Residual oil distribution evaluation method based on multi-scale joint numerical modeling

Abstract

The invention belongs to the technical field of quantitative characterization evaluation of residual oil in oilfield development, and discloses a residual oil distribution evaluation method based on multi-scale joint numerical modeling, which comprises the following steps of: determining characteristic parameters of related geology, fluid, engineering, production and the like of a to-be-analyzed and evaluated area of residual oil; establishing a comprehensive analysis model of the overall multi-scale residual oil value of the block according to various characteristic parameters; carrying out yield simulation pre-processing on all the oil production wells in the block based on the block overall multi-scale residual oil value comprehensive analysis model; fitting the predicted yield and the actual yield of the block overall multi-scale residual oil value comprehensive analysis model by adjusting parameters in the block overall multi-scale residual oil value comprehensive analysis model; and correcting the oil saturation simulation result of the reservoir near each well, obtaining the oil saturation distribution field map of the current reservoir, and analyzing and evaluating the remaining oil. The method has higher timeliness, can provide an accurate fracture parameter source for an oil reservoir numerical analysis model, and further ensures the accuracy of the distribution position and quantity of the remaining oil in the current reservoir.

Description

Technical Field

[0001] This invention relates to the field of quantitative characterization and evaluation technology of residual oil in oilfield development, and specifically to a method for evaluating the distribution of residual oil based on multi-scale joint numerical modeling. Background Technology

[0002] Currently, most oilfields in China still produce mainly conventional oil, and most of these oilfields have entered the high water-cut production stage. However, due to various factors such as geological structure, reservoir heterogeneity, sand body distribution patterns, and injection-production well network distribution, a large amount of residual oil resources are still distributed within the reservoirs. Accurately describing the distribution location and reserves of residual oil is an important research topic in the middle and late stages of water injection development in oilfields, and it is of great significance for improving recovery rate and adjusting development plans.

[0003] With the updating and iteration of residual oil tapping technology, the scale of residual oil research has been further refined from the two perspectives of macro and micro to the current four perspectives of micro scale, small scale, large scale and macro scale. The research methods have also developed into comprehensive geological analysis, mine monitoring and interpretation, laboratory experimental analysis and numerical simulation interpretation. However, different residual oil analysis methods have their own characteristics and applicability.

[0004] Numerical simulation, as one of the main research methods for quantitative analysis of remaining oil, primarily utilizes various dynamic and static data based on geological models, employing historical data fitting as an accuracy verification standard to understand various fluid and reservoir characteristics. This method is characterized by the use of diverse data types, a large simulation time span, and the potential for various stimulation measures on oil and water wells during the simulation period. Furthermore, it suffers from drawbacks such as the inability of the considered conditions to fully reflect actual block production and stimulation conditions, and the limited availability of criteria for verifying model accuracy. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method for evaluating the distribution of remaining oil based on multi-scale joint numerical modeling. By establishing a comprehensive numerical model of various types, such as a production geological model, a production dynamic analysis model, and a reservoir numerical analysis model, and by repeatedly correcting the simulation results to ensure the accuracy of the model, a quantitative evaluation and analysis of remaining oil is carried out.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0007] A method for evaluating the distribution of remaining oil based on multi-scale joint numerical modeling includes the following steps:

[0008] (1) Determine the relevant geological, fluid, engineering, and production characteristics of the area to be analyzed and evaluated for remaining oil, and establish a multi-scale numerical comprehensive analysis model of remaining oil for the entire block based on various characteristic parameters;

[0009] (2) Based on the multi-scale numerical comprehensive analysis model of remaining oil in the block, the production of all oil wells in the block is simulated and predicted.

[0010] (3) By adjusting the parameters in the overall multi-scale residual oil numerical comprehensive analysis model of the block, the predicted output of the overall multi-scale residual oil numerical comprehensive analysis model of the block is fitted to the actual output;

[0011] (4) Correct the simulation results of oil saturation of reservoirs near each well, obtain the current oil saturation distribution field map of reservoirs, and analyze and evaluate the remaining oil.

[0012] Furthermore, step (1) includes: establishing a multi-scale numerical comprehensive analysis model of remaining oil in the block, which includes a geological model, a production dynamic analysis model, and a reservoir numerical analysis model. The geological model provides the reservoir numerical analysis model with well information such as wellhead location and well trajectory, as well as reservoir attribute information such as porosity, permeability, initial oil saturation, and initial water saturation, and structural location information. The production dynamic analysis model provides the reservoir numerical analysis model with fracture information such as fracture length, height, and conductivity. Combined with relative permeability curves and PVT parameters, a numerical analysis model of the block's overall reservoir is established.

[0013] Furthermore, step (2) includes: after the establishment of the overall reservoir numerical analysis model of the block, the actual injection and production system of all oil production wells and water injection wells in the block is used as the injection and production system of the overall reservoir numerical analysis model of the block to simulate and predict the production output of the oil production wells.

[0014] Furthermore, step (3) includes: historically fitting the predicted production and actual production of all oil wells in the block to the parameters such as relative permeability, PVT, and fluid properties in the overall reservoir numerical analysis model of the block.

[0015] Furthermore, step (4) includes: comparing the oil saturation of the reservoir near each well after the historical fitting of production data in the overall reservoir numerical analysis model of the block with the current measured oil saturation of the reservoir. If the comparison results are inconsistent, the production dynamic analysis and production history fitting are repeated until the error between the predicted oil saturation and the measured oil saturation near each production well and injection well is within 10%. Then, the oil saturation field map is output to interpret and evaluate the current remaining oil distribution of the reservoir.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] Compared to existing reservoir numerical simulation methods, this invention firstly acquires information such as well information, reservoir attributes, and structural locations through a finely characterized geological model, fully considering the impact of reservoir heterogeneity on remaining oil saturation. Secondly, by establishing a production dynamic analysis model, this invention utilizes the production dynamic data of each oil and water well within the block to obtain current fracture parameters of wells that have undergone fracturing or acidizing. Compared to fracture parameters obtained using fracturing simulation software, this method is more timely and provides an accurate source of fracture parameters for reservoir numerical analysis models. Finally, based on historical fitting of production data, this invention further calibrates the model by comparing the simulated oil saturation near the wells with the measured oil saturation from well logging, thereby ensuring the accuracy of the current distribution location and quantity of remaining oil in the reservoir. Attached Figure Description

[0018] Figure 1 This is an analytical flowchart of a method for evaluating the distribution of residual oil based on multi-scale joint numerical modeling;

[0019] Figure 2 It is a detailed geological model of the remaining oil analysis and evaluation block;

[0020] Figure 3 It is the double logarithmic fitting curve of the production dynamics analysis model;

[0021] Figure 4 It is a numerical analysis model of the entire oil reservoir in the block;

[0022] Figure 5 It is a historical fitting curve between real production data and simulated production data;

[0023] Figure 6 It is a comparison between measured oil saturation and simulated oil saturation data;

[0024] Figure 7 This is a map showing the current oil saturation field distribution of the reservoir. Detailed Implementation

[0025] To make the technical problems, technical solutions, and advantages of the present invention clearer, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments. However, the scope of protection of the present invention is not limited to the following description:

[0026] Example 1

[0027] This invention provides a method for evaluating the distribution of remaining oil based on multi-scale joint numerical modeling, the specific implementation process of which is as follows: Figure 1 As shown, it includes the following steps:

[0028] (1) The established block-wide multi-scale residual oil numerical comprehensive analysis model includes a geological model, a production dynamic analysis model, and a reservoir numerical analysis model. The geological model provides the reservoir numerical analysis model with well information such as wellhead location and well trajectory, as well as reservoir attribute information such as porosity, permeability, initial oil saturation, and initial water saturation, and structural location information. The production dynamic analysis model provides the reservoir numerical analysis model with fracture information such as fracture length, height, and conductivity. Combined with relative permeability curves and PVT parameters, a block-wide reservoir numerical analysis model is established.

[0029] (2) After the establishment of the overall reservoir numerical analysis model of the block, the actual injection and production system of all oil production wells and water injection wells in the block is used as the injection and production system of the overall reservoir numerical analysis model of the block to simulate and predict the production of oil production wells.

[0030] (3) By adjusting parameters such as relative permeability, PVT, and fluid properties in the overall reservoir numerical analysis model of the block, the predicted production and actual production of all oil wells in the block are historically fitted.

[0031] (4) Compare the oil saturation of the reservoir near each well after the historical fitting of production data in the numerical analysis model of the overall reservoir of the block with the current measured oil saturation of the reservoir. If the comparison results are inconsistent, the production dynamic analysis and production history fitting are repeated until the error between the predicted oil saturation and the measured oil saturation near each production well and injection well is within 10%. Output the oil saturation field map to interpret and evaluate the current remaining oil distribution of the reservoir.

[0032] Step (1) specifically includes:

[0033] First, based on the actual wellhead location, well trajectory, and reservoir attribute information (including Ф, K, P, S) of the block... O S W Based on constructed data such as the distribution of stratified contour lines, as shown in Tables 1 and 2.

[0034] Table 1 Well trajectory data

[0035]

[0036] Table 2 Sub-layer Stratification Data

[0037] Explanation of serial number Small floor number Depth (m) Bottom depth (m) Thickness (m) Explanation of conclusions 37 qn1-12 1873.8 1875.1 1.3 dry layer 38 qn1-12 1875.1 1877.9 2.8 Oil and water in the same layer / qn1-12 1877.9 1885.2 7.3 / / qn1-13 1885.2 1893.4 8.2 / 39 qn1-14 1893.4 1894.8 1.4 Poor oil layer 40 qn1-14 1895.4 1896.1 0.7 Oil and water in the same layer 41 qn1-14 1897 1898 1 Oil and water in the same layer

[0038] Based on the above data, establish Figure 2 The model shows a detailed geological model of the remaining oil analysis and evaluation block. Next, analytical models for the production dynamics analysis of each well in the block are established, and historical data fitting is performed to correct the dynamic analysis model. This yields the current fracture parameters for each target well, providing data support for the fracture parameters in the overall reservoir numerical analysis model of the block. Figure 3To produce a double logarithmic fitting curve for the dynamic analysis model; finally, combining the existing relative permeability curves and PVT parameters of the block, where the PVT parameters are shown in Table 3, a model is established as follows. Figure 4 The numerical analysis model of the overall oil reservoir in the block shown.

[0039] Table 3 PVT parameters

[0040]

[0041] The software used for establishing the detailed geological model in this step is Petrel, the software used for establishing the production dynamic analysis model is Topaze, and the software used for establishing the overall reservoir numerical analysis model of the block is Wellwhiz. However, other software that meets the functional requirements can also be used in practical applications.

[0042] Step (2) specifically includes:

[0043] After the overall reservoir numerical analysis model of the block is established, the actual injection and production regime of all oil production wells and water injection wells in the block is used as the injection and production regime of the overall reservoir numerical analysis model of the block to simulate and predict the production output of oil production wells.

[0044] Step (3) specifically includes:

[0045] By adjusting parameters such as relative permeability, PVT, and fluid properties in the overall reservoir numerical analysis model of the block, historical fitting was performed on the predicted and actual production rates of all oil wells within the block. The historical fitting results are as follows: Figure 5 As shown.

[0046] Step (4) specifically includes:

[0047] The oil saturation near each well in the overall reservoir numerical analysis model of the block, after historical fitting of production data, is compared with the current measured oil saturation. If the comparison results are inconsistent, production dynamic analysis and historical fitting are repeated until the error between the predicted and measured oil saturation near each production well and injection well is within 10%. Based on the accurate prediction of oil saturation near each well, an oil saturation field map is output to interpret and evaluate the current distribution of remaining oil in the reservoir, providing a basis for subsequent adjustment of the injection-production well network and selection of oil and water well measures.

Claims

1. A method for evaluating the distribution of remaining oil based on multi-scale joint numerical modeling, characterized in that, Includes the following steps: (1) Determine the relevant geological, fluid, engineering, and production characteristic parameters of the area to be analyzed and evaluated for remaining oil, and establish a multi-scale numerical comprehensive analysis model of remaining oil for the entire block based on various characteristic parameters; (2) Based on the multi-scale numerical comprehensive analysis model of remaining oil in the block, the production of all oil wells in the block is simulated and predicted. (3) By adjusting the parameters in the overall multi-scale residual oil numerical comprehensive analysis model of the block, the predicted output of the overall multi-scale residual oil numerical comprehensive analysis model of the block is fitted to the actual output; (4) Correct the simulation results of oil saturation of reservoirs near each well, obtain the current oil saturation distribution field map of reservoirs, and analyze and evaluate the remaining oil.

2. The method for evaluating the distribution of remaining oil based on multi-scale joint numerical modeling as described in claim 1, characterized in that, Step (1) includes: establishing a multi-scale numerical comprehensive analysis model of remaining oil in the block, including a geological model, a production dynamic analysis model, and a reservoir numerical analysis model.

3. The method for evaluating the distribution of remaining oil based on multi-scale joint numerical modeling as described in claim 2, characterized in that, The geological model is a numerical analysis model for oil reservoirs, providing well information including wellhead location and well trajectory, as well as reservoir attribute information such as porosity, permeability, initial oil saturation, and initial water saturation, and structural location information.

4. The method for evaluating the distribution of remaining oil based on multi-scale joint numerical modeling as described in claim 2, characterized in that, The production dynamic analysis model provides the reservoir numerical analysis model with fracture information such as fracture length, height, and conductivity.

5. The method for evaluating the distribution of remaining oil based on multi-scale joint numerical modeling according to claim 2, characterized in that, The production dynamic analysis model, combined with the relative permeability curve and PVT parameters, establishes a numerical analysis model for the overall reservoir of the block.

6. The method for evaluating the distribution of remaining oil based on multi-scale joint numerical modeling according to claim 1, characterized in that, Step (2) includes: After the overall reservoir numerical analysis model of the block is established, the actual injection and production system of all oil production wells and water injection wells in the block is used as the injection and production system of the overall reservoir numerical analysis model of the block to simulate and predict the production output of oil production wells.

7. The method for evaluating the distribution of remaining oil based on multi-scale joint numerical modeling according to claim 1, characterized in that, Step (3) includes: historical fitting of the predicted production and actual production of all oil wells in the block by adjusting the relative permeability, PVT and fluid property parameters in the overall reservoir numerical analysis model of the block.

8. The method for evaluating the distribution of remaining oil based on multi-scale joint numerical modeling according to claim 1, characterized in that, Step (4) includes: comparing the oil saturation of the reservoir near each well after the historical fitting of production data in the overall reservoir numerical analysis model of the block with the current measured oil saturation of the reservoir. If the comparison results are inconsistent, the production dynamic analysis and production history fitting are repeated until the error between the predicted oil saturation and the measured oil saturation near each production well and injection well is within 10%. Then, the oil saturation field map is output to interpret and evaluate the current distribution of remaining oil in the reservoir.

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