A method and system for selecting layer and well for old well fracturing

Abstract

The application discloses a layer and well selecting method and system for old well fracturing, which comprises the following steps: collecting multiple production data of each well in a target fracturing area; counting the proportion of each production data corresponding to different layer positions, and preferably selecting multiple candidate layer positions based on the proportion; and classifying the well types of each well in different layer positions according to different fracturing measure categories based on the multiple production data of each well in each candidate layer position. The application can perform layer and well selecting tasks on the produced wells according to dynamic production data.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, and in particular to a method and system for selecting layers and wells for fracturing old wells. Background Technology

[0002] The acquisition, understanding, and analysis of geological and reservoir parameters are fundamental to subsequent engineering practices. However, in the development of some oilfields (such as some overseas oilfields), the acquisition of geological and reservoir data is costly and time-consuming, making it difficult to form a systematic and effective understanding of the geological and reservoir conditions in a timely manner to guide actual production.

[0003] In the existing technology "Well and Layer Selection Method for Fracturing and Acidizing Based on Grey Relational Analysis and Analytic Hierarchy Process" (CN202011631108.2), the weight of the target layer is determined by grey relational analysis and analytic hierarchy process. The pairwise comparison matrix and weight vector of the criterion layer to the target layer are determined, the combined weight vector of the scheme layer to the target layer is calculated, and the optimal well for fracturing and acidizing is determined based on the combined weight vector.

[0004] In the existing technology "A rapid decision-making method for repeated fracturing of coalbed methane wells" (CN202010691340.9), the remaining recoverable reserves of the coalbed methane well to be repeatedly fractured, the scale of the initial fracturing, and the dynamic situation of production and drainage after fracturing are comprehensively considered. Based on limited basic data, the comprehensive evaluation index for repeated fracturing of coalbed methane wells is quickly calculated.

[0005] In the existing technology "A method for selecting wells and layers for repeated fracturing of gas wells" (CN201711287988.4), mathematical statistics and dynamic analysis of gas reservoir engineering are applied to determine the judgment algorithm. The calculation is relatively simple, the factors affecting repeated fracturing are fully considered, the best wells and layers for repeated fracturing are selected, and the implementation accuracy is high.

[0006] In the existing technology "Process-based Fracturing Well and Layer Selection Method" (CN201910572781.4), a database system is used to closely integrate geology and technology, providing cross-disciplinary analysis and evaluation tools. It comprehensively utilizes statistical analysis, rapid prediction, and quantitative forecasting methods to improve the targeting and success rate of the process. It also proceduralizes mature technologies, realizes resource sharing, and provides important technical support for single-well production enhancement decisions and process optimization.

[0007] In summary, most existing technologies still rely on understanding geology and reservoirs to further select wells and layers, without further mining of production dynamic data. Summary of the Invention

[0008] The purpose of this invention is to provide a scheme for carrying out reservoir stimulation, layer selection, and well selection based on production dynamic data.

[0009] To address the aforementioned technical problems, this invention provides a method for selecting layers and wells for fracturing old wells, comprising: collecting multiple production data for each well within a target fracturing area; calculating the proportion of each production data corresponding to different layers; and, based on this, selecting multiple candidate layers by combining the proportion of wells in different layers; and classifying each well in different layers according to different fracturing measures based on the multiple production data of each well in each candidate layer.

[0010] Preferably, the multiple production data include, but are not limited to: production layer, daily liquid production, daily oil production, and water content.

[0011] Preferably, the step of selecting multiple candidate layers by statistically analyzing the proportion of each production data item corresponding to different layers and, based on this, combining the proportion of wells in different layers, includes: calculating the average daily fluid production and average daily oil production of all production wells in different layers; statistically analyzing the proportion of the average daily fluid production of different layers to the total daily fluid production of all layers, and the proportion of the average daily oil production of different layers to the total daily oil production of all layers, to obtain the proportion of daily fluid production and daily oil production of different layers; statistically analyzing the number of production wells in different layers to obtain the proportion of wells in different layers; and ranking the reservoir quality of each layer by comparing the cost, output, and benefits of each layer based on the proportion of daily fluid production, daily oil production, and wells in different layers, thereby selecting the multiple candidate layers.

[0012] Preferably, the plurality of candidate formations are selected if they meet the following conditions: when the percentage of the number of wells is the same, the formation with the higher percentage of daily oil production or daily liquid production; the formation with the higher percentage of daily oil production or daily liquid production; and the formation with the higher percentage of daily oil production or daily liquid production than the percentage of the number of wells.

[0013] Preferably, the step of classifying wells in different formations according to different fracturing measures based on the multiple production data of each well in each candidate formation includes: statistically analyzing the daily fluid production index, daily oil production index, and water cut index of each well in each candidate formation, and sorting each index in descending order within the same formation; classifying each well according to the sorting position of each index and the relationship between different indices of each well and the average value of the corresponding index, wherein the well types include a first type of well for implementing high-pressure fracturing technology for increasing production, a second type of well for implementing fracturing technology for wells with production potential, and a third type of well for implementing low-production and low-efficiency treatment.

[0014] Preferably, if the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is higher than the average daily oil production index of the current formation, and the water cut index is lower than the average water cut index of the current formation, then the well to be evaluated is identified as a first type of well; or, if the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is within the top first percentage in the daily oil production index ranking of the current formation, and the water cut index is lower than the average water cut index of the current formation, then the well to be evaluated is identified as a first type of well.

[0015] Preferably, if the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is lower than the average daily oil production index of the current formation, and the water cut index is lower than the water cut index of the current formation and is outside the first percentage in the ranking of water cut indexes of the current formation, then the well to be evaluated is determined to be a second type of well; or, if the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is outside the first percentage in the ranking of daily oil production indexes of the current formation, and the water cut index is lower than the water cut index of the current formation and is outside the first percentage in the ranking of water cut indexes of the current formation, then the well to be evaluated is determined to be a second type of well.

[0016] Preferably, if the daily liquid production index of the well to be evaluated in the current formation is lower than the average daily liquid production index of the current formation, and the daily oil production index is outside the top second percentage in the daily oil production index ranking of the current formation, and the water cut index is lower than the water cut index of the current formation and is outside the top first percentage in the water cut index ranking of the current formation, then the well to be evaluated is identified as the third type of well, and the second percentage is greater than the first percentage.

[0017] On the other hand, embodiments of the present invention provide a readable storage medium comprising a series of instructions for performing the steps of the method described above.

[0018] In addition, this invention also provides a layer and well selection system for fracturing old wells, comprising: a data collection module configured to collect multiple production data of each well in the target fracturing area; a layer selection module configured to calculate the proportion of each production data corresponding to different layers, and based on this, combined with the proportion of wells in different layers, to select multiple candidate layers; and a well selection module configured to classify each well in different layers according to different fracturing measures based on the multiple production data of each well in each candidate layer.

[0019] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0020] This invention proposes a method and system for selecting layers and wells for fracturing old wells. To overcome the practical difficulties of existing producing reservoirs, this method and system conduct in-depth analysis of production indicators such as fluid production, oil production, water cut, and number of operating wells. Through numerical analysis and horizontal comparison, it establishes the correlation between multiple indicators and evaluation standards, clarifies the distribution of geological sweet spots under the current well network, and then performs layer and well selection tasks on existing producing wells based solely on dynamic production data to establish reservoir stimulation well selection schemes. This invention, based on relative analysis, can perform layer selection on existing developed layers even when geological and reservoir analysis is lacking; moreover, based on relative analysis, it can conduct well selection work on existing producing wells even when geological and reservoir analysis is lacking.

[0021] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0023] Figure 1 This is a schematic diagram illustrating the steps of a layer selection and well selection method for fracturing old wells according to an embodiment of this application.

[0024] Figure 2 This is a schematic diagram of a stratigraphic analysis and evaluation chart in the stratigraphic selection and well selection method for fracturing old wells according to an embodiment of this application.

[0025] Figure 3 This diagram illustrates the percentage of wells in each layer when applying the layer selection and well selection method for fracturing old wells according to the embodiments of this application to an actual well site.

[0026] Figure 4 This is an example diagram illustrating the application of the layer selection and well selection method for fracturing old wells according to the embodiments of this application to the production data of each layer in an actual well site.

[0027] Figure 5 This is an example diagram illustrating the percentage of production data for each layer in an actual well site when applying the layer selection and well selection method for fracturing old wells according to the embodiments of this application.

[0028] Figure 6This is an example diagram illustrating the application of the layer and well selection method for fracturing old wells according to the embodiments of this application to the average production data indicators of each layer in an actual well site.

[0029] Figure 7 This is an example diagram illustrating the distribution characteristics of the proportion of each preferred layer when applying the layer selection and well selection method for fracturing old wells according to the embodiments of this application to an actual well site.

[0030] Figure 8 This is a block diagram of a layer selection and well selection system for fracturing old wells according to an embodiment of this application. Detailed Implementation

[0031] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that, as long as there is no conflict, the various embodiments and features in the various embodiments of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0032] Furthermore, the steps illustrated in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Also, although a logical order is shown in the flowcharts, in some cases the steps shown or described may be performed in a different order than that shown here.

[0033] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are also intended to include the plural. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components, and / or combinations thereof.

[0034] The acquisition, understanding, and analysis of geological and reservoir parameters are fundamental to subsequent engineering practices. However, in the development of some oilfields (such as some overseas oilfields), the acquisition of geological and reservoir data is costly and time-consuming, making it difficult to form a systematic and effective understanding of the geological and reservoir conditions in a timely manner to guide actual production.

[0035] In the existing technology "Well and Layer Selection Method for Fracturing and Acidizing Based on Grey Relational Analysis and Analytic Hierarchy Process" (CN202011631108.2), the weight of the target layer is determined by grey relational analysis and analytic hierarchy process. The pairwise comparison matrix and weight vector of the criterion layer to the target layer are determined, the combined weight vector of the scheme layer to the target layer is calculated, and the optimal well for fracturing and acidizing is determined based on the combined weight vector.

[0036] In the existing technology "A rapid decision-making method for repeated fracturing of coalbed methane wells" (CN202010691340.9), the remaining recoverable reserves of the coalbed methane well to be repeatedly fractured, the scale of the initial fracturing, and the dynamic situation of production and drainage after fracturing are comprehensively considered. Based on limited basic data, the comprehensive evaluation index for repeated fracturing of coalbed methane wells is quickly calculated.

[0037] In the existing technology "A method for selecting wells and layers for repeated fracturing of gas wells" (CN201711287988.4), mathematical statistics and dynamic analysis of gas reservoir engineering are applied to determine the judgment algorithm. The calculation is relatively simple, the factors affecting repeated fracturing are fully considered, the best wells and layers for repeated fracturing are selected, and the implementation accuracy is high.

[0038] In the existing technology "Process-based Fracturing Well and Layer Selection Method" (CN201910572781.4), a database system is used to closely integrate geology and technology, providing cross-disciplinary analysis and evaluation tools. It comprehensively utilizes statistical analysis, rapid prediction, and quantitative forecasting methods to improve the targeting and success rate of the process. It also proceduralizes mature technologies, realizes resource sharing, and provides important technical support for single-well production enhancement decisions and process optimization.

[0039] In summary, most existing technologies still rely on understanding geology and reservoirs to further select wells and layers, without further mining of production dynamic data.

[0040] To address the technical problems mentioned above, this application proposes a method and system for selecting reservoir layers and wells for fracturing old wells. This method and system can conduct in-depth analysis of production indicators such as fluid production, oil production, water cut, and number of wells in operation. Through numerical analysis and horizontal comparison, it establishes the correlation between multiple indicators and evaluation standards, clarifies the distribution of geological sweet spots under the current well network, and then establishes a reservoir stimulation well selection plan.

[0041] Figure 1 This is a schematic diagram illustrating the steps of a layer selection and well selection method for fracturing old wells according to an embodiment of this application. (Reference) Figure 1 The specific steps and flow of the layer selection and well selection method for fracturing old wells described in the embodiments of the present invention will be explained below.

[0042] Step S110 collects multiple production data points for each well in the target fracturing area. In this embodiment of the invention, the target fracturing area is the reservoir area to be stimulated. The multiple production data points include, but are not limited to: production layer, daily fluid production, daily oil production, and water cut.

[0043] In step S110, dynamic production data for all producing wells within the target oilfield within the target time range are read. This data should include at least several production parameters, such as production layer, daily fluid production, daily oil production, and water cut. It should be noted that in this embodiment of the invention, daily fluid production and daily oil production can be based on real-time statistics for the day, or on average daily values ​​over a certain production cycle, such as a week or month, to reduce the impact of daily data fluctuations.

[0044] Step S120: Based on the multiple production data of each well collected in step S110, calculate the proportion of each production data corresponding to different layers, and select multiple candidate layers based on the proportion of each production data corresponding to different layers and the proportion of wells in different layers.

[0045] In step S120, firstly, step S1201 (not shown) calculates the average daily fluid production and average daily oil production of all producing wells within different formations. In step S1201, well-average data for different formation indicators are calculated to achieve dimensionlessness; specifically, the average daily fluid production and average daily oil production of different formations are calculated.

[0046] Then, step S1202 (not shown) will calculate the proportion of the average daily liquid production of different layers to the total daily liquid production of all layers based on the average liquid production and average daily oil production of different layers (see...). Figure 4 ), and the proportion of the average daily oil production of different layers to the total daily oil production of all layers (see Figure 4 This allows us to obtain the daily liquid production and daily oil production percentages for different layers. Specifically, based on the average daily liquid production of different layers, the proportion of the average daily liquid production of each layer to the total liquid production of all layers is calculated, thus obtaining the daily liquid production percentage data for different layers. Similarly, based on the average daily oil production of different layers, the proportion of the average daily oil production of each layer to the total oil production of all layers is calculated, thus obtaining the daily oil production percentage data for different layers.

[0047] Step S1203 (not shown) involves counting the number of production wells in different strata to obtain the percentage of wells in each stratum. In step S1203, it is necessary to count the amount of production wells deployed in each stratum, then calculate the sum of the number of production wells in all strata, and finally calculate the percentage of production wells in each stratum relative to the total number of production wells in all strata, thus obtaining the percentage of wells in different strata. Figure 3 As shown.

[0048] Finally, in step S1204 (not shown), based on the proportion of daily liquid production, daily oil production, and number of wells of different layers, the reservoir quality of each layer is ranked (e.g., in order from best to worst) by comparing the cost, output, and benefits of each layer, thereby selecting multiple candidate layers.

[0049] Figure 2 This is a schematic diagram of a stratigraphic analysis and evaluation chart in the stratigraphic selection and well selection method for fracturing old wells, according to an embodiment of this application. Without considering actual data, based on the magnitude relationship of the three data points, an exhaustive method reveals a total of 12 combinations of the three indicators to form the chart, such as... Figure 2 As shown. In practical applications, the number of wells as a percentage of production can be used to represent the level of fixed investment, such as drilling and reservoir renovation costs; the production fluid percentage can be used to represent the level of operating costs, such as water and electricity costs; and the oil production percentage can be used to represent revenue, the only indicator that generates income.

[0050] By analyzing the above three indicators, we can evaluate the changes in the difference between operating costs and output of formations over time or the cost-effectiveness, thereby selecting multiple advantageous formations with high efficiency and / or high output and / or a complete production and injection well network, and ranking them from high to low according to their advantages.

[0051] Specifically, select multiple candidate formations that meet one or more of the following conditions: Condition 1: When the number of wells is the same, the formation with a higher percentage of daily oil production or daily liquid production (e.g., the daily oil production or daily liquid production percentage is among the top three); Condition 2: The formation with a higher percentage of daily oil production than daily liquid production; Condition 3: The formation with a higher percentage of daily oil production or daily liquid production than the percentage of the number of wells.

[0052] In practical applications, under the same well count ratio, a higher daily fluid production ratio indicates sufficient reservoir energy or a well-developed water injection well network, while a higher daily oil production ratio indicates higher oil content and a higher-quality reservoir. The difference between the daily fluid production ratio and the daily oil production ratio can reflect the input-output ratio to a certain extent. When the daily oil production ratio is higher than the daily fluid production ratio, it indicates the possibility of positive returns; the greater the difference, the higher the rate of return. When the daily oil production ratio is higher than the well count ratio, it indicates that the reservoir quality exceeds the average level. When the daily fluid production ratio is higher than the well count ratio, it indicates that the reservoir energy or the completeness of the production and injection well network exceeds the average level.

[0053] It should be noted that, in embodiments of the present invention, the stratigraphic level can be extended to the smallest unit of the well group.

[0054] Figure 2 This demonstrates the distribution characteristics of the proportion of reservoirs from poor to optimal, assuming the same percentage of wells. Figure 2 As shown,

[0055] The distribution characteristics of the case 1 type data are that it is the worst reservoir, and the proportion of wells in this layer is greater than the proportion of daily fluid production, and the proportion of daily fluid production is greater than the proportion of daily oil production.

[0056] The reservoirs with the distribution characteristics of the proportion data belonging to case2 are of higher quality than those corresponding to case1. The proportion of wells in this layer is greater than the proportion of daily fluid production, and the proportion of daily fluid production is approximately equal to the proportion of daily oil production.

[0057] The reservoirs with the distribution characteristics of the proportion data belonging to case3 are of higher quality than those corresponding to case2. The proportion of wells in this layer is greater than the proportion of daily liquid production, and the proportion of daily oil production is greater than the proportion of daily liquid production. Furthermore, the proportion of daily oil production is approximately equal to the proportion of wells.

[0058] The reservoirs with the distribution characteristics of the proportion data belonging to case4 are of higher quality than those corresponding to case3. The proportion of wells in this layer is greater than the proportion of daily liquid production, and the proportion of daily oil production is greater than the proportion of daily liquid production, and the proportion of daily oil production is greater than the proportion of wells.

[0059] The reservoirs with the distribution characteristics of the proportion data belonging to case5 are of higher quality than those corresponding to case4. The proportion of wells in this layer is approximately equal to the proportion of daily liquid production, and the proportion of daily oil production is lower than the proportion of daily liquid production, reaching the first difference threshold.

[0060] The reservoirs with the distribution characteristics of the proportion data belonging to case6 are of higher quality than those corresponding to case5. The proportion of wells in this layer is approximately equal to the proportion of daily liquid production, and the proportion of daily oil production is lower than the proportion of daily liquid production, reaching the second difference threshold. The second difference threshold is less than the first difference threshold.

[0061] The reservoirs with the distribution characteristics of the proportion data belonging to case7 are of higher quality than those corresponding to case6. This layer represents the most ideal distribution of proportion data, and the proportion of wells, daily fluid production, and daily oil production in this layer are all approximately equal.

[0062] The reservoirs with the distribution characteristics of the proportion data belonging to case8 are of higher quality than those corresponding to case7. The proportion of wells in this layer is approximately equal to the proportion of daily liquid production, and the proportion of daily oil production is higher than the proportion of daily liquid production.

[0063] The reservoirs with the distribution characteristics of the proportion data belonging to case9 are of higher quality than those corresponding to case8. The proportion of wells in this layer is lower than the proportion of daily liquid production, and the proportion of daily oil production is lower than the proportion of wells.

[0064] The reservoirs with the distribution characteristics of the proportion data belonging to case10 are of higher quality than those corresponding to case9. The proportion of wells in this layer is approximately equal to the proportion of daily oil production, and the proportion of daily liquid production is higher than the proportion of wells.

[0065] The reservoirs with the distribution characteristics of the proportion data belonging to case11 are of higher quality than those corresponding to case10. The proportion of wells in this layer is lower than the proportion of daily liquid production, and the proportion of daily liquid production is approximately equal to the proportion of daily oil production.

[0066] The reservoirs with the distribution characteristics of the proportion data belonging to case12 are of higher quality than those corresponding to case11. The proportion of wells in this layer is lower than the proportion of daily fluid production, and the proportion of fluid production is lower than the proportion of daily oil production.

[0067] like Figure 2 As shown, the step-down distribution of Case 1 indicates a typical worst-quality reservoir, and wells in this type should be shut down first when oil prices are low. The step-up distribution of Case 12 indicates a typical best-quality reservoir, and the most suitable reservoir for reservoir improvement and production enhancement.

[0068] Furthermore, when the daily fluid production or daily oil production of a certain layer equals the total fluid production or total oil production of that layer, only qualitative analysis can be performed. Alternatively, a quantitative comparison can be made between the fluid production or oil production percentages under the same well number percentage conditions. Quantitative comparisons are not possible if the well number percentages differ. When using single-layer well-average data, data under different well number percentage conditions are comparable.

[0069] Thus, through the sorting results of each layer completed in step S120, the present invention obtains a preset number of candidate layers with high reservoir quality, and then proceeds to step S130.

[0070] Step S130: Based on multiple production data corresponding to each production well in each candidate layer, classify each (production) well in the selected different candidate layers according to different fracturing measures.

[0071] In step S130, firstly, based on the daily production data set, daily oil production data set, and water cut data set of each production well in each candidate layer, the daily production index, daily oil production index, and water cut index of each well in each candidate layer are statistically analyzed, and each index in the same layer is sorted in descending order. Specifically, based on the daily fluid production data set of each production well in each candidate layer, an average value is calculated, and the average daily fluid production of different production wells in each candidate layer is used as the daily fluid production index of the corresponding production well. The daily fluid production indexes of different production wells in each layer are then sorted in descending order. Similarly, based on the daily oil production data set of each production well in each candidate layer, an average value is calculated, and the average daily oil production of different production wells in each candidate layer is used as the daily oil production index of the corresponding production well. The daily oil production indexes of different production wells in each layer are then sorted in descending order. Finally, based on the water cut data set of each production well in each candidate layer, an average value is calculated, and the average water cut of different production wells in each candidate layer is used as the water cut index of the corresponding production well. The daily water cut indexes of different production wells in each layer are then sorted in descending order.

[0072] After sorting the indicators, step S130 further classifies each production well according to its ranking position and the relationship between different production indicators and their corresponding average values. In this embodiment of the invention, the well types include: a first type of well for implementing high-pressure fracturing technology to boost production (these wells are selected high-oil-yield, low-water-cut wells); a second type of well for implementing fracturing technology for wells with production-boosting potential (these wells are selected low-fluid-yield, low-water-cut wells; these wells have production-boosting potential, but the potential is significantly lower than that of the first type of wells, but significantly higher than that of the third type of wells; large-scale and more aggressive fracturing measures are required to better release production capacity, because these single wells have sufficient energy, low water content, and have the characteristics of high potential for transformation and low risk); and a third type of well for implementing low-production, low-efficiency remediation (these wells are selected low-fluid-yield, low-oil-yield, and low-water-cut wells).

[0073] Before classification, this embodiment of the invention needs to calculate the corresponding average values ​​for different production data based on the current production well's oil production data set, fluid production data set, and water cut data set at the current formation. The production data of individual wells within the target formation are then summarized and analyzed for daily fluid production, daily oil production, and water cut indicators. A cross-screening process based on block production capacity characteristics and individual well management characteristics is designed.

[0074] In the first embodiment, if the daily liquid production index of the well to be evaluated in the current formation is lower than the average daily liquid production index of the current formation, and the daily oil production index is higher than the average daily oil production index of the current formation, and the water cut index is lower than the average water cut index of the current formation, then the well to be evaluated is identified as a first-class well; or, if the daily liquid production index of the well to be evaluated in the current formation is lower than the average daily liquid production index of the current formation, and the daily oil production index is within the top first percentage in the daily oil production index ranking of the current formation, and the water cut index is lower than the average water cut index of the current formation, then the well to be evaluated is identified as a first-class well.

[0075] In the second embodiment, if the daily liquid production index of the well to be evaluated in the current formation is lower than the average daily liquid production index of the current formation, and the daily oil production index is lower than the average daily oil production index of the current formation, and the water cut index is lower than the water cut index of the current formation and is outside the first percentage in the ranking of water cut indexes of the current formation, then the well to be evaluated is identified as a second type of well; or, if the daily liquid production index of the well to be evaluated in the current formation is lower than the average daily liquid production index of the current formation, and the daily oil production index is lower than the average daily oil production index of the current formation and is outside the first percentage in the ranking of daily oil production indexes of the current formation, and the water cut index is lower than the water cut index of the current formation and is outside the first percentage in the ranking of water cut indexes of the current formation, then the well to be evaluated is identified as a second type of well.

[0076] In the third embodiment, if the daily liquid production index of the well to be evaluated in the current formation is lower than the average daily liquid production index of the current formation, and the daily oil production index is outside the top second percentile in the daily oil production index ranking of the current formation, and the water cut index is lower than the water cut index of the current formation and is outside the top first percentile in the water cut index ranking of the current formation, then the well to be evaluated is determined to be the third type of well.

[0077] In this embodiment of the invention, the second percentage is greater than the first percentage. For example, the second percentage is 75% and the first percentage is 25%; or the second percentage is 80% and the first percentage is 20%; or other reasonable percentage data.

[0078] When the second percentage is 75% and the first percentage is 25%, the preferred classification of target wells can be carried out according to the following example conditions:

[0079] ① Class I wells with high oil production and low water cut (used to boost production): daily fluid production is lower than the average, daily oil production is higher than the average (or higher than the top 25% of values), and water cut is lower than the average.

[0080] ② Class II wells with low fluid production and low water cut: daily fluid production is lower than the average, daily oil production is lower than the average (or lower than the top 25%), and water cut is lower than the top 25%;

[0081] ③ Class III wells with low fluid production, low oil production, and low water content (low-yield and inefficient treatment): daily fluid production is lower than the average, daily oil production is lower than the top 75%, and water content is lower than the top 25%.

[0082] The above-described method for selecting layers and wells is applied to an oilfield to illustrate the application effects of this invention. This oilfield has been developed for 20 years, but has changed operators multiple times. Geological and reservoir data are fragmented and difficult to collect. Limited by development costs, it is difficult to conduct new coring work, hindering further improvement in geological and reservoir understanding.

[0083] The oilfield's production dynamics data were collected and processed. First, the data was categorized according to different stratigraphic layers, and the results are as follows: Figure 3 and Figure 4 As shown.

[0084] Layers J1 and J2 have a large number of wells, high fluid production, and the highest water cut, with an average water cut exceeding 90%, which is related to the long-term water injection development of these layers and exhibits characteristics of high water cut in the later stages of development. Layers J6 and J10 have relatively high water cuts, around 80%; however, layer J10 has fewer wells and lower production, and is not a primary development layer. See also Figure 4 .

[0085] Under the same well count ratio, a higher fluid production ratio indicates sufficient reservoir energy or a well-developed water injection well network, while a higher oil production ratio indicates higher oil content and a higher-quality reservoir. The difference between the fluid production ratio and the oil production ratio can reflect the input-output ratio to a certain extent; a higher oil production ratio indicates the possibility of positive returns, and the greater the difference, the greater the return. Layers J1 and J2 have a large number of wells and high fluid production, and are currently the main production layers. Excluding data from layers J1 and J2: layer J4 provided the highest oil production, superior to layer J6 with the same number of wells. See also... Figure 5 .

[0086] The high water cut of layers J1 and J2 results in relatively low oil production per well even under high average fluid production conditions, a characteristic of high development costs in the later stages of reservoir exploitation. Besides layers J1 and J2, layers J4 and J7 are production layers with significant potential. (See [link to relevant documentation]). Figure 6 and Figure 7 .

[0087] Based on the selected stratigraphic units, information on each well within the stratigraphic units is collected and analyzed, and daily fluid production, daily oil production, and water cut are collected and analyzed. A cross-screening process based on the block's production capacity characteristics and the characteristics of individual well measures is designed.

[0088] From the perspective of production output alone, this well selection plan can be divided into three types:

[0089] (1) Prioritize single wells with high oil content and low water content (to maximize production):

[0090] In principle, the daily liquid production should be less than 23m³. 3 Daily oil production exceeds 5.7m 3 Moisture content less than 50%;

[0091] (2) Prefer single wells with low liquid content and low water cut:

[0092] In principle, the daily liquid production should be less than 23m³. 3 Daily oil production is less than 5.7m 3 Moisture content less than 70%;

[0093] (3) Single wells with low liquid content, low oil content, and low water content (low-yield and inefficient treatment):

[0094] In principle, the daily liquid production should be less than 23m³. 3 Daily oil production is less than 3.4m 3 Moisture content is less than 90%.

[0095] Wells selected according to the above criteria are shown in Table 1 below. Wells 631, 232, 174, and 425 are consistent with the reservoir scheme selection and actual measures in the following year.

[0096] Table 1 Examples of Well Selection Results

[0097]

[0098] Based on the above-described layer and well selection method, this embodiment of the invention also provides a computer-readable storage medium storing a computer program. Executing the computer program runs a layer and well selection method for fracturing old wells. The computer program is capable of executing computer instructions, which include computer program code. The computer program code can be in the form of source code, object code, executable files, or some intermediate form.

[0099] Computer-readable storage media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0100] It should be noted that the contents of computer-readable storage media may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, the contents may be appropriately increased or decreased according to the requirements of legislation and patent practice. In other jurisdictions, computer-readable storage media may not include electrical carrier signals and telecommunication signals.

[0101] In addition, based on the above-mentioned method for selecting layers and wells for fracturing old wells, this embodiment of the invention also provides a system for selecting layers and wells for fracturing old wells.

[0102] Figure 8 This is a block diagram of a layer selection and well selection system for fracturing old wells, according to an embodiment of this application. Figure 8 As shown, the layer selection and well selection system described in this embodiment of the invention includes: a data collection module 81, a layer selection module 82, and a well selection module 83.

[0103] Specifically, the data collection module 81 is implemented according to the method described in step S110, and is configured to collect multiple production data of each well in the target fracturing area; the layer selection module 82 is implemented according to the method described in step S120, and is configured to calculate the proportion of each production data corresponding to different layers, and based on this, combined with the proportion of wells in different layers, select multiple candidate layers; the well selection module 83 is implemented according to the method described in step S130, and is configured to classify each well in different layers according to different fracturing measures based on the multiple production data of each well in each candidate layer.

[0104] This invention discloses a method and system for selecting reservoir layers and wells for fracturing old wells. To overcome the practical difficulties of existing producing reservoirs, this method and system conduct in-depth analysis of production indicators such as fluid production, oil production, water cut, and number of operating wells. Through numerical analysis and horizontal comparison, it establishes the correlation between multiple indicators and evaluation standards, clarifies the distribution of geological sweet spots under the current well network, and then establishes a reservoir stimulation well selection plan. This invention, based on relative analysis, can perform layer selection on existing developed layers even when geological and reservoir analysis is lacking; moreover, based on relative analysis, it can conduct well selection work on existing producing wells even when geological and reservoir analysis is lacking.

[0105] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0106] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0107] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0108] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0109] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0110] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A method for selecting layers and wells for fracturing old wells, characterized in that, include: Collect multiple production data points for each well within the target fracturing area; The proportion of each production data item corresponding to different layers is statistically analyzed. Based on this, and combined with the proportion of wells in different layers, multiple candidate layers are selected. These include: ranking the reservoir quality of each layer by comparing the cost, output, and benefits of each layer based on the proportion of daily fluid production, daily oil production, and the proportion of wells in different layers. The multiple candidate layers are selected using the following conditions: 1) When the proportion of wells in different layers is the same, the layer with the higher proportion of daily oil production or daily fluid production; 2) The layer with the higher proportion of daily oil production than the higher proportion of daily fluid production; 3) The layer with the higher proportion of daily oil production or daily fluid production than the higher proportion of wells. Based on the multiple production data of each well in each candidate formation, wells in different formations are classified according to different fracturing measures. This includes: statistically analyzing the daily fluid production, daily oil production, and water cut of each well in each candidate formation, and sorting each indicator in descending order within the same formation; classifying each well into different types based on the ranking position of each indicator and the relationship between different indicators and the average value of the corresponding indicators. These well types include: Type I wells for implementing high-pressure fracturing technology to boost production; Type II wells for implementing fracturing technology for wells with production potential; and Type III wells for implementing low-production and low-efficiency treatment. If the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is higher than the average daily oil production index of the current formation, and the water cut index is lower than the average water cut index of the current formation, then the well to be evaluated is identified as a first type of well; or, if the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is within the top first percentage in the daily oil production index ranking of the current formation, and the water cut index is lower than the average water cut index of the current formation, then the well to be evaluated is identified as a first type of well. If the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is lower than the average daily oil production index of the current formation, and the water cut index is lower than the water cut index of the current formation and is outside the first percentage in the ranking of water cut indexes of the current formation, then the well to be evaluated is identified as a second type of well; or, if the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is lower than the average daily oil production index of the current formation and is outside the first percentage in the ranking of daily oil production indexes of the current formation, and the water cut index is lower than the water cut index of the current formation and is outside the first percentage in the ranking of water cut indexes of the current formation, then the well to be evaluated is identified as a second type of well. If the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is outside the top second percentile in the daily oil production index ranking of the current formation, and the water cut index is lower than the water cut index of the current formation and is outside the top first percentile in the water cut index ranking of the current formation, then the well to be evaluated is identified as the third type of well, where the second percentile is greater than the first percentile.

2. The method for selecting layers and wells according to claim 1, characterized in that, The aforementioned production data include: production level, daily liquid production, daily oil production, and water content.

3. The method for selecting layers and wells according to claim 2, characterized in that, The step of selecting multiple candidate layers by statistically analyzing the proportion of each production data item corresponding to different layers and combining this with the proportion of wells in different layers also includes: Calculate the average daily fluid production and average daily oil production of all production wells in different formations; The proportion of daily liquid production of different layers to the total daily liquid production of all layers, and the proportion of daily oil production of different layers to the total daily oil production of all layers, are statistically analyzed to obtain the proportion of daily liquid production and daily oil production of different layers. The number of production wells in different strata is counted to obtain the percentage of wells in different strata.

4. A readable storage medium, characterized in that, It includes a series of instructions for performing the method steps as described in any one of claims 1 to 3.

5. A layer selection and well selection system for fracturing old wells, characterized in that, include: The data collection module is configured to collect multiple production data points from each well within the target fracturing area; The layer selection module is configured to statistically analyze the proportion of each production data item corresponding to different layers. Based on this, and combined with the well number proportion of different layers, multiple candidate layers are selected. These include: ranking the reservoir quality of each layer based on the proportion of daily fluid production, daily oil production, and well number, by comparing the cost, output, and benefits of each layer, and selecting the multiple candidate layers using the following conditions: 1) When the well number proportions are the same, the layer with the higher proportion of daily oil production or daily fluid production; 2) The layer with the higher proportion of daily oil production than the higher proportion of daily fluid production; 3) The layer with the higher proportion of daily oil production or daily fluid production than the higher proportion of well number. The well selection module is configured to classify wells within different formations according to different fracturing measures based on the multiple production data of each well in each candidate formation. This includes: statistically analyzing the daily fluid production, daily oil production, and water cut of each well in each candidate formation, and sorting each indicator within the same formation in descending order; classifying each well into different well types based on the ranking position of each indicator and the relationship between different indicators and the average value of the corresponding indicators. These well types include: Type I wells for implementing high-pressure fracturing technology to boost production; Type II wells for implementing fracturing technology for wells with production potential; and Type III wells for implementing low-production and low-efficiency remediation. If the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is higher than the average daily oil production index of the current formation, and the water cut index is lower than the average water cut index of the current formation, then the well to be evaluated is identified as a first type of well; or, if the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is within the top first percentage in the daily oil production index ranking of the current formation, and the water cut index is lower than the average water cut index of the current formation, then the well to be evaluated is identified as a first type of well. If the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is lower than the average daily oil production index of the current formation, and the water cut index is lower than the water cut index of the current formation and is outside the first percentage in the ranking of water cut indexes of the current formation, then the well to be evaluated is identified as a second type of well; or, if the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is lower than the average daily oil production index of the current formation and is outside the first percentage in the ranking of daily oil production indexes of the current formation, and the water cut index is lower than the water cut index of the current formation and is outside the first percentage in the ranking of water cut indexes of the current formation, then the well to be evaluated is identified as a second type of well. If the daily fluid production index of the well to be evaluated in the current formation is lower than the average daily fluid production index of the current formation, and the daily oil production index is outside the top second percentile in the daily oil production index ranking of the current formation, and the water cut index is lower than the water cut index of the current formation and is outside the top first percentile in the water cut index ranking of the current formation, then the well to be evaluated is identified as the third type of well, where the second percentile is greater than the first percentile.

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