High-water-content oil reservoir development effect evaluation and regulation method based on dynamic heterogeneity

Abstract

The invention relates to the technical field of oil-gas field development and recovery efficiency improvement, and particularly discloses a high-water-content oil reservoir development effect evaluation and regulation method based on dynamic heterogeneity, which realizes second-level real-time dynamic diagnosis by establishing a dynamic heterogeneity rapid evaluation model and directly solving a time of flight (TOF) and tracer equation based on a finite volume method. An evaluation system fusing multi-dimensional indexes such as TOF (Time of Flight) and a dynamic Lorentz coefficient is constructed, and collaborative quantitative evaluation of injection-production connectivity, displacement sweep strength and heterogeneous degree is realized; a layered regulation and control strategy based on seepage field grading is formed, differentiation measure optimization is achieved according to geological conditions, TOF (Time of Flight) equation grading and dynamic heterogeneous boundary, collaborative quantitative evaluation of injection-production connectivity, displacement wave and intensity and heterogeneous degree is achieved, and a differentiation regulation and control strategy is automatically generated based on an evaluation result. Therefore, the high-water-content oil reservoir remaining oil potential tapping precision and development economic benefits are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geological development, in particular to a high water-cut reservoir development effect evaluation and regulation method based on dynamic heterogeneity. BACKGROUND

[0002] After decades of exploitation, China's major continental oilfields have generally entered the "double-high" development stage of high recovery and high water cut (water cut > 80%), and the remaining oil resources potential is still large, but the distribution is highly complex. Reservoir heterogeneity is a key factor controlling recovery, and its quantitative characterization has always been a core problem in reservoir description.

[0003] After entering the high water cut period, the dynamic evolution of reservoir heterogeneity is crucial to the optimization of development strategies. Long-term water flooding intensifies dynamic heterogeneity, forming a complex pattern of "dominant seepage channel leading to local enrichment of remaining oil", resulting in the coexistence of high water cut and low recovery. Existing characterization methods are mostly based on static parameters (such as permeability variation coefficient, etc.), or use variogram and entropy weight method to construct comprehensive heterogeneity index. However, the dynamic heterogeneity effect caused by fluid saturation change far exceeds the static difference, and the dynamic coupling can make the interwell liquid production difference up to 100 times, and the fundamental mechanism lies in the dynamic evolution of reservoir connectivity structure. Traditional indicators do not consider the response of flow field, well pattern configuration and injection-production connectivity, and have weak correlation with recovery. Therefore, establishing a quantitative characterization system of dynamic heterogeneity and using it to guide development evaluation and remaining oil potential tapping have become the core problem of sustainable development of oilfields.

[0004] There are mainly two types of existing development effect evaluation methods: (1) Reservoir engineering method: relying on water cut, liquid production, decline rate and other indicators, using water drive characteristic curve to characterize well group dynamics, although widely used in the field, but it cannot reflect the dynamic changes of reservoir properties and fluid, and it is difficult to identify injection-production connectivity variation and early warning of ineffective circulation. When the water cut is > 80%, the prediction error increases significantly; traditional water drive curve is based on the assumption of homogeneous reservoir and stable flow state, which has poor applicability in high water cut heterogeneous reservoirs, and cannot quantify the injection-production correspondence and displacement front dynamics of single sand body.

[0005] (2) Reservoir numerical simulation method: can simulate the evolution of pressure and saturation field, but has obvious limitations: strong heterogeneous reservoirs require extremely dense grids, and the calculation time is long, up to several hours to several days; it is difficult to directly quantify dynamic indicators such as injection-production connectivity strength; high water cut period model is highly sensitive to grid and relative permeability curve, and the prediction result has large uncertainty.

[0006] In summary, the existing evaluation system has three major shortcomings: ① Lack of dynamic characterization, unable to quantify injection-production connectivity and displacement front dynamics; ② Single evaluation dimension, difficult to characterize the spatiotemporal evolution of sweep range and displacement strength; ③ High water cut stage adaptability is weak, and the development response to the reservoir with water cut >85% is slow. The fundamental bottleneck is the lack of dynamic heterogeneity evaluation mechanism, the difficulty in quantifying connectivity, and the low computational efficiency. SUMMARY

[0007] The purpose of the present application is to provide a high water cut reservoir development effect evaluation and regulation method based on dynamic heterogeneity, to solve the technical problems of the existing evaluation system, such as the lack of dynamic heterogeneity evaluation mechanism, the difficulty in quantifying connectivity, and the low computational efficiency.

[0008] To solve the above technical problems, the present application specifically provides the following technical solutions: The high water cut reservoir development effect evaluation and regulation method based on dynamic heterogeneity comprises the following specific steps: Step 100, rapid quantitative characterization of reservoir dynamic heterogeneity based on flow diagnosis: Constructing a seepage control, time of flight (TOF) equation and tracer equation, using finite volume method to discretize and solve to obtain target key data, then step-by-step calculation of well pair parameters, total flight time and flow / reservoir capacity, and obtaining dynamic heterogeneity coefficient through the curve with reservoir capacity as the horizontal axis and flow capacity as the vertical axis; Step 200, constructing a multi-dimensional reservoir development effect evaluation system: Fusing geological static parameters and dynamic parameters, introducing time of flight (TOF) equation and dynamic heterogeneity coefficient as core evaluation indexes, wherein the time of flight (TOF) equation is used to quantify the time efficiency of fluid migration to identify dominant channels and stagnant zones, and the dynamic heterogeneity coefficient is used to characterize the displacement uniformity evolution through the Lorenz curve, realizing the collaborative quantitative evaluation of injection-production connectivity, displacement sweep intensity and heterogeneity degree; Step 300, generating seepage field grading regulation strategy: According to the water-out ratio, remaining oil layer thickness and remaining oil saturation, target areas with development potential are screened; Using time of flight (TOF) equation combined with average displacement period of oilfield to diagnose displacement energy of target area; Based on dynamic heterogeneity coefficient and well group dynamic Lorenz coefficient range, strong / weak heterogeneity zones are distinguished according to heterogeneity regulation threshold; Then, according to the heterogeneity region type and displacement dynamic result, profile control and water plugging measures are taken for strong heterogeneity zones, and injection-production synchronous liquid lifting measures are selected for weak heterogeneity zones; Among them, before step 300, an oilfield exclusive threshold calibration database is established, and the adaptation range of time of flight (TOF) classification threshold and regulation threshold is determined through numerical simulation inversion and production dynamic correlation analysis.

[0009] As a preferred scheme of the present application, in step 100, the constructed time of flight equation comprises: a forward TOF equation from point source to grid, used for calculating the migration time of fluid from the point source of injection well to any grid of the oil reservoir; a backward TOF equation from grid to point sink, used for calculating the migration time of fluid from any grid of the oil reservoir to the point sink of production well; the sum of the forward TOF equation and the backward TOF equation is used to represent the difference of seepage resistance, the value of which is controlled by the coupling of porosity, permeability and injection-production intensity, fluid mobility, and the following is used: if the sum of the forward TOF equation and the backward TOF equation is less than the threshold of exclusive flow stagnation of the oilfield, it represents a strong seepage advantage area; if the sum of the forward TOF equation and the backward TOF equation is greater than the threshold of exclusive flow stagnation of the oilfield, it represents an un-impinged flow stagnation area, i.e. a potential target area.

[0010] As a preferred scheme of the present application, in the acquisition of target key data by discrete solution with finite volume method; first, the flow field velocity is acquired, including: directly extracting the flow velocity field result output by three-dimensional multiphase flow numerical simulation; or, for micro-compressible fluid, the flow field velocity is approximately acquired by solving the steady-state pressure equation; then, the time of flight equation and the tracer equation are discretized in a unified form, and the unified form of the equation is integrated by using the finite volume method.

[0011] As a preferred scheme of the present application, the unified form of the time of flight equation and the tracer equation is: ; wherein, is the quantity to be solved, represents the flow field velocity, represents the source-sink term vector, and when: , the unified form represents the time of flight equation; , the unified form represents the tracer equation; wherein, represents the tracer concentration, represents the sum of the forward TOF equation and the backward TOF equation, represents the storage capacity value.

[0012] As a preferred scheme of the present application, after the discretization of the unified form is completed, the linear equation group is obtained: wherein, represents a coefficient matrix, the elements of which are determined by grid permeability, porosity and boundary conditions; By solving the linear equations, the time-of-flight value distribution and the tracer concentration distribution are obtained.

[0013] As a preferred scheme of the present application, based on the solved tracer concentration: The tracer concentration of the target injection well is set to 1, and the tracer concentration of other injection wells is set to 0, and the injection well tracer is solved. The tracer concentration of the target production well is set to 1, and the tracer concentration of other production wells is set to 0, and the production well tracer is solved.

[0014] As a preferred scheme of the present application, all grids are arranged in ascending order of total TOF value, and flow capacity and storage capacity are calculated in turn, and a Lorenz curve with storage capacity as the horizontal axis and flow capacity as the vertical axis is drawn.

[0015] As a preferred scheme of the present application, target areas with development potential are screened according to water-out ratio, residual oil layer thickness and residual oil saturation, and the time-of-flight (TOF) equation is combined with the average displacement period T1 and T2 of the oilfield to diagnose the displacement energy of the target area, and three classification threshold values are specifically set: TOF≤T1, T1=0.3: strong displacement area, fluid is fully swept; T1<TOF<T2, T2=0.7: medium displacement area, fluid is generally swept; TOF≥T2: weak displacement area, insufficient driving energy, difficult to produce.

[0016] As a preferred scheme of the present application, based on the dynamic heterogeneity coefficient and the well group dynamic Lorenz coefficient range, the strong / weak heterogeneity area is divided according to the heterogeneity regulation threshold value, and the strong / weak heterogeneity area is divided according to the heterogeneity regulation threshold value, wherein, ; The range of is 2 to 5, represents the dynamic heterogeneity coefficient, represents the well group dynamic Lorenz coefficient range.

[0017] As a preferred scheme of the present application, for the strong heterogeneity area, measures such as profile control, water plugging, injection-production reconstruction and well pattern reorganization are taken; For the weak heterogeneity area, it is determined whether to enhance the displacement efficiency by injection-production synchronization liquid lifting or drilling infill wells according to the flow field development intensity.

[0018] The present application has the following beneficial effects compared with the prior art: The application breaks through the limitation of static parameter representation by fluid flow response characteristics, couples key dynamic parameters such as time of flight (TOF) and dynamic Lorentz coefficient, establishes a multi-dimensional development effect evaluation system, realizes the collaborative quantitative evaluation of injection-production connectivity, displacement sweep intensity and heterogeneity degree, and automatically generates a differentiated regulation strategy based on the evaluation results, thereby significantly improving the remaining oil tapping precision and development economic benefit of high water cut reservoirs.

[0019] The application overcomes the problems in the prior art that dynamic heterogeneity is difficult to quantify, injection-production connectivity is insufficiently represented, calculation efficiency is low and real-time decision cannot be made, and the adaptability of evaluation at the high water cut stage is poor. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only exemplary, and other drawings can be obtained by the provided drawings without creative labor for those skilled in the art.

[0021] Figure 1 It is a dynamic F-Φ curve diagram of the present application, showing the curve characteristics of homogeneous and heterogeneous reservoirs; Figure 2 It is a multi-dimensional development effect evaluation system constructed in the present application; Figure 3 It is a development effect dynamic diagnosis and optimization decision flowchart in the present application; Figure 4 It is a well location map constructed in the embodiment X block in the present application; Figure 5 It is the expected effect after comprehensive evaluation and adjustment of the X block in the present application. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0023] As Figure 1 , Figure 2 and Figure 3As shown, the present application provides a high water cut reservoir development effect evaluation and regulation method based on dynamic heterogeneity, which realizes real-time dynamic diagnosis at a second level by establishing a dynamic heterogeneity rapid evaluation model, directly solving the time of flight (TOF) equation and tracer equation based on the finite volume method, realizing the collaborative quantitative evaluation of injection-production connectivity, displacement sweep intensity and heterogeneity degree by constructing an evaluation system integrating TOF, dynamic Lorentz coefficient and other multi-dimensional indexes, and forming a hierarchical regulation strategy based on the seepage field, realizing differentiated measure optimization according to geological conditions, TOF classification and dynamic heterogeneity limits. The method significantly improves the development effect in the application of typical high water cut blocks: the calculation efficiency is improved by more than 1,000 times compared with traditional numerical simulation, the dynamic heterogeneity range is reduced by more than 40%, the block daily oil production is increased by 53m 3 , and the cumulative oil increment is predicted to be 7.69×10 4 m 3 (9.8% higher than before adjustment), and the ineffective water circulation is effectively inhibited. The present application is suitable for high water cut old oilfields, complex fault blocks and low permeability reservoirs, and has important industrial popularization value and economic benefits.

[0024] Comprise specific steps: Step 100, rapid quantitative characterization of reservoir dynamic heterogeneity based on flow diagnosis: The seepage control, time of flight (TOF) equation and tracer equation are constructed, the target key data is obtained by discrete solution with the finite volume method, and then the well pair parameters, total flight time and flow / reservoir capacity are calculated step by step, and the dynamic heterogeneity coefficient is obtained by the Lorentz curve with reservoir capacity as the horizontal axis and flow capacity as the vertical axis; Step 200, construct a multi-dimensional reservoir development effect evaluation system: Integrate geological static parameters and dynamic parameters, and introduce time of flight (TOF) and dynamic heterogeneity coefficient as core evaluation indexes, wherein time of flight (TOF) is used to quantify the time efficiency of fluid migration to identify dominant channels and stagnant zones, and dynamic heterogeneity coefficient aims to characterize displacement uniformity through Lorentz coefficient, realizing the collaborative quantitative evaluation of injection-production connectivity, displacement sweep intensity and heterogeneity degree; Step 300, generate seepage field hierarchical regulation strategy: According to the water-out ratio, remaining oil layer thickness and remaining oil saturation, target areas with development potential are screened; The time of flight (TOF) is combined with the average displacement period of the oilfield to diagnose the displacement energy of the target area; Based on the dynamic heterogeneity coefficient and the well group dynamic Lorentz coefficient range, the strong / weak heterogeneity area is divided according to the heterogeneity regulation threshold; According to the heterogeneity area type and displacement dynamic result, profile control and water plugging measures are taken for strong heterogeneity areas, and injection-production synchronous liquid lifting measures are selected for weak heterogeneity areas; Wherein, before step 300, an oilfield-specific threshold calibration database is established, and the adaptation range of the time-of-flight (TOF) classification threshold and the control threshold is determined through numerical simulation inversion and production performance correlation analysis.

[0025] In step 100, the constructed time-of-flight equation includes: a forward TOF equation from a point source to a grid, used to calculate the migration time of fluid from an injection well point source to any grid of the reservoir; a backward TOF equation from a grid to a point sink, used to calculate the migration time of fluid from any grid of the reservoir to a production well point sink; The sum of the forward TOF equation and the backward TOF equation is used to represent the difference in seepage resistance, which is controlled by the coupling of porosity, permeability, injection and production intensity, and fluid mobility, and the sum is: If the sum of the forward TOF equation and the backward TOF equation is less than the oilfield-specific stagnant flow threshold, it indicates a strong seepage advantage area; If the sum of the forward TOF equation and the backward TOF equation is greater than the oilfield-specific stagnant flow threshold, it indicates an un-impinged stagnant flow area, i.e., a potential target area.

[0026] In the process of obtaining target key data by discretization and solving with the finite volume method; First, obtain the flow field velocity, including: directly extracting the flow velocity field result output during three-dimensional multiphase flow numerical simulation; or, approximately obtaining the flow velocity field by solving the steady-state pressure equation for micro-compressible fluid; Then, discretize the time-of-flight equation and the tracer equation in a unified form, and integrate the equations in the unified form using the finite volume method.

[0027] The unified form of the time-of-flight equation and the tracer equation is: ; Wherein, is the quantity to be solved, represents the flow field velocity, represents the source-sink term vector, and when: , the unified form represents the time-of-flight equation; , the unified form represents the tracer equation; Wherein, represents the tracer concentration, represents the sum of the forward TOF equation and the backward TOF equation, represents the storage capacity value.

[0028] After discretization of the unified form, a linear equation system is obtained: wherein, represents a coefficient matrix, the elements of which are determined by grid permeability, porosity and boundary conditions; By solving the linear equation system, the time-of-flight value distribution and the tracer concentration distribution are obtained.

[0029] Based on the solved tracer concentration: The tracer concentration of the target injection well is set to 1, and the tracer concentration of other injection wells is set to 0, and the injection well tracer is solved. The tracer concentration of the target production well is set to 1, and the tracer concentration of other production wells is set to 0, and the production well tracer is solved.

[0030] All grids are arranged in ascending order of total TOF value, and flow capacity and storage capacity are calculated in turn, and a curve with storage capacity as the horizontal axis and flow capacity as the vertical axis is drawn.

[0031] According to the water-out ratio, the remaining oil layer thickness and the remaining oil saturation, target areas with development potential are screened, and the time-of-flight (TOF) equation is combined with the average displacement period T1 and T2 of the oilfield to diagnose the displacement energy of the target area. The specific setting of the three classification threshold values is as follows: TOF≤T1, T1=0.3: strong displacement area, fluid is fully swept; T1<TOF<T2, T2=0.7: medium displacement area, fluid is generally swept; TOF≥T2: weak displacement area, insufficient driving energy, difficult to produce.

[0032] Based on the dynamic heterogeneity coefficient and the well group dynamic Lorenz coefficient range, the strong / weak heterogeneity area is divided according to the heterogeneity regulation threshold value, wherein, ; the range of is 2 to 5, represents the dynamic heterogeneity coefficient, represents the well group dynamic Lorenz coefficient range.

[0033] For the strong heterogeneity area, measures such as profile control, water plugging, injection-production reconstruction and well pattern reorganization are taken; For the weak heterogeneity area, it is determined whether to enhance the displacement efficiency by injection-production synchronization or drilling infill wells according to the flow field development intensity.

[0034] The TOF equation is directly solved based on the finite volume method, which realizes real-time dynamic diagnosis and rapid response; through multi-dimensional index collaborative evaluation, the dynamic heterogeneity difference is reduced by more than 40%, which greatly improves the evaluation sensitivity and accuracy.

[0035] As Figure 4 , Figure 5 shown, in the actual application in the mine, taking the actual high water cut reservoir block as an example, the method is applied to development effect evaluation and regulation, and the effectiveness of the method is verified by numerical simulation and production dynamic data. The verification indexes include: the increase amplitude of daily oil production; cumulative incremental oil; dynamic heterogeneous range change; water drive control degree improvement, etc. The daily oil production of the block is increased by 53 m 3 , the cumulative incremental oil is 7.69 x 10 4 m 3 (9.8% higher than before adjustment), and the invalid water circulation phenomenon is effectively inhibited; at the same time, the method has wide applicability, which is not only suitable for high water cut old oilfield, but also can be popularized to complex fault block reservoir and low permeability reservoir.

[0036] Taking X block of an oilfield in eastern China as the application object, the actual effect of the method in dynamic regulation of high water cut oilfield is comprehensively evaluated. The block area is 0.91 km 2 , geological reserves are 305 x 10 4 t, it is a loose sand heavy oil reservoir with a burial depth of 1215-1338 m, with high porosity and high permeability characteristics, the average porosity is 32%, the average permeability is about 2600 mD, and the interlayer heterogeneity is significant. The viscosity of crude oil is 479-1170 mPa·s, which increases from west to east. The block has been developed since 1975, and has experienced natural energy exploitation and water drive development, and converted to polymer flooding in September 2020. By March 2024, the comprehensive water cut was 86%, the recovery degree was 34.4%, and it was a typical high water cut and high recovery "double high" reservoir, with 47 production wells, and the average daily oil production of single well was 4.5 t.

[0037] Based on CMG software, a numerical model (grid number 191,541) is established, and it is identified that long-term water drive forms obvious advantage seepage channel, and polymer flooding process is prone to channeling, which seriously affects the development effect. The method is applied to carry out system evaluation and regulation, and the specific steps are as follows: Step 1: Development effect analysis and remaining oil evaluation Under the background of polymer flooding development, the development effect of X block is evaluated based on the dynamic heterogeneous characterization method.

[0038] The total number of polymer flooding response wells in the whole area is 24, with a response efficiency of 69%, an average response time of 27 months, a net increase of 69 t / d in the average daily oil production of the response well group, and a decrease of 11.5 percentage points in the comprehensive water cut, reflecting the positive role of polymer flooding in expanding the swept volume and improving the mobility ratio. From the differences in dynamic response of typical production wells in the middle and east, it can be seen that the reservoir property heterogeneity has a significant impact on the development effect: the crude oil viscosity of D18-29 well in the middle is 1041 mPa·s, and the polymer injection has been effective for 9 months, with the daily oil production increasing from 2.3 t to 9.4 t and the water cut decreasing from 96.5% to 66.8%; while the D20-26 well in the east has not responded until 27 months after polymer injection, with the daily oil production increasing to only 6.8 t / d and the water cut still reaching 85.6%, indicating that the reservoir property in this area is poor and the chemical agent sweep efficiency is low.

[0039] Based on the time-of-flight (TOF) and dynamic Lorentz coefficient analysis, the remaining oil in the whole area can be divided into two main distribution types: one is the interwell retention type (accounting for more than 70%), mainly affected by the complex reservoir structure and the difference in layer permeability, making it difficult for the injected fluid to displace uniformly, which is the focus of future potential tapping; the other is the well-controlled enrichment type (accounting for about 30%), mainly distributed in the edge of the reservoir, with thin oil layers but good remaining oil preservation, which can be developed through infill wells or supplemental hole measures. As of March 2024, the remaining geological reserves in the whole area were 200×10 4 t, of which the main layer Ng35 contributed 97×10 4 t, with a recovery degree of 39.0%, higher than the average value of the oilfield, and the remaining oil distribution in the layer was characterized by high top and low bottom, which further increased the difficulty of tapping potential.

[0040] Step 2: Definition of technical limits by multi-index technology To scientifically guide the development adjustment, combined with the development effect evaluation and optimization adjustment process proposed in this paper, this study integrates geological static parameters, dynamic production response and economic development lower limit to establish a technical limit system for X block control measures.

[0041] 1. The geological limit takes economic feasibility as the core, sets the deployment threshold of new wells under the condition of 60 US dollars per barrel of oil price, requires the target area remaining oil saturation to be greater than 55%, effective thickness to be greater than 4 m, watered thickness ratio to be less than 45%, and distance from the edge of the water front to be more than 300 m, to ensure that the new well has sufficient material basis and good exploitation conditions. When taking measures such as plugging, supplemental hole, adjusting injection and liquid production, the lower limit of the parameters can be flexibly adjusted according to the actual situation to ensure that the adjustment area has sufficient material basis, so as to realize the incremental cumulative oil production after adjustment greater than the operation cost.

[0042] 2, TOF limit: Flow field diagnosis shows that the 10 chemical flooding ineffective wells in the region are mainly concentrated in the strong displacement area with TOF <20 days, indicating that high-speed percolation channels are prone to short-circuit flow, leading to the injection of polymer by fluid flushing, and the stability of water shutoff and profile control system decreases significantly. At the same time, statistics show that the remaining oil in the area with TOF >200 days cannot be produced.

[0043] According to the time of flight (TOF) parameter, the percolation field of the study area is divided into three types of dynamic regions: the first class is the strong advantage flow field (TOF ≤ 20 days), the percolation resistance is small, and the channeling flow is easy to occur; the second class is the transition area (20 days<TOF<200 days), the flow field development degree is moderate; the third class is the weak producing stagnant flow area (TOF ≥ 200 days), the fluid migration is slow, and the remaining oil is rich.

[0044] 3, Dynamic heterogeneity limit: The dynamic Lorenz coefficient range of well group is the core index for dynamic heterogeneity discrimination. Statistical analysis shows that the well group with dynamic Lorenz coefficient range >3 generally has problems such as uneven displacement and development of dominant channeling channels, so the dynamic Lorenz coefficient range >3 is used as the limit to judge the balance of displacement and guide the implementation of adjustment and control measures, providing quantitative decision basis for differentiated adjustment and control.

[0045] Step 3: Flow field classification and differentiated adjustment and control strategy Based on the evaluation results of percolation field classification and dynamic heterogeneity, this study proposes a set of classification adjustment strategy with “flow field identification-classification control” as the core.

[0046] For the first-class dominant channel area with TOF ≤ 20 days and dynamic Lorenz coefficient range >3, the key measures are water shutoff and profile control and polymer concentration improvement. By gradually increasing the polymer concentration from 2500 mg / L to 3200 mg / L, the large pores are effectively plugged, the channeling flow is inhibited, and the displacement efficiency is improved.

[0047] For the second-class transition area with TOF between 20-200 days and the third-class stagnant flow area with TOF ≥ 200 days, the focus is on injection-production parameter optimization and well pattern adjustment. By deploying infill wells or implementing supplemental hole measures in the area with remaining oil saturation greater than 55%, the reservoir producing degree is improved.

[0048] This strategy system emphasizes “combination of plugging and adjustment, hierarchical management”, which not only focuses on inhibiting the ineffective water circulation of high permeability channels, but also activates the potential of remaining oil in low permeability areas, realizing the synergy of advantage flow field inhibition and potential area strengthening, and providing a systematic and feasible adjustment and control path for high water cut oilfield development.

[0049] Step 4: Key adjustment measure implementation suggestion In the specific adjustment measures, the present application proposes three types of key measures according to the flow field diagnosis results and dynamic heterogeneous characteristics.

[0050] 1. For the production well in the fluid sparse area, such as D18-27 well, a liquid lifting measure is implemented, the liquid production is increased to 60 m 3 / d, the production pressure difference is increased, the fluid is guided into the low saturation area, and the well group displacement balance is improved.

[0051] 2. In the remaining oil highly enriched area (such as Ng35 layer D20X27 well south side), a horizontal well X1 is deployed, the TOF is less than 200 days, the remaining oil saturation is 60%, and the multi-stage fracturing and intelligent completion technology is used to realize directional potential tapping.

[0052] 3. The concentration and injection-production parameter differentiation adjustment is carried out for 12 polymer injection wells: the polymer injection well in the high permeability area uses super high concentration polymer to plug large pores; the injection-production ratio is flexibly adjusted according to the real-time dynamic monitoring data in the medium permeability area to balance the pressure field; and the periodic water injection and nano oil displacement agent injection are combined in the low permeability area to synergistically improve the microscopic oil displacement efficiency.

[0053] The three types of measures jointly constitute a three-dimensional adjustment mode of "liquid lifting and displacement guiding, infilling and production increasing, and combination of adjustment and plugging", which comprehensively improves the development efficiency of the block.

[0054] Step 5: development effect prediction and benefit evaluation The above control scheme is introduced into the CMG numerical simulator to predict the development effect of the method in 2024-2035.

[0055] 1. From the single well effect, the new drilled horizontal well X1 is expected to produce 8.95 m 3 of oil per day at the initial stage of opening, the water cut is 74.4%, the five-year cumulative oil production is 1.4×10 4 t, and the annual average water cut increase is controlled within 3%, effectively activating the interwell weakly producing area; the liquid lifting well D18-27 increases the daily oil production from 12 m 3 to 23 m 3 after lifting, the water cut decreases to 60.8%, the five-year cumulative oil production increases by 1.24×10 4 t, and the recovery degree increases by 0.6%.

[0056] 2. From the well group control effect, after the polymer concentration of the typical well group D21-28 is increased to 3200 mg / L, the average value of the dynamic Lorenz coefficient decreases from 0.24 to 0.17, and the range decreases from 4.05 to 2.4, indicating that the displacement balance is effectively improved.

[0057] 3. The comprehensive prediction results of the whole area show that the daily oil production of the block is increased by 53 m 3, and the peak oil production of 275 m 3 / d, 23.8% higher than the base case; and the cumulative incremental oil production of 7.69×10 4 m 3 (9.8% higher than the unadjusted case).

[0058] The prediction proves that the regulation strategy can significantly improve the development benefit of high water-cut oilfields, and provides an economic and effective development adjustment mode for similar reservoirs.

[0059] The above examples are only exemplary embodiments of the present application and are not intended to limit the present application, and the protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present application within the spirit and protection scope of the present application, and such modifications or equivalent replacements shall also be considered to fall within the protection scope of the present application.

Claims

1. A method for evaluating and controlling the development effect of high water-cut reservoirs based on dynamic heterogeneity, characterized in that, Including specific steps: Step 100: Rapid quantitative characterization of reservoir dynamic heterogeneity based on flow diagnostics: The flow control, time-of-flight (TOF) equations and tracer equations are constructed. The key target data are obtained by discretizing the solution using the finite volume method. Then, the well pair parameters, total time of flight and flow / reservoir capacity are calculated step by step. The dynamic heterogeneity coefficient is obtained by plotting the reservoir capacity on the horizontal axis and the flow capacity on the vertical axis. Step 200: Construct a multi-dimensional reservoir development effect evaluation system: By integrating static and dynamic geological parameters, the time of flight (TOF) and dynamic heterogeneity coefficient are introduced as core evaluation indicators. The time of flight (TOF) is used to quantify the timeliness of fluid transport to identify dominant channels and stagnant zones, while the dynamic heterogeneity coefficient is used to characterize displacement uniformity through the Lorentz coefficient, thereby achieving a synergistic quantitative evaluation of injection-production connectivity, displacement sweep intensity, and heterogeneity. Step 300: Generate a hierarchical control strategy for the seepage field. Target areas with development potential are selected based on the water flooding ratio, remaining oil layer thickness, and remaining oil saturation. The displacement energy of the target area is diagnosed by combining time of flight (TOF) with the average displacement cycle of the oilfield. Strong / weak heterogeneous zones are distinguished based on the dynamic heterogeneity coefficient and the range of the dynamic Lorentz coefficient of the well group, according to the heterogeneity control threshold. Furthermore, based on the type of heterogeneous region and the dynamic results of displacement, profile control and water shut-off measures are adopted for strongly heterogeneous regions, and simultaneous injection and production fluid extraction measures are selected for weakly heterogeneous regions. Before proceeding to step 300, an oilfield-specific threshold calibration database is established. Through numerical simulation inversion and production dynamic correlation analysis, the compatibility range between the time-of-flight (TOF) classification threshold and the control threshold is determined.

2. The method for evaluating and controlling the development effect of high water-cut oil reservoirs based on dynamic heterogeneity according to claim 1, characterized in that, In step 100, the flight time is calculated using the constructed flight time equation, which includes: The forward TOF equation from point source to grid is used to calculate the migration time of fluid from the injection well point source to any grid in the reservoir. The backward TOF equation from grid to sink is used to calculate the migration time of fluid from any grid in the reservoir to the production well sink. The sum of the forward TOF equation and the backward TOF equation is used to characterize the difference in seepage resistance. Its value is controlled by the coupling of porosity, permeability, injection-production intensity, and fluid mobility. Furthermore, it utilizes: The sum of the forward TOF equation and the backward TOF equation being less than the oilfield-specific stagnation threshold indicates a region with strong seepage dominance. If the sum of the forward TOF equation and the backward TOF equation is greater than the oilfield-specific stagnation threshold, it indicates that the stagnation zone has not been affected, i.e., the potential target area.

3. The method for evaluating and controlling the development effect of high water-cut reservoirs based on dynamic heterogeneity according to claim 2, characterized in that, In obtaining key target data through discrete solution using the finite volume method; First, obtain the flow field velocity, including: Directly extract the velocity field results output from the three-dimensional multiphase flow numerical simulation; Alternatively, the microcompressible fluid can be approximated by solving the steady-state pressure equation; The time-of-flight equation and the tracer equation are then discretized in a unified form, and the unified form of the equation is integrated using the finite volume method.

4. The method for evaluating and controlling the development effect of a high water cut reservoir based on dynamic heterogeneity according to claim 3, wherein The unified form of the travel time equation and the tracer equation is: ； in, For the quantity to be solved, Indicates the flow velocity. Represents the source and sink vectors. And when: , At that time, the unified form is expressed as the flight time equation; , In this case, the unified form is represented as the tracer equation; in, Indicates tracer concentration, This represents the sum of the forward TOF equations and the backward TOF equations. This represents the storage capacity value.

5. The method for evaluating and controlling the development effect of a high water cut reservoir based on dynamic heterogeneity according to claim 3, wherein After discretizing the unified form, a linear equation system is obtained: ,in, This represents the coefficient matrix, whose elements are determined by the grid permeability, porosity, and boundary conditions. By solving the linear equation system, the travel time value distribution and the tracer concentration distribution are obtained.

6. The method for evaluating and controlling the development effect of a high water cut reservoir based on dynamic heterogeneity according to claim 5, wherein Based on the solved tracer concentration: Set the tracer concentration of the target injection well to 1 and that of other injection wells to 0, and solve to obtain the injection well tracer; Set the tracer concentration of the target production well to 1 and that of other production wells to 0, and solve to obtain the production well tracer.

7. The method for evaluating and controlling the development effect of a high water cut reservoir based on dynamic heterogeneity according to claim 1, wherein Sort all grids in ascending order of total TOF value and calculate the flow capacity accordingly. and storage capacity And plot the Lorentz curve with storage capacity as the horizontal axis and flow capacity as the vertical axis.

8. The method for evaluating and controlling the development effect of a high water cut reservoir based on dynamic heterogeneity according to claim 1, wherein Screen the target areas with development potential according to the water flooding ratio, the remaining oil layer thickness and the remaining oil saturation, and use the travel time (TOF) equation combined with the average displacement periods T1 and T2 of the oilfield to diagnose the displacement energy of the target areas, and specifically set three-level classification thresholds: TOF ≤ T1, T1 = 0.3: Strong displacement area, with sufficient fluid sweep; T1 < TOF < T2, T2 = 0.7: Medium displacement area, with general fluid sweep; TOF ≥ T2: Weak displacement area, with insufficient driving energy and difficult to mobilize.

9. The method for evaluating and controlling the development effect of a high water cut reservoir based on dynamic heterogeneity according to claim 1, wherein The range of the dynamic heterogeneity coefficient and the dynamic Lorenz coefficient of the well group is used to distinguish between strong and weak heterogeneous zones according to the heterogeneity control threshold, and the strong and weak heterogeneous zones are further distinguished by the heterogeneity control threshold. ; The range is 2 to 5. Indicates the coefficient of dynamic heterogeneity. This indicates the range of dynamic Lorentz coefficients for the well group.

10. The method for evaluating and controlling the development effect of a high water cut reservoir based on dynamic heterogeneity according to claim 1, wherein For areas with strong heterogeneity, take measures such as profile control and water plugging, injection-production reconstruction and well pattern reorganization; For areas with weak heterogeneity, decide whether to enhance the displacement efficiency by simultaneous injection-production liquid lifting or drilling infill wells according to the development intensity of the flow field.

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