Three-dimensional well pattern multi-well integral fracturing model as well as preparation method and use method thereof

Abstract

The invention relates to the field of oil reservoir exploration and development, and discloses a three-dimensional well pattern multi-well integral fracturing model and a preparation method and using method.The preparation method comprises the steps that based on the structure of a target area reservoir and the structure of a target well pattern, a model blank is prepared from a prefabricated clay material, a reservoir feature simulation material and a plurality of simulation wellbores, and the model blank is prepared into a multi-well integral fracturing model; the prefabricated clay material is a material which can be sintered and cured at 160-240 DEG C; sintering the model blank to obtain a sintered and cured model; and a simulated well mouth is installed in the sintering curing model, and the three-dimensional well pattern multi-well overall fracturing model is obtained. According to the scheme provided by the invention, the three-dimensional well pattern multi-well integral fracturing model can be prepared, and then a fracturing simulation experiment can be carried out based on the three-dimensional well pattern multi-well integral fracturing model and related experimental data can be obtained, so that the well pattern design in the actual mining process can be optimized according to the related experimental data; comprising optimization of well spacing or layer spacing and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil reservoir exploration and development, in particular to a three-dimensional well pattern multi-well overall fracturing model, a three-dimensional well pattern multi-well overall fracturing model preparation method and a three-dimensional well pattern multi-well overall fracturing model use method. BACKGROUND

[0002] The three-dimensional well pattern multi-well overall fracturing development technology, also known as the cube-development technology, refers to a well arrangement mode of horizontal transverse multi-well and vertical longitudinal multi-layer, which divides the reservoir into multiple layers in the longitudinal direction, and each layer is arranged with multiple horizontal wells, such as shown in FIG. 1. Figure 1 The three-dimensional well pattern multi-well overall fracturing development technology can improve the overall utilization rate of the reservoir and achieve a high recovery rate, and thus is widely used in the field of oil reservoir development.

[0003] However, when the three-dimensional well pattern multi-well overall fracturing development technology is used for development, the well spacing or layer spacing design is often unreasonable, which leads to serious well interference and thus low production. SUMMARY

[0004] The present application aims to overcome the problem of low production caused by unreasonable well spacing or layer spacing design in the prior art, and provides a three-dimensional well pattern multi-well overall fracturing model and a preparation method and use method thereof.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a three-dimensional well pattern multi-well overall fracturing model preparation method, which comprises:

[0006] Based on the structure of the target area reservoir and the target well pattern structure, a model embryo is prepared by using a prefabricated clay-like material, a reservoir characteristic simulation material and multiple simulation wellbores, wherein the prefabricated clay-like material is a material that can be sintered and solidified at 160-240℃;

[0007] The model embryo is sintered to obtain a sintered and solidified model;

[0008] A simulation wellhead is installed in the sintered and solidified model to obtain a three-dimensional well pattern multi-well overall fracturing model.

[0009] In the present application, the prefabricated clay-like material comprises clay material, additives and water;

[0010] The clay material comprises sero frog eye clay, kaolinite, montmorillonite, pyrophyllite and sericite;

[0011] The additives comprise sodium carbonate and sodium bicarbonate.

[0012] In the embodiment of the present application, in the total material composed of the prepared clay material and the reservoir feature simulation material, the mass percentage of the clay material is 30% to 60%, the mass percentage of the reservoir feature simulation material is 22% to 58.5%, and the mass percentage of water is 10% to 15%;

[0013] In the embodiment of the present application, the mass percentage of sodium carbonate in the clay material is 1% to 2%, and the mass percentage of sodium bicarbonate in the clay material is 0.5% to 1%.

[0014] In the embodiment of the present application, the mass percentage of the Setouchi frog-eye clay in the clay material is 40% to 70%.

[0015] In the embodiment of the present application, the reservoir feature simulation material includes any one or more of carbon powder, carbon fiber, paraffin, carbon fiber cloth, nylon fabric, aluminum foil, copper sheet, copper wire, nylon fiber, and quartz sand.

[0016] In the embodiment of the present application, the plurality of simulation wellbores are all stainless steel pipes.

[0017] In the embodiment of the present application, before the model embryo is fired, the preparation method further includes:

[0018] drying the model embryo;

[0019] The firing of the model embryo includes:

[0020] firing the dried model embryo.

[0021] In the embodiment of the present application, the firing of the model embryo to obtain a sintered and solidified model includes:

[0022] placing the model embryo in an oven, heating the oven to a first target temperature at a first heating rate, and keeping the first target temperature constant for 1.5 hours to 2.5 hours, the first heating rate is 1.5 ℃ / min to 2.5 ℃ / min, and the first target temperature is 75 ℃ to 85 ℃;

[0023] heating the oven from the first target temperature to a second target temperature at a second heating rate, and keeping the second target temperature constant for 8 hours to 12 hours, the second heating rate is 0.5 ℃ / min to 1.5 ℃ / min, and the second target temperature is 100 ℃ to 110 ℃;

[0024] heating the oven from the second target temperature to a third target temperature at a third heating rate, and keeping the third target temperature constant for 18 hours to 22 hours, the third heating rate is 0.5 ℃ / min to 1.5 ℃ / min, and the third target temperature is 280 ℃ to 320 ℃;

[0025] The oven cools down from the third target temperature to a fourth target temperature at a preset cooling rate of 18-22 ℃ / 1h, and a sintered solidified model is obtained, wherein the fourth target temperature is 90-110 ℃.

[0026] The second aspect of the present application provides a three-dimensional well pattern multi-well overall fracturing model, which is prepared by the method for preparing a three-dimensional well pattern multi-well overall fracturing model.

[0027] The third aspect of the present application provides a use method of the three-dimensional well pattern multi-well overall fracturing model of the second aspect, which comprises:

[0028] A fracture detection device is installed in the three-dimensional well pattern multi-well overall fracturing model.

[0029] Fracturing fluid is injected into the simulated wellhead in the three-dimensional well pattern multi-well overall fracturing model.

[0030] In the embodiments of the present application, the fracture detection device comprises an acoustic emission monitoring device and / or a CT scanning device.

[0031] By adopting the method for preparing a three-dimensional well pattern multi-well overall fracturing model provided by the present application, the method comprises: based on the structure of a target area reservoir and a target well pattern structure, a model embryo is prepared by using a prefabricated clay-like material, a reservoir characteristic simulation material and a plurality of simulated wellbores, wherein the prefabricated clay-like material is a material that can be sintered and solidified at 160-240 ℃; the model embryo is sintered to obtain a sintered and solidified model; a simulated wellhead is installed in the sintered and solidified model to obtain a three-dimensional well pattern multi-well overall fracturing model. That is, the three-dimensional well pattern multi-well overall fracturing model can be prepared by the scheme provided in the embodiments of the present application, and then a fracturing simulation experiment can be carried out based on the three-dimensional well pattern multi-well overall fracturing model and relevant experimental data can be obtained, so that the well pattern design in the actual mining process can be optimized according to the relevant experimental data, including optimizing the well spacing or layer spacing, etc.

[0032] Other features and advantages of the embodiments of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings are included to provide a further understanding of the embodiments of the present application, and constitute a part of the specification, and are used together with the following specific embodiments to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the drawings:

[0034] Figure 1 A schematic diagram of a three-dimensional well pattern multi-well overall fracturing development technology in the prior art is schematically shown;

[0035] Figure 2 Fig. 1 is a flow diagram of a method for preparing a three-dimensional well pattern multi-well overall fracturing model according to an embodiment of the present application. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and superiorities of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. It should be understood that the specific embodiments described herein are merely used to explain and illustrate the embodiments of the present application, and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort fall within the scope of protection of the present application.

[0037] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are merely used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0038] In addition, if the embodiments of the present application involve descriptions of “first”, “second”, etc., the descriptions of “first”, “second”, etc. are merely for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first”, “second” can explicitly or implicitly include at least one of the features. In addition, the technical solutions of the various embodiments can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can implement the combination, and when the combination of the technical solutions contradicts each other or cannot be implemented, it should be considered that the combination of the technical solutions does not exist, and is not within the scope of protection claimed by the present application.

[0039] As described in the background, the three-dimensional well pattern multi-well overall fracturing development technology, also known as cube-development technology, refers to a well arrangement method of horizontal lateral multi-well and vertical longitudinal multi-layer, which divides the reservoir into multiple layers (such as 2-5 layers or more layers) in the longitudinal direction, and multiple horizontal wells (such as 4-6 horizontal wells or more horizontal wells) are arranged in each layer. Figure 1The Schlumberger compared the recovery of three development modes, respectively: 1) 5 old well completion production for 1 year, then 4 new well infill; 2) 5 old well completion production for 5 years, then infill 4 new wells; 3) stereoscopic development mode. The results show that the cumulative oil production of stereoscopic development is higher than that of the other two development modes. Because the multi-well overall fracturing development technology of stereoscopic well pattern can improve the overall utilization rate of the reservoir and achieve a high recovery rate, it is widely used in the field of reservoir development. However, when using the multi-well overall fracturing development technology of stereoscopic well pattern for development, the well spacing or layer spacing design is often unreasonable, resulting in serious well interference and low well group production. Therefore, the unconventional oil and gas development field at home and abroad believes that well pattern spacing is the key factor to determine the success or failure of stereoscopic development.

[0040] In view of this, an embodiment of the present application provides a stereoscopic well pattern multi-well overall fracturing model preparation method, as shown in the figure, which can include the following steps: Figure 2

[0041] Step 101, based on the structure of the target area reservoir and the target well pattern structure, a model embryo is prepared by using a precast clay-like material, a reservoir characteristic simulation material and a plurality of simulation wellbores, the precast clay-like material is a material that can be sintered and cured at 160-240°C.

[0042] The target area reservoir can be the reservoir of any area to be developed. The structure of the target area reservoir can include geological structure and reservoir characteristics. In actual application, the structure and characteristics of the target area reservoir can be determined based on seismic exploration, well interpretation, electromagnetic exploration, core analysis, chemical analysis, numerical simulation and the like.

[0043] The target well pattern structure can be a multi-layer horizontal well pattern structure planned to be used in the development process of a shale oil reservoir. From the target well pattern structure, information such as wellbore well type, lateral well spacing, vertical well spacing, oblique well spacing, horizontal well segment length and target layer segment where each horizontal well segment is located can be obtained. The wellbore well type generally includes a vertical well segment and a horizontal well segment, the lateral well spacing is generally 100-500 meters, the vertical well spacing is generally 40-200 meters, the oblique well spacing is generally 50-200 meters, and the horizontal well segment length is generally 1500-2500 meters. The target layer segment is the position data or depth data of the target well pattern in a certain specific layer of the shale oil reservoir. The specific layer can have a certain inclination, and accordingly, the target well pattern can also have a certain degree of inclination.

[0044] ​In view of the fact that the prior art usually uses high firing temperature, sometimes even more than 1000 degrees Celsius, to sinter and solidify the green body, which leads to a complicated process and high requirement for the firing equipment. In the embodiments of the present application, the material capable of sintering and solidifying at 160-240 degrees Celsius is used as the pre-prepared clay material for preparing the green body, so that the subsequent firing of the green body to obtain the sintered and solidified model can be realized at a lower temperature, greatly reducing the process difficulty, allowing the simulated well pattern to be placed in the green body for direct firing, allowing the reservoir characteristic simulation material to have more diversified choices, and reducing the equipment cost.

[0045] In order to obtain the sintered and solidified model at a lower temperature while the sintered and solidified model has similar physical properties to the target area reservoir, so that the subsequent fracturing simulation experiment is more accurate, the pre-prepared clay material can include clay material, additive and water; the clay material can include serizyme frog eye clay, kaolinite, montmorillonite, pyrophyllite and sericite; the additive can include sodium carbonate and sodium bicarbonate.

[0046] The ratio of the clay material, the additive and the water, the ratio of the serizyme frog eye clay, the kaolinite, the montmorillonite, the pyrophyllite and the sericite in the clay material, and the ratio of the sodium carbonate and the sodium bicarbonate in the additive can be set according to actual needs.

[0047] Preferably, in the total material composed of the pre-prepared clay material and the reservoir characteristic simulation material, the mass percentage of the clay material is 30%-60% (for example, it can be 30%, 40%, 50% or 60%, etc.), the mass percentage of the reservoir characteristic simulation material is 22%-58.5% (for example, it can be 22%, 30%, 40%, 50% or 58.5%, etc.), and the mass percentage of water is 10%-15% (for example, it can be 10%, 12% or 15%, etc.). The sodium carbonate is 1%-2% (for example, it can be 1%, 1.5% or 2%, etc.) of the clay material, and the sodium bicarbonate is 0.5%-1% (for example, it can be 0.5%, 0.8% or 1%, etc.) of the clay material, calculated in terms of mass ratio. In the clay material, the mass percentage of the serizyme frog eye clay is 40%-70%, and the mass percentage of the kaolinite, the montmorillonite, the pyrophyllite and the sericite is 30%-60%. For example, the mass percentage of the serizyme frog eye clay can be 40%, 50%, 60% or 70%, etc., and the mass percentage of the kaolinite, the montmorillonite, the pyrophyllite and the sericite can be 30%, 40%, 50% or 60%, etc. Based on this formula, the final three-dimensional well pattern multi-well fracturing model can be more stable.

[0048] Since adding too much reservoir characteristic simulation material will affect the sintering and solidification effect, and adding too little reservoir characteristic simulation material will affect the simulation effect of the three-dimensional well pattern multi-well overall fracturing model, by limiting the mass ratio of the reservoir characteristic simulation material to be 22% to 58.5%, a balance between the two can be achieved, and the sintering and solidification effect and the simulation effect can be considered.

[0049] In the embodiment of the application, the reservoir characteristic simulation material can be used to characterize and simulate the reservoir characteristics of the target area reservoir, including natural fractures, pores, lithology and lithofacies, sandy strips, bedding and laminations. In order to properly simulate the reservoir characteristics, the reservoir characteristic simulation material can include any one or more of carbon powder, carbon fiber, paraffin, carbon fiber cloth, nylon fabric, aluminum foil, copper sheet, copper wire, nylon fiber and quartz sand; wherein the carbon powder can further include nano carbon powder.

[0050] In actual application, the materials can be selected from carbon powder, carbon fiber, paraffin, carbon fiber cloth, nylon fabric, aluminum foil, copper sheet, copper wire, nylon fiber and quartz sand according to the specific reservoir characteristics to be simulated. In addition, appropriate forms of simulation materials can be selected according to the forms of various reservoir characteristics, such as granular, thin plate, linear, curved panel, flake and the like. Some examples of simulation materials selected for simulating various reservoir characteristics will be provided below:

[0051] The material for simulating pores in the target area reservoir can include carbon powder, carbon fiber, paraffin and the like. For example, carbon powder and carbon fiber can be used to simulate pores and fractures.

[0052] The material for simulating natural fractures in the target area reservoir can include carbon fiber cloth, nylon fabric, aluminum foil, paraffin, copper sheet and the like. For example, carbon fiber cloth can be used to simulate connected fractures, paraffin can be used to simulate connected natural fractures or faults with internal space, nylon fabric can be used to simulate small natural fractures or faults, aluminum foil can be used to simulate active natural fractures or faults, and copper sheet can be used to simulate larger fractures or closed faults.

[0053] The material for simulating lithology and lithofacies and sandy strips of the target area reservoir can include quartz sand, and the particle size of the quartz sand can be 20-140 mesh. In simulation, appropriate particle size of quartz sand can be selected according to actual conditions. For example, 10-20 mesh quartz sand can be used to simulate gravel, and 30-100 mesh quartz sand can be used to simulate sandy strips.

[0054] The material for simulating bedding and laminations of the target area reservoir can include carbon fiber, carbon fiber cloth, nylon fiber, nylon fabric, aluminum foil and the like.

[0055] In the embodiments of the present application, the plurality of simulated wellbores constitutes a simulated well pattern. The size scale (including well spacing, layer spacing, well length, etc.) of the simulated well pattern can be obtained by reducing the size scale of the target well pattern according to a first preset ratio. The first preset ratio can be set according to actual needs. For example, the first preset ratio can be (5000-10000):1, wherein the former corresponds to the target well pattern, and the latter corresponds to the simulated well pattern.

[0056] In the plurality of simulated wellbores, any simulated wellbore has a vertical well section and a horizontal well section. When determining the size (including pipe diameter, pipe thickness, etc.) of each simulated wellbore, the size of each wellbore in the target well pattern can be reduced according to a second preset ratio to obtain the size of each simulated wellbore. The second preset ratio can be set according to actual needs. For example, the second preset ratio can be (500-1000):1, wherein the former corresponds to the wellbore in the target well pattern, and the latter corresponds to the simulated wellbore.

[0057] To further accurately simulate each wellbore in the target well pattern, the plurality of simulated wellbores can all be stainless steel pipes. In specific implementation, the thickness, pipe diameter, and length, etc. of each simulated wellbore can be calculated according to the second preset ratio, and under the condition of ensuring the pipe wall pressure-bearing capacity, a stainless steel pipe with appropriate thickness and pipe diameter is processed into a stainless steel pipe with corresponding length as the simulated wellbore.

[0058] In the embodiments of the present application, the pre-prepared clay-based material and the reservoir characteristic simulation material can be used to prepare a reservoir embryo corresponding to the target area reservoir (having similar geological structure and reservoir characteristics to the target area reservoir), and a plurality of simulated wellbores are further arranged in the reservoir embryo, i.e. the model embryo is obtained. When preparing the reservoir embryo, the structure of the target area reservoir can be reduced according to a third preset ratio to obtain the size of the reservoir embryo. Specifically, the structure of the target area reservoir is reduced according to the third preset ratio, including: the geological structure and the reservoir characteristics in the target area reservoir are both reduced according to the third preset ratio. The third preset ratio can be set according to actual needs, for example, it can be (10000-50000):1, wherein the former corresponds to the target area reservoir, and the latter corresponds to the reservoir embryo.

[0059] In actual application, the process of preparing the model embryo can be as follows:

[0060] (1) The clay material, additives, and water are weighed according to the proportion, the clay materials are crushed and mixed, then the additives are added, and the mixture is ground and mixed with a grinder.

[0061] (2) According to the reservoir characteristics of the target area reservoir, appropriate reservoir characteristic simulation materials are selected.

[0062] (3) Based on the target well network structure, manufacture or select multiple corresponding simulated wells, and assemble the simulated well network based on the multiple simulated wells.

[0063] (4) Add the water weighed in step (1) to the material obtained in step (1) and stir evenly to form a viscous paste. Then, according to the structure of the reservoir in the target area and the structure of the target well network, shape the viscous paste, reservoir characteristic simulation material and simulated well network according to their respective positions to obtain the model embryo.

[0064] Step 102: The model blank is fired to obtain a sintered and solidified model.

[0065] In this embodiment of the application, the model preform is sintered to obtain a sintered and solidified model, which may specifically include:

[0066] The model preform is placed in an oven, which heats it to a first target temperature at a first heating rate, and then holds it at the first target temperature for 1.5 to 2.5 hours. The first heating rate is 1.5°C / min to 2.5°C / min, and the first target temperature is 75°C to 85°C. For example, the first target temperature can be held for 1.5 hours, 2 hours, or 2.5 hours; the first heating rate can be 1.5°C / min, 2°C / min, or 2.5°C / min; and the first target temperature can be 75°C, 80°C, or 85°C.

[0067] Then, the oven heats the food from the first target temperature to the second target temperature at a second heating rate, and holds the second target temperature for 8 to 12 hours. The second heating rate is 0.5℃ / min to 1.5℃ / min, and the second target temperature is 100℃ to 110℃. For example, the second target temperature can be held for 8, 9, 10, 11, or 12 hours; the first heating rate can be 0.5℃ / min, 1℃ / min, or 1.5℃ / min; and the second target temperature can be 100℃, 105℃, or 110℃.

[0068] Next, the oven heats the food from the second target temperature to the third target temperature at a third heating rate, and holds the third target temperature for 18 to 22 hours. The third heating rate is 0.5℃ / min to 1.5℃ / min, and the third target temperature is 280℃ to 320℃. For example, the third target temperature can be held for 18, 19, 20, 21, or 22 hours; the second heating rate can be 0.5℃ / min, 1℃ / min, or 1.5℃ / min; and the third target temperature can be 280℃, 290℃, 300℃, 310℃, or 320℃.

[0069] Finally, the oven is cooled from the third target temperature to the fourth target temperature at a preset cooling rate to obtain the sintered and solidified model. The preset cooling rate is 18℃ / 1h to 22℃ / 1h, and the fourth target temperature is 90℃ to 110℃. For example, the preset cooling rate is 18℃ / 1h, 19℃ / 1h, 20℃ / 1h, 21℃ / 1h, or 22℃ / 1h, and the fourth target temperature is 90℃, 100℃, or 110℃, etc.

[0070] In practical applications, in order to make the sintered solidified model obtained by firing more stable, before step 102, the method for preparing the three-dimensional well network multi-well overall fracturing model provided in this application embodiment may further include: drying the model embryo, then step 102 firing the model embryo to obtain the sintered solidified model, specifically including: firing the dried model embryo to obtain the sintered solidified model.

[0071] When drying the model blank, it can be placed in a cool and ventilated environment to dry slowly in the shade for 25 to 35 days. Then, it can be moved to an environment with sufficient sunlight to dry in the sun for 25 to 35 days before firing.

[0072] Step 103: Install a simulated wellhead in the sintered solidification model to obtain a three-dimensional well network multi-well overall fracturing model.

[0073] In this embodiment, the simulated wellhead and the inlet of the simulated wellbore can be connected by threads. When determining the size of the simulated wellhead, the size of the wellhead in the target well network structure can be reduced by a second preset ratio to obtain the size of the simulated wellhead. The wellhead can also be made of stainless steel tubing.

[0074] In practice, after the oven cools down from the third target temperature to the fourth target temperature at a preset cooling rate, the oven can be turned off. After the sintered and solidified model has cooled down, the sintered and solidified model can be taken out of the oven and installed at the simulated wellhead.

[0075] It is understood that the method for preparing a three-dimensional well network multi-well integrated fracturing model provided in this application includes: based on the structure of the reservoir in the target area and the structure of the target well network, preparing a model blank using prefabricated clay materials, reservoir characteristic simulation materials, and multiple simulated wellbores. The prefabricated clay materials are materials that can be sintered and solidified at 160℃-240℃; sintering the model blank to obtain a sintered and solidified model; and installing simulated wellheads in the sintered and solidified model to obtain a three-dimensional well network multi-well integrated fracturing model. That is, the scheme provided in this application can prepare a three-dimensional well network multi-well integrated fracturing model, and then fracturing simulation experiments can be conducted based on this model to obtain relevant experimental data. This allows for optimization of the well network design during actual mining, including optimizing well spacing or layer spacing. Furthermore, the relevant experimental data may also include fracturing parameters, which can be used to adjust the fracturing process during actual mining.

[0076] On the other hand, in existing technologies, it is difficult to obtain large rock samples from shale oil reservoirs, making it difficult to create a three-dimensional well network multi-well integrated fracturing model. However, based on the solution provided in the above embodiments of this application, it is easy to obtain embryos with similar geological structures and reservoir characteristics to shale oil reservoirs, thereby making it easier to create a three-dimensional well network multi-well integrated fracturing model.

[0077] Based on the method for preparing a three-dimensional well network multi-well integrated fracturing model provided in the above embodiments of this application, this application also provides a three-dimensional well network multi-well integrated fracturing model. This three-dimensional well network multi-well integrated fracturing model can be prepared using the method provided in the above embodiments.

[0078] It is understood that by adopting the three-dimensional well network multi-well integrated fracturing model provided in the embodiments of this application, fracturing simulation experiments can be carried out based on the three-dimensional well network multi-well integrated fracturing model and relevant experimental data can be obtained. In this way, the well network design in the actual mining process can be optimized based on these relevant experimental data, including optimizing well spacing or layer spacing, etc.

[0079] Based on the three-dimensional well network multi-well integrated fracturing model provided in the above embodiments of this application, this application also provides a method for using the three-dimensional well network multi-well integrated fracturing model, which may include: installing a fracture detection device in the three-dimensional well network multi-well integrated fracturing model; and injecting fracturing fluid into the simulated wellhead in the three-dimensional well network multi-well integrated fracturing model.

[0080] The crack detection device may include at least one of acoustic emission monitoring equipment and CT scanning equipment.

[0081] During fracturing simulation experiments, parameters such as the longitudinal and transverse well spacing, well network arrangement, and well length of the three-dimensional well network can be optimized based on the fracture test data obtained from the fracture detection device. Specifically, in the fracturing simulation experiment, the generation and extension of fractures in each simulated well during the simulated injection process can be obtained through acoustic emission monitoring and CT scanning, thereby obtaining the fracture length data of each simulated well in the longitudinal and transverse directions. After scaling up the fracture length data, the actual fracture length in the overall fracturing of multiple wells in the three-dimensional well network is obtained. When optimizing the three-dimensional well network, the goal is to ensure that the fractures in each section of each well do not come into contact with each other, and the parameters such as the longitudinal and transverse well spacing, well network arrangement, and well length of the three-dimensional well network are optimized.

[0082] In other words, the optimization of the three-dimensional well network is mainly based on the length of the fractures in each well in the longitudinal and lateral directions. Specifically, it aims to avoid the encounter or intersection of fractures between wells. Therefore, the well spacing in the longitudinal and lateral directions of the well network must be greater than the fracture length between two wells to ensure normal oil and gas well production. Without model tests, optimizing the well network lacks a basis and can only be guessed. However, based on the multi-well integrated fracturing model of the three-dimensional well network provided in the embodiments of this application, fracturing simulation experiments are conducted to obtain fracture experimental data. This data can then be scaled up proportionally to adjust the longitudinal and lateral well spacing of the well network to achieve the optimal condition.

[0083] It is understood that the method of using the three-dimensional well network multi-well integrated fracturing model provided in the embodiments of this application enables fracturing simulation experiments to be conducted based on the three-dimensional well network multi-well integrated fracturing model and relevant experimental data to be obtained. This allows for the optimization of well network design in the actual mining process based on the relevant experimental data, including optimization of well spacing or layer spacing.

[0084] The following will illustrate the method for preparing a multi-well integrated fracturing model of a three-dimensional well network provided in this application with specific examples. It should be understood that the following examples are merely specific implementation methods and do not imply an undue limitation on the solution of this application.

[0085] Example 1

[0086] 1. Weigh out 33.6 kg of Seto frog clay, 4.0 kg of kaolinite, 8.0 kg of montmorillonite, 1.2 kg of pyrophyllite, and 1.2 kg of sericite. After crushing and mixing, add 0.96 kg of sodium carbonate and 0.4 kg of sodium bicarbonate, and grind and mix them evenly with a grinder.

[0087] II. Carbon powder and carbon fiber are used to simulate reservoir pores and fractures; carbon fiber cloth is used to simulate interconnected fractures; 10-20 mesh quartz sand is used to simulate gravel; 30-100 mesh quartz sand is used to simulate sandy bands; paraffin wax sheets are used to simulate natural fractures or faults with internal spaces; nylon fabric is used to simulate small natural fractures or faults; aluminum foil is used to simulate active natural fractures or faults; and copper sheets are used to simulate larger fractures or closed faults. The total mass of the reservoir characteristic simulation materials is 20 kg.

[0088] III. In the target well network structure, the horizontal well spacing is 300 meters, the vertical well spacing is 100 meters, the inclined well spacing is 150 meters, and the horizontal well section length is 2000 meters, scaled down to a ratio of 10000:1. A simulated wellbore is constructed using stainless steel pipes with a wall thickness of 1.0 mm and a diameter of 5.0 mm, with threads machined at one end to serve as the wellhead.

[0089] 4. Gradually add water to the material obtained in step 1 and stir. Add a total of 10.64 kg of water and stir evenly to form a viscous paste. Then, according to the structure of the reservoir in the target area and the target well network structure, shape the viscous paste, reservoir characteristic simulation material, and simulated well network according to their respective positions to obtain the model embryo. The size of the model embryo is 30cm×30cm×30cm.

[0090] 5. Place the model embryo in a cool and ventilated environment to air dry slowly. After 30 days, move it to an environment with sufficient sunlight to dry in the sun for 30 days to obtain the dried model embryo.

[0091] VI. Place the dried model blank into a constant temperature oven and fire it according to the following process:

[0092] The temperature was increased from room temperature to 80°C at a rate of 2°C / min, and then held at 80°C for 2 hours.

[0093] The temperature was increased from 80℃ to 105℃ at a rate of 1℃ / 5.0min, and then held at 105℃ for 10 hours.

[0094] The temperature was increased from 105℃ to 300℃ at a rate of 1℃ / min, and then held at 300℃ for 20 hours.

[0095] The temperature is reduced from 300℃ to 100℃ at a rate of 20℃ / 1h.

[0096] After the above heating-cooling firing procedure, the model blank is sintered and solidified. The oven is then closed, and the sintered and solidified model is allowed to cool naturally in the oven before being taken out and installed at the simulated wellhead to obtain a three-dimensional well network multi-well overall fracturing model. Fracturing simulation experiments can then be carried out based on this three-dimensional well network multi-well overall fracturing model.

[0097] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0098] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for preparing a three-dimensional well network multi-well integrated fracturing model, characterized in that, The preparation method includes: Based on the structure of the reservoir in the target area and the structure of the target well network, a model embryo is prepared using prefabricated clay materials, reservoir characteristic simulation materials, and multiple simulated wells. The prefabricated clay materials are materials that can be sintered and solidified at 160℃-240℃. The model preform is sintered to obtain a sintered and solidified model; A simulated wellhead is installed in the sintered solidification model to obtain a three-dimensional well network multi-well overall fracturing model.

2. The method for preparing a three-dimensional well network multi-well integrated fracturing model according to claim 1, characterized in that, The precast clay material includes clay, additives, and water; The clay material includes Seto-origin frog clay, kaolinite, montmorillonite, pyrophyllite, and sericite. The additives include sodium carbonate and sodium bicarbonate.

3. The method for preparing a three-dimensional well network multi-well integrated fracturing model according to claim 2, characterized in that, In the total material composed of the precast clay material and the reservoir characteristic simulation material, the mass percentage of the clay material is 30% to 60%, the mass percentage of the reservoir characteristic simulation material is 22% to 58.5%, and the mass percentage of water is 10% to 15%. In this material, sodium carbonate accounts for 1% to 2% of the clay material by mass ratio, and sodium bicarbonate accounts for 0.5% to 1% of the clay material. In the clay material, the mass percentage of Seto frog-like clay is 40% to 70%.

4. The method for preparing a three-dimensional well network multi-well integrated fracturing model according to claim 1, characterized in that, The reservoir characteristic simulation materials include any one or more of the following: carbon powder, carbon fiber, paraffin wax, carbon fiber cloth, nylon fabric, aluminum foil, copper sheet, copper wire, nylon fiber, and quartz sand.

5. The method for preparing a three-dimensional well network multi-well integrated fracturing model according to claim 1, characterized in that, All of the simulated well shafts are stainless steel pipes.

6. The method for preparing a three-dimensional well network multi-well integrated fracturing model according to claim 1, characterized in that, Before firing the model embryo, the preparation method further includes: The model embryo was dried; The firing of the model embryo includes: The dried model blank is then fired.

7. The method for preparing a three-dimensional well network multi-well integrated fracturing model according to claim 1, characterized in that, The process of firing the model preform to obtain a sintered and solidified model includes: The model embryo is placed in an oven, which is heated to a first target temperature at a first heating rate, and held at the first target temperature for 1.5h to 2.5h. The first heating rate is 1.5℃ / min to 2.5℃ / min, and the first target temperature is 75℃ to 85℃. The oven heats the temperature from the first target temperature to the second target temperature at a second heating rate, and holds the temperature at the second target temperature for 8 to 12 hours. The second heating rate is 0.5℃ / min to 1.5℃ / min, and the second target temperature is 100℃ to 110℃. The oven is heated from the second target temperature to the third target temperature at a third heating rate, and held at the third target temperature for 18h to 22h. The third heating rate is 0.5℃ / min to 1.5℃ / min, and the third target temperature is 280℃ to 320℃. The oven is cooled from the third target temperature to the fourth target temperature at a preset cooling rate to obtain a sintered and solidified model. The preset cooling rate is 18℃ / 1h to 22℃ / 1h, and the fourth target temperature is 90℃ to 110℃.

8. A three-dimensional well network multi-well integrated fracturing model, characterized in that, The three-dimensional well network multi-well integrated fracturing model is prepared based on the method for preparing the three-dimensional well network multi-well integrated fracturing model according to any one of claims 1-7.

9. A method of using the three-dimensional well network multi-well integrated fracturing model as described in claim 8, characterized in that, The method of use includes: Install a fracture detection device in a three-dimensional well network multi-well integrated fracturing model; Fracturing fluid is injected into the simulated wellhead in the three-dimensional well network multi-well integrated fracturing model.

10. The method of use according to claim 9, characterized in that, The crack detection device includes acoustic emission monitoring equipment and / or CT scanning equipment.

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