Ultra-low permeability reservoir development well type optimization method based on oil layer stacking mode

Abstract

The invention discloses an ultra-low permeability reservoir development well type optimization method based on oil layer stacking modes. The method is specifically implemented according to the following steps that 1, the oil layer stacking modes are divided into a thick oil layer, a thin oil layer and a thin interbed according to ultra-low permeability reservoir sand body structure characteristics and reservoir physical property characteristics; 2, according to actual block reservoir parameters, oil reservoir mechanism models corresponding to three oil reservoir stacking modes of a thick oil reservoir, a thin interbed and a thin oil reservoir are established respectively; 3, a directional well, a highly-deviated well and a horizontal well are arranged in the thick oil layer oil reservoir mechanism model, the thin interbed oil reservoir mechanism model and the thin oil layer oil reservoir mechanism model respectively, and numerical simulation calculation is conducted through numerical simulation software; 4, well type optimization is conducted on the thick oil layer, the thin oil layer and the thin interbed according to calculation results of numerical simulation. The problems that in the prior art, the well type adaptability is poor, and the single well yield is low are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil reservoir well type optimization method, and relates to an ultra-low permeability oil reservoir development well type optimization method based on oil layer superimposed mode. BACKGROUND

[0002] The ultra-low permeability oil reservoirs in the Ordos Basin are rich in resources and have large overall scale of reserves, and are the main battlefield of oilfield productivity construction in the new area of Changqing Oilfield. The ultra-low permeability oil reservoirs in the Ordos Basin are mainly delta front subfacies deposition, and the sand bodies have the characteristics of small plane scale, vertical multi-layer superimposition, non-concentration and large thickness variation; in addition, the formation pressure coefficient is low, the reservoir physical property is poor, and the heterogeneity is strong, and development tests show poor well type adaptability, low single well production, and difficult water injection development effect. In order to further improve the development effect of the ultra-low permeability oil reservoirs, a well type optimization method considering the combination of oil layer superimposed mode and reservoir fluid percolation law is needed to improve the development effect of the ultra-low permeability oil reservoirs. SUMMARY

[0003] The purpose of the application is to provide an ultra-low permeability oil reservoir development well type optimization method based on oil layer superimposed mode, which solves the problems of poor well type adaptability and low single well production in the prior art.

[0004] The technical scheme adopted by the application is an ultra-low permeability oil reservoir development well type optimization method based on oil layer superimposed mode, which is implemented according to the following steps:

[0005] Step 1, according to the sand body structure characteristics and reservoir physical property characteristics of the ultra-low permeability oil reservoir, the oil layer superimposed mode is divided into three categories of thick oil layer, thin oil layer and thin interbedded layer;

[0006] Step 2, according to the actual block reservoir parameters, the oil reservoir mechanism model corresponding to the three oil layer superimposed modes of thick oil layer, thin interbedded layer and thin oil layer is respectively established;

[0007] Step 3, in the thick oil layer, thin interbedded layer and thin oil layer oil reservoir mechanism model, three well types of directional well, high-inclination well and horizontal well are respectively arranged, and numerical simulation calculation is respectively carried out by using a numerical simulation software;

[0008] Step 4, according to the calculation results of numerical simulation, the well type optimization is carried out for the thick oil layer, thin oil layer and thin interbedded layer.

[0009] The application is characterized in that:

[0010] The division basis in step 1 is:

[0011] The oil layer thickness is bounded by 12m, the interlayer thickness is bounded by 2m, when the interlayer thickness is greater than or equal to 2m, the reservoir is a thin interbed; when the interlayer thickness is less than 2m, if the oil layer thickness is greater than or equal to 12m, the reservoir is a thick oil layer, if the oil layer thickness is less than 12m, the reservoir is a thin oil layer.

[0012] In step 1, the stable interlayer does not develop in the thin oil layer and the thick oil layer, and the fracture completely penetrates the reservoir; the stable interlayer develops in the thin interbed, and the fracture only penetrates the layer.

[0013] In step 2, the reservoir burial depth, pressure data, anisotropy parameters, basic geological data and fluid parameters in the reservoir mechanism model corresponding to the three oil layer stacking modes of the thick oil layer, the thin interbed and the thin oil layer are set according to the actual block.

[0014] Step 3 is specifically:

[0015] In the thick oil layer reservoir mechanism model, three well types of directional wells, high-inclination wells and horizontal wells are arranged, and the numerical simulation results of the three well types are calculated by using the numerical simulation software;

[0016] In the thin interbed reservoir mechanism model, three well types of directional wells, high-inclination wells and horizontal wells are arranged, and the numerical simulation results of the three well types are calculated by using the numerical simulation software;

[0017] In the thin oil layer reservoir mechanism model, three well types of directional wells, high-inclination wells and horizontal wells are arranged, and the numerical simulation results of the three well types are calculated by using the numerical simulation software.

[0018] In step 3, when the directional wells, high-inclination wells and horizontal wells are arranged, the well pattern form is uniformly rectangular well pattern, and the well spacing and row spacing parameters are the same.

[0019] The numerical simulation results in step 3 include flow line distribution characteristics, single well production, water cut rising speed and ultimate recovery.

[0020] In step 3, if it is a thin interbed, the recovery of the main layer, the non-main layer and the whole thin interbed in the thin interbed when the interbed permeability difference is 1-8 times is also included when the numerical simulation is performed by using the numerical simulation software, wherein the main layer refers to a single oil layer with a production contribution greater than 50%, and the non-main layer refers to a single oil layer with a production contribution less than or equal to 50%.

[0021] Step 4 is specifically:

[0022] Comprehensive comparison in thick oil layer reservoir mechanism model respectively arranged directional well, high angle deviated well, horizontal well when the streamline distribution characteristics, single well production, water cut rising speed and ultimate recovery, determine the best well type suitable for thick oil layer;

[0023] Comprehensive comparison in thin interbedded reservoir mechanism model respectively arranged directional well, high angle deviated well, horizontal well when the streamline distribution characteristics, single well production, water cut rising speed and ultimate recovery, determine the best well type suitable for thin interbedded;

[0024] Comprehensive comparison in thin interbedded reservoir mechanism model respectively arranged directional well, high angle deviated well, horizontal well when the streamline distribution characteristics, single well production, water cut rising speed and ultimate recovery, determine the best well type suitable for thin interbedded.

[0025] The beneficial effects of the present application are:

[0026] The present application is based on the sand body structure characteristics and reservoir physical property characteristics of the ultra-low permeability reservoir, divides the oil layer superposition mode, uses the numerical simulation calculation result of the reservoir, and comprehensively compares the streamline distribution characteristics, single well production, water cut rising speed and ultimate recovery and other parameter indexes, determines the well type of different oil layer superposition modes, and the well type selected according to the method of the present application has good adaptability, and the corresponding single well production is improved.

[0027] According to the actual situation verification, compared with the conventional development mode, the development mode selected by the method of the present application improves the single well production of the block by at least 1.0 t / d. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is the flow chart of the well type optimization method of the ultra-low permeability reservoir development based on the oil layer superposition mode of the present application;

[0029] Figure 2 It is the schematic diagram of thick oil layer, thin oil layer and thin interbedded divided in the well type optimization method of the ultra-low permeability reservoir development based on the oil layer superposition mode of the present application;

[0030] Figure 3 It is the thin interbedded reservoir mechanism model diagram established in embodiment 3 of the present application;

[0031] Figure 4 It is the thick oil layer reservoir mechanism model diagram established in embodiment 3 of the present application;

[0032] Figure 5 It is the thin layer oil reservoir mechanism model diagram established in embodiment 3 of the present application;

[0033] Figure 6 It is the single well production comparison curve diagram of thick oil layer of different well types simulated in embodiment 3 of the present application;

[0034] Figure 7 is a single well cumulative production comparison curve diagram of different well types of thick oil layers simulated in embodiment 3 of the present application;

[0035] Figure 8 is a water cut rise comparison curve diagram of different well types of thick oil layers simulated in embodiment 3 of the present application;

[0036] Figure 9 is a single well production comparison curve diagram of different well types of thin interbedded oil layers simulated in embodiment 3 of the present application;

[0037] Figure 10 is a single well cumulative production comparison curve diagram of different well types of thin interbedded oil layers simulated in embodiment 3 of the present application;

[0038] Figure 11 is a water cut rise comparison curve diagram of different well types of thin interbedded oil layers simulated in embodiment 3 of the present application;

[0039] Figure 12 is a recovery ratio curve diagram of different permeability differentials of thin interbedded oil layers simulated in embodiment 3 of the present application;

[0040] Figure 13 is a recovery ratio contribution rate distribution diagram of different permeability differentials of thin interbedded oil layers simulated in embodiment 3 of the present application;

[0041] Figure 14 is a single well production comparison curve diagram of different well types of thin oil layers simulated in embodiment 3 of the present application;

[0042] Figure 15 is a single well cumulative production comparison curve diagram of different well types of thin oil layers simulated in embodiment 3 of the present application; DETAILED DESCRIPTION

[0043] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0044] Embodiment 1

[0045] The well type optimization method for the ultra-low permeability reservoir based on the oil layer stacking mode is shown in the flow chart of Figure 1 , and is implemented according to the following steps:

[0046] Step 1, according to the sand body structure characteristics and the reservoir physical property characteristics of the ultra-low permeability reservoir, the oil layer stacking mode is divided into three categories of thick oil layer, thin oil layer and thin interbedded layer, and the division basis is:

[0047] The oil layer thickness is bounded by 12 m, the interlayer thickness is bounded by 2 m, when the interlayer thickness is greater than or equal to 2 m, the reservoir is a thin interbed; when the interlayer thickness is less than 2 m, if the oil layer thickness is greater than or equal to 12 m, the reservoir is a thick oil layer, if the oil layer thickness is less than 12 m, the reservoir is a thin oil layer; and the stable interlayer is not developed in the thin oil layer and the thick oil layer, and the fracture completely penetrates the reservoir; the stable interlayer is developed in the thin interbed, and the fracture only penetrates the layer position.

[0048] Step 2, according to the actual block reservoir parameters, three oil layer superimposed modes corresponding to the reservoir mechanism model of thick oil layer, thin interbed and thin oil layer are respectively established;

[0049] Step 3, in the reservoir mechanism model of thick oil layer, three well types of directional well, high angle deviated well and horizontal well are respectively arranged, and the numerical simulation results of the three well types are respectively calculated by using the numerical simulation software;

[0050] In the reservoir mechanism model of thin interbed, three well types of directional well, high angle deviated well and horizontal well are respectively arranged, and the numerical simulation results of the three well types are respectively calculated by using the numerical simulation software;

[0051] In the reservoir mechanism model of thin oil layer, three well types of directional well, high angle deviated well and horizontal well are respectively arranged, and the numerical simulation results of the three well types are respectively calculated by using the numerical simulation software;

[0052] The numerical simulation results include flow line distribution characteristics, single well production, water cut rising speed and ultimate recovery rate, if it is a thin interbed, the recovery rates of the main layer, the non-main layer and the whole thin interbed when the interbed permeability difference is 1-8 times are also included in the numerical simulation by using the numerical simulation software, wherein the main layer refers to the single oil layer with a production contribution of more than 50%, and the non-main layer refers to the single oil layer with a production contribution of less than or equal to 50%.

[0053] Step 4, the flow line distribution characteristics, single well production, water cut rising speed and ultimate recovery rate when the directional well, the high angle deviated well and the horizontal well are respectively arranged in the reservoir mechanism model of thick oil layer are comprehensively compared to determine the best well type suitable for the thick oil layer;

[0054] The flow line distribution characteristics, single well production, water cut rising speed and ultimate recovery rate when the directional well, the high angle deviated well and the horizontal well are respectively arranged in the reservoir mechanism model of thin interbed are comprehensively compared to determine the best well type suitable for the thin interbed;

[0055] The flow line distribution characteristics, single well production, water cut rising speed and ultimate recovery rate when the directional well, the high angle deviated well and the horizontal well are respectively arranged in the reservoir mechanism model of thin oil layer are comprehensively compared to determine the best well type suitable for the thin oil layer.

[0056] Example 2

[0057] On the basis of Example 1, the reservoir burial depth, pressure data, anisotropy parameters, basic geological data, and fluid parameters in the reservoir mechanism model corresponding to the three oil layer stacking modes of thick oil layer, thin interbed, and thin oil layer in Step 2 are set according to the actual block.

[0058] In Step 3, when the directional well, high-deviation well, and horizontal well are arranged, the well pattern form is uniformly rectangular well pattern, and the well spacing and row spacing parameters are the same.

[0059] Example 3

[0060] This example takes the L1 reservoir in Ordos Basin as an example, including the following steps:

[0061] Step 1, oil layer stacking mode division

[0062] Due to the development of interlayer in ultra-low permeability reservoir, the thickness difference between reservoir and interlayer is large, and the single sand body lateral contact pattern is divided into three types: single sand body main body splicing, single sand body edge splicing, and mudstone separation. Among them, the single sand body main body splicing has the best connectivity and is most beneficial to injection-production relationship. The vertical stacking pattern of single sand body is divided into three types: separation type, superposition type, and cut-and-fold type, among which the cut-and-fold type sand body has the best connectivity and is most beneficial to injection-production relationship. Through statistical analysis of multiple profiles, it is found that the thickness of single well drilled sand body and the distance from the single sand body boundary are linearly positively correlated, that is, the width and thickness of single sand body are linearly positively correlated, and the width-thickness ratio of different sedimentary systems is different, which is between 75-90, 290-310, and 125-150. The formation thickness has a significant effect on the development effect of different well types, and needs to be divided into thick oil layer and thin oil layer; the large interlayer (≥2m) has a greater impact on the development effect of horizontal wells, and needs to be divided into reservoir geological patterns with and without large interlayer; the small interlayer (<2m) has a smaller impact on the development effect of different well types, and does not need to be divided into geological patterns separately. Combined with the single sand body shape, lateral stacking mode, vertical stacking mode analysis, and the analysis results of reservoir plane, lateral heterogeneity, and non-pressing and interlayer distribution characteristics, the oil layer stacking mode of Triassic ultra-low permeability reservoir in the basin is divided into three categories: thick oil layer, thin oil layer, and thin interbed. Among them, the oil layer thickness is divided by 12m, and the interlayer thickness is divided by 2m. When the interlayer thickness is greater than or equal to 2m, the reservoir is thin interbed; when the interlayer thickness is less than 2m, if the oil layer thickness is greater than or equal to 12m, the reservoir is thick oil layer, and if the oil layer thickness is less than 12m, the reservoir is thin oil layer. Stable interlayer is not developed in thin oil layer and thick oil layer, and fractures can completely penetrate the reservoir; stable interlayer is developed in thin interbed, and fractures only penetrate the layer.

[0063] As Figure 2As shown, the schematic diagram of the thick oil layer, the thin oil layer and the thin interbedding divided in this embodiment; from Figure 2 It can be seen that the thick oil layer is longitudinally continuous, the interlayer is not developed (the thickness is less than 2m), the cumulative thickness of the oil layer is greater than or equal to 12m; the thin oil layer is longitudinally continuous, the interlayer is not developed (the thickness is less than 2m), the cumulative thickness in the longitudinal direction is less than 12m, the thin interbedding is poor in longitudinal continuity, the interlayer is developed (the thickness is greater than or equal to 2m), and the average thickness of each layer is less than 12m.

[0064] Step 2, mechanism model establishment

[0065] Combined with the reservoir parameters of the actual block, the mechanism models corresponding to the three oil layer superimposed modes of the thick oil layer, the thin interbedding and the thin oil layer are respectively established, the reservoir burial depth, pressure data, anisotropy parameters, basic geological data and fluid parameters of the models are set according to the actual block, and this time, the parameters of the L oil reservoir Chang 6 oil layer are taken as an example to design the parameters, wherein the interlayer permeability ratio of the thin interbedding reservoir is 1-8 times, which is prepared for the next well type optimization. Figures 3-5 As shown, the thin interbedding reservoir mechanism model, the thick oil layer reservoir mechanism model and the thin oil layer reservoir mechanism model established in this embodiment are respectively shown.

[0066] Step 3, reservoir numerical simulation prediction

[0067] Three well types of directional wells, high-angle wells and horizontal wells are arranged in the three mechanism models corresponding to the thick oil layer, the thin interbedding and the thin oil layer respectively, the well pattern form is uniformly rectangular well pattern, the well spacing and row spacing parameters are the same, numerical simulation software is used for numerical simulation calculation, and the numerical simulation includes flow line distribution characteristics, single well production, water cut rising speed and ultimate recovery.

[0068] Step 4, thick oil layer model well type optimization.

[0069] As shown, the single well production comparison curves of the thick oil layer with different well types, the single well cumulative production comparison curves of the thick oil layer with different well types and the water cut rising law comparison curves of the thick oil layer with different well types are respectively shown. Figures 6-8 The calculation results of the thick oil layer model show that the flow line of the directional well is narrow and sparse, the flow line of the high-angle well is wide and dense, and the horizontal well is in the middle; the single well production of the high-angle well is the highest, the stable production time is the longest, the single well cumulative production in 20 years is the highest, the water cut rising speed is the slowest, the recovery degree is the largest, the horizontal well is the second, and the directional well is the worst; therefore, the flow line distribution characteristics, the single well production, the water cut rising speed and the ultimate recovery are comprehensively considered, and the best well type is determined to be the high-angle well.

[0070] Step 5, thin interbedding oil layer model well type optimization.

[0071] As shown, the single well production comparison curves of the thin interbedding with different well types, the single well cumulative production comparison curves of the thin interbedding with different well types and the water cut rising law comparison curves of the thin interbedding with different well types are respectively shown. Figures 9-11As shown in the figures, they are respectively: thin interbedded different well type single well production comparison curve, thin interbeded different well type single well cumulative production comparison curve, thin interbeded different well type water cut rising law comparison curve, thin interbedded oil layer longitudinal large inclination well fracture is better for the collection effect of flow line, horizontal well is affected by the barrier layer and only one layer is developed; the single well production of large inclination well is the highest, the stable production time is the longest, the 20-year single well cumulative production is the highest, the water cut rising speed is the slowest, the recovery degree is the largest, the straight well is the second, and the horizontal well is the worst; the best well type is large inclination well.

[0072] Further, for thin interbedded oil layers, considering the influence of the permeability ratio of each small layer on the production, another eight schemes with permeability ratio from 1 to 8 are designed, such as Figures 12-13 As shown in the figures, they are respectively: thin interbedded different well type single well production comparison curve, thin interbeded different well type single well cumulative production comparison curve, thin interbedded different well type water cut rising law comparison curve, thin interbedded oil layer longitudinal large inclination well fracture is better for the collection effect of flow line, horizontal well is affected by the barrier layer and only one layer is developed; the single well production of large inclination well is the highest, the stable production time is the longest, the 20-year single well cumulative production is the highest, the water cut rising speed is the slowest, the recovery degree is the largest, the straight well is the second, and the horizontal well is the worst; the best well type is large inclination well.

[0073] Step 6, thin oil layer model well type optimization.

[0074] As shown in the figures, they are respectively: thin interbedded different well type single well production comparison curve, thin interbeded different well type single well cumulative production comparison curve, thin interbedded different well type water cut rising law comparison curve, thin interbedded oil layer longitudinal large inclination well fracture is better for the collection effect of flow line, horizontal well is affected by the barrier layer and only one layer is developed; the single well production of large inclination well is the highest, the stable production time is the longest, the 20-year single well cumulative production is the highest, the water cut rising speed is the slowest, the recovery degree is the largest, the straight well is the second, and the horizontal well is the worst; the best well type is large inclination well. Figures 14-15 As shown in the figures, they are respectively: thin interbedded different well type single well production comparison curve, thin interbeded different well type single well cumulative production comparison curve, thin interbedded different well type water cut rising law comparison curve, thin interbedded oil layer longitudinal large inclination well fracture is better for the collection effect of flow line, horizontal well is affected by the barrier layer and only one layer is developed; the single well production of large inclination well is the highest, the stable production time is the longest, the 20-year single well cumulative production is the highest, the water cut rising speed is the slowest, the recovery degree is the largest, the straight well is the second, and the horizontal well is the worst; the best well type is large inclination well.

[0075] Example 4

[0076] On the basis of example 2, the method of the application is used to verify the development effect after well type selection in A and B oilfields, wherein A and B oilfields are both thin interbedded oil layers and are developed by large inclination wells; according to step 3, the permeability ratio value is calculated, wherein the permeability ratio value of A oilfield is less than 3 and the development effect of large inclination well is good; the permeability ratio value of B oilfield is greater than or equal to 3 and the development effect of large inclination well is poor.

[0077] Example 5

[0078] On the basis of Example 2, the development effects before and after the method of the application is used in Huaqing Oilfield are compared. The comparison before and after shows that the initial single-well production of the high-deviation well produced in the later period is 3.6-4.0 t / d, the annual production reaches 3.2-3.7 t / d, which is 1.2-1.5 t / d higher than that of the block produced in 2019, and the development effect is significantly improved. The initial single-well production of the ultra-short horizontal well is 3.2 t / d, and the annual single-well production reaches 2.8 t / d. Compared with the short horizontal well (300-400 m), the degree of water drive control in the horizontal section is increased, and the production per 100 m of horizontal section is increased by 1.8 t / d.

Claims

1. A method for optimizing well types in ultra-low permeability reservoirs based on oil layer stacking patterns, characterized in that, The specific steps are as follows: Step 1: Based on the structural characteristics of sand bodies and reservoir properties of ultra-low permeability reservoirs, the oil layer stacking patterns are divided into three categories: thick oil layers, thin oil layers, and thin interbedded layers. Step 2: Based on the actual reservoir parameters of the block, establish reservoir mechanism models corresponding to three oil layer stacking modes: thick oil layer, thin interbedded layer and thin oil layer. Step 3: Arrange three types of wells—directional wells, highly deviated wells, and horizontal wells—in the reservoir mechanism models of thick oil layers, thin interbedded layers, and thin oil layers, respectively, and perform numerical simulation calculations using numerical simulation software. Step 4: Based on the numerical simulation results, select the best well type for thick oil layers, thin oil layers, and thin interbedded layers.

2. The method for optimizing development well types in ultra-low permeability reservoirs based on oil layer stacking patterns according to claim 1, characterized in that, The division criteria in step 1 are as follows: The oil layer thickness is defined as 12m, and the interlayer thickness is defined as 2m. When the interlayer thickness is greater than or equal to 2m, the reservoir is a thin interlayer. When the interlayer thickness is less than 2m, if the oil layer thickness is greater than or equal to 12m, the reservoir is a thick oil layer. If the oil layer thickness is less than 12m, the reservoir is a thin oil layer.

3. The method for optimizing development well types in ultra-low permeability reservoirs based on oil layer stacking patterns according to claim 2, characterized in that, In step 1, stable interlayers are not developed in thin oil layers and thick oil layers, and fractures completely penetrate the reservoir; stable interlayers are developed in thin interlayers, and fractures only penetrate the layer in which they are located.

4. The method for optimizing development well types in ultra-low permeability reservoirs based on oil layer stacking patterns according to claim 3, characterized in that, In step 2, the reservoir depth, pressure data, anisotropic parameters, basic geological data, and fluid parameters in the reservoir mechanism models corresponding to the three oil layer stacking modes of thick oil layer, thin interlayer, and thin oil layer are all set according to the actual block.

5. The method for optimizing development well types in ultra-low permeability reservoirs based on oil layer stacking patterns according to claim 4, characterized in that, Step 3 specifically involves: Three well types—directional wells, highly deviated wells, and horizontal wells—were deployed in the thick oil reservoir mechanism model, and numerical simulation software was used to calculate the numerical simulation results for each of the three well types. Three well types—directional wells, highly deviated wells, and horizontal wells—were deployed in a thin interbedded reservoir mechanism model, and numerical simulation software was used to calculate the numerical simulation results for each of the three well types. Three well types—directional wells, highly deviated wells, and horizontal wells—were arranged in the thin oil reservoir mechanism model, and numerical simulation software was used to calculate the numerical simulation results for each of the three well types.

6. The method for optimizing development well types for ultra-low permeability reservoirs based on oil layer stacking patterns according to claim 5, characterized in that, In step 3, when arranging directional wells, highly deviated wells, and horizontal wells, a rectangular well network is uniformly adopted, with the same well spacing and row spacing parameters.

7. The method for optimizing development well types in ultra-low permeability reservoirs based on oil layer stacking patterns according to claim 6, characterized in that, The numerical simulation results in step 3 include streamline distribution characteristics, single-well production, water cut rise rate, and final recovery rate.

8. The method for optimizing development well types in ultra-low permeability reservoirs based on oil layer stacking patterns according to claim 6, characterized in that, If the layer in step 3 is a thin interbedded layer, then when performing numerical simulation using numerical simulation software, the recovery rate of the main layer, non-main layer and the thin interbedded layer as a whole are also included when the permeability difference between the layers in the thin interbedded layer reservoir is 1-8 times. Among them, the main layer refers to a single oil layer with a production contribution of more than 50%, and the non-main layer refers to a single oil layer with a production contribution of less than or equal to 50%.

9. The method for optimizing development well type of ultra-low permeability reservoirs based on oil layer stacking mode according to claim 7, wherein step 4 specifically comprises: By comprehensively comparing the streamline distribution characteristics, single-well production, water cut rise rate and final recovery rate when directional wells, highly deviated wells and horizontal wells are deployed in the thick oil reservoir mechanism model, the optimal well type suitable for thick oil reservoirs is determined. By comprehensively comparing the streamline distribution characteristics, single-well production, water cut rise rate and final recovery rate when directional wells, highly deviated wells and horizontal wells are deployed in the thin interbedded reservoir mechanism model, the optimal well type suitable for thin interbedded reservoirs is determined. By comprehensively comparing the streamline distribution characteristics, single-well production, water cut rise rate, and final recovery rate when directional wells, highly deviated wells, and horizontal wells are deployed in the thin oil reservoir mechanism model, the optimal well type suitable for thin oil reservoirs is determined.

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