Ultra-thin interbedded low-permeability shale oil reservoir intelligent fracturing test sample fine manufacturing method

Abstract

This invention discloses a method for precisely fabricating intelligent fracturing test samples of ultrathin interbedded low-permeability shale oil reservoirs. The method includes preparing printing materials to represent the characteristics of each reservoir layer, loading them into various material supply tanks; creating a 3D model of the reservoir fracturing test sample using a central controller, and generating a printing program using an embedded operating system; the printing program controls the 3D printer to zero-align, controls the material supply during printing, and controls the Z-axis coordinate controller along the Z-axis coordinate track, the X and Y-axis coordinate controllers along the X and Y-axis coordinate tracks, and the mounting chassis to adjust their positions during printing; and controls the 3D printer to complete the printing of the reservoir fracturing test sample according to the printing program. This invention utilizes 3D printing to fabricate fracturing test samples of offshore ultrathin interbedded low-permeability shale oil reservoirs, providing a more intuitive, accurate, and precise method. It can precisely and quantitatively characterize the reservoir's porosity-permeability mechanical properties and heterogeneous changes, providing strong technical support for the quantitative experimental evaluation of production enhancement measures.

Description

Technical Field

[0001] This invention belongs to the field of petroleum extraction technology, and in particular relates to a method for the precise preparation of intelligent fracturing test samples for ultra-thin interbedded low-permeability shale oil reservoirs. Background Technology

[0002] Low-permeability reservoirs are widely distributed in my country, and their production will play a crucial role in China's future oil and gas production, becoming one of the new main drivers for increasing oil and gas reserves and production. Low-permeability reservoirs have poor porosity and permeability conditions and low initial production capacity; practice has shown that fracturing is one of the effective measures to increase production.

[0003] Existing methods for preparing fracturing test samples for offshore ultrathin interbedded low-permeability shale oil reservoirs are seriously inadequate, failing to meet the requirements for the repeatability of scientific experiments and unable to simulate the characteristics of ultrathin interbedded low-permeability reservoirs.

[0004] There are currently three main methods for preparing fracturing test samples from ultra-thin interbedded low-permeability shale oil reservoirs at sea: The first type is the sample preparation method for fracturing tests using natural ultrathin interbedded low-permeability reservoir rock outcrops. Currently, there are few types of natural ultrathin interbedded low-permeability reservoir rock outcrops, and their characteristics in the natural environment are quite different from those of underground reservoirs. In addition, during the sampling process, the processing stress causes great damage to the original characteristics of the sample. At present, the fracturing test results carried out using the sample preparation method for fracturing tests using natural ultrathin interbedded low-permeability reservoir rock outcrops are often far from the actual situation.

[0005] The second type is the artificial fracturing test sample preparation method. This method uses manual stirring and stacking to prepare samples, which results in low precision in operation. The means of adjusting the reservoir characteristics in the horizontal, vertical and internal directions are limited and lacks reproducibility. Each sample is different, which leads to insufficient accuracy and comparability of the test results.

[0006] The third category is the artificial prefabricated mold fracturing test sample preparation method. This type of method has many structural components, and the changes of the sample after being subjected to force are often constrained by the prefabricated structure, which does not match the real situation. Therefore, it also greatly limits the scope of application of this type of method. Samples prepared by this type of method are often suitable for research in a single specific direction. Summary of the Invention

[0007] The problem to be solved by this invention is to provide a method for the precise preparation of intelligent fracturing test samples for ultrathin interbedded low-permeability shale oil reservoirs. This method meets the requirements of scientific experiment repeatability and can quantitatively characterize the porosity and permeability mechanical properties and heterogeneity changes of offshore ultrathin interbedded low-permeability shale oil reservoirs.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for finely preparing intelligent fracturing test samples of ultrathin interbedded low-permeability shale oil reservoirs, comprising the following steps: S1: Prepare printing materials to simulate the characteristics of each layer of an ultra-thin interlayered low-permeability shale oil reservoir at sea. The printing materials are of various types and are respectively loaded into various corresponding special material supply tanks. The material supply tanks are connected to a cooling system to keep the pigments in the material supply tanks in a low-temperature and easily flowable state. S2: The central controller performs 3D modeling of the fracturing test samples of the offshore ultra-thin interbedded low-permeability shale oil reservoir, uses the embedded operating system to intelligently generate the printing program, conducts temperature field evolution prediction analysis during the sample printing process, formulates cooling schemes, and controls the sample temperature to be below the critical cracking temperature throughout the process. S3: The printing program intelligently controls the 3D printer to complete the zeroing process through the numerical control signal line; S4: The printing program intelligently controls the raw material supply pump through the CNC signal line, and ensures the supply of raw materials from the raw material supply tank through the raw material supply pipeline; it intelligently controls the cooling pump through the cooling signal line, and draws coolant from the coolant tank through the coolant supply line, sprays coolant to cool the sample throughout the printing process, and collects sample temperature data in real time to correct the temperature field so as to dynamically adjust the cooling and printing process. S5: The printing program intelligently controls the Z-axis coordinate controller along the Z-axis coordinate track, and the X and Y-axis coordinate controllers along the X and Y-axis tracks and the mounting chassis through the CNC signal line to complete the position adjustment during the printing process; S6: The printing program intelligently controls the 3D printer through the CNC signal line to complete the printing of fracturing test samples of offshore ultra-thin interlayered low-permeability shale oil reservoirs according to the printing program.

[0009] Furthermore, in step S1, N types of raw materials are added as needed and loaded into the corresponding N raw material supply tanks.

[0010] Furthermore, the raw material supply tank is connected to the coolant tank via a coolant intelligent control valve and the coolant supply line. The raw material supply tank is also equipped with a stirring device to keep the pigment temperature below 40 degrees Celsius.

[0011] Furthermore, in S2, the 3D modeling content includes the length, width, and height of the sample, the thickness of each layer, and the type and ratio of printing materials used for each pixel position in each layer plane.

[0012] Furthermore, the printing material used for each pixel of each plane is set according to the actual porosity and permeability mechanical properties and heterogeneity changes of the ultrathin interlayered reservoir.

[0013] Furthermore, in S4, the raw material supply tank includes a first raw material supply tank and a second raw material supply tank, and N more raw material supply tanks may be added as needed, with each type of raw material having the same feeding principle.

[0014] Furthermore, in step S4, the printing program intelligently controls the raw material supply pump through the CNC signal line, and ensures the supply of raw materials from the raw material supply tank through the raw material supply pipeline during the printing process; Furthermore, the properties of the printing raw material are precisely controlled based on the porosity and permeability mechanical characteristics and heterogeneity changes of the offshore ultra-thin interbedded low-permeability shale oil reservoir, so as to infinitely approximate the actual reservoir characteristics.

[0015] Furthermore, the present invention also provides a device for finely preparing intelligent fracturing test samples for ultrathin interbedded low-permeability shale oil reservoirs. The device operates the aforementioned method for finely preparing intelligent fracturing test samples for ultrathin interbedded low-permeability shale oil reservoirs. It includes a 3D printer connected to a central controller via a numerical control signal line. The 3D printer is connected to a raw material supply tank via a raw material supply pipeline and a raw material supply pump. The central controller is connected to the raw material supply pump via the numerical control signal line. The device also includes a coolant supply line. One end of the coolant supply line is connected to a coolant tank via a cooling pump. The other end of the coolant supply line is connected to both the raw material supply tank and the 3D printer. A coolant intelligent control valve is connected between the coolant supply line and the raw material supply tank. The central controller is connected to the 3D printer, the coolant intelligent control valve, and the cooling pump via a cooling signal line.

[0016] The advantages and positive effects of this invention are: 1. This invention utilizes 3D printing to prepare fracturing test samples for offshore ultrathin interbedded low-permeability shale oil reservoirs. Compared with traditional methods for preparing fracturing test samples from natural ultrathin interbedded low-permeability reservoir rock outcrops, artificial fracturing test samples, and artificial prefabricated mold fracturing test samples, this method is more intuitive, accurate, and intelligent in preparing test samples.

[0017] 2. This invention precisely prints fracturing test samples of ultra-thin interbedded low-permeability shale oil reservoirs at sea, pixel by pixel. The sample preparation is highly precise, with accurate adjustments to reservoir characteristics in the lateral and longitudinal directions and internally. It is highly reproducible. By precisely controlling the properties of the printing raw materials and the sample temperature during the printing process, it can ensure that the characteristics of each test sample are highly consistent, eliminating the experimental result errors caused by large differences in test samples. This ensures the accuracy and comparability of the test results, and can precisely and quantitatively characterize the porosity and permeability mechanical properties and heterogeneity changes of ultra-thin interbedded low-permeability shale oil reservoirs at sea. It provides strong technical support for the quantitative experimental evaluation of large-scale intelligent fracturing and other production enhancement measures in ultra-thin interbedded low-permeability shale oil reservoirs at sea. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention.

[0019] In the picture: 1. Central controller; 2. CNC signal cables; 3. 3D printer; 4. Z-axis coordinate controller; 5. Z-axis coordinate track; 6. X and Y-axis coordinate controllers; 7. X and Y axis coordinate tracks and mounting chassis; 8. Raw material supply pump; 9. Raw material supply pipeline; 10. First raw material supply tank; 11. Second raw material supply tank; 12. Sample; 13. Coolant supply line; 14. Coolant pump; 15. Coolant tank; 16. Cooling signal line; 17. Coolant intelligent control valve. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] The embodiments of the present invention will be further described below with reference to the accompanying drawings: like Figure 1As shown, the intelligent fracturing test sample preparation device for ultrathin interbedded low-permeability shale oil reservoirs includes a 3D printer 3. The 3D printer 3 is sequentially connected to a Z-axis coordinate controller 4, a Z-axis coordinate track 5, an X and Y-axis coordinate controller 6, an X and Y-axis coordinate track, and a mounting chassis 7. The 3D printer 3 is connected to a central controller 1 via a numerical control signal line 2. The 3D printer 3 is connected to a first raw material supply tank 10 and a second raw material supply tank 11 via a raw material supply pipeline 9 and a raw material supply pump 8. The central controller 1 is connected to the raw material supply pump 8 via the numerical control signal line 2.

[0024] In use, the central controller 1 sends signals to the 3D printer 3, Z-axis coordinate controller 4, Z-axis coordinate track 5, X and Y axis coordinate controller 6, X and Y axis coordinate track and mounting chassis 7, and raw material supply pump 8 through the CNC signal line 2, driving each component to work according to the printing program.

[0025] It also includes a coolant supply line 13, one end of which is connected to a coolant tank 15 via a coolant pump 14, and the other end of which is connected to a first raw material supply tank 10, a second raw material supply tank 11, and a 3D printer 3. A coolant intelligent control valve 17 is connected between the coolant supply line 13 and the raw material supply tank. The central controller 1 is connected to the 3D printer 3, the coolant intelligent control valve 17, and the coolant pump 14 via a cooling signal line 16.

[0026] In use, the central controller 1 sends signals to the 3D printer 3, the coolant intelligent control valve 17 and the cooling pump 14 via the cooling signal line 16, driving each component to cool down according to the temperature required by the printing program.

[0027] Using the aforementioned intelligent fracturing test sample preparation device for ultra-thin interbedded low-permeability shale oil reservoirs, and operating the method for preparing intelligent fracturing test samples for ultra-thin interbedded low-permeability shale oil reservoirs, the following steps are included. S1: Preparation of printing raw materials.

[0028] Printing materials are prepared to simulate the characteristics of various layers in an ultrathin interbedded low-permeability shale oil reservoir at sea. Based on the diversity of ultrathin interbedded reservoir characteristics, and to achieve a precise and near-perfect approximation of real reservoir characteristics, printing materials with various properties are prepared. The porosity and permeability mechanical properties (such as porosity, permeability, elastic modulus, Poisson's ratio, compressive strength, etc.) of each printing material are designed and proportioned according to actual measured data of the target reservoir. The prepared printing materials with different properties are loaded into various corresponding material supply tanks. Specifically, in this embodiment, the printing materials are loaded into the first material supply tank 10 and the second material supply tank 11. Preferably, N types of materials can be added as needed, loaded into the corresponding N material supply tanks. The material supply tanks employ a special cooling and stirring design to keep the pigment temperature below 40 degrees Celsius and maintain good fluidity.

[0029] S2: 3D modeling and printing program generation.

[0030] The central controller 1 performs 3D modeling of the fracturing test sample 12 of the offshore ultra-thin interbedded low-permeability shale oil reservoir. The embedded operating system intelligently generates a printing program, conducts temperature field evolution prediction and analysis during the sample printing process, and formulates a cooling scheme to ensure the sample temperature remains below the critical fracturing temperature. Specifically, the 3D modeling includes the sample's length, width, height, the thickness of each layer, and the type and ratio of printing material used at each pixel within each layer. Preferably, the printing material used at each pixel in each layer is set according to the actual porosity and permeability mechanical characteristics and heterogeneity variations of the ultra-thin interbedded reservoir. The properties of the printing material are finely controlled based on the porosity and permeability mechanical characteristics and heterogeneity variations of the offshore ultra-thin interbedded low-permeability shale oil reservoir to approximate the actual reservoir characteristics. Specifically, the printing program includes parameters such as the motion trajectory of each coordinate axis, the timing of material supply switching, printing speed, and layer thickness control.

[0031] S3: Printer to zero.

[0032] The printing program intelligently controls the 3D printer 3 via the CNC signal line 2 to complete the zeroing operation, that is, to calibrate the relative position of the print head and the mounting chassis to ensure the accuracy of the printing start position.

[0033] S4: Raw material supply control.

[0034] The printing program intelligently controls the raw material supply pump 8 via the CNC signal line 2. The raw material supply pump 8 draws the corresponding raw material from the corresponding raw material supply tank through the raw material supply pipeline 9 and delivers it to the print head of the 3D printer 3, ensuring the supply of raw materials during the printing process. Specifically, the raw material supply tanks provided in this embodiment include a first raw material supply tank 10 and a second raw material supply tank 11. N raw material supply tanks can be added as needed. The feeding principle of each raw material is the same, and the start, stop and flow rate of the supply pump are controlled by the central controller 1 according to the program timing.

[0035] S5: Three-dimensional motion control.

[0036] The printing program intelligently controls the Z-axis coordinate controller 4 to move along the Z-axis coordinate track 5 via the CNC signal line 2, realizing the lifting and lowering between printing layers; simultaneously, it controls the X and Y axis coordinate controllers 6 to move along the X and Y axis tracks 7, achieving precise positioning of the print head in the horizontal plane. The mounting chassis is used to support the sample 12 being printed, ensuring the stability of the sample 12 during the printing process.

[0037] S6: Sample printing and production.

[0038] The printing program intelligently controls the 3D printer 3 via the CNC signal line 2 to precisely print the fracturing test sample 12 of the offshore ultra-thin interbedded low-permeability shale oil reservoir layer by layer and pixel by pixel according to the printing program.

[0039] The 3D printer integrates a cooling system that sprays cooling fluid to cool the sample throughout the printing process and collects sample temperature data in real time to correct the temperature field, so as to dynamically adjust the cooling and printing process. After each layer is completed, the Z-axis increases by one layer thickness, and the next layer is printed until the entire three-dimensional sample 12 is completed.

[0040] The advantages and positive effects of this invention are: 1. This invention utilizes 3D printing to prepare fracturing test samples for offshore ultrathin interbedded low-permeability shale oil reservoirs. Compared with traditional methods for preparing fracturing test samples from natural ultrathin interbedded low-permeability reservoir rock outcrops, artificial fracturing test samples, and artificial prefabricated mold fracturing test samples, this method is more intuitive, accurate, and intelligent in preparing test samples.

[0041] 2. This invention precisely prints fracturing test samples of ultra-thin interbedded low-permeability shale oil reservoirs at sea, pixel by pixel. The sample preparation is highly precise, with accurate adjustments to reservoir characteristics in the lateral and longitudinal directions and internally. It is highly reproducible. By precisely controlling the properties of the printing raw materials and the sample temperature during the printing process, it can ensure that the characteristics of each test sample are highly consistent, eliminating the experimental result errors caused by large differences in test samples. This ensures the accuracy and comparability of the test results, and can precisely and quantitatively characterize the porosity and permeability mechanical properties and heterogeneity changes of ultra-thin interbedded low-permeability shale oil reservoirs at sea. It provides strong technical support for the quantitative experimental evaluation of large-scale intelligent fracturing and other production enhancement measures in ultra-thin interbedded low-permeability shale oil reservoirs at sea.

[0042] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for precisely preparing intelligent fracturing test samples of ultrathin interbedded low-permeability shale oil reservoirs, characterized by: Includes the following steps, S1: Prepare printing materials to simulate the characteristics of each layer of an ultra-thin interlayered low-permeability shale oil reservoir at sea. The printing materials are of various types and are respectively loaded into various corresponding special material supply tanks. The material supply tanks are connected to a cooling system to keep the pigments in the material supply tanks in a low-temperature and easily flowable state. S2: The central controller performs 3D modeling of the fracturing test samples of the offshore ultra-thin interbedded low-permeability shale oil reservoir, uses the embedded operating system to intelligently generate the printing program, conducts temperature field evolution prediction analysis during the sample printing process, formulates cooling schemes, and controls the sample temperature to be below the critical cracking temperature throughout the process. S3: The printing program intelligently controls the 3D printer to complete the zeroing process through the numerical control signal line; S4: The printing program intelligently controls the raw material supply pump through the CNC signal line, and ensures the supply of raw materials from the raw material supply tank through the raw material supply pipeline; it intelligently controls the cooling pump through the cooling signal line, and draws coolant from the coolant tank through the coolant supply line, sprays coolant to cool the sample throughout the printing process, and collects sample temperature data in real time to correct the temperature field so as to dynamically adjust the cooling and printing process. S5: The printing program intelligently controls the Z-axis coordinate controller along the Z-axis coordinate track, and the X and Y-axis coordinate controllers along the X and Y-axis tracks and the mounting chassis through the CNC signal line to complete the position adjustment during the printing process; S6: The printing program intelligently controls the 3D printer through the CNC signal line to complete the printing of fracturing test samples of offshore ultra-thin interlayered low-permeability shale oil reservoirs according to the printing program.

2. The method of claim 1, wherein the method is used to make an intelligent fracturing test sample of an ultra-thin interbedded low-permeability shale oil reservoir. In step S1, N types of raw materials are added as needed and loaded into the corresponding N raw material supply tanks.

3. The method for fine fabrication of intelligent fracturing test samples of ultrathin interbedded low-permeability shale oil reservoirs according to claim 1 or 2, characterized in that: The raw material supply tank is connected to the coolant tank via a coolant intelligent control valve and the coolant supply line. The raw material supply tank is also equipped with a stirring device to keep the pigment temperature below 40 degrees Celsius.

4. The method for fine making of intelligent fracturing test sample of ultrathin interbedded low permeability shale oil reservoir according to claim 1 or 2, characterized in that: In S2, the 3D modeling content includes the length, width, and height of the sample, the thickness of each layer, and the type and ratio of printing materials used for each pixel position in each layer plane.

5. The method of claim 4, wherein the method further comprises: The printing material used for each pixel of each layer is set according to the actual porosity and permeability mechanical properties and heterogeneous changes of the ultrathin interlayered reservoir.

6. The method for fine fabrication of intelligent fracturing test samples of ultra- thin interbedded low-permeability shale oil reservoirs according to claim 1 or 2, characterized in that: In S4, the raw material supply tank includes a first raw material supply tank and a second raw material supply tank, and N more raw material supply tanks may be added as needed. The feeding principle of each raw material is the same.

7. The method for fine fabrication of intelligent fracturing test samples of ultra- thin interbedded low-permeability shale oil reservoirs according to claim 1 or 2, characterized in that: In step S4, the printing program intelligently controls the raw material supply pump through the CNC signal line, and ensures the supply of raw materials from the raw material supply tank through the raw material supply pipeline during the printing process.

8. The method for fine fabrication of intelligent fracturing test samples of ultra- thin interbedded low-permeability shale oil reservoirs according to claim 1 or 2, characterized in that: The properties of the printing raw materials are precisely controlled based on the porosity and permeability mechanical characteristics and heterogeneity changes of the ultra-thin interbedded low-permeability shale oil reservoirs at sea, so as to infinitely approximate the actual reservoir characteristics.

9. A device for the precise preparation of intelligent fracturing test samples for ultra-thin interbedded low-permeability shale oil reservoirs, characterized in that: The method for finely preparing intelligent fracturing test samples for ultrathin interbedded low-permeability shale oil reservoirs according to any one of claims 1 to 8 includes a 3D printer. The 3D printer is connected to a central controller via a numerical control signal line. The 3D printer is connected to a raw material supply tank via a raw material supply pipeline and a raw material supply pump. The central controller is connected to the raw material supply pump via the numerical control signal line. The method also includes a coolant supply line. One end of the coolant supply line is connected to a coolant tank via a coolant pump. The other end of the coolant supply line is connected to both the raw material supply tank and the 3D printer. A coolant intelligent control valve is connected between the coolant supply line and the raw material supply tank. The central controller is connected to the 3D printer, the coolant intelligent control valve, and the coolant pump via a cooling signal line.

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