulation in heavy oil reservoirs with strong edge and bottom water. Background Technology

[0002] In conventional heavy oil reservoir water displacement, viscosity reducer-assisted water flooding is a commonly used and effective cold production mode. Its main production problem is water channeling in the later stage, which has a relatively small impact area in the entire displacement stage. Nitrogen foam regulation can effectively improve the water channeling problem in water flooding and increase the displacement area of ​​heavy oil, but gas channeling is prone to occur in the later stage.

[0003] For heavy oil reservoirs with edge and bottom water, in addition to the aforementioned problems (water channeling in viscosity reducer-assisted modulating and gas channeling in foam-assisted modulating), there is also the fundamental issue of rapid edge and bottom water intrusion. Therefore, these reservoirs typically require a combination of multiple modulating methods. Consequently, technologies such as foam-viscosity reducer-foam agent combination or composite modulating have emerged in oilfields. Although viscosity reducer and foam agent modulating technologies are relatively mature, there is a lack of good field implementation experience for alternating between the two. In particular, a mature and systematic implementation plan has not been developed for fundamental questions such as "how to alternate injections? how many times to alternate? when to alternate injections?"

[0004] Therefore, for heavy oil reservoirs with strong edge and bottom water, this invention provides a method for determining the technical parameters of alternating nitrogen foam and viscosity reducer for dynamic displacement, providing technical support for the formulation of dynamic displacement schemes to suppress water cut rise and improve recovery in heavy oil reservoirs with strong edge and bottom water. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and to provide a method for determining the technical parameters of alternating nitrogen foam-viscosity reducer regulation in heavy oil reservoirs with strong edge and bottom water.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including,

[0009] A nitrogen foam-viscosity reducer alternating injection scheme was used to regulate and drive heavy oil reservoirs with strong edge and bottom water.

[0010] Establish a typical field model for nitrogen foam-viscosity reducer alternating regulation and displacement technology in heavy oil reservoirs with strong edge and bottom water;

[0011] We designed numerical simulation schemes with different alternating drive parameters, using output-input ratio, cycle net profit, and recovery rate increase as evaluation indicators. Through simulation results of typical mine models, we determined the technical parameters of alternating drive cycle, drive rotation, and drive timing.

[0012] As a preferred embodiment of the method for determining the parameters of the nitrogen foam-viscosity reducer alternating regulation and displacement technology for heavy oil reservoirs with strong edge and bottom water as described in this invention, the typical field model is established using the CMG reservoir numerical simulation software STARS simulator based on the basic reservoir parameters and actual production conditions of the target heavy oil reservoir block.

[0013] As a preferred embodiment of the method for determining the parameters of the nitrogen foam-viscosity reducer alternating regulation technology for heavy oil reservoirs with strong edge and bottom water as described in this invention, the basic reservoir parameters include porosity, permeability, saturation, crude oil viscosity, reservoir depth, temperature, and pressure.

[0014] As a preferred embodiment of the method for determining the technical parameters of nitrogen foam-viscosity reducer alternating displacement technology in heavy oil reservoirs with strong edge and bottom water as described in this invention, the technical parameters of alternating displacement cycle, displacement rounds, and displacement timing are determined respectively through simulation results of typical field models.

[0015] The determination of the alternating drive cycle includes

[0016] Based on the full-stage water drive scheme, oil production data is output by simulating the operation results through a typical mining field model.

[0017] Ensure that the parameters of drive cycle and drive timing are consistent, design different alternating drive cycle schemes, and output the oil production data of each scheme;

[0018] Calculate the periodic oil increase under different alternation cycles and basic schemes, and calculate the output-input ratio under different alternation cycles based on the periodic oil increase and investment costs.

[0019] Using the output-input ratio as an evaluation indicator, the optimal alternating drive cycle is determined;

[0020] The determination of the alternating drive sequence includes...

[0021] Based on the determined and preferred alternating drive cycle, and ensuring that the drive timing parameters are consistent, different drive cycle schemes are designed, and the oil production data of each scheme is output.

[0022] Calculate the periodic net profit corresponding to different schemes, and use the periodic net profit as an evaluation index to determine the preferred drive cycle;

[0023] The determination of the timing for alternating drive adjustment includes...

[0024] Based on the full-stage water drive scheme, oil production data is output by simulating the operation results through a typical mining field model.

[0025] Based on the determined and preferred alternating drive cycle and drive rotation, different drive timing schemes are designed, and oil production data for each scheme are output.

[0026] Calculate the increase in recovery rate and cumulative oil production under different timing of adjustment and basic schemes. Use the increase in recovery rate as the evaluation index to determine the optimal timing of adjustment.

[0027] As a preferred embodiment of the method for determining the parameters of the alternating regulation and displacement technology of nitrogen foam and viscosity reducer in heavy oil reservoirs with strong edge and bottom water as described in this invention, the alternating regulation and displacement involves first injecting nitrogen foam and then injecting viscosity reducer, alternating between the two.

[0028] As a preferred embodiment of the method for determining the parameters of the alternating regulation and driving technology of nitrogen foam and viscosity reducer in heavy oil reservoirs with strong edge and bottom water as described in this invention, the regulation and driving cycle is the number of months in a year during the non-regulation and driving phase, wherein the regulation and driving cycle is in months.

[0029] As a preferred embodiment of the method for determining the parameters of the nitrogen foam-viscosity reducer alternating displacement technology for heavy oil reservoirs with strong edge and bottom water as described in this invention, the displacement cycle is the number of times a complete nitrogen foam-viscosity reducer-water injection cycle is repeated, wherein the displacement cycle is measured in years.

[0030] As a preferred embodiment of the method for determining the parameters of the alternating regulation and displacement technology of nitrogen foam and viscosity reducer in heavy oil reservoirs with strong edge and bottom water as described in this invention, the timing of the regulation and displacement is when the water cut reaches the target value.

[0031] As a preferred embodiment of the method for determining the parameters of the nitrogen foam-viscosity reducer alternating regulation and displacement technology for heavy oil reservoirs with strong edge and bottom water as described in this invention, the parameters determined by the method can guide the formulation of on-site regulation and displacement schemes, achieve the goals of suppressing edge and bottom water inrush and blocking water channeling, adjusting the heterogeneous inrush of the displacement plane, expanding the displacement area and displacement efficiency, and thus improving the recovery rate of heavy oil.

[0032] As a preferred embodiment of the method for determining the parameters of the nitrogen foam-viscosity reducer alternating regulation technology for heavy oil reservoirs with strong edge and bottom water as described in this invention, the method can be used in the fields of water flooding, foam flooding, and multi-component thermal recovery displacement and huff and puff for ordinary heavy oil reservoirs and extra-heavy oil.

[0033] Beneficial effects of this invention:

[0034] (1) The present invention adopts a scheme of alternating injection of nitrogen foam and viscosity reducer. ，Nitrogen foam is injected first, followed by viscosity reducer, and the two are injected alternately. During the injection, nitrogen foam can block large channels, adjust the liquid absorption profile, and prevent cross-flow step by step, which greatly reduces the cross-flow of the subsequently injected viscosity reducer, improves the viscosity reduction efficiency of crude oil, reduces the water cut of the oil well, and improves the utilization of the oil layer. The synergistic effect of nitrogen foam, viscosity reducer and flooding combines the advantages of oil displacement and plugging, and the process is relatively simple. It has better injection performance and oil washing efficiency in the reservoir and can significantly reduce the residual oil saturation.

[0035] (2) The method for determining the driving parameters of the present invention can guide the formulation of the driving scheme on site, so as to suppress the inrush of the edge and bottom water, block the water channel, adjust the heterogeneous inrush of the displacement plane, expand the displacement area and displacement efficiency, improve the recovery rate of heavy oil and achieve the effect of improving economic benefits. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0037] Figure 1 This is a flowchart illustrating the method for determining the parameters of the alternating nitrogen foam-viscosity reducer regulation technique for heavy oil reservoirs with strong edge and bottom water, as described in this invention.

[0038] Figure 2 The figure shows the numerical simulation model (typical model of the mine) of strong edge bottom water heavy oil nitrogen foam-viscosity reducer alternating regulation and driving established in Embodiment 2 of the present invention.

[0039] Figure 3 This is a graph showing the determination of the optimal alternating drive cycle in Embodiment 2 of the present invention.

[0040] Figure 4 This is a graph showing the optimal alternating drive sequence determined in Embodiment 2 of the present invention.

[0041] Figure 5 This is a graph showing the determination of the optimal alternating drive timing in Embodiment 2 of the present invention.

[0042] Figure 6 The curves showing the water cut and oil production rate under the optimal scheme in Embodiment 2 of the present invention are shown. Detailed Implementation

[0043] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0044] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0045] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0046] The input standards in this embodiment of the invention are as follows:

[0047] Nitrogen is priced at 1.5 yuan per cubic meter; foaming agent and viscosity reducer concentration is 0.5%, priced at 10,000 yuan per ton; oil price is priced at 60 US dollars per barrel.

[0048] Example 1

[0049] Reference Figure 1 This embodiment provides a method for determining the technical parameters of alternating nitrogen foam-viscosity reducer regulation in heavy oil reservoirs with strong edge and bottom water, specifically as follows:

[0050] S1: Establish a typical numerical model of the field for simulating nitrogen foam-viscosity reducer alternating regulation and driving in heavy oil reservoirs with strong edge and bottom water;

[0051] Based on the basic reservoir parameters and actual production conditions of heavy oil reservoir blocks, a typical numerical model describing the nitrogen foam-viscosity reducer alternating regulation and displacement technology in heavy oil reservoirs with strong edge and bottom water was established using the STARS simulator, a CMG reservoir numerical simulation software.

[0052] The alternating driving method involves first injecting nitrogen foam, then injecting a viscosity reducer, alternating between the two.

[0053] S2: Design numerical simulation schemes with different alternating drive parameters, and determine the preferred drive parameters through simulation results of typical numerical models;

[0054] A1: Determine the alternating drive cycle:

[0055] Based on the full-stage water drive scheme, oil production data is output by simulating the operation results through a typical mining field model.

[0056] First, ensure that the parameters of drive cycle and drive timing are consistent, design different alternating drive cycle schemes, and output the oil production data of each scheme;

[0057] Next, calculate the periodic oil increase under different alternation cycles and the basic scheme, and calculate the output-input ratio under different alternation cycles based on the periodic oil increase and investment costs.

[0058] Finally, the optimal alternating drive cycle was determined using the output-input ratio as an evaluation index.

[0059] The driving cycle is the number of months in a year that are not part of the driving cycle, measured in months. Specifically, in this invention, the driving cycle consists of the number of months for foam driving, the number of months for viscosity reducer driving, and the number of months for water driving.

[0060] A2: Determine the alternating drive sequence:

[0061] First, based on the alternating drive cycle determined in step A1, ensure that the drive timing is consistent, design different nitrogen foam-viscosity reducer drive cycle schemes, and output the oil production data of each scheme.

[0062] Next, calculate the periodic net profit corresponding to different plans;

[0063] Finally, using cyclical net profit as an evaluation indicator, the preferred drive cycle is determined.

[0064] Among them, the number of times the drive cycle is repeated is the number of times a complete nitrogen foam-viscosity reducer-water injection cycle is repeated, measured in years.

[0065] A3: Determine the timing for alternating drive adjustments:

[0066] Based on the full-stage water drive scheme, oil production data is output by simulating the operation results through a typical mining field model.

[0067] First, based on the alternating drive cycle and drive rotation determined in steps A1 and A2, design different drive timing schemes and output the oil production data for each scheme.

[0068] Next, the recovery rate increase and cumulative oil production were calculated under different timing of the adjustment and the basic scheme.

[0069] Finally, the optimal timing for oil recovery was determined using the increase in oil recovery rate as an evaluation indicator.

[0070] Among them, the timing of adjustment and driving is when the moisture content reaches the target value.

[0071] S3: Based on the determined drive adjustment parameters, formulate a drive adjustment plan and perform drive adjustment.

[0072] By determining the regulation and displacement parameters in steps S1 and S2, a regulation and displacement scheme for the target reservoir block is formulated. Regulating and displacement according to this scheme can achieve the goals of suppressing edge and bottom water inrush, blocking water channeling, adjusting heterogeneous inrush of the displacement plane, expanding the displacement area and displacement efficiency, improving heavy oil recovery, and enhancing economic benefits.

[0073] Example 2

[0074] Reference Figures 2-6 To verify the beneficial effects of the present invention, this embodiment provides a specific application of a method for determining the technical parameters of alternating nitrogen foam-viscosity reducer regulation in heavy oil reservoirs with strong edge and bottom water, specifically as follows:

[0075] S1: Establish a typical numerical model of the field for simulating nitrogen foam-viscosity reducer alternating regulation and displacement in heavy oil reservoirs with strong edge and bottom water;

[0076] The target heavy oil reservoir block A has been identified. The basic reservoir parameters and actual production conditions of this block are as follows:

[0077] Porosity 27%, permeability 1700mD, saturation 81%, crude oil viscosity 2871mPa·s, reservoir depth 2100m, temperature 85℃, pressure 22MPa, 2 injection wells and 2 production wells;

[0078] Based on the basic reservoir parameters and production conditions of Block A, a typical numerical model describing the nitrogen foam-viscosity reducer alternating displacement technology in heavy oil reservoirs with strong edge and bottom water was established using the STARS simulator, a CMG reservoir numerical simulation software. Figure 2 As shown, Figure 2 In the diagram, A1 represents the left injection well, A2 the right injection well, A3 the left production well, A the right production well, and A5 the typical grid of the mine model. The planar grid of the mine model is divided into 20m×20m sections, with 18 sub-layers in the vertical direction, for a total of 7098 grids.

[0079] S2: Design numerical simulation schemes with different alternating drive parameters, and determine the preferred drive parameters through simulation results of typical numerical models;

[0080] A1: Determine the alternating drive cycle:

[0081] The basic scheme is based on full-stage water flooding, i.e., the number of months of foam flooding: the number of months of viscosity reducer flooding: the number of months of water flooding = 0:0:12. The oil production data is output by simulating the operation results through a typical field model.

[0082] To ensure consistency in the alternation of drive cycles and timing, specifically, the alternation cycle is 1 year, and the timing is when the water content is 95%. Six different alternation cycle schemes are designed, as shown in Table 1:

[0083] Table 1. Cycle schemes for different alternating drive adjustments

[0084]

[0085] Output the oil production data for each scheme in Table 1, calculate the periodic oil increase under different alternation cycles and the basic scheme, and calculate the output-input ratio under different alternation cycles, taking into account investment costs. The results are as follows: Figure 3 As shown, using the cycle increase in oil volume and the output-input ratio as evaluation criteria, it can be seen that when the alternating drive cycle is foam drive months: viscosity reducer drive months: water drive months = 2:2:8, the output-input ratio of this scheme has a significant advantage. Therefore, the scheme of foam drive months: viscosity reducer drive months: water drive months = 2:2:8 is the optimal drive cycle in this embodiment.

[0086] A2: Determine the alternating drive sequence:

[0087] Based on the adjustment cycle determined in step A1, that is, the alternating adjustment cycle is foam flooding months: viscosity reducer flooding months: water flooding months = 2: 2: 8;

[0088] To ensure consistent timing of the adjustment process, specifically at a moisture content of 95%, different nitrogen foam-viscosity reducer adjustment cycle schemes were designed. Eight different adjustment cycle schemes were designed, as shown in Table 2.

[0089] Table 2. Different alternating drive schemes

[0090]

[0091] Output the oil production data for each scheme in Table 2, calculate the corresponding periodic net profit for different schemes, and the results are as follows: Figure 4 As shown, using the periodic net profit as an evaluation index, it can be seen that when the drive cycle is 2 years, the periodic net profit of this scheme has a significant advantage. Therefore, the scheme with a drive cycle of 2 years is the optimal drive cycle in this embodiment.

[0092] A3: Determine the timing for alternating drive adjustments:

[0093] Based on the driving cycle determined in step A1 and the driving cycle determined in step A2, the alternating driving cycle is foam driving months: viscosity reducer driving months: water driving months = 2:2:8, and the driving cycle is 2 years.

[0094] Based on the full-stage water drive scheme, five different drive timing schemes were designed, as shown in Table 3:

[0095] Table 3 Timing schemes for different alternating drive adjustments

[0096]

[0097] Output the oil production data for each scheme in Table 3, calculate the recovery rate increase and cumulative oil increase under different displacement timings and the basic scheme, and the results are as follows: Figure 5As shown, using the increase in recovery rate as the evaluation index, it can be seen that when the timing of the adjustment and driving is when the water cut is 90%, the increase in recovery rate under the corresponding scheme is the largest. Based on this, the optimal timing for adjustment and driving in this embodiment is determined to be when the water cut is 90%.

[0098] S3: Based on the determined drive adjustment parameters, formulate a drive adjustment plan and perform drive adjustment.

[0099] Step S2 determined the optimal alternating displacement scheme. The optimal alternating displacement cycle is 2:2:8 months for nitrogen foam flooding: 7 years for viscosity reducer flooding: 90% water flooding. Based on this scheme, multiple simulations were conducted using CMG numerical simulation software. The results are as follows: Figure 6 As shown, the modified drive scheme obtained through this embodiment increases the cumulative oil production by 840,000 tons compared with pure water drive, improves the recovery rate by 1.42% compared with pure water drive, and increases the total profit by 16.078 million yuan compared with pure water drive.

[0100] It is evident that the present invention can effectively guide the formulation of on-site flood control schemes, thereby suppressing the inrush of water from the edge and bottom, blocking water channeling, adjusting the heterogeneous inrush of the displacement plane, expanding the displacement area and displacement efficiency, and achieving the effect of improving the recovery rate of heavy oil, thus obtaining the best economic benefits.

[0101] In summary, this invention employs a synergistic regulation and displacement method using nitrogen foam and a viscosity reducer. Nitrogen, due to its high compressibility and elasticity, low density, and inertness, offers better enhanced oil recovery. Foam, with its high apparent viscosity, water-blocking properties (but not oil-blocking), and ability to improve the oil-water mobility ratio, compensates for nitrogen's tendency to channel. The viscosity reducer significantly lowers crude oil viscosity, greatly increasing oil washing efficiency. This invention's nitrogen foam-viscosity reducer displacement method combines the oil displacement and plugging advantages of all three components, with a relatively simple process. It exhibits better injection performance and oil washing efficiency in reservoirs and can significantly reduce residual oil saturation.

[0102] The method for determining the adjustment and displacement parameters of this invention can guide the formulation of on-site adjustment and displacement schemes, thereby achieving the effects of suppressing the inrush of water from the edge and bottom, blocking water channeling, adjusting the heterogeneous inrush of the displacement plane, expanding the displacement area and displacement efficiency targets, increasing the recovery rate of heavy oil, and improving economic benefits.

[0103] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for determining the technical parameters of alternating nitrogen foam-viscosity reducer regulation in heavy oil reservoirs with strong edge and bottom water, characterized in that: include, A nitrogen foam-viscosity reducer alternating injection scheme was used to regulate and drive heavy oil reservoirs with strong edge and bottom water. Establish a typical field model for nitrogen foam-viscosity reducer alternating regulation and displacement technology in heavy oil reservoirs with strong edge and bottom water; We designed numerical simulation schemes with different alternating drive parameters, using output-input ratio, cycle net profit, and recovery rate increase as evaluation indicators. Through simulation results of typical mine models, we determined the technical parameters of alternating drive cycle, alternating drive rounds, and alternating drive timing. Determining the alternating drive cycle includes, Based on the full-stage water drive scheme, oil production data is output by simulating the operation results through a typical mining field model. Ensure that the parameters of drive cycle and drive timing are consistent, design different alternating drive cycle schemes, and output the oil production data of each scheme; Calculate the periodic oil increase under different alternation cycles and basic schemes, and calculate the output-input ratio under different alternation cycles based on the periodic oil increase and investment costs. The output-input ratio is used as an evaluation indicator to determine the alternating drive cycle; Determining the alternating drive sequence includes, Based on a defined alternating drive cycle, and ensuring consistent drive timing parameters, design different drive cycle schemes and output oil production data for each scheme. Calculate the periodic net profit corresponding to different schemes, and use the periodic net profit as an evaluation index to determine the driving cycle; Determining the timing of the alternating drive includes, Based on the full-stage water drive scheme, oil production data is output by simulating the operation results through a typical mining field model. Based on a defined alternating drive cycle and drive rotation number, different drive timing schemes are designed, and oil production data for each scheme is output. Calculate the increase in recovery rate and cumulative oil production under different timing of adjustment and basic schemes, and use the increase in recovery rate as the evaluation index to determine the timing of adjustment.

2. The method for determining the technical parameters of alternating nitrogen foam-viscosity reducer regulation in heavy oil reservoirs with strong edge and bottom water as described in claim 1, characterized in that: The typical field model is established using the STARS simulator, a CMG reservoir numerical simulation software, based on the reservoir basic parameters and actual production conditions of the target heavy oil reservoir block.

3. The method for determining the technical parameters of alternating nitrogen foam-viscosity reducer regulation in strong edge-bottom water heavy oil reservoirs as described in claim 2, characterized in that: The basic reservoir parameters include porosity, permeability, saturation, crude oil viscosity, reservoir depth, temperature, and pressure.

4. The method for determining the technical parameters of alternating nitrogen foam-viscosity reducer regulation in strong edge-bottom water heavy oil reservoirs as described in claim 1, characterized in that: The alternating driving method involves first injecting nitrogen foam, then injecting a viscosity reducer, alternating between the two.

5. The method for determining the technical parameters of alternating nitrogen foam-viscosity reducer regulation in heavy oil reservoirs with strong edge and bottom water as described in claim 1, characterized in that: The drive adjustment cycle is the number of months in a year's production time that are not in the drive adjustment phase, and the drive adjustment cycle is in months.

6. The method for determining the technical parameters of alternating nitrogen foam-viscosity reducer regulation in strong edge-bottom water heavy oil reservoirs as described in claim 1, characterized in that: The term "adjustment cycle" refers to the number of times a complete nitrogen foam-viscosity reducer-water injection cycle is repeated, with the adjustment cycle measured in years.

7. The method for determining the technical parameters of alternating nitrogen foam-viscosity reducer regulation in strong edge-bottom water heavy oil reservoirs as described in claim 1, characterized in that: The timing for adjusting the flow is when the moisture content reaches the target value.

8. The method for determining the technical parameters of alternating nitrogen foam-viscosity reducer regulation in heavy oil reservoirs with strong edge and bottom water as described in any one of claims 1 to 7, characterized in that: The method is used in water flooding and foam flooding of ordinary heavy oil reservoirs, as well as multi-component thermal recovery and displacement, and huff and puffing of extra-heavy oil.

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