Method and device for realizing staged fracturing of horizontal wells using knot-type temporary plugging agent

Abstract

The embodiment of the present invention provides a method and device for realizing staged fracturing of horizontal wells by using a knot-type temporary plugging agent, which belongs to the field of oil and gas field engineering. The method comprises: obtaining multi-cluster perforation parameters of the target well section; constructing a weighted graph representing the connectivity relationship between the perforations based on the multi-cluster perforation parameters, and dividing all perforations into multiple fracturing clusters by using a spectral clustering algorithm; for each perforation, generating matching knot-type temporary plugging agent structural parameters according to the aperture, hole direction and resistance parameters of the corresponding perforation, and configuring the corresponding knot-type temporary plugging agent; delivering the configured knot-type temporary plugging agent into the wellbore in sequence according to the order of the fracturing clusters to complete the staged fracturing operation. The solution of the present invention improves the accuracy and stability of inter-stage isolation, reduces the risk of energy crossflow, and improves the overall efficiency and adaptability of staged fracturing.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas field engineering, and in particular to a method for realizing staged fracturing of a horizontal well by using a knotted temporary plugging agent and a device for realizing staged fracturing of a horizontal well by using a knotted temporary plugging agent. Background Art

[0002] In the development of unconventional oil and gas reservoirs, multi-cluster perforation staged fracturing technology for horizontal wells has become an important means of increasing productivity. To achieve effective segmentation, conventional practices typically use bridge plugs or soluble particle-based temporary plugging agents to temporarily isolate well sections. Bridge plugs present complex downhole operations, a high risk of setting failure, and the need for drilling and milling flowback. They are particularly difficult to apply in conditions such as wellbore deformation or repeated fracturing. In contrast, while soluble particle-based or fiber-composite temporary plugging agents can be pumped to perform temporary plugging operations, they still have technical shortcomings such as high plugging uncertainty, difficulty in controlling the plugging location, and a low temporary plugging success rate.

[0003] Current particle-based temporary plugging technologies generally adopt a "bulk accumulation" approach, relying on particles to form an interception structure near the perforations. However, the fluid path in the wellbore is complex, the perforation distribution space varies greatly, and the aperture, direction, and flow resistance of different perforations are all different. Temporary plugging agents with a single particle size or structure are difficult to effectively match for each hole, often leading to problems such as off-target plugging, inter-stage energy crossflow, and fracturing failure. In addition, most existing temporary plugging agents lack the "structural adaptability" to match specific perforation characteristics, and cannot achieve automatic identification and customized configuration before staged fracturing, affecting operational efficiency and plugging accuracy. Therefore, there is an urgent need for a temporary plugging solution with precise adaptation capabilities to improve the temporary plugging stability and fracturing isolation quality in the multi-cluster perforation environment of horizontal wells. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a method and apparatus for achieving staged fracturing of horizontal wells using a knotted temporary plugging agent, so as to at least solve the problems of uncontrollable plugging position and poor structural adaptability of the temporary plugging agent in the prior art.

[0005] To achieve the above objectives, the present invention provides, in a first aspect, a method for implementing staged fracturing of a horizontal well using a knot-type temporary plugging agent, the method comprising: obtaining multi-cluster perforation parameters of a target well section; constructing a weighted graph representing the connectivity relationship between perforations based on the multi-cluster perforation parameters, and dividing all perforations into multiple fracturing clusters using a spectral clustering algorithm; for each perforation, generating matching knot-type temporary plugging agent structural parameters based on the aperture, hole orientation, and resistance parameters of the corresponding perforation, and configuring the corresponding knot-type temporary plugging agent; and delivering the configured knot-type temporary plugging agent into the wellbore in sequence according to the order of the fracturing clusters to complete the staged fracturing operation.

[0006] Optionally, the multi-cluster perforation parameters include: any one or more of the spatial position of the perforation, the aperture size, the aperture angle and the estimated flow resistance; the multi-cluster perforation parameters are collected based on a multi-arm acoustic imaging logging tool; the radial image output by the multi-arm acoustic imaging logging tool is parsed into a three-dimensional coordinate system of the perforation space, and combined with the well trajectory information, the perforation azimuth and the wellbore offset angle are obtained; the aperture size is calculated by an imaging inversion fitting method and normalized to a preset size grade; the estimated flow resistance is obtained by calculating the wellbore roughness, the angle between the perforation direction and the wellbore axis, and the local flow velocity disturbance coefficient.

[0007] Optionally, in the process of constructing a weighted graph representing the connectivity relationship between perforations, the method further includes: the weight of each edge of the weighted graph includes the Euclidean distance between perforations, the cosine value of the perforation angle, and the flow possibility factor; the weights of all edges are normalized, and non-main paths are clipped using a threshold value; in the spectral clustering, the k-order eigenvector of the Laplace matrix is used as the embedding space reference, and the number of clusters is set according to the principle of maximum eigenvalue difference.

[0008] Optionally, the structural parameters of the knot-type temporary plugging agent include: any one or more of knot diameter, knot morphology type, effective length of the rope body, number of rope ends and material grade; the structural parameters are generated by a fuzzy logic algorithm, wherein the input variables of the fuzzy logic algorithm are the perforation aperture grade, perforation inclination grade and resistance grade, and the output variable of the fuzzy logic algorithm is a preset structural grade label; each preset structural grade label corresponds to a specific structural configuration, including any one or more of the material type, manufacturing batch number and adaptive dissolution time parameters.

[0009] Optionally, during the configuration of the corresponding knot-type temporary plugging agent, the method further includes: after the knot-type temporary plugging agent is configured on the ground, it is encapsulated in a degradable shell, and the shell is molded using a thermoplastic polymer or a wax-based material; an identifiable identifier is embedded on the surface of each shell, including a radio frequency tag or a QR code, for calibrating its matching perforation number and delivery sequence; after the shell enters the manifold system, it is cracked or dissolved by the action of a shear valve or a diameter-changing device, thereby releasing the knot body to enter the perforation cluster position.

[0010] Optionally, during the process of delivering the configured knot-type temporary plugging agent into the wellbore in sequence according to the order of the fracturing clusters, the method further includes: pausing pumping after each stage of fracturing is completed, and keeping the knot-type temporary plugging agent delivered in the previous stage at pressure maintained and stationary in the wellbore so that it is stably embedded in a position adjacent to the target perforation; before the fracturing operation continues, the effect of the delivery of the temporary plugging agent is determined by the initial fracturing displacement / pressure ratio to determine whether effective plugging is established; if the leakage indicator of the fracturing fluid is detected to exceed a preset threshold, the knot-type temporary plugging agent of the same stage is added and the pressure is maintained again until plugging is established.

[0011] A second aspect of the present invention provides a knot-type temporary plugging agent device for achieving staged fracturing of horizontal wells, the device comprising: an acquisition unit for obtaining multi-cluster perforation parameters of a target well section; a processing unit for constructing a weighted graph representing the connectivity relationship between perforations based on the multi-cluster perforation parameters, and dividing all perforations into multiple fracturing clusters using a spectral clustering algorithm; a configuration unit for generating matching knot-type temporary plugging agent structural parameters for each perforation based on the aperture, hole direction and resistance parameters of the corresponding perforation, and performing corresponding knot-type temporary plugging agent configuration; and an execution unit for delivering the configured knot-type temporary plugging agent into the wellbore in sequence according to the order of the fracturing clusters to complete the staged fracturing operation.

[0012] Optionally, the knot body of the knot-type temporary plugging agent is formed by knotting multiple strands of polymer braided rope, the diameter of the knot body is larger than the perforation aperture it is adapted to, the rope ends of the knot-type temporary plugging agent are at least four single-strand end ropes, and a winding reinforcement section is provided between the rope body of the knot-type temporary plugging agent and the rope ends of the knot-type temporary plugging agent; the knot form of the knot-type temporary plugging agent is a ball knot, a double knot or a multiple interwoven knot, which is generated according to a ratio setting; each knot-type temporary plugging agent is made by an one-piece molding process and is provided with a unique structural coding label.

[0013] Optionally, the knot-type temporary plugging agent is encapsulated in a soluble shell; the thickness of the soluble shell is less than 2 mm; the soluble shell is prepared by wax injection or compression molding, and the material of the soluble shell is polylactic acid, degradable polyester or natural wax-based composite material; the two halves of the soluble shell are molded together by heat sealing, and the inner surface of the shell and the body form a limiting fitting groove structure; an optical or radio frequency identification mark is set on the surface of the soluble shell for identifying the sequence and positioning number in the manifold.

[0014] On the other hand, the present invention provides a computer-readable storage medium having instructions stored thereon, which, when executed on a computer, enables the computer to execute the above-mentioned method for implementing staged fracturing of a horizontal well using a knot-type temporary plugging agent.

[0015] Through the above technical solution, the present invention obtains the parameters of multiple cluster perforations in the target well section, constructs a weighted graph based on the spatial position relationship between the perforations, the perforation angle, and the flow characteristics, and uses a spectral clustering algorithm to automatically segment the perforations, effectively identifying the optimal fracturing cluster division strategy in the well section. Combining the aperture, direction, and resistance characteristics of each perforation, the matching knot-type temporary plugging agent structural parameters are further generated to achieve a customized configuration of one knot per perforation. By sequentially delivering the configured temporary plugging agent in cluster order, it forms a precise plug at the corresponding perforation, thereby improving the accuracy and stability of inter-segment isolation, reducing the risk of energy crossflow, and improving the overall efficiency and adaptability of staged fracturing.

[0016] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present invention, but do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings:

[0018] Figure 1 This is a flowchart of the steps of a method for implementing staged fracturing of a horizontal well using a knot-type temporary plugging agent provided by one embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of a comparison of fracturing curves provided by one embodiment of the present invention;

[0020] Figure 3 The present invention provides a structural diagram of an apparatus for implementing staged fracturing of horizontal wells using a knot-type temporary plugging agent, according to one embodiment of the present invention. DETAILED DESCRIPTION

[0021] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0022] Figure 1 This is a flowchart of the steps of a method for implementing staged fracturing of horizontal wells using a knot-type temporary plugging agent provided by one embodiment of the present invention. Figure 1 As shown, an embodiment of the present invention provides a method for implementing staged fracturing of a horizontal well using a knot-type temporary plugging agent, the method comprising:

[0023] Step S10: obtaining multi-cluster perforation parameters of the target well section.

[0024] Specifically, the multi-cluster perforation parameters include: any one or more of the spatial position of the perforation, aperture size, aperture angle and flow resistance estimation value; the multi-cluster perforation parameters are collected based on a multi-arm acoustic imaging logging tool; the radial image output by the multi-arm acoustic imaging logging tool is parsed into a three-dimensional coordinate system of the perforation space, and combined with the well trajectory information, the perforation azimuth and the wellbore offset angle are obtained; the aperture size is calculated by an imaging inversion fitting method and normalized to a preset size grade; the flow resistance estimation value is obtained by calculating the wellbore roughness, the angle between the perforation direction and the wellbore axis, and the local flow velocity disturbance coefficient.

[0025] In this embodiment of the present invention, to achieve intelligent identification and precise adaptation of multiple clusters of perforations within a well section, it is first necessary to obtain key parameter information for each cluster of perforations and construct a comprehensive, quantifiable perforation database. These cluster perforation parameters include, but are not limited to, any one or more of the perforation's spatial location, aperture size, perforation angle, and estimated flow resistance. These parameters are collected by a multi-arm acoustic imaging logging tool deployed within the wellbore. The radial acoustic imaging data acquired during the logging process reflects the wellbore wall integrity and the structural morphology of each perforation.

[0026] The image data output by the logging tool is a radial grayscale image of the wellbore inner wall expanded 360°. The perforation boundary contours are extracted through image recognition and edge enhancement algorithms. The coordinate information of each perforation in three-dimensional space is reconstructed based on the tool's depth calibration and wellbore trajectory data, thus constructing a complete perforation spatial position model. In this model, the geometric center of the perforation is represented by the three-dimensional coordinates , its direction is from the hole to the angle and the angle with the wellbore axis describe.

[0027] Furthermore, for each perforation aperture size, an imaging inversion fitting method is used to estimate its equivalent diameter, and the measured actual aperture data is normalized and divided into multiple discrete levels, for example, by the following formula:

[0028]

[0029] in, is the measured aperture of the current perforation, The estimated flow resistance of the perforation is calculated based on a combination of multiple factors, including the roughness of the wellbore wall, the angle between the perforation azimuth and the main axis of the wellbore, and the expected degree of disturbance of the fracturing fluid in the local area. It can be expressed as:

[0030]

[0031] in, is the roughness factor near the perforation, is the perforation inclination angle, represents the local disturbance velocity change, is the empirical weight coefficient. Through the above approach, a high-dimensional, structured multi-cluster perforation characteristic parameter library can be established, providing a data foundation for subsequent map construction, intelligent cluster segmentation, and structural matching of knot-type temporary plugging agents, ensuring the target accuracy and adaptability of subsequent plugging operations.

[0032] Step S20: Based on the multi-cluster perforation parameters, a weighted graph representing the connectivity relationship between perforations is constructed, and a spectral clustering algorithm is used to divide all perforations into multiple fracturing clusters.

[0033] Specifically, in the process of constructing a weighted graph representing the connectivity relationship between perforations, the method further includes: the weight of each edge of the weighted graph includes the Euclidean distance between perforations, the cosine value of the perforation angle, and the flow possibility factor; the weights of all edges are normalized, and non-main paths are clipped using a threshold value; in the spectral clustering, the k-order eigenvector of the Laplacian matrix is used as the embedding space benchmark, and the number of clusters is determined according to the principle of maximum eigenvalue difference.

[0034] In the embodiment of the present invention, based on the obtained multi-cluster perforation parameters, in order to realize intelligent staged fracturing, it is necessary to build a connectivity model that can reflect the geometric relationship between the holes and the flow interference characteristics. To this end, a structural modeling method based on graph theory is proposed. By constructing a weighted undirected graph , where the node set V represents all perforation points, the edge set E represents the connectivity between two points, and the weight matrix W reflects the physical association strength of each edge. Specifically, the edge weight between each two perforations is It is determined by the following three parameters:

[0035] 1) Euclidean distance between perforations , representing geometric proximity.

[0036] 2) Cosine similarity of hole angle , representing directional consistency.

[0037] 3) Liquidity possibility factor , which is used to evaluate the possible degree of interconnection between two pores in the fracturing fluid flow field.

[0038] The weights are defined as follows:

[0039]

[0040] in, is the distance attenuation factor, ensuring that the influence of distant nodes on the results is weakened. This composite weight reflects the comprehensive degree of geometric proximity, directional consistency and flow coupling between perforations.

[0041] Furthermore, after forming a complete weighted graph, in order to improve the clustering quality, all edge weights are normalized and a lower threshold is set to trim edges below the threshold to prevent weakly connected paths from interfering with the clustering structure. The threshold can be set adaptively based on the edge weight distribution, such as setting it to a certain percentile of the mean of all edge weights. After the graph is constructed, the spectral clustering algorithm is used to perform fracturing cluster division on the nodes in the graph. The specific method is: construct a symmetric normalized Laplace matrix of the graph , extracting the eigenvectors corresponding to the first k smallest eigenvalues to form a characteristic subspace and perform k-means clustering. The number of clusters k is determined based on the difference between the eigenvalues of the Laplace matrix (eigengap), and the k value corresponding to the point with the largest difference is taken as the optimal number of clusters.

[0042] Based on the solution of the present invention, automatic identification of the optimal fracturing cluster is achieved, the accuracy of isolation between fracturing stages is improved, and the risk of energy crossflow is reduced. It is particularly suitable for horizontal well conditions with uneven perforation distribution, scattered directions or complex wellbore trajectories.

[0043] Step S30: for each perforation, generating matching knot-type temporary plugging agent structural parameters according to the aperture, hole direction and resistance parameters of the corresponding perforation, and configuring the corresponding knot-type temporary plugging agent.

[0044] Specifically, the structural parameters of the knot-type temporary plugging agent include: any one or more of knot diameter, knot morphology type, effective rope length, number of rope ends and material grade; the structural parameters are generated by a fuzzy logic algorithm, wherein the input variables of the fuzzy logic algorithm are the perforation aperture grade, perforation inclination grade and resistance grade, and the output variable of the fuzzy logic algorithm is a preset structural grade label; each preset structural grade label corresponds to a specific structural configuration, including any one or more of the material type, manufacturing batch number and adaptive dissolution time parameters.

[0045] In this embodiment of the present invention, after achieving automatic segmentation of multiple clusters of perforations, to ensure effective plugging of each perforation, it is necessary to further generate corresponding knot-type temporary plugging agent structural parameters based on the structural characteristics and fluid properties of each perforation, thereby achieving "perforation-level matched plugging." In this implementation, a structural adaptation method based on a fuzzy logic algorithm is employed to generate a corresponding temporary plugging agent structural configuration model based on the characteristic parameters of each perforation. This model serves as the basis for subsequent customization and formulation of the temporary plugging agent on the surface.

[0046] The input parameters for each perforation include, but are not limited to, three dimensions of normalized features: size level, angle level, and resistance level. These features are derived from the output of the previous stage of data normalization. To represent the fuzzy input vector, it can be expressed as:

[0047]

[0048] in, is the aperture grade of the i-th perforation, is the inclination grade, is the resistance level, and all three are mapped to the closed interval [0,1]. The above input vectors are fed into fuzzy logic reasoning, and fuzzy mapping is performed using a set of preset three-dimensional fuzzy rule bases. The rule base is constructed based on the experience of domain experts and historical blocking case data, for example:

[0049] 1) If S is large, A is steep, and R is high, the output structure level is L3 (large structure + reinforced rope + slow-release material).

[0050] 2) If S is small, A is flat, and R is medium, the output structure level is L1 (compact structure + short rope end).

[0051] Output a structure grade tag (Structure Grade Tag), such as L1, L2, L3, etc., which is used to call the corresponding structure configuration template. Each tag is mapped to a set of structural parameter combinations, including but not limited to:

[0052] 1) Diameter of the body (such as 10mm, 15mm, 20mm, etc.).

[0053] 2) Knot type (single ball knot, double knot, multiple knot).

[0054] 3) Effective length of the rope (such as 50mm, 70mm, 90mm).

[0055] 4) Number of rope ends (4, 6, or 8).

[0056] 5) Material grade (such as fast-dissolving / medium-dissolving / slow-dissolving PGA / PLA composite yarn).

[0057] 6) With additional information such as manufacturing batch number, material ratio code, matching bottom hole temperature range, etc.

[0058] This hierarchical structure configuration can be standardized and stored in a preset structural parameter database. The fuzzy output results will directly index this database to generate manufacturing orders or deployment instructions for ground delivery. This structural matching method based on multi-parameter fuzzy mapping significantly improves the adaptability and plugging stability of temporary plugging agents under complex perforation conditions. In particular, under conditions with inconsistent perforation distribution directions, large aperture variations, and strong wellbore disturbances, it can avoid problems such as "universal plugging agent structure plugging failure" or "plugging off-target," ensuring that each delivered knot-type temporary plugging agent fully fits the target hole.

[0059] In one possible implementation, knots of different sizes (e.g., 18-22 mm and 14-16 mm) exhibit distinct characteristics in terms of plugging effectiveness. Knot size significantly impacts perforation adaptability, pressure response, and fluid resistance. Therefore, selecting the appropriate knot size is crucial for fracturing effectiveness.

[0060] 1) 18-22mm knots: Suitable for sealing larger holes. These knots offer high sealing capabilities and can effectively seal larger pores during pressure testing. Under high pressure, these knots offer a stable sealing effect and can maintain a tight seal for extended periods, making them suitable for sealing interlayer segments and in the later stages of fracturing.

[0061] 2) 14-16mm knot: Suitable for sealing smaller holes. Although its sealing ability is slightly inferior to that of the 18-22mm knot, it still demonstrates good sealing results when dealing with smaller holes or areas with lower pressure requirements. The 14-16mm knot provides excellent sealing stability, especially when addressing smaller cracks or pores.

[0062] like Figure 2 When using knotted temporary plugging agents for plugging, knot size significantly affects the pressure response. For example, the total amount of sand added in Section 6 was 80.6 tons, and in Section 9, 120.3 tons. As the total amount of sand added increased, the knot's plugging ability decreased. When 18-22 mm knots were deployed, the initial pressure rise was larger (e.g., 16 MPa), while 14-16 mm knots typically exhibited a lower initial pressure rise. During use, larger knots quickly and effectively sealed the perforations, generating a significant pressure response. This characteristic has been verified in multiple well sections. In areas with high porosity, smaller knots (e.g., 14-16 mm) help improve plugging efficiency, as they fill more pores and enhance sealing. In areas with lower porosity or larger perforations, larger knots (e.g., 18-22 mm) better meet plugging requirements and avoid incomplete plugging caused by undersized knots.

[0063] In another possible implementation, in this example, to achieve structural adaptation between the knotted temporary plugging agent and each perforation, a fuzzy logic algorithm is not used. Instead, a rapid matching method based on a "structural grade template + static matching index" is introduced. Specifically, the perforations within the well section are first divided into several typical operating condition combinations based on preset aperture ranges, inclination angle intervals, and resistance classification rules. Each combination is assigned a corresponding structural template number, such as Type A, B, or C.

[0064] During the construction preparation phase, based on wellbore logging data and perforation parameter collection, each perforation's parameters are compared against a structure template table, allowing each perforation to be quickly assigned to the corresponding structure type based on its range. For example, a perforation with a small aperture, medium inclination, and high resistance is assigned to "Structure Type C," while a perforation with a large aperture, low inclination, and low resistance is assigned to "Structure Type A." Each structure type corresponds to a set of standardized manufacturing parameters, including body shape, dimensions, rope length, and rope end configuration.

[0065] During the factory manufacturing process, all structural types of knotted temporary plugging agents are prefabricated and coded according to the template number. The ground batching calls the corresponding type of knotted agent from the temporary plugging agent storage unit according to the matching results of the perforation and the structural template. The delivery sequence corresponds one-to-one with the perforation sequence to ensure that each temporary plugging agent structure is compatible with its target perforation parameters. This method eliminates the need for online calculation and dynamic reasoning processes and is suitable for well section fracturing projects with relatively concentrated perforation types. It has the advantages of fast structural configuration response speed and convenient on-site batch operation. Through the fast index mapping relationship between the structural template and the perforation template, the "stereotyped matching" plugging strategy under simplified conditions is realized, which can also ensure the temporary plugging accuracy and inter-section isolation effect.

[0066] Specifically, in one possible implementation, the 10 sections of the casing are pressurized together. Sections 1-10 are designed to be perforated using continuous tubing, with 12 clusters per section, a density of 3 holes per cluster, and a total of 36 holes. Section 10 has 5 clusters per section, a density of 8 holes per cluster, and a total of 40 holes. Section 1 actually has 12 clusters perforated, totaling 36 holes, and sections 2-4 have 14 clusters perforated, totaling 42 holes. A total of 162 holes are perforated in the first four sections. For each section, the amount of temporary plugging agent applied needs to be adjusted based on the geological characteristics, hole size, and number of holes. For example:

[0067] Sections 1 to 4: Because the perforations in these sections are uniform and small in diameter, 165 18-22mm knotted temporary plugging agents were used. Each section was injected twice to ensure that every perforation was effectively plugged.

[0068] Sections 5 to 10: These sections have larger holes or some deformation, so the amount of temporary plugging agent used is gradually increased. The specific amount is adjusted based on actual construction conditions. For example, Section 5 uses 80 18-22mm knots, and Section 6 uses 94 18-22mm knots. The amount of temporary plugging agent is increased in real time based on any difficulties in adding sand or pressure changes during construction.

[0069] At the beginning of each construction phase, smaller knots (14-16mm) are selected for placement to seal smaller holes first and improve initial sealing. Subsequently, 18-22mm knots are used to supplement the holes to ensure complete and effective sealing.

[0070] When pressure fluctuations or sand addition are encountered, increase the amount of temporary plugging agent added. Especially for areas with larger apertures or developed cracks, increase the number of 18-22mm knots to improve plugging stability.

[0071] Specifically, during the implementation process, the placement of knot temporary plugging agents is carried out through a dedicated filling device to ensure that the temporary plugging agent in each section can be accurately placed at the target location. After each placement, pressure monitoring and microseismic monitoring are required to confirm the placement of the knot temporary plugging agent. The amount of temporary plugging agent and the particle size distribution of the subsequent sections are adjusted according to the real-time monitoring data to ensure effective sealing between the sections. During the placement process of each stage, the pumping program needs to be precisely controlled. Before construction, the appropriate liquid pumping displacement (such as 16m³ / min) is set to ensure that the knot temporary plugging agent is smoothly placed at the bottom of the well. Especially in the subsequent stages, the pumping flow and pressure are controlled to avoid excessive pressure fluctuations or uneven distribution of the temporary plugging agent. In order to ensure the plugging effect, batch placement is usually adopted, for example, each section is divided into 2 to 4 additions to avoid construction difficulties and pressure risks caused by excessive placement at one time.

[0072] Step S40: The configured knot-type temporary plugging agent is sequentially delivered into the wellbore in the order of the fracturing clusters to complete the staged fracturing operation.

[0073] Specifically, during the process of delivering the configured knot-type temporary plugging agent into the wellbore in sequence according to the order of the fracturing clusters, the method further includes: pausing pumping after each stage of fracturing is completed, and maintaining the pressure and keeping the knot-type temporary plugging agent delivered in the previous stage in the wellbore so that it is stably embedded in a position adjacent to the target perforation; before the fracturing operation continues, the effect of the delivery of the temporary plugging agent is determined by judging whether effective plugging is established through the initial fracturing displacement / pressure ratio; if the leakage indicator of the fracturing fluid is detected to exceed a preset threshold, the knot-type temporary plugging agent of the same stage is added and the pressure is maintained again until plugging is established.

[0074] In this embodiment of the present invention, after configuring the knotted temporary plugging agent structure, to achieve efficient and reliable staged fracturing, the configured knotted temporary plugging agent is delivered into the wellbore stage by stage according to the pre-defined fracturing cluster sequence. This is closely coordinated with the actual fracturing process to ensure that the target perforation clusters are effectively plugged before each stage of fracturing. This embodiment utilizes intermittent delivery and a real-time plugging verification mechanism to achieve both precision and safety in temporary plugging operations.

[0075] Specifically, after completing the injection operation for the current fracturing stage, the fracturing pump is suspended on-site. While maintaining stable wellbore pressure, the knotted temporary plugging agent corresponding to the next fracturing cluster is injected into the high-pressure manifold via surface delivery and then pushed into the wellbore using displacement fluid. To prevent drift or accumulation of the temporary plugging agent within the pipe, the amount of temporary plugging agent delivered each time is determined based on the number of perforations, using a "one knot per perforation" or "fixed cluster matching" method.

[0076] When the knotted temporary plugging agent descends near the target section, pumping is paused and pressure is maintained in the wellbore for a period of time (e.g., 3-5 minutes). This allows the knotted structure to deploy in the fluid environment, wedge into the perforation channel, and attach to the periphery of the hole to effectively seal the hole. This resting period is particularly important for the knotted structure, helping it to fully conform to the complex borehole wall in a non-rigid state and improve plugging stability. Before proceeding to the next fracturing operation, the initial fracturing flow rate and pressure change rate are monitored in real time to determine whether the current section has been successfully sealed. If the initial pressure rise is slow, the flow rate increases abnormally, or there is a rapid pressure drop during injection, it can be considered that the temporary plugging effect is poor, possibly indicating incomplete plugging or dislocation of the knot. In this case, injection is immediately suspended and additional knotted temporary plugging agent of the same type is injected. The "injection-maintaining-observation" process is repeated until the wellhead pressure response meets the preset criteria (e.g., the initial fracturing pressure is at least 10% higher than the stable pressure of the previous section, or the flow rate fluctuation is within the tolerance range).

[0077] The present invention's solution enhances the robustness of plugging operations through a combination of injection, static placement, feedback analysis, and dynamic adjustment, ensuring controlled, highly isolated operating conditions before each fracturing operation. This approach is particularly suitable for environments with complex perforation structures, widely varying temporary plugging agent configurations, or significant well section differences.

[0078] In one possible implementation, sand addition difficulties during fracturing operations typically manifest as abnormally high pressure or excessive filtration loss, resulting in an inability to effectively carry sand particles or excessive pumping pressure. During the sand addition process, as pressure gradually increases, some sections of the wellbore experience abnormal pressure increases. This can be particularly dramatic when the filtration layer is uneven or crack propagation is hindered. Excessive filtration loss or poor cracking complicates sand movement and distribution, leading to uneven sand concentration and impacting effective fracture support and propagation.

[0079] During the repeated "delivery-maintain pressure-observation" process, the present invention utilizes a temporary plugging agent to seal restricted cracks or perforations during sand addition, preventing sand loss or blockage. The temporary plugging agent effectively isolates the already fractured area and reduces pressure fluctuations during sand addition. In sections where sand addition is difficult, an 18-22mm temporary plugging agent is used to ensure proper closure of cracks in high-pressure areas, thereby reducing pressure fluctuations in subsequent fracturing stages. By applying the temporary plugging agent in batches (e.g., two to four times per section), pressure is stabilized after each application, preventing sudden pressure fluctuations from impacting the operation.

[0080] Based on real-time pressure monitoring data, pumping flow and pressure are adjusted to avoid equipment failure or crack rupture caused by excessive pumping pressure. In these situations, the pumping flow is reduced (for example, from 4.0 m³ / min to 2.0 m³ / min) to maintain a stable construction schedule. In sections where sand addition is difficult and pressure fluctuations are large, a cross-linking fluid is used to expand cracks and increase their receptivity, thereby reducing the rate and frequency of pressure increases. During the sand addition process, low-concentration silt sand slugs are used to avoid the sudden pressure increases caused by high-concentration sand plugs. Low-concentration silt sand slugs effectively distribute the sand, ensuring even delivery and avoiding pressure spikes.

[0081] Furthermore, real-time pressure monitoring is crucial during the sand injection process. By using microseismic and pressure monitoring equipment, the construction team can obtain real-time pressure status within the construction section and adjust strategies promptly. For example, during the sand injection process in sections 5 and 6, if a sharp increase in pressure or difficulty in sand injection is detected, the team can immediately reduce the pumping pressure, adjust the amount of temporary plugging agent, or modify the liquid ratio.

[0082] Figure 3 This is a structural diagram of a device for implementing staged fracturing of horizontal wells using a knot-type temporary plugging agent, provided by one embodiment of the present invention. Figure 3 As shown, an embodiment of the present invention provides a device for realizing staged fracturing of horizontal wells by using a knot-type temporary plugging agent, the device comprising: an acquisition unit for acquiring multi-cluster perforation parameters of a target well section; a processing unit for constructing a weighted graph representing the connectivity relationship between perforations based on the multi-cluster perforation parameters, and dividing all perforations into multiple fracturing clusters by using a spectral clustering algorithm; a configuration unit for generating matching knot-type temporary plugging agent structural parameters for each perforation according to the aperture, hole direction and resistance parameters of the corresponding perforation, and performing corresponding knot-type temporary plugging agent configuration; and an execution unit for delivering the configured knot-type temporary plugging agent into the wellbore in sequence according to the order of the fracturing clusters to complete the staged fracturing operation.

[0083] Preferably, the knot body of the knot-type temporary plugging agent is formed by knotting multiple strands of polymer braided rope, the diameter of the knot body is larger than the perforation aperture to which it is adapted, the rope ends of the knot-type temporary plugging agent are at least four single-strand end ropes, and a winding reinforcement section is provided between the rope body of the knot-type temporary plugging agent and the rope ends of the knot-type temporary plugging agent; the knot body form of the knot-type temporary plugging agent is a ball knot, a double knot or a multiple interwoven knot, which is generated according to the ratio setting; each knot-type temporary plugging agent is made by an one-piece molding process and is provided with a unique structural coding label.

[0084] In the embodiments of the present invention, the knotted temporary plugging agent's structural design fully considers the physical properties of downhole perforation channels and the fluid forces acting during the fracturing process. Using multiple strands of polymer braided rope as raw material, a specific knotting method is used to create a stable knot. The knot is the core plugging element of the temporary plugging agent, and its diameter is designed to be larger than the corresponding perforation diameter. This creates a wedging effect after pumping to the perforation location, ensuring the stability and impact resistance of the plugging position.

[0085] The knot is preferably formed from multiple strands of rope through a mechanized knotting process, offering a good balance of flexibility and rigidity. Depending on the perforation type, it can be formed using a ball knot, a double knot, or a multi-braided knot. The ball knot is compact and suitable for small-diameter perforations; the double knot has an additional external reinforcement ring for improved plugging stability; and the multi-braided knot is suitable for high-angle or irregular perforations, offering enhanced deformation and conformability.

[0086] The rope body of the knotted temporary plugging agent is the intermediate section connecting the knot body and the terminal strands, and its length is adjustable according to preset parameters. At least four single-stranded ropes are attached to the end of the rope body as the rope ends. These rope ends spread radially in the fluid environment, covering the perimeter of the perforation, helping to increase contact area, fill gaps, and further limit the movement of the knot body within the perforation. To enhance structural stability, a winding reinforcement section is provided between the rope body and the rope ends. This section is treated with a dense braiding or localized bonding process to improve local tensile and torsional resistance, preventing structural separation or fracture under complex stress conditions downhole.

[0087] Each knotted temporary plugging agent is manufactured using an integrated molding process, eliminating the structural weaknesses associated with segmented splicing and ensuring the continuity and stability of overall strength. To facilitate surface identification and downhole tracking, each temporary plugging agent is given a unique structural coding tag during the manufacturing process. This tag can be attached to the surface of the rope or inside the shell using an RFID electronic chip, QR code printing, or hot pressing. It identifies its type, structural parameters, applicable segment number, and dissolution time number.

[0088] Preferably, the knot-type temporary plugging agent is encapsulated in a soluble shell; the thickness of the soluble shell is less than 2 mm; the soluble shell is prepared by wax injection or compression molding, and the material of the soluble shell is polylactic acid, degradable polyester or natural wax-based composite material; the two halves of the soluble shell are molded together by heat sealing, and the inner surface of the shell and the body form a limited fitting groove structure; an optical or radio frequency identification mark is set on the surface of the soluble shell for identifying the sequence and positioning number in the manifold.

[0089] In an embodiment of the present invention, to improve the pumping stability and directional release accuracy of the knotted temporary plugging agent in a high-pressure fluid system, the knotted temporary plugging agent is encapsulated in a soluble shell. This shell provides physical protection for the knot, maintaining its compact shape and stable posture during transportation, storage, and pumping, and preventing entanglement, overlap, or deformation of multiple temporary plugging agents. Furthermore, the soluble shell provides a controlled release mechanism, rapidly dissolving or rupturing upon entering the wellbore, enabling immediate release and precise deployment of the knotted structure.

[0090] The soluble shell is preferably less than 2mm thick, minimizing its impact on the outer diameter while ensuring structural strength, facilitating smooth passage through manifold elbows and reducers. The shell can be manufactured using either wax injection molding or compression molding. Wax injection molding is suitable for applications requiring high precision and batch consistency, while compression molding is more suitable for rapid production of shaped materials such as polyester shells.

[0091] Polylactic acid (PLA), biodegradable polyester, or natural wax-based composites are preferred for their shell materials, offering excellent processability, controlled solubility at bottomhole temperatures, and environmentally friendly properties, including zero contamination of fracturing fluids and the absence of toxic byproducts. The two halves of the shell are joined together using a heat-sealed mold process, ensuring reliable sealing and overall strength after molding, while also facilitating natural separation when dissolved in shearing devices or wellbore fluids.

[0092] To improve the recognition efficiency and delivery sequence control accuracy of knotted temporary plugging agents in the surface delivery system, the outer surface of the soluble shell is equipped with an optical or radio frequency identification tag. The optical tag can be implemented using a QR code, bar code inkjet printing, or laser etching, and is suitable for automatic loading modules that are read by a vision system. The radio frequency tag uses a miniature RFID tag embedded in the shell material. After packaging, it can be identified by a wireless scanning device to read the matching perforation number, structure type, and fracturing cluster sequence number of the temporary plugging agent. This identification mechanism can be linked with the manifold control system to ensure that each temporary plugging agent is delivered in a predetermined sequence.

[0093] An embodiment of the present invention further provides a computer-readable storage medium having instructions stored thereon, which, when executed on a computer, enables the computer to execute the above-mentioned method for implementing staged fracturing of a horizontal well using a knot-type temporary plugging agent.

[0094] Those skilled in the art will appreciate that all or part of the steps in the methods described in the aforementioned embodiments can be performed by instructing the relevant hardware through a program. The program, stored in a storage medium, includes instructions for causing a microcontroller, chip, or processor to execute all or part of the steps in the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0095] The above describes in detail the optional embodiments of the present invention in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, a variety of simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the scope of protection of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner unless there is any contradiction. In order to avoid unnecessary repetition, the embodiments of the present invention will no longer describe the various possible combinations separately.

[0096] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A method for realizing staged fracturing of horizontal wells using a knot-type temporary plugging agent, characterized in that: The method comprises: Obtain multi-cluster perforation parameters of the target well section; among them, The multi-cluster perforation parameters include: Any one or more of the spatial position of the perforation, the aperture size, the perforation angle, and the estimated value of the flow resistance; The multi-cluster perforation parameters are acquired based on a multi-arm acoustic imaging logging tool; The radial image output by the multi-arm acoustic imaging logging tool is parsed into a three-dimensional coordinate system of the perforation space, and combined with the well trajectory information, the perforation azimuth and the wellbore offset angle are obtained; The aperture size is calculated by an imaging inversion fitting method and normalized to a preset size level; The estimated value of flow resistance is obtained by calculating the roughness of the wellbore wall, the angle between the perforation direction and the wellbore axis, and the local flow velocity disturbance coefficient; Based on the multi-cluster perforation parameters, a weighted graph representing the connectivity relationship between perforations is constructed, and a spectral clustering algorithm is used to divide all perforations into multiple fracturing clusters; wherein, In the process of constructing a weighted graph representing connectivity relationships between perforations, the method further includes: The weight of each side of the weighted graph includes the Euclidean distance between perforations, the cosine value of the perforation angle, and the flow possibility factor; Normalize the weights of all edges and use a threshold to prune non-main paths; In the spectral clustering algorithm, the k-order eigenvector of the Laplacian matrix is used as the embedding space benchmark, and the number of clusters is set by the maximum eigenvalue difference principle; For each perforation, the matching knot-type temporary plugging agent structural parameters are generated according to the corresponding perforation aperture, hole direction and resistance parameters, and the corresponding knot-type temporary plugging agent is configured; The configured knot-type temporary plugging agent is delivered into the wellbore in the order of the fracturing clusters to complete the staged fracturing operation.

2. The method according to claim 1, characterized in that The structural parameters of knot-type temporary plugging agent include: Any one or more of knot diameter, knot shape type, effective rope length, number of rope ends and material grade; The structural parameters are generated by a fuzzy logic algorithm, wherein the input variables of the fuzzy logic algorithm are the perforation aperture level, the perforation inclination level and the resistance level, and the output variable of the fuzzy logic algorithm is a preset structural level label; Each preset structural level label corresponds to a specific structural configuration, including any one or more of material type, manufacturing batch number, and adaptive dissolution time parameters.

3. The method according to claim 1, characterized in that During the configuration of the corresponding knot-type temporary plugging agent, the method further includes: After being deployed on the ground, the knot-type temporary plugging agent is encapsulated in a degradable shell, which is molded using a thermoplastic polymer or wax-based material; Each shell is embedded with an identifiable mark, including a radio frequency tag or a QR code, to identify the matching perforation number and delivery sequence; After entering the manifold system, the shell is cracked or dissolved by the shear valve or the reducer, thereby releasing the knot body to enter the perforation cluster position.

4. The method according to claim 1, wherein During the process of delivering the configured knot-type temporary plugging agent into the wellbore in sequence according to the order of the fracturing clusters, the method further comprises: After each stage of fracturing is completed, pumping is stopped and the knot-type temporary plugging agent delivered in the previous stage is kept at pressure in the wellbore to ensure that it is stably embedded near the target perforation. Before the fracturing operation continues, the effect of the temporary plugging agent is determined by the initial fracturing displacement / pressure ratio to determine whether the plugging is effectively established; If the leakage indication of the fracturing fluid is detected to exceed the preset threshold, the same section of knot-type temporary plugging agent is added and the pressure is maintained again until the plugging is established.

5. A device for realizing staged fracturing of horizontal wells using a knot-type temporary plugging agent, characterized in that: The device is applied to the method for realizing staged fracturing of horizontal wells using a knot-type temporary plugging agent as described in any one of claims 1 to 4, and the device comprises: Acquisition unit, used to obtain multi-cluster perforation parameters of target well section; a processing unit configured to construct a weighted graph representing connectivity relationships between perforations based on the multi-cluster perforation parameters, and to divide all perforations into a plurality of fracturing clusters using a spectral clustering algorithm; The configuration unit is used to generate matching knot-type temporary plugging agent structural parameters for each perforation according to the aperture, hole direction and resistance parameters of the corresponding perforation, and to configure the corresponding knot-type temporary plugging agent; The execution unit is used to deliver the configured knot-type temporary plugging agent into the wellbore in the order of the fracturing clusters to complete the staged fracturing operation.

6. The device according to claim 5, characterized in that The knotted temporary plugging agent is formed by knotting multiple strands of polymer braided rope. The diameter of the knotted temporary plugging agent is larger than the perforation aperture to which it is adapted. The rope ends of the knotted temporary plugging agent are at least four single-strand end ropes. A winding reinforcement section is provided between the rope body of the knotted temporary plugging agent and the rope ends of the knotted temporary plugging agent. The knot-type temporary plugging agent has a ball knot, a double knot or a multiple interwoven knot, which is generated according to the ratio setting; Each knot-type temporary plugging agent is made through an one-piece molding process and is provided with a unique structural coding label.

7. The device according to claim 6, characterized in that The knot-type temporary plugging agent is encapsulated in a soluble shell; The thickness of the soluble shell is less than 2 mm; The soluble shell is prepared by wax injection or compression molding process, and the material of the soluble shell is polylactic acid, degradable polyester or natural wax-based composite material; The two halves of the soluble shell are molded together by heat sealing, and the inner surface of the shell and the body form a limited fitting groove structure; The surface of the soluble shell is provided with an optical or radio frequency identification mark for identifying the sequence and positioning number in the manifold.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores instructions, which, when executed on a computer, enable the computer to execute the method for realizing staged fracturing of a horizontal well by using a knot-type temporary plugging agent as claimed in any one of claims 1 to 4.

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