Interwell connectivity evaluation method based on fracturing interference data
By analyzing the pressure curves and weighted response values of fracturing interference data, the problem of relying on geological models in existing interwell connectivity evaluation methods is solved, and low-cost and efficient interwell connectivity evaluation is achieved.
Patent Information
- Application Number
- CN202410323706.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-21
- Publication Date
- 2025-09-23
AI Technical Summary
Existing inter-well connectivity evaluation methods rely on the quality of geological models, resulting in low evaluation accuracy, high cost, complex operation, and poor versatility.
By analyzing fracturing interference data, including pressure curve drawing of fracturing wells and monitoring wells, interference type classification and weighted pressure response value calculation, the cost and complexity of connectivity evaluation between fracturing wells and monitoring wells are reduced.
It realizes simple and easy inter-well connectivity evaluation, reduces costs and improves the accuracy and versatility of evaluation.
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Figure CN120688899A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of oil and gas field exploration, and in particular to a method for evaluating inter-well connectivity based on fracturing interference data. Background Art
[0002] In the field of oil and gas field exploration and development, the significance of studying interwell connectivity lies in understanding the geological and fluid connectivity between different oil and gas wells in the oil and gas field, so as to formulate the optimal oil production and development plan and maximize the recovery rate. In addition, studying interwell connectivity can also reduce environmental risks and improve economic benefits. It is of great significance to the efficient development of oil and gas fields, reducing costs and reducing environmental risks.
[0003] Currently, the following methods are available for evaluating interwell connectivity: geological connectivity evaluation based on geological models and well logging data; interwell fluid connectivity evaluation based on dynamic data and numerical simulation; and interwell physical property inversion evaluation based on well logging data and interwell fluid dynamic data. The interwell connectivity evaluation obtained through these evaluation methods has many advantages, including high result accuracy, comprehensive evaluation content, and a wide range of applications. However, these connectivity evaluation methods often require a large amount of actual data support and are also highly dependent on the quality of the geological model. The quality of the geological model will directly affect the accuracy of the evaluation results. These connectivity evaluation methods are also relatively complex, requiring a large amount of manpower, material, and financial resources during the evaluation process, resulting in high costs. Furthermore, the evaluation results are highly dependent on the geological model, making them less versatile. Summary of the Invention
[0004] The purpose of this application is to provide a well connectivity evaluation method based on fracturing interference data, which overcomes the shortcomings of other methods such as complex operating procedures, multiple operation requirements and high costs, reduces the cost of connectivity evaluation between fracturing wells and monitoring wells, and the method is simple and easy to implement.
[0005] This application is implemented as follows:
[0006] The present application provides a method for evaluating inter-well connectivity based on fracturing interference data, comprising the following steps:
[0007] S1. Analyze and process the fracturing wells and corresponding monitoring wells involved in the fracturing interference data;
[0008] S2. Divide the fracturing sections according to the fracturing time of the fracturing well, and draw a pressure curve diagram of the fracturing well and the corresponding monitoring well during the fracturing process;
[0009] S3. Classify the fracturing interference type of the fracturing well;
[0010] S4. Calculating the pressure response value changes of different fracturing interference types based on the pressure response characteristics of the monitoring well corresponding to the fracturing well;
[0011] S5. Based on the fracturing interference type and geological data, an interference weight value is given for each fracturing section. The weighted interference pressure response value of each monitoring well is calculated by combining the interference weight value and the pressure response value of different fracturing interference types. The percentage of the interference pressure response value of each monitoring well to the interference pressure response values of all monitoring wells is calculated.
[0012] In some optional implementation schemes, before step S1, the fracturing interference data are collated and the well groups are divided according to the field production data to determine the fracturing wells and monitoring wells.
[0013] In some optional implementation schemes, data mining methods are used to organize and improve the fracturing interference data.
[0014] In some optional implementation schemes, when analyzing and processing the fracturing wells and monitoring wells involved in the fracturing interference data, missing values and abnormal values are processed by interpolation.
[0015] In some optional implementation schemes, when analyzing and processing the fracturing wells and monitoring wells involved in the fracturing interference data, the influence of the data variable dimension and variation range is eliminated by using the range normalization method.
[0016] In some optional embodiments, when dividing the fracturing stages by the fracturing time of the fracturing well, the fracturing stages are divided based on the fracturing time of the construction well.
[0017] In some optional embodiments, the fracturing interference types are classified based on the fracturing curve characteristics and pressure response characteristics of the monitoring well corresponding to the fracturing well.
[0018] In some optional embodiments, the percentage of the interference pressure response value of each monitoring well to the interference pressure response values of all monitoring wells is used to measure the percentage of the degree of connectivity between the fracturing well and the monitoring well.
[0019] The beneficial effects of the present application are as follows: the inter-well connectivity evaluation method based on fracturing interference data provided by the present application comprises the following steps: analyzing and processing the fracturing wells and corresponding monitoring wells involved in the fracturing interference data; dividing the fracturing sections according to the fracturing time of the fracturing wells, and drawing pressure curves of the fracturing wells and the corresponding monitoring wells during the fracturing process; dividing the fracturing interference types of the fracturing wells; calculating the changes in pressure response values of different fracturing interference types according to the pressure response characteristics under the monitoring wells corresponding to the fracturing wells; giving interference weight values of each fracturing section based on the fracturing interference type and geological data, calculating the weighted interference pressure response values of each monitoring well by combining the interference weight values and the pressure response values of different fracturing interference types, and calculating the percentage of the interference pressure response value of each monitoring well to the interference pressure response values of all monitoring wells. The inter-well connectivity evaluation method based on fracturing interference data provided in this application evaluates the connectivity between the fracturing well and the monitoring well by utilizing the wellhead pressure monitoring data of the fracturing well and the monitoring well during the fracturing process. It can overcome the shortcomings of other methods such as complex operating procedures, multiple operation requirements, and high costs, reduce the cost of connectivity evaluation between fracturing wells and monitoring wells, and the method is simple and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.
[0021] Figure 1 A flow chart of a method for evaluating well connectivity based on fracturing interference data provided in an embodiment of the present application;
[0022] Figure 2 A schematic diagram of pressure curves of a fracturing well and a corresponding monitoring well in the well connectivity evaluation method based on fracturing interference data provided in an embodiment of the present application;
[0023] Figure 3 A schematic diagram of pressure response in which the interference type is a fracturing shadow interference response in the well connectivity evaluation method based on fracturing interference data provided in an embodiment of the present application;
[0024] Figure 4 A schematic diagram of pressure response in an inter-well connectivity evaluation method based on fracturing interference data provided in an embodiment of the present application, where the interference type is a pressure-through interference response;
[0025] Figure 5 A schematic diagram of pressure response to simultaneous effects of multiple interferences in the well connectivity evaluation method based on fracturing interference data provided in an embodiment of the present application;
[0026] Figure 6 A line graph showing the pressure change values of each monitoring well during the fracturing process of each section of a fracturing well in the inter-well connectivity evaluation method based on fracturing interference data provided in an embodiment of the present application;
[0027] Figure 7 A histogram of the connectivity percentages between fracturing wells and monitoring wells in the well connectivity evaluation method based on fracturing interference data provided in an embodiment of the present application. DETAILED DESCRIPTION
[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with 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 of the embodiments.
[0029] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.
[0030] The features and performance of the inter-well connectivity evaluation method based on fracturing interference data of the present application are further described in detail below with reference to the examples.
[0031] like Figure 1 As shown, the present application provides a method for evaluating well connectivity based on fracturing interference data, comprising the following steps:
[0032] S0. Arrange the fracturing interference data and divide the well groups according to the field production data to determine the fracturing wells and monitoring wells;
[0033] S1. Read the pressure monitoring data of the fracturing well and monitoring well during the fracturing process, draw a pressure-time curve, and determine whether the curve contains missing values or outliers. If missing values or outliers exist, use the DT interpolation method to handle the missing and outlier data. After confirming the data integrity, use the min-max normalization method to normalize the data itself to obtain the standardized time and pressure data;
[0034] Specifically, the DT interpolation method includes the following steps:
[0035] Calculate information gain: IG(X, Y) = H(Y) - H(Y|X);
[0036] Where: X is an existing feature in the sample; Y is the target variable of the sample; H(Y) is the entropy of Y; H(Y|X) is the conditional entropy of Y under the condition of the existing feature X.
[0037] Decision tree construction: Select the feature with the largest information gain from the sample as a node, branch on this node to obtain several child nodes. Then recursively operate on the child nodes until the predetermined decision tree depth is reached or the number of child node samples is too small (for example, <3) to split into new nodes.
[0038] Predicting missing values: For a sample with missing values, starting from the root node, follow the branches of the decision tree in sequence, and select specific child nodes to get the prediction result.
[0039] Fill missing values: Finally, fill the prediction results to the corresponding missing value positions in the original dataset.
[0040] When building a decision tree, some distance metrics are usually used to judge the similarity between samples. Here we choose Euclidean distance to judge H(Y|X), which is the conditional entropy between node X and node Y.
[0041] Where weight = s / x;
[0042] Where: W xy is the conditional entropy between node x and node y;
[0043] k is the relative distance and coordinates;
[0044] s is the number of feature dimensions;
[0045] x is the number of current coordinates.
[0046] The data is linearly transformed through min-max normalization, mapping the values to [0, 1].
[0047]
[0048] Among them: min is the minimum value in the data;
[0049] max is the maximum value in the data;
[0050] n is the number of data bits;
[0051] j is the current position of the data.
[0052] S2. Based on the standardized time and pressure data, the fracturing time period is divided into X segments according to the construction time of the fracturing well, and then a curve of the fracturing well construction pressure and the monitoring well wellhead pressure during the fracturing process is drawn, such as Figure 2 As shown, Figure 2The scattered points in the middle represent the wellhead pressure during the fracturing operation of each fracturing stage; the continuous pressure curve is the wellhead pressure of the monitoring well during the fracturing operation of each stage of the fracturing well. This figure shows the changing characteristics of the monitoring well pressure during the fracturing operation of each fracturing stage;
[0053] S3. Based on the characteristics of the pressure curve change of the monitoring well, combined with the pressure response laws of the three types of fracturing interference types, namely, fracturing shadow interference, pressure penetration interference, and simultaneous action of multiple interference mechanisms, the fracturing interference type between each fracturing section of the fracturing well and the monitoring well is determined, such as Figure 3 、 Figure 4 and Figure 5 As shown;
[0054] Among them: Fracturing shadow interference: There is no direct fracture communication between the fracturing well and the adjacent well, and the pressure in the observation well continues to rise slowly due to the fracturing stress field or fracturing pressure field, which appears as a smooth rising curve on the monitoring curve;
[0055] Breakthrough interference: When fracturing directly connects two wells, when the instantaneous pressure rise is greater than a certain value, it can be considered as a breakthrough. After the fracturing is completed, the crack may fail, forming a peak-valley line on the monitoring curve;
[0056] Multiple interference mechanisms are acting simultaneously: The monitoring well pressure fluctuates, and multiple connectivity mechanisms are acting simultaneously, which may lead to layer channeling. The monitoring curve shows multiple broken lines.
[0057] S4. Counting the pressure response characteristics of the corresponding monitoring wells during the action time of each fracturing stage of the fracturing well, and calculating the wellhead pressure change value under different types of fracturing interference in each monitoring well;
[0058] The pressure change value during the pressure rise stage is:
[0059]
[0060] The pressure change value during the pressure drop stage is:
[0061]
[0062] Where: ΔP i is the pressure rise response value of each fracturing stage;
[0063] ΔX i is the pressure drop response value of each fracturing stage;
[0064] ΔK i is the pressure rise change value of the fracturing section;
[0065] ΔQ i is the pressure drop change value of the fracturing stage.
[0066] S5. Based on the fracturing interference type and geological data, the interference weight value of each fracturing section and the wellhead pressure change value under different types of fracturing interference in each monitoring well are given. On the basis of determining the weight coefficient of each interference type, the weighted average method is used to determine the percentage of pressure change between each fracturing section of the fracturing well and the monitoring well. This percentage can represent the percentage of connectivity between the fracturing section and the monitoring well in the connectivity between the fracturing well and the monitoring well, thereby achieving a semi-quantitative evaluation of the degree of connectivity between each fracturing section of the fracturing well and the monitoring well.
[0067] The weighted evaluation method is a multi-attribute decision analysis method used to evaluate the pros and cons of several candidate solutions (or options). It quantifies the performance of each solution on different attributes and assigns different weights to each attribute to calculate the total score of each solution and ultimately select the solution with the highest score.
[0068] Specifically, the weighted evaluation method includes the following steps:
[0069] Determine the attributes of the evaluation: First, it is necessary to determine the attributes of the evaluation, namely the three types of well-to-well interference that have been divided: fracturing shadow interference, multiple interference mechanisms acting simultaneously, and pressure penetration interference.
[0070] Determine weights: Different attributes need to be assigned different weights. These weights reflect the importance of each attribute to the overall evaluation. Based on experience and the interwell pressure response characteristics of the test area, the weight of multiple interference mechanisms acting simultaneously is generally set to standard 1. The weights of fracturing shadow interference and multiple interference mechanisms acting simultaneously are as follows:
[0071] Fracturing shadow interference < interference caused by multiple interference mechanisms acting simultaneously < pressure penetration interference;
[0072] Establish an evaluation model: Quantify the performance of each solution on different attributes into a score. You can use methods such as weighted scoring and comparative judgment to obtain the score of each solution on each attribute.
[0073]
[0074] Where: n is the number of fracturing stages in the fracturing well;
[0075] S is the standardized monitoring well pressure response value;
[0076] X k is the weight coefficient of each interference type;
[0077] F i Pressure response value of each fracturing stage;
[0078] k is the interference type.
[0079] Select the best solution: Based on the scores, select the solution with the highest score as the final result.
[0080] The present invention is further described in detail below with reference to actual data processing examples.
[0081] Example 1
[0082] This embodiment provides a method for evaluating inter-well connectivity based on fracturing interference data, comprising the following steps:
[0083] S1. Sampling the pressure monitoring data of the fracturing wells and the corresponding monitoring wells, analyzing the inter-well pressure interference data after sampling, processing the missing values and outliers in the data by DT interpolation method, and then standardizing the data by max-min normalization method;
[0084] S2. Divide the fracturing sections by the fracturing time of the fracturing well, divide the monitoring data of the fracturing well into X sections according to the construction time of the fracturing well, and then draw the pressure curves corresponding to each fracturing section of the fracturing well and each fracturing section of the monitoring well during the fracturing process, such as Figure 2 As shown, a scatter plot is used to represent the operation pressure of the fracturing well, and a line graph is used to represent the pressure response curve characteristics of each monitoring well in the monitoring well group to the fracturing well.
[0085] S3. Classify the types of fracturing interference based on the pressure curve change characteristics of the monitoring well.
[0086] The interference types of the 32 fracturing stages were divided and classified according to the numerical characteristics and curve characteristics of the pressure response of each monitoring well in the monitoring well group, as shown in Table 1. To facilitate data processing, different interference types are represented by letters, specifically: Class A interference: fracturing shadow interference; Class B interference: multiple interference mechanisms acting simultaneously; Class C interference: pressure penetration interference;
[0087] Table 1 Numerical characteristics of pressure response and curve characteristics of each monitoring well to classify interference types
[0088]
[0089]
[0090] S4. Calculate the pressure value changes of different interference fracturing types based on the pressure response characteristics of the monitoring well group corresponding to the fracturing well; first calculate the pressure response value of the monitoring well in each fracturing section, and then calculate the interference pressure change value of the monitoring well group during the fracturing process of the fracturing well. Figure 6 shown.
[0091] Table 2 Changes in interference pressure received by the monitoring well during the fracturing process of the fracturing well
[0092]
[0093]
[0094] S5. Based on the interference type and geological data, the interference weight value of each fracturing section is given. The weighted interference pressure response value of each monitoring well is calculated by combining the weight and the pressure response value of different interference types. Finally, the percentage of the interference pressure response value of each monitoring well to the interference pressure response value of the entire monitoring well group is calculated. This percentage can represent the percentage of the connectivity between the fracturing well and the monitoring well, thereby realizing a semi-quantitative evaluation of the connectivity between the fracturing well and the monitoring well group.
[0095] Different weight values are assigned to each interference type feature according to the data characteristics of the test area. Here, the interference caused by multiple factors acting simultaneously is set as the standard weight 1, the fracturing shadow interference is set as the standard 0.5, and the pressure penetration interference is set as the standard 1.5.
[0096] The weighted average method is used to determine the degree of connectivity, and a semi-quantitative evaluation of the connectivity between each fracturing section of the fracturing well and the monitoring well group is achieved. Figure 7 shown.
[0097] The inter-well connectivity evaluation method based on fracturing interference data provided in the embodiment of the present application directly uses the wellhead pressure monitoring data of the fracturing well and the monitoring well during the fracturing process to evaluate the degree of connectivity between the fracturing well and the monitoring well. The method is not only simple and easy to use, but also overcomes the shortcomings of other methods such as complex operating procedures, multiple operation requirements, and high costs, thereby reducing the cost of connectivity evaluation between fracturing wells and monitoring wells.
[0098] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.
Claims
1. A method for evaluating interwell connectivity based on fracturing interference data, characterized in that: The following steps are involved: S1. Analyze and process the fracturing wells and corresponding monitoring wells involved in the fracturing interference data; S2. Divide the fracturing sections according to the fracturing time of the fracturing well, and draw a pressure curve diagram of the fracturing well and the corresponding monitoring well during the fracturing process; S3. Classify the fracturing interference type of the fracturing well; S4. Calculating the pressure response value changes of different fracturing interference types based on the pressure response characteristics of the monitoring well corresponding to the fracturing well; S5. Based on the fracturing interference type and geological data, an interference weight value is given for each fracturing section. The weighted interference pressure response value of each monitoring well is calculated by combining the interference weight value and the pressure response value of different fracturing interference types. The percentage of the interference pressure response value of each monitoring well to the interference pressure response values of all monitoring wells is calculated.
2. The inter-well connectivity evaluation method based on fracturing interference data according to claim 1, characterized in that: Before step S1, the fracturing interference data is collated and the well groups are divided according to the field production data to determine the fracturing wells and monitoring wells.
3. The inter-well connectivity evaluation method based on fracturing interference data according to claim 1, characterized in that: Data mining methods are used to organize and improve the fracturing interference data.
4. The method for evaluating well connectivity based on fracturing interference data according to claim 1, characterized in that: When analyzing and processing the fracturing wells and monitoring wells involved in the fracturing interference data, the missing values and abnormal values are processed by interpolation method.
5. The inter-well connectivity evaluation method based on fracturing interference data according to claim 1, characterized in that: When analyzing and processing the fracturing wells and monitoring wells involved in the fracturing interference data, the range normalization method is used to eliminate the influence of the data variable dimension and variation range.
6. The inter-well connectivity evaluation method based on fracturing interference data according to claim 1, characterized in that: When dividing the fracturing stages by the fracturing time of the fracturing well, the fracturing stages are divided based on the fracturing time of the construction well.
7. The inter-well connectivity evaluation method based on fracturing interference data according to claim 1, characterized in that: The types of fracturing interference are divided based on the fracturing curve characteristics and pressure response characteristics of the corresponding monitoring wells of the fracturing wells.
8. The inter-well connectivity evaluation method based on fracturing interference data according to claim 1, characterized in that: The percentage of the interference pressure response value of each monitoring well to the interference pressure response values of all monitoring wells is used to measure the percentage of connectivity between the fracturing well and the monitoring well.