A method for designing a production system of a reconstructed well by seam and hole finding

Abstract

The present application relates to the technical field of oil and gas field development, and particularly relates to a method for designing production system of a well transformed by seam following and hole finding, comprising: collecting parameter information of oil and gas wells which have been subjected to the "seam following and hole finding method" construction in the early stage; establishing a functional relationship between the production system and the parameter of the oil and gas well according to the collected parameter information; obtaining the parameter information of a target oil and gas well; bringing the parameter information of the target oil and gas well into the obtained functional relationship to calculate the preliminary data of the production system of the target oil and gas well; producing according to the preliminary data of the production system, and recording the production in a certain period; optimizing the production system of the target oil and gas well according to the production in a certain period; and repeating the foregoing steps until the target oil and gas well stops production. The present application comprehensively considers the influence of geological and engineering factors on the production system, establishes a dynamic design method of the production system of the oil and gas well after being transformed by the "seam following and hole finding method", and guides the efficient development of the oil and gas well subjected to the "seam following and hole finding method".

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, specifically to a method for designing a production system for modified wells that uses fracture-following cavitation. Background Technology

[0002] Fractured-vuggy reservoirs occupy a very important position in the world's oil and gas resources. It is estimated that more than one-third of the world's carbonate reservoirs are fractured-vuggy. For deep or ultra-deep carbonate oil and gas wells with well-developed natural fractures, the current methods of stimulation are conventional acidizing and acid fracturing. Conventional acidizing uses acid to react with the blockage around the well to achieve the effect of unblocking. However, the range of acid action is limited. Conventional acidizing can only stimulate the reservoir in the near-wellbore area. It is difficult to effectively etch fractures at distant points to form sufficient conductivity. Acid fracturing uses high-volume, high-pressure injection to create one or more artificial fractures in the formation. The orientation of artificial fractures is affected by formation stress and extends along the direction of the maximum horizontal principal stress in the formation. It can only connect the caves through which the artificial fractures pass. Its ability to connect the reservoir is poor and the construction risk is high. At the same time, due to the complex geological conditions of carbonate reservoirs, strong heterogeneity, and large formation stress differences, it is difficult to activate natural fractures, resulting in low utilization of natural fractures. To address this, a "fracture-following cavern finding method" was proposed. In reservoirs with naturally developed fractures, acid in the wellbore flows slowly along the fracture zone at low pressure, connecting the natural fractures and surrounding caverns in different directions. The purpose of this method is to activate natural fractures and connect fracture-cavity carbonate reservoirs.

[0003] After activating natural fractures, the "fracturing method" puts oil and gas wells into production. During production, due to the extraction of oil and gas, the reservoir stress changes, and the activated natural fractures may close again. Therefore, it is necessary to design a reasonable production system (i.e., nozzle size) according to the specific conditions of the oil and gas well to prevent the activated natural fractures from closing quickly and to extend the effectiveness of the "fracturing method".

[0004] Currently, there is no production regime design method for the "fracturing and cavitation finding method" developed for the stimulated wells. With the rapid application of the "fracturing and cavitation finding method" in oil and gas fields, it is necessary to propose a production regime design method for the stimulated wells using the fracturing and cavitation finding method to promote the efficient development of carbonate oil and gas reservoirs.

[0005] In summary, this invention provides a method for designing a production system for modified wells that uses a cavitation-following approach. Summary of the Invention

[0006] To address the aforementioned technical problems in the prior art, this invention provides a method for designing a production system for modified wells using the "fracturing and cavitation" approach, guiding the efficient development of oil and gas wells using this method.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] A method for designing a production system for modified wells that uses cavitation tracing to locate cavities includes the following steps:

[0009] S1. Collect parameter information of oil and gas wells that have been constructed using the "fracturing method" in the early stage;

[0010] S2. Based on the parameter information collected in step S1, establish the functional relationship between the production system and the oil and gas well parameters;

[0011] S3. Obtain parameter information of the target oil and gas well;

[0012] S4. Substitute the parameter information of the target oil and gas well into the functional relationship obtained in step S2 to calculate the preliminary data of the production system of the target oil and gas well.

[0013] S5. Produce according to the preliminary data of the production system calculated in step S4, and record the output within a certain period.

[0014] S6. Optimize the production system of the target oil and gas wells based on the output within a certain period;

[0015] S7, repeat steps S5 and S6 until the target oil and gas well stops producing.

[0016] Furthermore, the parameter information of the oil and gas well in step S1 includes geological parameters, engineering parameters, and production system.

[0017] Furthermore, geological parameters include formation pressure, vertical stress, minimum horizontal principal stress, maximum horizontal principal stress, density of natural fractures, density of caverns, water content, and reservoir thickness.

[0018] Engineering parameters include total acid volume and acid injection / discharge rate;

[0019] The production system includes the diameter of the nozzle.

[0020] Furthermore, in step S1, the daily production decline rate of the oil and gas well is less than 0.5%.

[0021] Furthermore, the functional relationship between production regime and oil and gas well parameters is represented by a multiple linear regression model:

[0022]

[0023] Where Y represents the column vector matrix of the production system, b represents the coefficient matrix, and X represents the parameter information matrix of the oil and gas well.

[0024] Furthermore, the certain period in step S5 is set to 1 month.

[0025] Furthermore, the specific methods for optimizing the production regime of the target oil and gas well in step S6 include:

[0026] If the average daily production decline rate within a certain period is less than 0.5%, the parameter information of the target oil and gas well and the parameter information of the oil and gas well collected in step S1 are used together as the raw data, and steps S2-S4 are repeated to obtain new production system data of the target oil and gas well.

[0027] If the average daily output decline rate is greater than or equal to 0.5% within a certain period, the production system will be scaled down by one model.

[0028] Furthermore, the sample size of the oil and gas well parameter information collected in step S1 is greater than 10.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] This invention collects parameter information from developed fracture-following wells for oil and gas exploration, establishes a functional relationship between geological parameters, engineering parameters, and production regimes, and guides the production regime of target oil and gas wells. It monitors the average daily production of target oil and gas wells, then uses feedback to adjust the functional relationship and dynamically regulate the production regime. Taking into account the influence of geological and engineering factors on the production regime, it establishes a dynamic design method for the production regime of oil and gas wells modified using the fracture-following method, guiding the efficient development of wells using this method. This increases oil and gas production by more than 30% while preventing rapid fracture closure. Attached Figure Description

[0031] Figure 1 This is a flowchart of the design method of the present invention. Detailed Implementation

[0032] The technical solution of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0033] Example 1

[0034] This invention provides a method for designing a production system for modified wells using a cavitation-following approach, such as... Figure 1 As shown, it includes the following steps:

[0035] S1. Collect parameter information for oil and gas wells that have undergone the "fracture-following cavern method" in the previous stage. The parameter information for oil and gas wells includes geological parameters, engineering parameters, and production regime. Geological parameters include formation pressure, vertical stress, minimum horizontal principal stress, maximum horizontal principal stress, natural fracture density, cavern density, water cut, and reservoir thickness. Engineering parameters include total acid volume and acid injection / discharge rate. Production regime includes nozzle diameter. Furthermore, the daily production decline rate of the oil and gas wells should be less than 0.5%. The collected parameters are shown in Table 1.

[0036] Table 1. Parameter information of the early-stage oil and gas wells in Example 1.

[0037]

[0038] S2. Based on the parameter information collected in step S1, establish the functional relationship between the production regime and the oil and gas well parameters; the functional relationship between the production regime and the oil and gas well parameters is represented by a multiple linear regression model:

[0039]

[0040] Where Y represents the column vector matrix of the production regime, b represents the coefficient matrix, and X represents the parameter information matrix of the oil and gas well; fitting is performed using MATLAB software, where:

[0041]

[0042] The coefficient matrix b is calculated as follows:

[0043]

[0044] Therefore, the production system and geological and engineering parameters satisfy a functional relationship:

[0045]

[0046] Where y represents the nozzle size in the production system. For formation pressure, For vertical stress, For the minimum principal stress in the horizontal direction, The maximum principal stress is horizontal. Density of natural cracks Density of the cave Moisture content, For reservoir thickness, For the total amount of acid, This refers to the acid injection discharge volume.

[0047] S3. Obtain parameter information for the target oil and gas well. Parameter information includes geological parameters and engineering parameters. Geological parameters include formation pressure, vertical stress, minimum horizontal principal stress, maximum horizontal principal stress, natural fracture density, cavern density, water cut, and reservoir thickness. Engineering parameters include total acid volume and acid injection / discharge rate. Specific parameters are shown in Table 2.

[0048] Table 2. Parameter information of the target oil and gas well in Example 1

[0049]

[0050] S4. Substitute the parameter information of the target oil and gas well into the function relationship obtained in step S2, and calculate the preliminary data of the production system of the target oil and gas well as 12mm.

[0051] S5. Produce for one month according to the preliminary data of the production system calculated in step S4, and record the output within one month;

[0052] S6. Based on the monthly production, the average daily decline rate is 0.35%, which meets the requirement that the average daily production decline rate of the target oil and gas well is less than 0.5% within one month. Then, the parameter information of the target oil and gas well and the corresponding production system data are added to the parameter information of the oil and gas well collected in step S1 and used together as the original data. Steps S2-S4 are repeated to obtain the new production system data of the target oil and gas well. The production system of the target oil and gas well obtained by recalculation is still 12mm. Then, production is carried out again for one month with a nozzle diameter of 12mm, and the cycle is repeated.

[0053] S7, repeat steps S5 and S6 until the target oil and gas well stops producing.

[0054] Example 2

[0055] This invention provides a method for designing a production system for modified wells using a cavitation-following approach, such as... Figure 1 As shown, it includes the following steps:

[0056] S1. Collect parameter information for oil and gas wells that have previously undergone "fracture-following cavern finding" construction. This parameter information includes geological parameters, engineering parameters, and production regime. Geological parameters include formation pressure, vertical stress, minimum horizontal principal stress, maximum horizontal principal stress, natural fracture density, cavern density, water cut, and reservoir thickness. Engineering parameters include total acid volume and acid injection / discharge rate. Production regime includes nozzle diameter. Furthermore, the daily production decline rate of the oil and gas wells should be less than 0.5%. The collected parameters are shown in Table 3.

[0057] Table 3 shows the parameter information of the early-stage oil and gas wells in Example 2.

[0058]

[0059] S2. Based on the parameter information collected in step S1, establish the functional relationship between the production regime and the oil and gas well parameters; the functional relationship between the production regime and the oil and gas well parameters is represented by a multiple linear regression model:

[0060]

[0061] Where Y represents the column vector matrix of the production regime, b represents the coefficient matrix, and X represents the parameter information matrix of the oil and gas well; fitting is performed using MATLAB software, where:

[0062]

[0063] The coefficient matrix b is calculated as follows:

[0064]

[0065] Therefore, the production system and geological and engineering parameters satisfy a functional relationship:

[0066]

[0067] Where y represents the nozzle size in the production system. For formation pressure, For vertical stress, For the minimum principal stress in the horizontal direction, The maximum principal stress is horizontal. Density of natural cracks Density of the cave Moisture content, For reservoir thickness, For the total amount of acid, This refers to the acid injection discharge volume.

[0068] S3. Obtain parameter information for the target oil and gas well. Parameter information includes geological parameters and engineering parameters. Geological parameters include formation pressure, vertical stress, minimum horizontal principal stress, maximum horizontal principal stress, natural fracture density, cavern density, water cut, and reservoir thickness. Engineering parameters include total acid volume and acid injection / discharge rate. Specific parameters are shown in Table 4.

[0069] Table 4. Parameter information of the target oil and gas well in Example 2

[0070]

[0071] S4. Substitute the parameter information of the target oil and gas well into the function relationship obtained in step S2, and calculate the preliminary data of the production system of the target oil and gas well as 14mm.

[0072] S5. Produce for one month according to the preliminary data of the production system calculated in step S4, and record the output within one month;

[0073] S6. Based on the monthly production, the average daily decline rate is 0.8%. If the average daily production decline rate of the target oil and gas well is greater than 0.5% within one month, the production system will be scaled down by one model, that is, the nozzle diameter will be reduced by 1mm, and a nozzle with a diameter of 13mm will be used; production will continue.

[0074] S7, repeat steps S5 and S6 until the target oil and gas well stops producing.

[0075] The above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for designing the diameter of an oil nozzle in a modified well using a method of finding cavities by following cracks, characterized in that, Includes the following steps: S1. Collect parameter information of oil and gas wells that have been constructed using the fracture-following hole-finding method in the early stage; S2. Based on the parameter information collected in step S1, establish a functional relationship between the nozzle diameter and the oil and gas well parameters; S3. Obtain parameter information of the target oil and gas well; S4. Substitute the parameter information of the target oil and gas well into the function relationship obtained in step S2 to calculate the preliminary data of the nozzle diameter of the target oil and gas well. S5. Produce according to the preliminary data of the nozzle diameter calculated in step S4, and record the output within a certain period. S6. Optimize the nozzle diameter of the target oil and gas well based on the production output within a certain period; S7, repeat steps S5 and S6 until the target oil and gas well stops producing; The parameter information for oil and gas wells in step S1 includes geological parameters and engineering parameters; The functional relationship between nozzle diameter and oil and gas well parameters is represented by a multiple linear regression model: Where Y represents the column vector matrix of nozzle diameter, b represents the coefficient matrix, and X represents the parameter information matrix of the oil and gas well. The specific methods for optimizing the nozzle diameter of the target oil and gas well in step S6 include: If the average daily production decline rate within a certain period is less than 0.5%, the parameter information of the target oil and gas well and the parameter information of the oil and gas well collected in step S1 are used together as the original data, and steps S2-S4 are repeated to obtain the new nozzle diameter data of the target oil and gas well. If the average daily output decline rate is greater than or equal to 0.5% within a certain period, the nozzle diameter will be reduced by one size.

2. The method for designing the nozzle diameter of a modified well according to claim 1, characterized in that, Geological parameters include formation pressure, vertical stress, minimum horizontal principal stress, maximum horizontal principal stress, density of natural fractures, density of caverns, water content, and reservoir thickness. The engineering parameters include the total amount of acid and the acid injection / discharge rate.

3. The method for designing the nozzle diameter of a modified well according to claim 1, characterized in that, In step S1, the daily production decline rate of the oil and gas well is less than 0.5%.

4. The method for designing the nozzle diameter of a modified well according to claim 1, characterized in that, The certain period in step S5 is set to 1 month.

5. The method for designing the nozzle diameter of a modified well according to claim 1, characterized in that, The sample size of the oil and gas well parameter information collected in step S1 is greater than 10.

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