Layer and well selection method and system for old well fracturing

Abstract

The invention discloses a layer and well selection method and system for old well fracturing. The method comprises the steps that multiple items of production data of each well in a target fracturing area are collected; counting the proportion of each item of production data corresponding to different layers, and on the basis, optimizing a plurality of alternative layers in combination with the well number proportions of the different layers; and according to multiple items of production data of each well in each alternative horizon, performing well type classification on each well in different horizon according to different fracturing measure categories. According to the invention, the layer and well selection task can be carried out on the produced well according to the dynamic production data.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field development, and in particular to a layer and well selection method and system for old well fracturing. Background Art

[0002] The acquisition, understanding and analysis of geological and reservoir parameters are the basis for subsequent engineering practice. However, in the development process of some oil fields (such as some overseas oil fields), the acquisition cost of geological and reservoir data is high and the cycle is long, making it difficult to form a systematic and effective understanding of geology and reservoirs in time to guide actual production conditions.

[0003] In the prior art "Method for well and layer selection for fracturing and acidizing based on grey correlation method and analytic hierarchy process" (CN202011631108.2), the weight of the target layer is determined based on the grey correlation method and analytic hierarchy process, and the pairwise comparison matrix and weight vector of the criterion layer for the target layer are determined, the combined weight vector of the scheme layer for the target layer is calculated, and the optimal well for fracturing and acidizing is determined according to the combined weight vector.

[0004] In the prior art "A rapid decision-making method for well selection for repeated fracturing of coalbed methane wells" (CN202010691340.9), the remaining recoverable reserves of the coalbed methane wells to be repeated fracturing, the scale of the initial fracturing, and the post-fracturing production dynamics are comprehensively considered, and the comprehensive evaluation indicators for well selection for repeated fracturing of coalbed methane wells are quickly calculated based on limited basic data.

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

[0006] In the existing technology "Process-based Fracturing Well and Layer Selection Method" (CN201910572781.4), based on the database system, geology and technology are closely integrated, providing a cross-professional analysis and evaluation tool, and comprehensively using statistical analysis, rapid prediction, and quantitative prediction methods to improve the process targeting and success rate; mature technology is programmed to achieve resource sharing, providing important technical support for single well production increase decision-making and process optimization.

[0007] In summary, most of the existing technologies are still based on the understanding of geology and reservoirs to further carry out well and layer selection work, and no further mining of production dynamic data has been carried out. Summary of the invention

[0008] The purpose of the present invention is to provide a solution that can carry out reservoir transformation and layer selection and well selection work based on production dynamic data.

[0009] In order to solve the above technical problems, an embodiment of the present invention provides a layer and well selection method for old well fracturing, including: collecting multiple production data of each well in the target fracturing area; counting the proportion of each production data corresponding to different layers, and based on this, combined with the proportion of the number of wells in different layers, preferably multiple alternative layers; according to the multiple production data of each well in each alternative layer, each well in the different layers is classified according to different fracturing measures.

[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, in counting the proportion of each production data corresponding to different layers, based on this, combined with the proportion of the number of wells in different layers, the step of selecting multiple alternative layers includes: calculating the average daily liquid production and the average daily oil production of all production wells in different layers; counting the proportion of the average daily liquid production of different layers to the daily liquid production of all layers, and the proportion of the average daily oil production of different layers to the daily oil production of all layers, to obtain the daily liquid production proportion and daily oil production proportion of different layers; counting the number of production wells in different layers, so as to obtain the proportion of the number of wells in different layers; according to the daily liquid production proportion, daily oil production proportion and well number proportion of different layers, by comparing the cost, output and benefit of each layer, the reservoir quality of each layer is ranked, so as to select the multiple alternative layers.

[0012] Preferably, the multiple alternative layers that meet the following conditions are selected: when the proportion of the number of wells is the same, the layer with a higher daily oil production proportion or a higher daily liquid production proportion; the layer with a higher daily oil production proportion than the daily liquid production proportion; the layer with a higher daily oil production proportion or a higher daily liquid production proportion than the proportion of the number of wells.

[0013] Preferably, in the step of classifying the well types of each well in different layers according to different fracturing measures categories based on the multiple production data of each well in each alternative layer, it includes: counting the daily liquid production index, daily oil production index and water content index of each well in each alternative layer, and sorting each indicator in the same layer in descending order; classifying each well according to the sorting position of each indicator and the relationship between the different indicators of each well and the average value of the corresponding indicators, the well types include a first type of well for implementing production-boosting fracturing technology, a second type of well for implementing fracturing technology for wells with production-increasing potential, and a third type of well for implementing low-yield and low-efficiency management.

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

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

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

[0017] On the other hand, an embodiment of the present invention provides a readable storage medium, which contains a series of instructions for executing the method steps as described above.

[0018] In addition, an embodiment of the present invention further provides a layer and well selection system for fracturing old wells, including: a data collection module, which is configured to collect multiple production data of each well in the target fracturing area; a layer selection module, which is configured to count the proportion of each production data corresponding to different layers, and based on this, combined with the proportion of the number of wells in different layers, multiple alternative layers are preferred; a well selection module, which is configured to classify each well in different layers according to different fracturing measures according to the multiple production data of each well in each alternative layer.

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

[0020] The present invention proposes a layer selection and well selection method and system for fracturing old wells. In order to overcome the actual difficulties existing in the actual production of oil reservoirs, the method and system conduct in-depth analysis on production indicators such as liquid production, oil production, water content, and number of wells opened, establish the correlation between multiple indicators and evaluation standards through numerical analysis and horizontal comparison, clarify the distribution of geological sweet spots under the current well network, and then carry out layer selection and well selection tasks for produced wells based only on dynamic production data to establish a reservoir transformation well selection plan. Based on relative analysis, the present invention can optimize the layer position in the existing developed layer on the basis of the lack of geological and reservoir analysis knowledge; and based on relative analysis, on the basis of the lack of geological and reservoir analysis knowledge, well selection can be carried out on the basis of existing production wells.

[0021] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

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

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

[0025] Figure 3 This is an example diagram of the percentage of wells in each layer in an actual well site when the layer and well selection method for old well fracturing according to an embodiment of the present application is applied.

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

[0027] Figure 5 This is an example diagram of the percentage of production data of each layer in an actual well site when the layer and well selection method for old well fracturing in an embodiment of the present application is applied.

[0028] Figure 6This is an example diagram of the average values ​​of production data indicators of each layer in an actual well site when the layer and well selection method for old well fracturing according to an embodiment of the present application is applied.

[0029] Figure 7 This is an example diagram of the data distribution characteristics of the proportion of each preferred layer when the layer and well selection method for old well fracturing according to an embodiment of the present application is applied to an actual well site.

[0030] Figure 8 This is a module block diagram of a layer and well selection system for fracturing old wells according to an embodiment of the present application. DETAILED DESCRIPTION

[0031] The following will describe the implementation methods of the present invention in detail with reference to the accompanying drawings and embodiments, so that the implementation process of how the present invention applies 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 of the present invention and the various features in the embodiments can be combined with each other, and the technical solutions formed are all within the protection scope of the present invention.

[0032] In addition, the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions. Also, although a logical sequence is shown in the flowchart, in some cases, the steps shown or described can be performed in a sequence different from that here.

[0033] The terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms "one", "one" and "item" used herein are also intended to include plural numbers. It should also be understood that the terms "include" and / or "comprise" used herein specify the existence of stated features, integers, steps, operations, units and / or components, without excluding the existence 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 the basis for subsequent engineering practice. However, in the development process of some oil fields (such as some overseas oil fields), the acquisition cost of geological and reservoir data is high and the cycle is long, making it difficult to form a systematic and effective understanding of geology and reservoirs in time to guide actual production conditions.

[0035] In the prior art "Method for well and layer selection for fracturing and acidizing based on grey correlation method and analytic hierarchy process" (CN202011631108.2), the weight of the target layer is determined based on the grey correlation method and analytic hierarchy process, and the pairwise comparison matrix and weight vector of the criterion layer for the target layer are determined, the combined weight vector of the scheme layer for the target layer is calculated, and the optimal well for fracturing and acidizing is determined according to the combined weight vector.

[0036] In the prior art "A rapid decision-making method for well selection for repeated fracturing of coalbed methane wells" (CN202010691340.9), the remaining recoverable reserves of the coalbed methane wells to be repeated fracturing, the scale of the initial fracturing, and the post-fracturing production dynamics are comprehensively considered, and the comprehensive evaluation indicators for well selection for repeated fracturing of coalbed methane wells are quickly calculated based on limited basic data.

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

[0038] In the existing technology "Process-based Fracturing Well and Layer Selection Method" (CN201910572781.4), based on the database system, geology and technology are closely integrated, providing a cross-professional analysis and evaluation tool, and comprehensively using statistical analysis, rapid prediction, and quantitative prediction methods to improve the process targeting and success rate; mature technology is programmed to achieve resource sharing, providing important technical support for single well production increase decision-making and process optimization.

[0039] In summary, most of the existing technologies are still based on the understanding of geology and reservoirs to further carry out well and layer selection work, and no further mining of production dynamic data has been carried out.

[0040] In order to solve the technical problems in the above-mentioned background technology, the embodiment of the present application proposes a layer selection and well selection method and system for old well fracturing. The method and system can conduct in-depth analysis on production indicators such as liquid production, oil production, water content and number of wells, establish the correlation between multiple indicators and evaluation criteria through numerical analysis and horizontal comparison, clarify the distribution of geological sweet spots under the current well network, and then establish a reservoir transformation well selection plan.

[0041] Figure 1 This is a schematic diagram of the steps of the layer selection and well selection method for fracturing an old well according to an embodiment of the present application. Figure 1 The specific steps of the layer and well selection method for old well fracturing described in the embodiment of the present invention are described below.

[0042] Step S110 collects multiple production data about each well in the target fracturing area. In the embodiment of the present invention, the target fracturing area is the reservoir area to be transformed. The multiple production data include but are not limited to: production layer, daily liquid production, daily oil production and water content.

[0043] In step S110, the production dynamic data of all production wells in the target oil field within the target time range are read, which should at least include multiple production data such as production layer, daily liquid production, daily oil production and water content. It should be noted that in the embodiment of the present invention, the daily liquid production and daily oil production can use the real-time statistical results of the day, or the daily average values ​​within a certain production cycle such as the week or month to reduce the impact of single-day data fluctuations.

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

[0045] In step S120, first, step S1201 (not shown) calculates the average daily liquid production and the average daily oil production of all production wells in different layers. In step S1201, the well average data of different layer indicators are calculated for dimensionless, specifically calculating the average daily liquid production and the average daily oil production of different layers.

[0046] Then, step S1202 (not shown) calculates the proportion of the daily average liquid production of different layers to the daily average oil production of all layers according to the average liquid production of different layers (see Figure 4 ), and the proportion of the average daily oil production of different layers to the daily oil production of all layers (see Figure 4 ), thereby obtaining the daily liquid production ratio and daily oil production ratio of different strata. Specifically, according to the average daily liquid production of different strata, the ratio of the average daily liquid production of each stratum to the total liquid production of all strata is calculated, thereby obtaining the daily liquid production ratio data of different strata. In addition, according to the average daily oil production of different strata, the ratio of the average daily oil production of each stratum to the total oil production of all strata is calculated, thereby obtaining the daily oil production ratio data of different strata.

[0047] Step S1203 (not shown) counts the number of production wells in different layers, so as to obtain the proportion of the number of wells in different layers. In step S1203, it is necessary to count the data volume of the production wells deployed in each layer, and then calculate the sum of the number of production wells in all layers. Finally, the proportion of the number of production wells in each layer to the total number of production wells in all layers is calculated, so as to obtain the proportion of the number of wells in different layers, such as Figure 3 shown.

[0048] Finally, step S1204 (not shown) ranks the reservoir quality of each layer (for example, from best to worst) according to the daily liquid production ratio, daily oil production ratio and number of wells ratio of different layers by comparing the cost, output and benefit of each layer, thereby selecting multiple alternative layers.

[0049] Figure 2 This is a schematic diagram of the stratum analysis and evaluation chart in the layer selection and well selection method for old well fracturing in the embodiment of the present application. Without considering the actual data, according to the size relationship of the three data items, it can be known through exhaustive method that there are a total of 12 combinations of charts under the three indicators, such as Figure 2 In actual application, the well number ratio can be used to refer to the fixed investment level, such as drilling, storage and transformation costs; the liquid production ratio can be used to refer to the operating cost level, such as water and electricity costs; and the oil production ratio can be used to refer to income, the only indicator that generates revenue.

[0050] Through the analysis of the above three indicators, the change of the difference between the operating cost and output of the layer over time or the cost-effectiveness can be evaluated, so as to select multiple advantageous layers with high benefits and / or high output and / or complete production and injection well network, and rank them from high to low according to their advantages.

[0051] Specifically, multiple candidate layers that meet one or more of the following conditions are selected: Condition 1: when the proportion of well numbers is the same, the layer with a higher daily oil production proportion or a higher daily liquid production proportion (for example, the daily oil production proportion or the daily liquid production proportion data are in the top three); Condition 2: the layer with a higher daily oil production proportion than the daily liquid production proportion; Condition 3: the layer with a higher daily oil production proportion or a higher daily liquid production proportion than the proportion of well numbers.

[0052] In actual application, under the same ratio of wells, the higher the ratio of daily liquid production, the more sufficient the reservoir energy or the more perfect the water injection well network. The higher the ratio of daily oil production, the higher the oil content and the better the reservoir quality. The difference between the ratio of daily liquid production and the ratio of daily oil production can reflect the input-output ratio to a certain extent. When the ratio of daily oil production is higher than the ratio of daily liquid production, it indicates the possibility of positive returns. The greater the difference, the higher the rate of return. When the ratio of daily oil production is higher than the ratio of wells, it means that the quality of the reservoir exceeds the average level. When the ratio of daily liquid production is higher than the ratio of wells, it means that the reservoir energy or the perfection of the production and injection well network exceeds the average level.

[0053] It should be noted that the embodiment of the present invention can extend the horizon to the smallest unit of the well group.

[0054] Figure 2 The data distribution characteristics of the proportion of poor reservoirs to optimal reservoirs are shown when the proportion of wells is the same. Figure 2 As shown,

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

[0056] The reservoir with the data distribution characteristics of case 2 is superior to that of case 1. The proportion of wells in this layer is greater than the proportion of daily liquid production, and the proportion of daily liquid production is approximately equal to the proportion of daily oil production.

[0057] The reservoir with the data distribution characteristics of case 3 is superior to that of case 2. The proportion of wells in this layer is greater than the proportion of daily liquid production, and the proportion of daily oil production is higher than the proportion of daily liquid production. The proportion of daily oil production is approximately equal to the proportion of wells.

[0058] The reservoir with the data distribution characteristics of case 4 is superior to that of case 3. The proportion of wells in this layer is greater than the proportion of daily liquid production, and the proportion of daily oil production is higher than the proportion of daily liquid production, and the proportion of daily oil production is higher than the proportion of wells.

[0059] The reservoir with the data distribution characteristics of case 5 is superior to the reservoir corresponding to case 4. 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 by reaching the first difference threshold.

[0060] The reservoir with the data distribution characteristics of case 6 is superior to the reservoir corresponding to case 5. 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 by reaching the second difference threshold, where the second difference threshold is less than the first difference threshold;

[0061] The reservoir with the distribution characteristics of proportion data belonging to case 7 is superior to the reservoir corresponding to case 6. This layer has the most ideal distribution of proportion data. The proportion of wells, daily liquid production and daily oil production in this layer are all approximately equal.

[0062] The reservoirs with the data distribution characteristics of case 8 are superior to those of case 7. 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 that of daily liquid production.

[0063] The reservoirs with the data distribution characteristics of case 9 are superior to those of case 8. 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 data distribution characteristics of case 10 are superior to those of case 9. 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 reservoir with the data distribution characteristics of case 11 is superior to the reservoir corresponding to case 10. 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 reservoir with the data distribution characteristics of case 12 is superior to that of case 11. The proportion of wells in this layer is lower than the proportion of daily liquid production, and the proportion of liquid production is lower than the proportion of daily oil production.

[0067] like Figure 2 As shown in the figure, the step-down data distribution characteristics of Case 1 are typical of the worst reservoirs, and such wells should be shut down first when oil prices are low. The step-up data distribution characteristics of Case 12 are typical of the best-quality reservoirs, and are the most suitable reservoir layers for storage conversion, production improvement, and efficiency improvement.

[0068] In addition, when the daily liquid production or daily oil production of a certain layer is the total liquid production or total oil production of the current layer, only qualitative analysis can be performed, or quantitative comparison can be made for the liquid production ratio or oil production ratio under the same well number ratio condition. Quantitative comparison cannot be made when the well number ratio is different. When using the single-layer well average data, the data under different well number ratio conditions are comparable.

[0069] In this way, the present invention obtains a preset number of candidate strata with high reservoir quality through the sorting results of the strata completed in the above step S120, and then enters step S130.

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

[0071] In step S130, first, based on the daily liquid production data group, daily oil production data group and water cut data group of each production well in each alternative layer, the daily liquid production index, daily oil production index and water cut index of each well in each alternative layer are counted, and each indicator in the same layer is sorted in descending order. Specifically, according to the daily liquid production data group of each production well in each alternative layer, the average value data is calculated, so that the average daily liquid production of different production wells in each alternative layer is used as the daily liquid production index of the corresponding production well, and the daily liquid production indexes of different production wells in each layer are sorted in descending order; according to the daily oil production data group of each production well in each alternative layer, the average value data is calculated, so that the average daily oil production of different production wells in each alternative layer is used as the daily oil production index of the corresponding production well, and the daily oil production indexes of different production wells in each layer are sorted in descending order; according to the water cut data group of each production well in each alternative layer, the average value data is calculated, so that the average water cut of different production wells in each alternative layer is used as the water cut index of the corresponding production well, and the daily water cut indexes of different production wells in each layer are sorted in descending order.

[0072] After sorting the indicators, step S130 will also classify each production well according to the sorting position of each (production) indicator and the relationship between the different (production) indicators of each well and the corresponding indicator average value. In the embodiment of the present invention, the well types include: a first type of wells for implementing the production impact high fracturing technology (this type of well is a selected well with high oil production and low water content), a second type of wells for implementing the fracturing technology of wells with production potential (this type of well is a selected well with low liquid production and low water content, which has the potential for production increase but the potential is significantly lower than that of the first type of well, but significantly higher than that of the third type of well, and more active fracturing measures such as large-scale need to be implemented to better release production capacity, because this type of single well has sufficient energy and low water content, and has the characteristics of large transformation potential and low risk) and a third type of wells for implementing low-yield and low-efficiency management (this type of well is a selected well with low liquid production, low oil production and low water content).

[0073] Before classification, the embodiment of the present invention needs to calculate the corresponding average values ​​for different production data items according to the oil production data group, liquid production data group and water content data group of the current production well in the current layer. The production data of the single well in the target layer is summarized, and the daily liquid production, daily oil production and water content indicators are sorted and analyzed, and a cross-screening process based on the block production capacity characteristics and the single well measure characteristics is designed.

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

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

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

[0077] In the embodiment of the present 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 the target well can be carried out according to the following conditions:

[0079] ① Class I wells with high oil production and low water content (used for production boost): daily liquid production is lower than the average, daily oil production is higher than the average (or higher than the top 25%), and water content is lower than the average;

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

[0081] ③ Class III wells with low liquid production, low oil production and low water content (low production and inefficient management): daily liquid 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 layer selection and well selection method is applied to an oil field to specifically illustrate the application effect of the present invention. The oil field has been developed for 20 years, but the operator has changed many times in the middle. The geological and reservoir data are fragmented and difficult to collect. Due to the limitation of development cost, it is difficult to carry out new coring work and further improve the understanding of geology and reservoir.

[0083] The oilfield production dynamic data was collected and processed and analyzed. First, different layers were classified and processed. The results are as follows: Figure 3 and Figure 4 shown.

[0084] The J1 and J2 layers have a large number of wells, a large amount of liquid production, and the highest water content, with an average water content of more than 90%, which is related to the long-term water injection development of this layer and has the characteristics of high water content in the late development period; the J6 and J10 layers have a relatively high water content of about 80%; the J10 layer has few wells and low production, and is not a major layer; see Figure 4 .

[0085] Under the same well number ratio condition, the higher the liquid production ratio is, the more sufficient the reservoir energy is or the better the water injection well network is; the higher the oil production ratio is, the higher the oil content is and the better the reservoir quality is; the difference between the liquid production ratio and the oil production ratio can reflect the input-output ratio to a certain extent; the higher the oil production ratio is, the more positive the return is; the greater the difference is, the greater the rate of return is; the J1 and J2 layers have a large number of wells and a large liquid production, and are currently the main production layers; excluding the J1 and J2 layer data: the J4 layer provides the highest oil production, which is better than the J6 layer with the same number of wells; see Figure 5 .

[0086] The high water content of J1 and J2 layers leads to a lower single-well oil production under the condition of high average single-well liquid production, which is a development feature with higher costs in the later stage of reservoir exploitation. In addition to J1 and J2 layers, J4 and J7 layers are production layers with great potential, see Figure 6 and Figure 7 .

[0087] On the basis of the selected layer, the information of each well in the layer is summarized, the daily liquid production, daily oil production and water cut indicators are sorted and analyzed, and a cross-screening process based on the block production capacity characteristics and single well measure characteristics is designed.

[0088] From the perspective of well selection, there are three well selection schemes from the perspective of production:

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

[0090] In principle, the daily liquid production is less than 23m 3 、Daily oil production is higher than 5.7m 3 , water content is less than 50%;

[0091] (2) Single wells with low liquid and low water content are preferred:

[0092] In principle, the daily liquid production is less than 23m 3 、Daily oil production is less than 5.7m 3 , water content is less than 70%;

[0093] (3) Single wells with low liquid, low oil and low water content (low production and low efficiency management):

[0094] In principle, the daily liquid production is less than 23m 3 、Daily oil production is less than 3.4m 3 , water content is less than 90%.

[0095] According to the above standards, the measure wells were selected, as shown in Table 1 below, among which 631, 232, 174, and 425 were consistent with the well selection and actual measures of the reservoir plan for the following year.

[0096] Table 1 Example of well selection results

[0097]

[0098] Based on the above-mentioned layer selection and well selection method, an embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored, and the computer program is executed to run a layer selection and well selection method for fracturing an old well. The computer program can run computer instructions, and the computer instructions include computer program code, and the computer program code can be in source code form, object code form, executable file, or some intermediate form, etc.

[0099] Computer-readable storage media may include: any entity or device that can carry computer program code, recording media, USB flash drives, mobile hard disks, 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 content contained in computer-readable storage media can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, the content contained in computer-readable storage media does not include electrical carrier signals and telecommunication signals.

[0101] In addition, based on the above-mentioned layer selection and well selection method for old well fracturing, an embodiment of the present invention further provides a layer selection and well selection system for old well fracturing.

[0102] Figure 8 Module block diagram of the layer selection and well selection system for old well fracturing in the embodiment of the present application. Figure 8 As shown, the layer and well selection system described in the embodiment of the present 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 count the proportion of each production data corresponding to different layers, and based on this, combined with the proportion of the number of wells in different layers, multiple alternative layers are preferred; 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 according to the multiple production data of each well in each alternative layer.

[0104] The present invention discloses a layer selection and well selection method and system for old well fracturing. In order to overcome the practical difficulties existing in the actual production of oil reservoirs, the method and system conduct in-depth analysis on production indicators such as liquid production, oil production, water content, and number of wells opened, establish the correlation between multiple indicators and evaluation standards through numerical analysis and horizontal comparison, clarify the distribution of geological sweet spots under the current well network, and then establish a reservoir transformation well selection plan. Based on relative analysis, the present invention can optimize the layer position in the existing developed layer on the basis of the lack of geological and reservoir analysis knowledge; and based on relative analysis, on the basis of the lack of geological and reservoir analysis knowledge, the well selection work can be carried out on the basis of existing production wells.

[0105] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any person familiar with the technology within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

[0106] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0107] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0108] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures, processing steps or materials disclosed herein, but should be extended to equivalent substitutions of these features understood by ordinary technicians in the relevant field. It should also be understood that the terms used herein are only used for the purpose of describing specific embodiments and are not meant to be limiting.

[0109] The "one embodiment" or "embodiment" mentioned in the specification means that the specific features, structures or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "embodiment" appearing in various places throughout the specification do not necessarily refer to the same embodiment.

[0110] Although the embodiments disclosed in the present invention are as above, the contents described are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A layer selection and well selection method for fracturing old wells, characterized in that: include: Collect multiple production data for each well within the target fracturing area; Count the proportion of each production data corresponding to different layers, and based on this, combine the proportion of wells in different layers to select multiple candidate layers; According to the multiple production data of each well in each candidate layer, each well in different layers is classified according to different fracturing measures.

2. The layer and well selection method according to claim 1, characterized in that: The multiple production data include but are not limited to: production layer, daily liquid production, daily oil production and water content.

3. The layer and well selection method according to claim 2, characterized in that: In the step of calculating the proportion of each production data corresponding to different layers, based on this, combined with the proportion of the number of wells in different layers, selecting multiple candidate layers includes: Calculate the average daily liquid production and daily oil production of all production wells in different layers; The proportion of the average daily liquid production of different layers to the daily liquid production of all layers, and the proportion of the average daily oil production of different layers to the daily oil production of all layers are calculated to obtain the proportion of daily liquid production and daily oil production of different layers; Count the number of production wells in different layers to obtain the proportion of wells in different layers; According to the daily liquid production proportion, daily oil production proportion and number of wells of different layers, the reservoir advantages and disadvantages of each layer are ranked by comparing the cost, output and benefit of each layer, so as to select the multiple candidate layers.

4. The layer and well selection method according to claim 3, characterized in that: Select the multiple candidate layers that meet the following conditions: In the case where the proportion of the number of wells is the same, the layer with a higher proportion of the daily oil production or the daily liquid production; The layer where the daily oil production ratio is higher than the daily liquid production ratio; The stratum where the daily oil production ratio or the daily liquid production ratio is higher than the well number ratio.

5. The layer and well selection method according to any one of claims 1 to 4, characterized in that: The step of classifying each well in different strata according to different fracturing measures according to the multiple production data of each well in each candidate strata comprises: Count the daily liquid production index, daily oil production index and water content index of each well in each candidate layer, and sort each index in the same layer in descending order; According to the ranking position of each indicator and the relationship between the different indicators of each well and the corresponding indicator average value, each well is classified into a well type, which includes the first type of wells used for implementing production-boosting fracturing technology, the second type of wells used for implementing fracturing technology for wells with production-increasing potential, and the third type of wells used for implementing low-yield and low-efficiency management.

6. The layer and well selection method according to claim 5, characterized in that: If the daily liquid production index of the well to be evaluated in the current layer is lower than the average daily liquid production index of the current layer, and the daily oil production index is higher than the average daily oil production index of the current layer, and the water cut index is lower than the average water cut index of the current layer, then the well to be evaluated is determined as the first type of well; or, If the daily liquid production index of the well to be evaluated in the current layer is lower than the average daily liquid production index of the current layer, and the daily oil production index is within the top first percentage in the daily oil production index ranking of the current layer, and the water cut index is lower than the average water cut index of the current layer, then the well to be evaluated is determined as the first type of well.

7. The layer and well selection method according to claim 5, characterized in that: If the daily liquid production index of the well to be evaluated in the current layer is lower than the average daily liquid production index of the current layer, and the daily oil production index is lower than the average daily oil production index of the current layer, and the water cut index is lower than the water cut index of the current layer and is outside the first percentage in the water cut index ranking of the current layer, then the well to be evaluated is determined as the second type of well; or, If the daily liquid production index of the well to be evaluated in the current layer is lower than the average daily liquid production index of the current layer, and the daily oil production index is outside the first percentage in the daily oil production index ranking of the current layer, and the water cut index is lower than the water cut index of the current layer and is outside the first percentage in the water cut index ranking of the current layer, then the well to be evaluated is determined as the second type of well.

8. The layer and well selection method according to claim 5, characterized in that: If the daily liquid production index of the well to be evaluated in the current layer is lower than the average daily liquid production index of the current layer, and the daily oil production index is outside the top second percentage in the daily oil production index ranking of the current layer, and the water cut index is lower than the water cut index of the current layer and is outside the top first percentage in the water cut index ranking of the current layer, then the well to be evaluated is determined as the third type of well, and the second percentage is greater than the first percentage.

9. A readable storage medium, characterized in that: It contains a series of instructions for executing the method steps as claimed in any one of claims 1 to 8.

10. A layer and well selection system for fracturing old wells, characterized in that: include: a data collection module configured to collect a plurality of production data for each well within a target fracturing zone; The layer selection module is configured to count 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 is configured to classify each well in different layers according to different fracturing measures according to the multiple production data of each well in each candidate layer.

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