Method and device for screening oil wells suitable for water plugging in fault-karst reservoir

Abstract

The invention discloses a method and device for screening oil wells suitable for water plugging in a fault-karst reservoir, and the method comprises the steps: obtaining the water plugging evaluation characteristics of each oil well in the fault-karst reservoir to be evaluated, the water plugging evaluation characteristics including geologic characteristics, fracture-cavity structure characteristics, flooding degree characteristics and oil-water relation characteristics; according to the water plugging evaluation characteristics of each oil well, quantitatively calculating a corresponding water plugging effectiveness potential index; and preferably selecting the oil well with the water plugging potential according to the water plugging effectiveness potential index of each oil well. According to the method, the selection of the oil well suitable for water plugging in the fault-karst oil reservoir is realized, and the accuracy of well selection is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil drilling engineering, and particularly relates to a method and device for screening oil wells suitable for water plugging in fractured-vuggy reservoirs. Background Art

[0002] The fractured-vuggy reservoirs in the Tarim Basin are fault-controlled reservoirs, which are characterized by a large oil column height and high single-well productivity. However, the formation pressure of the fractured-vuggy reservoirs drops rapidly, the bottom-hole flowing pressure attenuation slows down, and the production gas-oil ratio can still remain stable. With the continuous progress of development, the bottom water energy breaks through continuously and channels into the wells along the dominant channels, affecting the exploitation of the remaining oil around the wells, resulting in a large amount of remaining oil remaining underground, seriously affecting the productivity, but the water plugging efficiency of some reservoirs is relatively low.

[0003] In the prior art, there is no decision-making method for water plugging well selection specifically for fractured-vuggy reservoirs. Most of the well selection decision-making methods only make decisions on water plugging well selection for oil wells such as horizontal wells and gas injection wells. In addition, only single indicators such as logging curves, pressure drop curves, and water cut size indexes are used for water plugging well selection, and no further consideration is given from the perspectives of the potential of the oil wells and whether water plugging measures are worthwhile. In addition, the prior art does not consider the water plugging decision-making method from the perspectives of geology, production, etc., and the selected indicators cannot comprehensively consider the actual situation of water plugging in oil wells. Therefore, the selected oil wells may not have the greatest potential.

[0004] Therefore, there is an urgent need for a method for screening and determining oil wells suitable for water plugging in fractured-vuggy reservoirs. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for considering water plugging decisions from the perspectives of geology, production, etc., so as to plug oil wells suitable for water plugging in fractured-vuggy reservoirs, and thus achieve the purpose of increasing oil production.

[0006] To solve the above technical problems, an embodiment of the present invention provides a method for screening oil wells suitable for water plugging in fractured-vuggy reservoirs, including: obtaining the water plugging evaluation characteristics of each oil well in the fractured-vuggy reservoir to be evaluated, where the water plugging evaluation characteristics include geological characteristics, fracture-cavity structure characteristics, water flooding degree characteristics, and oil-water relationship characteristics; quantitatively calculating the corresponding water plugging effectiveness potential index according to the water plugging evaluation characteristics of each oil well; and preferably selecting oil wells with water plugging potential according to the water plugging effectiveness potential index of each oil well.

[0007] Preferably, in the step of quantitatively calculating the corresponding water plugging effectiveness potential index according to the water plugging evaluation characteristics of each oil well, it includes: according to the geological characteristics, determining the first factor potential index representing the influence degree of the geological characteristics on the water plugging effect by analyzing the geological characteristics of the fracture-cavity body where the current wellbore is located; according to the fracture-cavity structure characteristics communicated around the current wellbore, determining the second factor potential index representing the influence degree of the fracture-cavity structure characteristics on the water plugging effect by analyzing the type of fracture-cavity structure to which the water plugging position belongs; according to the water flooding degree characteristics, determining the third factor potential index representing the influence degree of the water flooding degree characteristics on the water plugging effect by analyzing the type of water cut increase change after production of the current wellbore; according to the oil-water relationship characteristics, determining the fourth factor potential index representing the influence degree of the oil-water relationship characteristics on the water plugging effect by calculating the water body multiple representing the water body energy; and calculating the water plugging effectiveness potential index according to the factor potential indexes and the corresponding weights.

[0008] Preferably, in the step of determining the first factor potential index representing the influence degree of the geological characteristics on the water plugging effect by analyzing the geological characteristics of the fracture-cavity body where the current wellbore is located according to the geological characteristics, it includes: when the geological characteristics of the fracture-cavity body where the current wellbore is located is a fracture-cavity body fracture zone, determining the first factor potential index as the first potential value of the first factor; when the geological characteristics of the fracture-cavity body where the current wellbore is located is the core of the fracture-cavity body, determining the first factor potential index as the second potential value of the first factor; when the geological characteristics of the fracture-cavity body where the current wellbore is located is a composite karst area, determining the first factor potential index as the third potential value of the first factor, where the first potential value of the first factor is higher than the second potential value of the first factor, and the second potential value of the first factor is higher than the third potential value of the first factor.

[0009] Preferably, in the step of determining the second factor potential index representing the influence degree of the fracture-cavity structure characteristics on the water plugging effect by analyzing the type of fracture-cavity structure to which the water plugging position belongs according to the fracture-cavity structure characteristics communicated around the current wellbore, it includes: when the type of fracture-cavity structure to which the current water plugging position belongs is a cavity-edge fracture type, determining the second factor potential index as the first potential value of the second factor; when the type of fracture-cavity structure to which the current water plugging position belongs is a horizontal well and cavity parallel type, determining the second factor potential index as the second potential value of the second factor; when the type of fracture-cavity structure to which the current water plugging position belongs is a cavity-top fracture type, determining the second factor potential index as the third potential value of the second factor; when the type of fracture-cavity structure to which the current water plugging position belongs is a cavity-bottom fracture type, determining the second factor potential index as the fourth potential value of the second factor, where the first potential value of the second factor is higher than the second potential value of the second factor, and the second potential value of the second factor is higher than the third potential value of the second factor, and the third potential value of the second factor is higher than the fourth potential value of the second factor.

[0010] Preferably, in the step of determining the potential index of the third factor characterizing the influence degree of the water flooding degree characteristics on the water plugging effect by analyzing the water cut rising change type of the current wellbore after production according to the water flooding degree characteristics, it includes: when the water cut rising change type of the current wellbore after production is a slow rising type, determining the potential index of the third factor as the first potential value of the third factor; when the water cut rising change type of the current wellbore after production is a fluctuating rising type, determining the potential index of the third factor as the second potential value of the third factor; when the water cut rising change type of the current wellbore after production is a rapid rising type, determining the potential index of the third factor as the third potential value of the third factor; when the water cut rising change type of the current wellbore after production is a step rising type, determining the potential index of the third factor as the fourth potential value of the third factor; when the water cut rising change type of the current wellbore after production is a violent water flooding type, determining the potential index of the third factor as the fifth potential value of the third factor, wherein, the first potential value of the third factor is higher than the second potential value of the third factor, and the second potential value of the third factor is higher than the third potential value of the third factor, and the third potential value of the third factor is higher than the fourth potential value of the third factor, and the fourth potential value of the third factor is higher than the fifth potential value of the third factor.

[0011] Preferably, in the step of determining the potential index of the fourth factor characterizing the influence degree of the oil-water relationship characteristics on the water plugging effect by calculating the water body multiple characterizing the water body energy according to the oil-water relationship characteristics, it includes: when the current water body multiple is less than or equal to the first preset threshold, determining the potential index of the fourth factor as the first potential value of the fourth factor; when the current water body multiple is greater than the first preset threshold and less than or equal to the second preset threshold, determining the potential index of the fourth factor as the second potential value of the fourth factor, wherein, the second preset threshold is greater than the first preset threshold; when the current water body multiple is greater than the second preset threshold, determining the potential index of the fourth factor as the third potential value of the fourth factor, wherein, the first potential value of the fourth factor is higher than the second potential value of the fourth factor, and the second potential value of the fourth factor is higher than the third potential value of the fourth factor.

[0012] Preferably, the weight of the first factor potential index is higher than the weight of the second factor potential index, and the weight of the second factor potential index is higher than the weight of the third factor potential index, and the weight of the third factor potential index is higher than the weight of the fourth factor potential index, wherein, the weight of the first factor potential index is 30% - 40%, the weight of the second factor potential index is 20% - 30%, the weight of the third factor potential index is 10% - 20%, and the weight of the fourth factor potential index is 10% - 20%.

[0013] On the other hand, an embodiment of the present invention further provides a device for screening oil wells suitable for water plugging in a fractured-vuggy reservoir, including: an acquisition module configured to obtain the water plugging evaluation characteristics of each oil well in the fractured-vuggy reservoir to be evaluated, where the water plugging evaluation characteristics include geological characteristics, fracture-vug structure characteristics, water flooding degree characteristics, and oil-water relationship characteristics; a calculation module configured to quantitatively calculate the corresponding water plugging effectiveness potential index according to the water plugging evaluation characteristics of each oil well; and a selection module configured to preferably select oil wells with water plugging potential according to the water plugging effectiveness potential index of each oil well.

[0014] Compared with the prior art, one or more of the above embodiments may have the following advantages or beneficial effects:

[0015] The present invention proposes a method and a device for screening oil wells suitable for water plugging in a fractured-vuggy reservoir. The method and the device obtain the water plugging evaluation characteristics of each oil well in the fractured-vuggy reservoir to be evaluated; quantitatively calculate the corresponding water plugging effectiveness potential index according to the water plugging evaluation characteristics of each oil well; and preferably select oil wells with water plugging potential according to the water plugging effectiveness potential index of each oil well. The present invention realizes the selection of oil wells suitable for water plugging for the fractured-vuggy reservoir from evaluation characteristics such as geology, fracture-vug structure, water flooding degree, and oil-water relationship, effectively improves the accuracy of well selection, and thus targets well selection and water plugging to exploit the unproduced remaining oil and achieve the purpose of increasing oil production.

[0016] Other features and advantages of the present invention will be described in the following description, and some of them will become obvious from the description, or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings are used to provide a further understanding of the present invention and constitute a part of the description. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0018] Figure 1 It is a schematic diagram of the steps of the method for screening oil wells suitable for water plugging in a fractured-vuggy reservoir according to an embodiment of the present application.

[0019] Figure 2 It is a schematic diagram of the water breakthrough water flooding type curve of the method for screening oil wells suitable for water plugging in a fractured-vuggy reservoir according to an embodiment of the present application.

[0020] Figure 3 It is a schematic diagram of the water content fluctuating upward type curve of the method for screening oil wells suitable for water plugging in a fractured-vuggy reservoir according to an embodiment of the present application.

[0021] Figure 4Schematic diagram of the water cut slow-rising type curve of the method for screening oil wells suitable for water plugging in fractured solution reservoirs according to the embodiments of the present application.

[0022] Figure 5 Schematic diagram of the water cut step-rising type curve of the method for screening oil wells suitable for water plugging in fractured solution reservoirs according to the embodiments of the present application.

[0023] Figure 6 Schematic diagram of the water cut rapid-rising type curve of the method for screening oil wells suitable for water plugging in fractured solution reservoirs according to the embodiments of the present application.

[0024] Figure 7 Schematic diagram of the water plugging construction curve of the method for screening oil wells suitable for water plugging in fractured solution reservoirs according to the embodiments of the present application.

[0025] Figure 8 Schematic diagram of the structure of the device for screening oil wells suitable for water plugging in fractured solution reservoirs according to the embodiments of the present application. Detailed implementation manners

[0026] The following will describe in detail the implementation manners of the present invention in conjunction with the drawings and embodiments, so as to fully understand how the present invention uses technical means to solve technical problems and achieve the implementation process of technical effects and implement accordingly. It should be noted that as long as there is no conflict, the various embodiments in the present invention and the various features in each embodiment can be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.

[0027] In addition, the steps shown in the flowchart of the drawings can be executed in a computer device such as a set of computer executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0028] The terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms "a" and "an" used herein are also intended to include the plural. It should also be understood that the terms "comprises" and / or "comprising" used herein specify the presence of the stated features, integers, steps, operations, units and / or components, and do not exclude the presence or addition of one or more other features, integers, steps, operations, units, components and / or their combinations.

[0029] To solve one or more technical problems described in the background art, embodiments of the present invention provide a method and device for screening oil wells suitable for water plugging in fractured-vuggy reservoirs. By optimizing water plugging-related factors, a comprehensive well selection process is formed to screen out oil wells with greater potential, improve the current situation of low water plugging efficiency in fractured-vuggy reservoirs, and provide support for enhancing the recovery factor in fractured-vuggy reservoirs. Specifically, in order to select oil wells suitable for water plugging in fractured-vuggy reservoirs, the present invention obtains evaluation characteristics such as the geology, fracture-vug structure, water flooding degree, and oil-water relationship of each oil well, and determines the water plugging potential for the fractured-vuggy reservoir to be evaluated based on the foregoing evaluation characteristics, thereby effectively improving the accuracy of well selection.

[0030] Figure 1 It is a schematic diagram of the steps of the method for screening oil wells suitable for water plugging in fractured-vuggy reservoirs according to an embodiment of the present application, which specifically includes the following steps.

[0031] Step S110 obtains the water plugging evaluation characteristics of each oil well in the fractured-vuggy reservoir to be evaluated. Among them, the water plugging evaluation characteristics include geological characteristics, fracture-vug structure characteristics, water flooding degree characteristics, and oil-water relationship characteristics.

[0032] Specifically, the geological background of an oil well is the basis for whether the oil well has potential. Therefore, it is necessary to clarify the geological background of the oil well. When the oil well is completed, in order to increase the productivity of the oil well, acid fracturing completion is often carried out to artificially create fractures to communicate with distal reservoirs. Therefore, the fracture-vug structure can often characterize the oil storage situation of the oil well. In addition, during the process of oil well production, formation water will continuously flow into the well along the preferential channels. Therefore, the type of rising water cut in the oil well can reflect the fracture-vug development around the well to a certain extent. And during the production process, there is usually a game between oil and water. Therefore, it is necessary to clarify the magnitude of the water body energy, and then determine the magnitude of the water plugging potential through the magnitude of the water body multiple.

[0033] After clarifying the water plugging evaluation characteristics to be collected, information such as the geological background, fracture-vug structure, degree of rising water cut, and water body multiple of each to-be-evaluated oil well in the fractured-vuggy reservoir to be evaluated is obtained, and then the geological characteristics, fracture-vug structure characteristics, water flooding degree characteristics, and oil-water relationship characteristics of each oil well in the fractured-vuggy reservoir to be evaluated are determined.

[0034] After obtaining the water plugging evaluation characteristics of each oil well in the fractured-vuggy reservoir to be evaluated, in the subsequent step S120, based on the water plugging evaluation characteristics of each oil well, the potential effectiveness potential indicators corresponding to each evaluation characteristic can be determined from several factor potential indicators corresponding to the evaluation characteristics such as geological characteristics, fracture-vug structure characteristics, water flooding degree characteristics, and oil-water relationship characteristics.

[0035] Step S120 quantitatively calculates the water plugging effectiveness potential indicators of the corresponding oil wells according to the water plugging evaluation characteristics of each oil well.

[0036] In one embodiment, in the step of quantitatively calculating the corresponding water plugging effectiveness potential index according to the water plugging evaluation characteristics of each oil well, it is necessary to determine the potential index of the influence degree of the evaluation characteristics of each oil well on the water plugging effect according to the evaluation characteristics of each oil well, so as to obtain the water plugging effectiveness potential index of each oil well. The specific implementation method is as follows:

[0037] According to the geological characteristics, determine the potential index of the first factor characterizing the influence degree of the geological characteristics on the water plugging effect by analyzing the geological characteristics of the fault-karst body where the current wellbore is located;

[0038] According to the fracture-cavity structure characteristics communicated around the current wellbore, determine the potential index of the second factor characterizing the influence degree of the fracture-cavity structure characteristics on the water plugging effect by analyzing the type of fracture-cavity structure to which the water plugging position belongs;

[0039] According to the water flooding degree characteristics, determine the potential index of the third factor characterizing the influence degree of the water flooding degree characteristics on the water plugging effect by analyzing the type of water cut increase change after production of the current wellbore;

[0040] According to the oil-water relationship characteristics, determine the potential index of the fourth factor characterizing the influence degree of the oil-water relationship characteristics on the water plugging effect by calculating the water body multiple representing the water body energy;

[0041] Calculate the water plugging effectiveness potential index of the current oil well according to each factor potential index and the corresponding weights (the potential index of the first factor and its weight, the potential index of the second factor and its weight, the potential index of the third factor and its weight, the potential index of the fourth factor and its weight).

[0042] In one embodiment, analyze the geological characteristics of the fault-karst body where the current wellbore is located according to the location of the current wellbore, and then determine the potential index of the first factor used to characterize the influence degree of the geological characteristics on the water plugging effect based on the geological characteristics of the fault-karst body. Different potential indexes correspond to different geological characteristics of the fault-karst body, and then determine the size of the potential value based on different potential indexes. The specific implementation method is as follows:

[0043] When the geological characteristics of the fault-karst body where the current wellbore is located are the fault-karst body fracture zone, determine that the potential index of the first factor is the first potential value of the first factor;

[0044] When the geological characteristics of the fault-karst body where the current wellbore is located are the core of the fault-karst body, determine that the potential index of the first factor is the second potential value of the first factor;

[0045] When the geological characteristics of the current wellbore in the fracture-cavity body are in a composite karst area, the potential index of the first factor is determined as the third potential value of the first factor. Among them, in the embodiments of the present invention, the first potential value of the first factor is higher than the second potential value of the first factor, and the second potential value of the first factor is higher than the third potential value of the first factor.

[0046] Specifically, a reservoir profile is depicted for the current wellbore, and based on the depicted reservoir profile, the geological characteristics of the fracture-cavity body where the current wellbore is located are determined. Then, based on these geological characteristics, the potential value of the first factor corresponding to the current wellbore is determined. Among them, it can be determined that the first potential value of the first factor is higher than the second potential value of the first factor, and the second potential value of the first factor is higher than the third potential value of the first factor based on the statistical analysis of the previous construction wells, or the size relationship of the potential values of the first factor can be determined based on actual applications. This specification does not limit this.

[0047] In one embodiment, based on the fracture-cavity structure to which the current water plugging position belongs, its corresponding fracture-cavity structure characteristics are determined. Then, the potential value of the corresponding second factor can be determined based on these fracture-cavity structure characteristics. The specific implementation method is as follows:

[0048] When the fracture-cavity structure type to which the current water plugging position belongs is the type of fracture beside the cavity, the potential index of the second factor is determined as the first potential value of the second factor;

[0049] When the fracture-cavity structure type to which the current water plugging position belongs is the type of parallel connection of horizontal well and cavity, the potential index of the second factor is determined as the second potential value of the second factor;

[0050] When the fracture-cavity structure type to which the current water plugging position belongs is the type of fracture at the top of the cavity, the potential index of the second factor is determined as the third potential value of the second factor;

[0051] When the fracture-cavity structure type to which the current water plugging position belongs is the type of fracture at the bottom of the cavity, the potential index of the second factor is determined as the fourth potential value of the second factor. Among them, in the embodiments of the present invention, the first potential value of the second factor is higher than the second potential value of the second factor, the second potential value of the second factor is higher than the third potential value of the second factor, and the third potential value of the second factor is higher than the fourth potential value of the second factor.

[0052] Specifically, in the case where the remaining oil is mainly concentrated in the fracture-cavity edge reservoir body after acid fracturing communication and bottom water breakthrough, the fracture-cavity structure of the current water plugging position is determined as the type of fracture at the top of the cavity; in the case where there is a horizontal well connected to the fracture-cavity after acid fracturing communication, the fracture-cavity structure of the current water plugging position is determined as the type of parallel connection of horizontal well and cavity; in the case where the remaining oil is mainly concentrated in the top reservoir body after acid fracturing communication and bottom water breakthrough, the fracture-cavity structure of the current water plugging position is determined as the type of fracture at the top of the cavity; in the case where the remaining oil is mainly concentrated in the bottom reservoir body after acid fracturing communication and bottom water breakthrough, the fracture-cavity structure of the current water plugging position is determined as the type of fracture at the top of the cavity.

[0053] Moreover, obtain the potential value corresponding to the well in the early stage of construction, as well as the fracture-cavity structure corresponding to the well in the early stage of construction, and then statistically analyze to obtain that the potential value of the fracture-cavity structure is that the first potential value of the second factor is higher than the second potential value of the second factor, and the second potential value of the second factor is higher than the third potential value of the second factor, and the third potential value of the second factor is higher than the fourth potential value of the second factor.

[0054] In a possible embodiment, after the wellbore enters production, obtain the water cut after the current wellbore produces, and then determine the current type of water cut increase change. Further, determine the potential value of the third factor of the current wellbore through the type of water cut increase change, which is convenient for subsequent well selection decision-making based on the potential value of the third factor. The specific implementation method is as follows:

[0055] When the type of water cut increase change after the current wellbore produces is a slow increase type, determine that the potential index of the third factor is the first potential value of the third factor;

[0056] When the type of water cut increase change after the current wellbore produces is a fluctuating increase type, determine that the potential index of the third factor is the second potential value of the third factor;

[0057] When the type of water cut increase change after the current wellbore produces is a rapid increase type, determine that the potential index of the third factor is the third potential value of the third factor;

[0058] When the type of water cut increase change after the current wellbore produces is a step increase type, determine that the potential index of the third factor is the fourth potential value of the third factor;

[0059] When the type of water cut increase change after the current wellbore produces is a violent water flooding type, determine that the potential index of the third factor is the fifth potential value of the third factor. Among them, in the embodiment of the present invention, the first potential value of the third factor is higher than the second potential value of the third factor, and the second potential value of the third factor is higher than the third potential value of the third factor, and the third potential value of the third factor is higher than the fourth potential value of the third factor, and the fourth potential value of the third factor is higher than the fifth potential value of the third factor.

[0060] Among them, the water cut increase rate can be understood as the percentage of water cut increase per 1% of the geological reserves produced.

[0061] Figure 2 It is a schematic diagram of the violent water flooding type curve of the water cut for the method for screening oil wells suitable for water plugging in a fault-karst reservoir in the embodiment of the present application. Figure 3 It is a schematic diagram of the fluctuating water cut increase type curve of the water cut for the method for screening oil wells suitable for water plugging in a fault-karst reservoir in the embodiment of the present application. Figure 4 It is a schematic diagram of the slow water cut increase type curve of the water cut for the method for screening oil wells suitable for water plugging in a fault-karst reservoir in the embodiment of the present application.Figure 5 Schematic diagram of the water cut step - rising type curve of the method for screening oil wells suitable for water plugging in fractured - solution reservoirs in the embodiments of this application. Figure 6 Schematic diagram of the water cut rapidly - rising type curve of the method for screening oil wells suitable for water plugging in fractured - solution reservoirs in the embodiments of this application. Combined with Figures 2 to 6 , the water cut rising types of the method for screening oil wells suitable for water plugging in fractured - solution reservoirs described in the embodiments of the present invention are described.

[0062] Specifically, the water cut rising types include explosive water flooding type, fluctuating rising type, slowly rising type, step - rising type, and rapidly rising type. The main basis for judging the water cut rising type is the speed of water cut rising. As Figures 2 - 6 shown, f w is the water cut, Q0 is the daily oil production; the explosive water flooding type means that the water cut f w suddenly rises to a relatively high value, generally above 90%, and correspondingly, the daily oil production Q0 will rapidly decrease; the fluctuating rising type means that the water cut f w generally shows an upward trend, but there will be fluctuating changes. Correspondingly, the daily oil production Q0 will also fluctuate and decrease; the slowly rising type means that the rising trend of the water cut f w is a slow process, its slope is relatively small, generally below 0.5, and correspondingly, the daily oil production Q0 will also slowly decrease; the step - rising type means that the overall trend of the water cut f w is upward, but at a certain stage, due to certain water plugging measures, etc., the water cut f w will tend to be stable within a period of time and then show a gradually rising state. Correspondingly, there will also be steps in the daily oil production Q0; the rapidly rising type means that the slope of the water cut f w curve is relatively high, generally around 0.5, the water cut f w shows a relatively fast rising trend, and correspondingly, the daily oil production Q0 shows a rapidly decreasing trend.

[0063] In one embodiment, the water cut rising type can be determined according to the dynamic change state of the water cut f w and the dynamic change state of the daily oil production Q0, and further determine the corresponding potential value under the third factor corresponding to the current water cut type.

[0064] In a possible embodiment, the oil - water relationship can, to a certain extent, reflect the situation of the oil - water game. The size of the water body energy can be represented by the water body multiple. For oil wells with large water body energy, slugs with stronger plugging ability need to be used, that is, the potential value of the corresponding fourth factor is determined by the water body multiple. The specific implementation method is as follows:

[0065] When the current water body multiple is less than or equal to the first preset threshold, determine that the fourth factor potential index is the first potential value of the fourth factor;

[0066] When the current water body multiple is greater than the first preset threshold and less than or equal to the second preset threshold, determine that the fourth factor potential index is the second potential value of the fourth factor, where, in the embodiments of the present invention, the second preset threshold is greater than the first preset threshold;

[0067] When the current water body multiple is greater than the second preset threshold, determine that the fourth factor potential index is the third potential value of the fourth factor. Where, in the embodiments of the present invention, the first potential value of the fourth factor is higher than the second potential value of the fourth factor, and the second potential value of the fourth factor is higher than the third potential value of the fourth factor.

[0068] It should be noted that the water body multiple can be understood as the ratio of the water body volume of the bottom water to the ground reserve of crude oil, that is, water body multiple = water body volume / ground reserve of crude oil.

[0069] For example, the first preset threshold can be 25, and the second preset threshold can be 50. When the water body multiple of the current wellbore is less than or equal to 25, the fourth factor potential index is the first potential value of the fourth factor; when the current water body multiple is greater than 25 and less than or equal to 50, determine that the fourth factor potential index is the second potential value of the fourth factor; when the current water body multiple is greater than 50, determine that the fourth factor potential index is the third potential value of the fourth factor. Among them, the first potential value of the fourth factor is greater than the second potential value of the fourth factor, and the second potential value of the fourth factor is greater than the third potential value of the fourth factor.

[0070] In one embodiment, after determining the effectiveness potential index corresponding to each water plugging evaluation feature, the effectiveness potential index can be calculated based on the factor potential indexes. In the calculation process, in order to improve the accuracy of oil well selection in the water plugging process of well selection, the weight of each water plugging evaluation feature can be set, and then a more accurate evaluation can be carried out for the water plugging influence indexes with different importance based on the weight. The specific implementation method is as follows:

[0071] In the embodiments of the present invention, the weight of the first factor potential index is higher than the weight of the second factor potential index, and the weight of the second factor potential index is higher than the weight of the third factor potential index, and the weight of the third factor potential index is higher than the weight of the fourth factor potential index.

[0072] In a specific embodiment, the weight of the first factor potential index is 30% - 40%, the weight of the second factor potential index is 20% - 30%, the weight of the third factor potential index is 10% - 20%, and the weight of the fourth factor potential index is 10% - 20%.

[0073] Preferably, when selecting oil wells with water plugging potential based on the water plugging effectiveness potential index of each oil well, the optimization operation of the oil wells can be carried out in the order of the first factor potential index, the second factor potential index, the third factor potential index, and the fourth factor potential index. Moreover, a comprehensive evaluation of the water plugging potential oil wells can be conducted by combining the weights of the first factor potential index, the second factor potential index, the third factor potential index, and the fourth factor potential index.

[0074] Step S130 selects oil wells with water plugging potential according to the water plugging effectiveness potential index of each oil well.

[0075] Specifically, oil wells with greater water plugging potential can be selected according to the magnitude of the water plugging effectiveness potential index of each oil well, thereby realizing targeted well selection for water plugging, exploiting the unproduced remaining oil, and achieving the purpose of increasing oil production.

[0076] When applying the method for screening oil wells suitable for water plugging in a fault-karst reservoir described in the embodiments of the present invention to the fault-karst reservoir where Well TPY1 is located, it is used to determine whether the current well is suitable for water plugging.

[0077] Figure 7 It is a schematic diagram of the water plugging construction curve of the method for screening oil wells suitable for water plugging in a fault-karst reservoir according to the embodiments of the present application. As Figure 7 shown, taking Well TPY1 as an example, the method for screening oil wells suitable for water plugging in a fault-karst reservoir is described. Specifically, after Well TPY1 is vertically charged by the main fault, it will be adjusted to this well along the thrust fault. The regional oil and gas are enriched, located in the fault-karst fracture zone, with a cumulative oil production of 18,800 tons. The reservoir body is concentrated in the upper part of the wellbore. The acid fracturing shows communication with large karst bodies. After the bottom water breaks through, the remaining oil is mainly concentrated in the top reservoir body. The bottom water mainly breaks through rapidly through high-angle fractures, resulting in a rapid increase in water cut during the pumping production period. The water body multiple of this well is 65 (>50), so the total amount of plugging agent selected is >180 m 3 . The construction is carried out by the reverse injection method without pulling the tubing string. The cumulative injection of the plugging agent is 372 m3, the cumulative injection of water is 192 m 3 , the cumulative injection of diluted gel is 100 m 3 , the cumulative injection of weighted gel is 50 m 3 , and the cumulative injection of water glass is 30 m 3 . After the shut-in well period, it produces by natural flow. The daily liquid production is 47.5 t, the daily oil production is 6.9 t, and the water cut is 85.6%.

[0078] Based on the above method for screening oil wells suitable for water plugging in a fault-karst reservoir, the present invention also provides a device for screening oil wells suitable for water plugging in a fault-karst reservoir. The device for screening oil wells suitable for water plugging in a fault-karst reservoir is used to implement the above-mentioned method for screening oil wells suitable for water plugging in a fault-karst reservoir.

[0079] Figure 8 This is a schematic structural diagram of the device for screening oil wells suitable for water plugging in a fractured solution reservoir in an embodiment of the present application. As Figure 8 shown, the device for screening oil wells suitable for water plugging in a fractured solution reservoir according to an embodiment of the present invention includes: an acquisition module 801, a calculation module 802, and a selection module 803.

[0080] The acquisition module 801 is implemented according to the method described in step S110 above, and is configured to obtain the water plugging evaluation characteristics of each oil well in the fractured solution reservoir to be evaluated. The water plugging evaluation characteristics include geological characteristics, fracture-cavity structure characteristics, water flooding degree characteristics, and oil-water relationship characteristics. The calculation module 802 is implemented according to the method described in step S120 above, and is configured to quantitatively calculate the corresponding water plugging effectiveness potential index according to the water plugging evaluation characteristics of each oil well. The selection module 803 is implemented according to the method described in step S130 above, and is configured to preferably select oil wells with water plugging potential according to the water plugging effectiveness potential index of each oil well.

[0081] The present invention provides a method and device for screening oil wells suitable for water plugging in a fractured solution reservoir. The method and device obtain the water plugging evaluation characteristics of each oil well in the fractured solution reservoir to be evaluated. The water plugging evaluation characteristics include geological characteristics, fracture-cavity structure characteristics, water flooding degree characteristics, and oil-water relationship characteristics. According to the water plugging evaluation characteristics of each oil well, the corresponding water plugging effectiveness potential index is quantitatively calculated. According to the water plugging effectiveness potential index of each oil well, oil wells with water plugging potential are preferably selected. The present invention selects oil wells suitable for water plugging in a fractured solution reservoir from multiple evaluation characteristics such as geology, fracture-cavity structure, water flooding degree, and oil-water relationship, effectively improving the accuracy of well selection, thereby carrying out targeted well selection and water plugging, exploiting the unproduced remaining oil, and achieving the purpose of increasing oil production.

[0082] 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 those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

[0083] In the description of the present invention, unless otherwise specified, "a plurality of" means two or more; the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention. In addition, terms such as "first", "second", "third", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0084] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "coupled" 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 directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0085] 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 extend to equivalent alternatives of these features understood by those of ordinary skill in the relevant art. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments and do not mean to limit.

[0086] The "one embodiment" or "embodiment" mentioned in the specification means that the specific features, structures or characteristics described in connection with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "embodiment" that appear throughout the specification do not necessarily all refer to the same embodiment.

[0087] The embodiments of the present invention are given for purposes of illustration and description, and are not exhaustive or limit the present invention to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are selected and described to better illustrate the principles and practical applications of the present invention, and enable those of ordinary skill in the art to understand the present invention and thus design various embodiments with various modifications suitable for specific purposes.

[0088] Although the disclosed embodiments of the present invention are as above, the content described above is only an embodiment adopted for the convenience of understanding the present invention, and is not intended to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed by the present invention. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A method for screening oil wells suitable for water plugging in fractured solution reservoirs, characterized in that, Including: Obtaining the water plugging evaluation characteristics of each oil well in the to-be-evaluated solution-channeled reservoir, where the water plugging evaluation characteristics include geological characteristics, fracture-cavity structure characteristics, water flooding degree characteristics, and oil-water relationship characteristics; Quantitatively calculating the corresponding water plugging effectiveness potential index according to the water plugging evaluation characteristics of each oil well; Optimizing the oil wells with water plugging potential according to the water plugging effectiveness potential index of each oil well.

2. The method according to claim 1, wherein In the step of quantitatively calculating the corresponding water plugging effectiveness potential index according to the water plugging evaluation characteristics of each oil well, it includes: According to the geological characteristics, determining the first factor potential index representing the influence degree of geological characteristics on the water plugging effect by analyzing the geological characteristics of the solution-channel where the current wellbore is located; According to the fracture-cavity structure characteristics communicated around the current wellbore, determining the second factor potential index representing the influence degree of fracture-cavity structure characteristics on the water plugging effect by analyzing the type of fracture-cavity structure to which the water plugging position belongs; According to the water flooding degree characteristics, determining the third factor potential index representing the influence degree of water flooding degree characteristics on the water plugging effect by analyzing the type of water cut increase change after production of the current wellbore; According to the oil-water relationship characteristics, determining the fourth factor potential index representing the influence degree of oil-water relationship characteristics on the water plugging effect by calculating the water body multiple representing the water body energy; Calculating the water plugging effectiveness potential index according to each factor potential index and the corresponding weight.

3. The method according to claim 2, wherein In the step of determining the first factor potential index representing the influence degree of geological characteristics on the water plugging effect by analyzing the geological characteristics of the solution-channel where the current wellbore is located according to the geological characteristics, it includes: When the geological characteristics of the solution-channel where the current wellbore is located are the solution-channel fracture zone, determining the first factor potential index as the first potential value of the first factor; When the geological characteristics of the solution-channel where the current wellbore is located are the solution-channel core part, determining the first factor potential index as the second potential value of the first factor; When the geological characteristics of the solution-channel where the current wellbore is located are the complex karst area, determining the first factor potential index as the third potential value of the first factor, where the first potential value of the first factor is higher than the second potential value of the first factor, and the second potential value of the first factor is higher than the third potential value of the first factor.

4. The method according to claim 2 or 3, characterized in that In the step of determining the second factor potential index representing the influence degree of fracture-cavity structure characteristics on the water plugging effect by analyzing the type of fracture-cavity structure to which the water plugging position belongs according to the fracture-cavity structure characteristics communicated around the current wellbore, it includes: When the type of fracture-cavity structure to which the current water plugging position belongs is the edge-of-cavity fracture type, determining the second factor potential index as the first potential value of the second factor; When the type of fracture-cavity structure to which the current water plugging position belongs is the parallel type of horizontal well and cavity, determining the second factor potential index as the second potential value of the second factor; When the type of fracture-cavity structure to which the current water plugging position belongs is the top-of-cavity fracture type, determining the second factor potential index as the third potential value of the second factor; When the fracture-vug structure type to which the current water shutoff and plugging position belongs is the bottom hole fracture type, determine that the second factor potential index is the fourth potential value of the second factor, where the first potential value of the second factor is higher than the second potential value of the second factor, and the second potential value of the second factor is higher than the third potential value of the second factor, and the third potential value of the second factor is higher than the fourth potential value of the second factor.

5. The method according to any one of claims 2 to 4, characterized in that, In the step of determining the third factor potential index characterizing the influence degree of the water flooding degree characteristics on the water shutoff effect by analyzing the water cut rising change type of the current wellbore after production according to the water flooding degree characteristics, it includes: When the water cut rising change type of the current wellbore after production is the slow rising type, determine that the third factor potential index is the first potential value of the third factor; When the water cut rising change type of the current wellbore after production is the fluctuating rising type, determine that the third factor potential index is the second potential value of the third factor; When the water cut rising change type of the current wellbore after production is the rapid rising type, determine that the third factor potential index is the third potential value of the third factor; When the water cut rising change type of the current wellbore after production is the step rising type, determine that the third factor potential index is the fourth potential value of the third factor; When the water cut rising change type of the current wellbore after production is the violent water flooding type, determine that the third factor potential index is the fifth potential value of the third factor, where the first potential value of the third factor is higher than the second potential value of the third factor, and the second potential value of the third factor is higher than the third potential value of the third factor, and the third potential value of the third factor is higher than the fourth potential value of the third factor, and the fourth potential value of the third factor is higher than the fifth potential value of the third factor.

6. The method according to any one of claims 2 to 5, characterized in that In the step of determining the fourth factor potential index characterizing the influence degree of the oil-water relationship characteristics on the water shutoff effect by calculating the water body multiple characterizing the water body energy according to the oil-water relationship characteristics, it includes: When the current water body multiple is less than or equal to the first preset threshold, determine that the fourth factor potential index is the first potential value of the fourth factor; When the current water body multiple is greater than the first preset threshold and less than or equal to the second preset threshold, determine that the fourth factor potential index is the second potential value of the fourth factor, where the second preset threshold is greater than the first preset threshold; When the current water body multiple is greater than the second preset threshold, determine that the fourth factor potential index is the third potential value of the fourth factor, where the first potential value of the fourth factor is higher than the second potential value of the fourth factor, and the second potential value of the fourth factor is higher than the third potential value of the fourth factor.

7. The method according to any one of claims 2 to 6, characterized in that, The weight of the first factor potential index is higher than that of the second factor potential index, and the weight of the second factor potential index is higher than that of the third factor potential index, and the weight of the third factor potential index is higher than that of the fourth factor potential index, wherein the weight of the first factor potential index is 30% to 40%, the weight of the second factor potential index is 20% to 30%, the weight of the third factor potential index is 10% to 20%, and the weight of the fourth factor potential index is 10% to 20%.

8. A device for screening oil wells suitable for water plugging in fractured solution reservoirs, characterized in that, Including: An acquisition module configured to obtain the water plugging evaluation characteristics of each oil well in the to-be-evaluated solution-collapse reservoir, where the water plugging evaluation characteristics include geological characteristics, fracture-cavity structure characteristics, water flooding degree characteristics, and oil-water relationship characteristics; A calculation module configured to quantitatively calculate the corresponding water plugging effectiveness potential index according to the water plugging evaluation characteristics of each oil well; A selection module configured to preferably select the oil wells with water plugging potential according to the water plugging effectiveness potential index of each oil well.

9. A computing device, characterized in that, Including: A memory and a processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing computer-executable instructions, and when the computer-executable instructions are executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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