A simulation device and method for interlayer steering of a thick multi-thin reservoir reconstruction layer

Abstract

The present application relates to the technical field of oil and gas field development reservoir reconstruction, and discloses a kind of thick multi-thin reservoir reconstruction interlayer steering simulation experiment device and method, comprising the following steps: step S1: based on the principle of similarity to establish the indoor experiment device of layered reconstruction interlayer steering;Step S2: at least two longitudinal processing intervals are divided, the number of perforations, perforation diameter and perforation position are set, and the perforation diameter after the diameter expansion of each perforation in the construction process is theoretically calculated;At least based on the parameter setting of preflush, sand-carrying fluid and wellbore steel grade, the diameter of temporary plugging ball is set;Step S3: according to the similarity principle, the sand injection amount of each longitudinal processing interval in the experimental process is set, the pump injection simulation program in the indoor experiment device is carried out to carry out sand injection reconstruction by pumping fracturing fluid, and the interlayer steering simulation experiment is completed.The thick multi-thin reservoir reconstruction interlayer steering simulation experiment device and method of the present application improve the longitudinal reconstruction effect of thick multi-thin reservoir and the degree of reserves production, and improve the single well production.

Description

Technical Field

[0001] This invention relates to the technical field of reservoir stimulation in oil and gas field development, and in particular to an experimental apparatus and method for simulating interlayer turning in the stimulation of extremely thick and multi-thin reservoirs. Background Technology

[0002] Currently, with the increasing proportion of large-thick and multi-thin reservoirs in my country's exploration areas, the demand for layered and segmented stimulation technology is growing. These reservoirs have large spans, dispersed perforation sections, well-developed natural fractures, and strong interlayer heterogeneity. If a general acid injection process is used during stimulation, the fracture system will not be uniformly stimulated vertically. To increase reservoir utilization and improve stimulation effectiveness, temporary plugging and redirection fracturing is often necessary. The purpose of temporary plugging and redirection fracturing is mainly to plug existing fractures and fracture new ones, and it is one of the effective measures to increase single-well production. The principle of interlayer and intra-fracture redirection using temporary plugging materials is to use chemical particles, fibers, or other materials as temporary plugging agents during fracturing. By sealing existing artificial / natural fractures, the formation pore pressure or net fracture pressure is increased, causing the fluid to redirect within the formation and open natural or new fractures in other directions or segments. After fracturing, the plugging agent dissolves in formation water or fracturing fluid, achieving intra-segment opening of sealed fractures and increasing the stimulation volume of each segment.

[0003] The mechanical mechanism of crack deflection by temporary plugging materials can be mainly divided into three cases:

[0004] 1. Single crack propagation: The temporary plugging agent effectively seals the opening or end of an existing crack, forming a relatively dense temporary plugging material filter cake. On the one hand, it reduces liquid loss, making it difficult for fluid pressure to be transmitted to the crack tip, thereby reducing pressure transmission efficiency and slowing down the crack propagation rate. On the other hand, it forms an artificial barrier, improving the fracture toughness of the crack tip, blunting the crack leading edge, and making it difficult for the crack to continue to propagate forward.

[0005] 2. Competitive Fracturing of Multiple Fractures: Multiple fractures exist within the reservoir section, each requiring different pressures to open. When pumped fluid initially opens a portion of the fractures, temporary plugging material selectively seals one or more fractures. As fluid injection continues, the net pressure within the fracture increases, and new hydraulic fractures extend along secondary fractures with lower fracturing pressures or along a weak point. Currently, staged fracturing in oilfield design is based on this scenario of multiple fractures competing for opening and extension within the reservoir.

[0006] 3. Reservoir heterogeneous anisotropic extended fracture reversal: Temporary plugging materials effectively plug the artificially opened fractures. When the net pressure reaches a certain critical value, local stress fields and weak surfaces meet certain mechanical conditions, new fractures will be opened, thus causing the artificial fractures to reversal.

[0007] Currently, there is insufficient targeted approach for the modification of extremely thick reservoirs with multiple thin layers both domestically and internationally. The number of layers for stratification using packers is limited and the operation is risky. The ideal number of layers for most wells in extremely thick reservoirs with multiple thin layers is 4-6, but stratification tools can only achieve 3 layers of modification, which limits the degree of reservoir opening and the utilization of reserves. Summary of the Invention

[0008] The purpose of this invention is to provide an experimental device and method for simulating the interlayer turning of a very thick reservoir with multiple thin layers. The design is highly operable and can fully transform multiple small layers in the vertical direction of a very thick reservoir with multiple thin layers, thereby improving the vertical transformation effect and reserve utilization of the reservoir, greatly increasing the production of a single well, and contributing to long-term stable production.

[0009] To achieve the above objectives, the present invention provides a method for simulating interlayer deflection in the stimulation of extremely thick reservoirs with multiple thin layers, comprising the following steps:

[0010] Step S1: Establish an indoor experimental device for interlayer rotation based on the principle of similarity;

[0011] Step S2: Based on the thickness of multiple vertical reservoir layers, divide the well into at least two vertical processing sections. Set the number of perforations, perforation diameter, and perforation position of the vertical well in the indoor experimental device according to each of the vertical processing sections. Theoretically calculate the perforation diameter of each perforation after enlargement during the construction process. Set the diameter of the temporary plugging ball based at least on the parameters of the pre-flush fluid, the sand-carrying fluid, and the wellbore steel grade.

[0012] Step S3: Based on the principle of similarity, set the amount of sand added to each of the longitudinal processing layers during the experiment, and carry out the pumping simulation program in the indoor experimental device to modify the sand addition by pumping fracturing fluid, and complete the interlayer turning simulation experiment.

[0013] As a preferred embodiment, the pumping simulation program includes the following steps: sequentially adding sand to the longitudinal processing section of the vertical wellbore from bottom to top.

[0014] As a preferred embodiment, the three longitudinal processing sections of the vertical wellbore from bottom to top are the first section, the second section, and the third section. When pumping 120% of the designed fracturing fluid into the first section, a temporary plugging ball corresponding to the first section is added.

[0015] After temporarily plugging the first section, the second section is pumped with 100% of the designed fracturing fluid, and the corresponding temporary plugging ball for the second section is added;

[0016] After temporarily plugging the second layer, the third layer is pumped with 80% of the designed fracturing fluid, and the corresponding temporary plugging ball is added to complete the modification construction.

[0017] As a preferred embodiment, at least two longitudinally connected reservoirs with a thickness of less than 15m are divided into the same longitudinal processing segment, and a single reservoir with a thickness greater than 15m is divided into at least two longitudinal processing segments, with the thickness of each longitudinal processing segment being less than or equal to 15m.

[0018] As a preferred embodiment, each of the longitudinal processing segments is provided with a first temporary plugging ball, a second temporary plugging ball, and a third temporary plugging ball. The perforation diameter of the longitudinal processing segment is a, the diameter of the first temporary plugging ball is 0.8a, the diameter of the second temporary plugging ball is a, and the diameter of the third temporary plugging ball is 1.2a.

[0019] As a preferred embodiment, the number of the first temporary plugging ball, the second temporary plugging ball, and the third temporary plugging ball are each 1 / 3 of the total number of temporary plugging balls in the longitudinal processing section.

[0020] As a preferred embodiment, the number of temporary plugging balls is three times the number of perforations in the corresponding longitudinal processing section.

[0021] As a preferred embodiment, the pre-fluid is a low-viscosity liquid with a viscosity of <20 mPa·s.

[0022] As a preferred embodiment, the proppant-carrying fluid is a non-crosslinked fracturing fluid with a viscosity of 30-60 mPa·s.

[0023] An experimental device for simulating inter-layer turning in the stimulation of a large-thick, multi-thin reservoir includes a connecting pipe, a casing, a mixer, a water pump, a vertical wellbore, and a water tank for storing fracturing fluid. The mixer is installed in the water tank, which is connected to the vertical wellbore via the connecting pipe. The casing is fitted around the outer periphery of the vertical wellbore. The peripheral wall of the vertical wellbore has perforations, which communicate with the casing. The casing is connected to the water tank via the connecting pipe.

[0024] Compared with existing technologies, the experimental device and method for simulating interlayer turning in the stimulation of extremely thick and multi-thin reservoirs, as described in this invention, have the following advantages: They can clearly identify the key factors that determine whether temporary plugging and stratified stimulation of extremely thick and multi-thin reservoirs can achieve stratification, enabling full stimulation of multiple vertical sub-layers and providing technical support for improving the stimulation effect of such reservoirs. The technical method provided by this invention is highly operable and is of great significance for achieving full vertical utilization and reserve control and production enhancement in the temporary plugging and stratified stimulation of extremely thick and multi-thin reservoirs. It can significantly improve the vertical stimulation effect and reserve utilization of such reservoirs, greatly increase single-well production, promote long-term stable production, significantly improve the development benefits of extremely thick and multi-thin reservoirs, and has broad application prospects. Attached Figure Description

[0025] Figure 1This is a schematic diagram of the structure of the interlayer turning simulation experimental device for the modification of extremely thick and thin reservoirs according to an embodiment of the present invention.

[0026] Figure 2 This is a cross-sectional schematic diagram illustrating the principle of diameter expansion after erosion and wear of the perforation hole.

[0027] Figure 3 This is a schematic diagram of the side circumferential surface of a perforation hole after it has been eroded and worn, illustrating the principle of diameter expansion.

[0028] In the picture:

[0029] 10. Connecting pipe; 11. Casing; 12. Mixer; 13. Water pump; 14. Vertical well shaft; 15. Water tank; 16. Perforation. Detailed Implementation

[0030] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0031] In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" used to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0032] In the description of this invention, it should be understood that the terms "connected," "linked," and "fixed," etc., used in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or a welded connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly defined. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] like Figures 1 to 3 As shown in the preferred embodiment of the present invention, a method for simulating interlayer turning in the stimulation of a large-thick, multi-thin reservoir includes the following steps:

[0034] Step S1: Establish an indoor experimental device for interlayer rotation based on the principle of similarity;

[0035] Step S2: Based on the thickness of each sub-layer and the distance between sub-layers in the longitudinal multi-layer structure, divide the structure into at least two longitudinal processing segments. Set the number, diameter, and position of perforations 16 in the vertical wellbore 14 in the indoor experimental device according to each longitudinal processing segment. Theoretically calculate the diameter of each perforation 16 after enlargement during the construction process. Set the diameter of the temporary plugging ball based at least on the parameters of the pre-flush fluid, the sand-carrying fluid, and the wellbore steel grade.

[0036] In step S2, the thickness of each sublayer and the distance between sublayers in the vertical multilayer structure are important bases for dividing the vertical processing sections. The thickness and physical properties of each sublayer vary. For sections with larger thickness and better physical properties, the scale of stimulation should be appropriately increased to ensure that the main producing layers are fully stimulated. "Good physical properties" refers to reservoirs assessed as Class II or above (reservoir porosity > 10%, permeability > 1 mD). "Appropriately increasing the scale of stimulation" is a relative value; it refers to increasing the scale compared to the average level.

[0037] It should be noted that the perforation density X is set at 10-16 holes / m, meaning that the number of perforations within 1m of the vertical wellbore 14 in the longitudinal direction is set at 10-16. The total length of the vertical wellbore 14 in the longitudinal direction is Y, and the total number of perforations 16 in the vertical wellbore 14 is equal to X * Y. The perforation diameter is set at 8mm-10mm. Adjacent perforations 16 in the circumferential direction of the vertical wellbore 14 are spaced at 60° intervals, and adjacent perforations 16 in the height direction are spaced apart. Figure 3 As shown, the perforations 16 on the sidewall of the vertical wellbore 14 are arranged in a spiral shape.

[0038] It should be noted that, as Figures 2 to 3 As shown, the dashed line represents the enlarged perforation 16. Perforation 16 enlargement during construction refers to an erosion wear phenomenon where the diameter of the perforation 16 increases due to the impact of high-speed liquids such as fracturing fluid carrying solid particles. In step S2, the actual perforation size is calculated using a theoretical mathematical model formula. In this formula, the actual perforation diameter is a function of the erosion rate, which depends on the proppant concentration and the fluid velocity through the perforation 16. The theoretical mathematical model expression is:

[0039]

[0040] In the formula, D represents the equivalent perforation diameter (in); t represents time (in minutes); W represents the time difference (in minutes); tot Represents the total mass of proppant pumped during the time difference, in lbs (N). tot Represents the total quantity of casing 11 and perforation 16, in units; t inj γ represents the pumping time of the proppant, in minutes; γ represents the perforation 16 direction correction factor, which can be approximated as 1 when the particle erosion angle is less than 180 degrees, and is dimensionless; w p(t) represents the proppant mass, lb; N represents the number of perforations 16 per cluster of casing 11, units; v(t) represents the fluid velocity, m / s; C d Represents the flow coefficient, which is dimensionless.

[0041] Step S3: Based on the principle of similarity, set the amount of sand added to each longitudinal processing layer during the experiment, carry out the pumping simulation program in the indoor experimental device to modify the sand addition by pumping fracturing fluid, and complete the interlayer turning simulation experiment.

[0042] In step S3, the single-stage sand addition amount is determined based on the total sand body thickness and the sand addition strength limit during fracturing operations, and the experimental process is designed using the principle of similarity. The calculation of the single-stage sand addition amount is based on existing technology.

[0043] The interlayer turning simulation experiment method for the stimulation of extremely thick and multi-thin reservoirs in this invention can clarify the key factors for achieving stratification in the temporary plugging and stratification stimulation of extremely thick and multi-thin reservoirs, and realize the full stimulation of multiple small layers in the vertical direction, providing technical support for improving the stimulation effect of extremely thick and multi-thin reservoirs. The technical method provided by this invention is highly operable and has significant implications for achieving full vertical utilization and reserve control and production enhancement in the temporary plugging and stratification stimulation of extremely thick and multi-thin reservoirs. It can significantly improve the vertical stimulation effect and reserve utilization of extremely thick and multi-thin reservoirs, greatly increase the production of single wells, facilitate long-term stable production, significantly improve the development benefits of extremely thick and multi-thin reservoirs, and has broad application prospects.

[0044] It should be noted that the similar principles in steps S1 and S3 include:

[0045] ① Geometric similarity: This requires that the boundary shape of the model is similar to that of the prototype, and that the corresponding linear dimensions are in the same proportion. Geometric similarity includes length similarity, area similarity, and volume similarity.

[0046] ② Physical similarity: This includes kinematic similarity and dynamic similarity. Kinematic similarity refers to similar parameters such as velocity, time, and acceleration; dynamic similarity refers to similar parameters such as force, density, viscosity, and temperature.

[0047] ③ Boundary condition similarity: In addition to the similarity of the flow process, the initial and boundary conditions must also be similar. That is, the initial and boundary conditions of the simulation should be consistent with the prototype.

[0048] As one example, the wellbore steel grade selected is Tianjin Steel TP140V, whose mechanical properties are as follows: resistance to external extrusion is 90.0 MPa, resistance to internal pressure is 103.5 MPa, tensile strength is greater than 1034 MPa, and yield strength is greater than 965-1172 MPa.

[0049] Furthermore, the pumping simulation procedure includes the following steps: proppant is added sequentially from bottom to top to the longitudinally processed sections of the vertical wellbore 14. By dividing the reservoir into multiple longitudinally processed sections in step S2, and then adding proppant in segments according to these sections in step S3, the aim is to achieve layered (segmented) fracturing stimulation. Adding proppant in each segment is the purpose of layered and segmented fracturing stimulation. The role of proppant addition is to support the artificial fractures, ensuring they have a certain conductivity, and ultimately achieving the goal of increasing oil and gas well production.

[0050] Furthermore, the vertical wellbore 14 has three longitudinal processing sections from bottom to top: the first section, the second section, and the third section. When pumping 120% of the designed fracturing fluid into the first section, a temporary plugging ball corresponding to the first section is added.

[0051] After temporarily plugging the first stage, pump 100% of the designed fracturing fluid into the second stage and add the corresponding temporary plugging ball for the second stage;

[0052] After temporarily plugging the second section, the third section is pumped with 80% of the designed fracturing fluid, and a temporary plugging ball corresponding to the third section is added to complete the reservoir stimulation operation. During reservoir stimulation perforation, three longitudinal processing sections are perforated simultaneously. After perforation, during the pumping process of the first section, although the other two sections have higher in-situ stress, due to the formation's permeability, a pressure differential will cause seepage and a small amount of fluid ingress. Therefore, the first section is pumped with 120% of the designed volume, with 90-100% of the fluid entering the first section, and the remaining small amount of fracturing fluid entering the other two sections, ultimately achieving balanced fluid ingress in the first, second, and third sections. It should be noted that the calculation of the fracturing fluid design volume is based on existing technology. As one embodiment, the preset fracturing fluid volume is obtained through simulation and optimization using reservoir stimulation fracturing software.

[0053] Furthermore, at least two vertically connected reservoirs with a thickness of less than 15m are divided into the same vertical processing segment, while a single reservoir with a thickness greater than 15m is divided into at least two vertical processing segments, each with a thickness of less than or equal to 15m. This division into vertical processing segments serves as the basis for fully modifying the reservoir.

[0054] Furthermore, each longitudinal processing section is equipped with a first temporary plugging ball, a second temporary plugging ball, and a third temporary plugging ball. The diameter of the perforation 16 in the longitudinal processing section is 'a', the diameter of the first temporary plugging ball is 0.8a, the diameter of the second temporary plugging ball is 'a', and the diameter of the third temporary plugging ball is 1.2a. The diameter of the perforation 16 in the vertical wellbore 14 may be either reduced, unchanged, or expanded. Therefore, three different diameters of temporary plugging balls are used to demonstrate the temporary plugging effect of different diameter temporary plugging balls. The aim is to use different temporary plugging balls to seal the perforation 16 holes and maximize the temporary plugging effect.

[0055] Specifically, the number of the first, second, and third temporary blocking balls is one-third of the total number of temporary blocking balls in this longitudinal processing section.

[0056] Furthermore, the number of temporary plugging balls is three times the number of perforations 16 in the corresponding longitudinal processing section.

[0057] Furthermore, the pre-fluid is a low-viscosity liquid, with a viscosity <20 mPa·s. Low-viscosity liquids facilitate the formation of complex artificial meshes and allow for larger modification volumes.

[0058] Furthermore, the proppant-carrying fluid is a non-crosslinked fracturing fluid with a viscosity of 30-60 mPa·s. The low viscosity of the non-crosslinked fracturing fluid is beneficial for construction and for carrying proppant into smaller fractures, thereby increasing the effective repair volume.

[0059] An experimental device for simulating interlayer turning in the stimulation of extremely thick and thin reservoirs, such as Figure 1 As shown, the system includes a connecting pipe 10, a casing 11, a mixer 12, a water pump 13, a vertical wellbore 14, and a water tank 15 for storing fracturing fluid. The mixer 12 is installed in the water tank 15, which is connected to the vertical wellbore 14 via the connecting pipe 10. The casing 11 is fitted around the outer periphery of the vertical wellbore 14. The peripheral wall of the vertical wellbore 14 has perforations 16, which connect the vertical wellbore 14 to the casing 11. The casing 11 is connected to the water tank 15 via the connecting pipe 10. In the experiment, the water pump 13 pumps simulated fracturing fluid carrying proppant from the water tank 15 into the simulated vertical wellbore 14. The fracturing fluid is ejected from the perforations 16 of the vertical wellbore 14 into the casing 11. The fracturing fluid in the casing 11 flows back to the water tank 15 through the connecting pipe 10 to form a circulation. The mixer 12 keeps the proppant in a suspended state to ensure the proppant carrying capacity of the fracturing fluid as much as possible.

[0060] One embodiment:

[0061] In step S1, the indoor experimental device for interlayer turning based on the principle of similarity includes a water tank 15, a mixer 12, a water pump 13, a simulated vertical well shaft 14, and a casing 11. The total height of the vertical well shaft 14 is 150cm. The thickness of the cement covering the casing 11 is set at 2-3cm to simulate the well completion cement sheath. The outer diameter of the casing 11 is 127mm, and the thickness of the casing 11 is 11.5-12.09mm.

[0062] In step S2, based on the reservoir structure, each sub-layer is 50cm thick and the spacing is equivalent to 50cm. The model vertical wellbore 14 is longitudinally divided into 3 longitudinal processing segments. Each longitudinal processing segment has 5 perforations 16 evenly distributed circumferentially. The diameter of the perforations 16 in the first segment is set to 8mm, and the diameters of the perforations 16 in the second and third segments are set to 10mm respectively.

[0063] The actual hole size after enlargement during the construction process is calculated using a theoretical mathematical model formula. The expression of the theoretical mathematical model is as follows:

[0064]

[0065] In the formula, D represents the equivalent perforation diameter (in); t represents time (in minutes); Δt represents the time difference (in minutes); W tot Represents the total mass of proppant pumped during the time difference, in lbs (N). tot Represents the total quantity of casing 11 and perforation 16, in units; t inj γ represents the pumping time of the proppant, in minutes; γ represents the perforation 16 direction correction factor, which can be approximated as 1 when the particle erosion angle is less than 180 degrees, and is dimensionless; w p (t) represents the proppant mass, lb; N represents the number of perforations 16 per cluster of casing 11, units; v(t) represents the fluid velocity, m / s; C d Represents the flow coefficient, which is dimensionless.

[0066] The sand concentration is set at 200 kg / m³. 3 The fracturing fluid discharge rate is 0.5 m³. 3 / min, proppant particle size is 40 / 70 mesh quartz sand, erosion time is 6h. Substituting the above set parameter values ​​into formula (1), the actual hole size after enlargement of each hole is calculated to be 10.72~12.73mm.

[0067] In step S2, the size of the temporary plugging ball is mainly based on the combination of temporary plugging balls. The diameter of the temporary plugging ball is 0.8 times, 1.0 times, and 1.2 times the diameter of the perforation 16 in each layer, respectively, accounting for 1 / 3 of the total number of temporary plugging balls in the longitudinal processing layer. The total number of temporary plugging balls is 3 times the number of perforation 16 in the corresponding longitudinal processing layer.

[0068] In step S3, the design single-section sand addition amount is set to 15m³. 3 The average sand ratio is 10%, and the total liquid volume is designed to be 150m³ based on the relationship between the amount of sand added per stage and the sand ratio. 3 .

[0069] In step S3, the pumping simulation program includes the following steps:

[0070] ①The first section is 0.5m 3 Fracturing fluid was pumped at a flow rate of / min for 6 hours, with a sand addition of 18m³. 3 Add 15 temporary blocking balls to ensure that the first level section is fully modified in the event of diversion.

[0071] ②After temporarily blocking the first section, continue at 0.5m. 3 Inject fracturing fluid at a pump flow rate of / min, with a sand addition rate of 15m³ / min.3 The second sub-layer fracturing operation was carried out. After 5 hours of pumping, 15 temporary plugging balls were added to temporarily plug the second sub-layer.

[0072] ③ After temporarily plugging the second layer, pump fracturing fluid at a rate of 0.5 m³ / min, and add 12 m³ of fracturing sand. 3 The third-level renovation construction was carried out, and the pumping simulation program was completed after 4 hours of pumping.

[0073] According to the design, the pumping simulation program was completed using experimental equipment, and a total of 450 cubic meters of fracturing fluid was pumped into the three sections during the fracturing construction. 3 45m of sand was added. 3 Analysis of the simulated vertical wellbore 14 showed that the first section had 5 perforations 16 temporarily plugged, the second section had 5 perforations 16 temporarily plugged, and the third section had 5 perforations 16 temporarily plugged. The construction of the modification process was relatively successful. Fiber optic monitoring during construction confirmed that the stratified temporary plugging and reversal modification of three longitudinal processing sections in a simulated thick and thin reservoir with a span of 150m was achieved.

[0074] In summary, this invention provides an experimental apparatus and method for simulating interlayer turning in the stimulation of extremely thick and thin reservoirs. It clarifies the key factors for achieving stratification in the temporary plugging and stratification stimulation of extremely thick and thin reservoirs, enabling full stimulation of multiple vertical sub-layers and providing technical support for improving the stimulation effect of such reservoirs. The technical method provided by this invention is highly operable and is of great significance for achieving full vertical utilization and reserve control and production enhancement in the temporary plugging and stratification stimulation of extremely thick and thin reservoirs. It can significantly improve the vertical stimulation effect and reserve utilization of extremely thick and thin reservoirs, greatly increase single-well production, facilitate long-term stable production, and significantly improve the development benefits of extremely thick and thin reservoirs, demonstrating broad application prospects.

[0075] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and substitutions without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A simulation experiment method for interlayer turning in the stimulation of extremely thick reservoirs with multiple thin layers, characterized in that: Includes the following steps: Step S1: Establish an indoor experimental device for interlayer rotation based on the principle of similarity; Step S2: Based on the thickness of multiple longitudinal reservoir layers, divide the well into at least two longitudinal processing sections. Set the number of perforations, perforation diameter, and perforation location in the vertical wellbore of the indoor experimental device according to each of the longitudinal processing sections. Theoretically calculate the perforation diameter of each perforation after enlargement during the construction process. Set the temporary plugging ball diameter based at least on parameters of the pre-flush fluid, sand-carrying fluid, and wellbore steel grade. At least two longitudinally connected reservoirs with a thickness of less than 15m are divided into the same longitudinal processing segment, and a single reservoir with a thickness greater than 15m is divided into at least two longitudinal processing segments, with the thickness of each longitudinal processing segment being less than or equal to 15m. Each of the longitudinal processing segments is provided with a first temporary plugging ball, a second temporary plugging ball, and a third temporary plugging ball. The perforation diameter of the longitudinal processing segment is a, the diameter of the first temporary plugging ball is 0.8a, the diameter of the second temporary plugging ball is a, and the diameter of the third temporary plugging ball is 1.2a. The number of the first temporary plugging ball, the second temporary plugging ball, and the third temporary plugging ball are each 1 / 3 of the total number of temporary plugging balls in the longitudinal processing section. The number of temporary plugging balls is three times the number of perforations in the corresponding longitudinal processing section; In a vertical wellbore, adjacent perforations are spaced 60° apart in the circumferential direction, and adjacent perforations are spaced apart in the vertical direction. The perforations on the circumferential sidewall of the vertical wellbore are arranged in a spiral pattern. Step S3: Based on the principle of similarity, set the amount of sand added to each of the longitudinal processing layers during the experiment, and carry out the pumping simulation program in the indoor experimental device to modify the sand addition by pumping fracturing fluid, and complete the interlayer turning simulation experiment.

2. The method according to claim 1, wherein the method is characterized by: The pumping simulation program includes the following steps: sand is added to the longitudinal processing section of the vertical wellbore sequentially from bottom to top for modification.

3. The method according to claim 2, wherein the method is characterized by: The three longitudinal processing sections of the vertical wellbore from bottom to top are the first section, the second section and the third section. When pumping 120% of the designed fracturing fluid into the first section, a temporary plugging ball corresponding to the first section is added. After temporarily plugging the first section, the second section is pumped with 100% of the designed fracturing fluid, and the corresponding temporary plugging ball for the second section is added; After temporarily plugging the second layer, the third layer is pumped with 80% of the designed fracturing fluid, and the corresponding temporary plugging ball is added to complete the modification construction.

4. The method of claim 1, wherein the method is a method of giant thick multi- thin reservoir reconstruction interlayer steering simulation experiment. The pre-fluid is a low-viscosity liquid with a viscosity of <20 mPa·s.

5. The method of claim 1, wherein the method is a giant thick multi- thin reservoir reconstruction interlayer diversion simulation experiment method. The sand-carrying fluid is a non-crosslinked fracturing fluid with a viscosity of 30-60 mPa·s.

6. A simulation device for interlayer diversion of a thick multi-thin reservoir reconstruction layer, used for the simulation method for interlayer diversion of a thick multi-thin reservoir reconstruction layer according to any one of claims 1-5, characterized in that: The system includes a connecting pipe, casing, a mixer, a water pump, a vertical wellbore, and a water tank for storing fracturing fluid. The mixer is installed in the water tank, which is connected to the water pump via the connecting pipe. The water pump is connected to the vertical wellbore, and the casing is fitted around the outer periphery of the vertical wellbore. The peripheral wall of the vertical wellbore has perforations, which communicate with the casing. The casing is connected to the water tank via the connecting pipe.

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