Method, system and equipment for analyzing tripping-in capacity of well completion pipe string

Abstract

The invention discloses a well completion pipe string tripping-in capacity analysis method, system and equipment, and belongs to the technical field of oil and gas engineering.The method includes the steps that a friction torque mechanical theoretical model is adopted, and a full-shaft equivalent friction coefficient is obtained through fitting of measured data in the simulated drifting stage; according to the equivalent friction coefficient obtained through fitting, the deformation state of the open hole segmented well completion pipe string is calculated and analyzed, and therefore it is ensured that the well completion pipe string can be safely tripped in; meanwhile, different encountering resistances are arranged in a distributed mode, the deformation state of the pipe column in the tripping-in process of the well completion pipe column is calculated and analyzed, the critical encountering resistance is determined according to the deformation state of the pipe column, a more objective and reliable encountering resistance value is provided for control over the tripping-in process of the pipe column, the tripping-in safety of the pipe column is improved, and meanwhile the construction efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas engineering, and in particular relates to a method, system and equipment for analyzing the running capability of a completion string. Background Art

[0002] As oil and gas exploration and development continue to develop towards deep and ultra-deep oil and gas reservoirs, high-angle well and horizontal well drilling and completion technologies are increasingly widely used. The wellbore trajectory of a horizontal well usually consists of a vertical section, an inclined section (increase or decrease section), and a stable section (including a horizontal section). During the completion operation, in the vertical section, the pipe string can be smoothly lowered under its own gravity. However, when it reaches the curved section, due to the irregular wellbore trajectory, the contact area between the pipe string and the well wall continues to increase, and the friction resistance received by the pipe string continues to increase. The pipe string is blocked during the lowering process and cannot be smoothly lowered to the bottom of the well. At the same time, in the curved section, as the wellbore bends, the pipe string is subjected to bending stress. Bending stress increases as the radius of curvature of the wellbore decreases. When it exceeds the allowable stress of the pipe, it will cause the pipe string to break. After the pipe string enters the horizontal section, the wellbore inclination angle is approximately 90°, so the pipe string will be completely attached to the well wall, and the friction resistance between the formation and the pipe string will be further increased, which may cause the pipe string to be subjected to greater friction resistance. Especially for horizontal wells with long horizontal sections, when the tubing cannot enter the well smoothly, a certain axial load needs to be applied at the wellhead. Under the action of excessive axial load, the completion tubing is prone to buckling and deformation. When the buckling and deformation of the completion tubing reaches a certain degree, friction "locking" occurs between the tubing and the casing (or formation). At this time, the axial force cannot be transmitted downward, and the completion tubing cannot be lowered to the bottom of the well.

[0003] At present, ultra-deep and highly deviated wells / horizontal wells mostly use open hole segmented completion to improve the testing effect. The segmented completion string carries multiple downhole tools such as packers and sliding sleeves, and the string structure is complex. When the string is lowered on site, a simulated string is usually used to clear the well, smooth the wellbore, create good wellbore conditions, and ensure that the completion string of multiple packers can pass smoothly. When simulating the well, it is usually required that the resistance in the casing section does not exceed 30kN and the open hole section does not exceed 50kN. Then the completion string is lowered, and the resistance encountered during the lowering process does not exceed 50kN. However, the existing technology has the following problems:

[0004] (1) Whether the completion string can be lowered is directly determined on site based on whether the simulated well-drilling is successful. This lacks quantitative means and does not clearly define the specific stress conditions during the lowering of the completion string.

[0005] (2) The resistance encountered when simulating the wellbore and the completion string is an empirical value, which lacks a theoretical basis and cannot describe the deformation of the string when the resistance is encountered.

[0006] In addition, a lot of research has been conducted at home and abroad on the problem of string running, and some theoretical models and analysis methods have been formed. For example, application number 201310662837.8 (a method for simulating string stiffness to run a well) proposes a method for running a well using different combinations of string running wells for different sections of highly deviated wells and horizontal wells. 2015207204411.9 (composite simulation well running gauge) discloses a well running tool composed of a conventional well running gauge and a milling column. The above methods all directly propose a combination of string running wells, and do not consider the actual measurement of friction torque of well running in different sections, and cannot obtain the actual friction coefficient of the wellbore to analyze the actual string running ability. CN202010537089.0 (a method for evaluating the running ability of string running in complex formations based on virtual contact points) proposes a method for solving the contact point position and contact force between the string and the well wall based on virtual contact point modeling, and for the working conditions of sliding drilling and rotary drilling, uses the friction coefficient of logging data to analyze the string running ability. This method is to analyze the feasibility of running high-rigidity through-hole drill strings and thick-walled casings in the process of directional well drilling. It is not suitable for the passability analysis of multiple packer strings in ultra-deep and highly deviated wells and horizontal wells. CN201310513452.5 (A multi-layer injection string passability analysis method) discloses a multi-layer injection string string passability analysis method. However, this method is mainly aimed at the layered injection string in the multi-layer water injection operation in the exploitation of oil and gas reservoirs, and is not suitable for ultra-deep and highly deviated wells and horizontal wells. Summary of the invention

[0007] In order to solve the problem that the existing technology cannot accurately and effectively realize the analysis of the running-in capability of the segmented completion string in ultra-deep and highly deviated wells / horizontal wells, the present invention provides a method, system and equipment for analyzing the running-in capability of the completion string. The present invention uses a friction torque mechanics model to simulate the actual measured data of the well as the input parameters, and fits the equivalent friction coefficient of different sections of the whole wellbore. Then, the feasibility of running-in is analyzed for the actual completion string structure, and the deformation state of the string under critical resistance and resistance is obtained, thereby providing more accurate and reliable technical support for the running-in process of the completion string.

[0008] The present invention is achieved through the following technical solutions:

[0009] A method for analyzing the running capability of a completion string, the method comprising:

[0010] Collect the measured data of the simulated well-drilling operation and process the measured data to obtain the measured data of the normal tripping of the pipe string;

[0011] The processed measured data are used as input parameters of the friction torque mechanics theoretical model to obtain the equivalent friction coefficient of the entire wellbore;

[0012] According to the equivalent friction coefficient of the whole wellbore obtained by fitting, the feasibility of running the completion string is analyzed;

[0013] Different resistances are set respectively, deformation states of the completion string under different resistances are obtained, and critical resistances are determined according to the deformation states of the completion string to guide the control of the completion string lowering process.

[0014] Compared with the prior art, whether the completion string can be lowered is directly determined only based on whether the simulated well clearing is smooth, however, the simulated well clearing cannot reflect the actual stress condition of the completion string, and thus cannot effectively and reliably ensure that the completion string can be safely lowered. Based on this, the present invention adopts a friction torque mechanics theoretical model, and uses the measured data of the simulated well clearing stage to fit the equivalent friction coefficient of the entire wellbore, and calculates and analyzes the deformation state of the open hole segmented completion string according to the fitted equivalent friction coefficient, so as to ensure that the completion string can be safely lowered; in addition, the existing encounter resistance during simulated well clearing and completion string lowering usually adopts empirical values, which is affected by the experience level of the engineering personnel and cannot ensure the safe lowering of the completion string. Based on this, the present invention distributes different encounter resistances, calculates and analyzes the deformation state of the completion string during the lowering process, and determines the critical encounter resistance according to the deformation state of the string, so as to provide a more objective and reliable encounter resistance value for the string lowering process control, improves the string lowering safety, and improves the construction efficiency at the same time.

[0015] As a preferred embodiment, the measured data collected by the present invention include the time, hanging weight, well depth, torque and mud performance parameters under corresponding working conditions of the simulated well-drilling operation;

[0016] The collected measured data are processed as follows:

[0017] The collected measured data are processed to eliminate the measured data of abnormal pipe string conditions during the lifting and lowering of the pipe string, so as to obtain the measured data of normal pipe string tripping and lowering.

[0018] As a preferred embodiment, the friction torque mechanics theoretical model adopted in the present invention is specifically as follows: in the straight well section, the tubing is regarded as an ideal flexible body, and the stiffness effect of the tubing is not considered, that is, the contact force between the tubing and the well wall is calculated using a soft rod model; in the curved well section, the tubing is regarded as a spring with stiffness, which produces additional pressure on the well wall, and the friction resistance of the tubing is calculated using an equivalent rigid rod model.

[0019] Compared with the existing technology of analyzing the force of the tubing string through a soft rod model or a rigid rod model, the present invention adopts a friction torque mechanics theoretical model combining a soft rod model and a rigid rod model to analyze the force during the tubing string lowering process, which improves the calculation efficiency and is more in line with the engineering accuracy requirements of ultra-deep and highly deviated wells / horizontal wells open hole segmented completion technology.

[0020] As a preferred embodiment, the present invention adopts a friction torque mechanics theoretical model based on measured data to solve the force of the micro-element segment of the tubing string, and integrates the force of each micro-element segment of the entire wellbore to obtain the force of the entire tubing string. Then, the force of the entire tubing string is compared with the suspended weight in the measured data, so as to calculate the equivalent friction coefficient under the simulated measured data of the well.

[0021] As a preferred embodiment, the present invention uses a friction torque mechanics theoretical model based on measured data to respectively calculate the friction coefficient of the casing section and the equivalent friction coefficient of the open hole section.

[0022] As a preferred embodiment, the present invention analyzes whether the open hole segmented completion string can be lowered to the preset well depth based on the equivalent friction coefficient obtained by fitting. If yes, the completion string can be lowered smoothly. Otherwise, the well operation is continued to reduce the friction coefficient.

[0023] As a preferred embodiment, the present invention sets different encounter resistances respectively, and analyzes whether the completion string buckles during the running process and the buckling position, and determines and outputs the encounter resistance critical value based on the analysis result.

[0024] As a preferred embodiment, the present invention distributes different resistance forces within the range of 0-50 kN.

[0025] In a second aspect, the present invention provides a completion string running capability analysis system, the system comprising:

[0026] The data acquisition module is used to collect the measured data of the simulated well-drilling operation and process the measured data to obtain the measured data of the normal tripping of the pipe string;

[0027] The fitting module uses the processed measured data as the input parameters of the friction torque mechanics theoretical model to obtain the equivalent friction coefficient of the entire wellbore;

[0028] The feasibility analysis module analyzes the feasibility of running the completion string based on the fitted equivalent friction coefficient of the entire wellbore; and

[0029] The resistance analysis module sets different resistances respectively, obtains the deformation state of the completion string under different resistances, and determines the critical resistance according to the deformation state of the completion string to guide the control of the completion string running process.

[0030] In a third aspect, the present invention proposes a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the analysis method of the present invention when executing the computer program.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] The present invention adopts a friction torque mechanics theoretical model, utilizes the measured data of the simulated well-passing stage to fit the equivalent friction coefficient of the whole wellbore, calculates and analyzes the deformation state of the open hole segmented completion string according to the fitted equivalent friction coefficient, so as to ensure that the completion string can be safely lowered; at the same time, the present invention also calculates and analyzes the deformation state of the completion string during the lowering of the completion string by distributing different encounter resistances, and determines the critical encounter resistance according to the deformation state of the string, so as to provide a more objective and reliable encounter resistance value for the control of the string lowering process, thereby improving the safety of string lowering and the construction efficiency.

[0033] The present invention adopts a friction torque mechanics theoretical model combining a soft rod model and a rigid rod model to perform force analysis during the running of the pipe string, thereby improving the calculation efficiency and meeting the engineering accuracy requirements of ultra-deep and highly deviated wells / horizontal wells open hole segmented completion technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0035] Figure 1 The figure is a schematic diagram of a method flow of an embodiment of the present invention.

[0036] Figure 2 Schematic diagram of force analysis of soft rod model.

[0037] Figure 3 Schematic diagram of load distribution on the microelement section of the pipe string.

[0038] Figure 4 4 is a system principle block diagram of an embodiment of the present invention.

[0039] Figure 5 Schematic diagram of wellbore trajectory parameters for an ultra-deep and highly deviated well / horizontal well.

[0040] Figure 6 This is a well depth-suspended weight diagram obtained based on the measured data collected at the simulated well drilling site.

[0041] Figure 7 It is the fitting result of the equivalent friction coefficient of the whole wellbore.

[0042] Figure 8 The results of the analysis of the running capability of the open hole segmented completion string are shown in Figure 2.

[0043] Fig. 9 This is the axial load distribution diagram of the entire well string when the resistance is 45kN. DETAILED DESCRIPTION

[0044] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0045] Example 1

[0046] In view of the on-site demand for open-hole segmented completion technology in ultra-deep and highly deviated wells / horizontal wells (wherein, wells with a depth greater than 6000m are ultra-deep wells, and wells with an inclination angle between 55-85° or horizontal wells with an inclination angle greater than 85° are highly deviated wells / horizontal wells), there is a lack of an accurate and effective method for analyzing the running-in capability of the tubing, which makes it impossible to guide the safe and smooth running-in of the completion tubing. This embodiment proposes a method for analyzing the running-in capability of the completion tubing, which adopts a wellbore friction torque mechanics model, and uses the measured data collected at the simulated well-passing operation site as input parameters to fit the equivalent friction coefficient of the entire wellbore, and analyzes the running-in capability of the open-hole segmented completion tubing according to the equivalent friction coefficient; in addition, the method also obtains the critical running-in capability value by distributing different encounter resistances and according to whether buckling occurs and the buckling position during the running-in process of the tubing, thereby providing accurate and reliable data support for on-site construction.

[0047] Specific as Figure 1 As shown, the method proposed in this embodiment includes the following steps:

[0048] Step 1: collect measured data of simulated well-drilling operation and process the measured data to obtain measured data of normal tripping of the pipe string.

[0049] Step 2: Use the processed measured data as input parameters of the friction torque mechanics theoretical model to obtain the equivalent friction coefficient of the entire wellbore.

[0050] Step 3: Analyze the feasibility of running the completion string based on the fitted equivalent friction coefficient of the entire wellbore.

[0051] Step 4, respectively setting different resistances, obtaining the deformation state of the completion string under different resistances, and determining the critical resistance according to the deformation state of the completion string to guide the control of the completion string running process.

[0052] In an optional implementation manner, the measured data collected in step 1 include data such as the time, hanging weight, well depth, torque, and mud performance under corresponding working conditions of the simulated well clearance operation. Before lowering the completion string, the well clearance string consisting of a single milling column and a three-milling column is usually used on site to carry out two simulated well clearance operations. During the well clearance operation, the well logging system will record the corresponding time, hanging weight, torque and other parameters, which are the measured data. Afterwards, these data are screened and processed to eliminate the hanging weight and torque when the string encounters obstruction during the lifting and lowering of the string and other complex (abnormal) situations, and only retain the time, hanging weight, torque and mud performance parameters under corresponding working conditions when the string is normally raised and lowered.

[0053] An optional implementation method, step 2 uses a theoretical model of friction torque mechanics of tubing in wellbore suitable for ultra-deep and highly deviated wells / horizontal wells, and fits the friction coefficient that conforms to the measured data for analysis of the actual completion tubing running capability. Compared with the existing method of determining the feasibility of running the completion tubing only based on the simulated well results, this embodiment calculates the friction coefficient in combination with the measured data, and analyzes the feasibility of running the tubing based on the calculated friction coefficient, which is more objective and accurate, so that the analysis of the running capability of tubing in ultra-deep and highly deviated wells / horizontal wellbore can be realized more reliably and effectively, providing more accurate, reliable and efficient technical support for on-site construction.

[0054] There are two main mechanical analysis models for calculating the friction torque of downhole pipes: the soft rod model and the rigid rod model. The two mechanical analysis models have their own advantages and disadvantages in practical applications.

[0055] Among them, the soft rod model does not consider the influence of tubing stiffness and stabilizer. In smooth wellbore conditions with small curvature, it is used to calculate the friction torque of the tubing section with small stiffness, and can obtain good results. This model is also mainly used in existing commercial software; however, this model will produce large errors when the wellbore curvature changes greatly or the tubing stiffness is large, especially in high-angle wells, and ideal calculation results cannot be obtained.

[0056] The calculation results of the rigid rod model have higher accuracy in wellbore with larger curvature or larger string stiffness. However, when the model is used in smooth wellbore with smaller curvature and smaller stiffness, the calculation results are difficult to converge and the stability of the solution is poor.

[0057] In view of the above situation, this embodiment adopts the friction torque mechanics theoretical model to carry out the calculation and analysis of the force of the downhole tubular string according to the trajectory change characteristics of ultra-deep and highly deviated wells / horizontal wells, which can improve the calculation efficiency and meet the engineering precision requirements. The basic idea of ​​the friction torque mechanics theoretical model is: (1) First, in a straight wellbore, the tubular string is regarded as an ideal flexible body, and the stiffness effect of the tubular string is not considered, and its contact force is calculated (soft rod model); (2) In a curved wellbore, the tubular string is regarded as a spring with stiffness, which generates additional pressure on the well wall, thereby generating friction resistance (equivalent rigid rod model).

[0058] Specifically, assume that A and B are any two adjacent points along the wellbore trajectory, and their well inclination angle and azimuth angle are α and A , and α B , Let o1 be the midpoint of the AB trajectory, o1x1 be the tangent direction of the AB arc, o1y1 be the perpendicular direction of the AB arc, o1-x1y1z1 form a right-handed coordinate system, o-xyz is a fixed coordinate system, oz is perpendicular to the ground and downward, such as Figure 2 According to the geometric relationship, the direction cosines s1, s2, s3 of o1x1, o1y1, o1z1 and the oz axis are:

[0059]

[0060]

[0061]

[0062] In ultra-deep and highly deviated wells / horizontal wells, for the deflection section, based on the wellbore trajectory measurement data of two adjacent points, the load acting on the string can be equivalent to the midpoint of the microelement section, such as Figure 3 As shown in the figure, the pipe string is mainly affected by its own weight and end resistance during the lowering process. When entering the curved well section, the pipe string will contact the well wall. The contact pressure on the dogleg plane is calculated as follows:

[0063]

[0064] Where N y is the contact pressure between the pipe string and the wellbore wall in the dogleg plane, N; T B is the axial tension at point B, N; △L is the length of the micro-unit section of the AB string, m; W is the effective weight of the micro-unit section of the string, N / m; ρ m is the density of the liquid in the wellbore, kg / m 3 ρ T is the density of the pipe material, kg / m 3 ; β is the central angle (dogleg angle) corresponding to the AB section of the pipe string, (°).

[0065] The contact pressure between the tubing and the wellbore wall in the o1z1 direction is simply the component of the effective weight of the tubing in the well fluid in the z direction:

[0066]

[0067] Since the actual tubing has a certain rigidity, additional friction will be generated. The relationship between the rigidity force of the tubing microelement section in the curved wellbore and the curvature of the wellbore is:

[0068]

[0069] In the formula, F s is the accessory pressure per unit length of the string stiffness effect acting on the well wall, N; E is the elastic modulus of the string material, GPa; I is the moment of inertia of the cross section of the string material, m 2 ; h is the curvature radius of the pipe, m; α o is the well inclination angle at the center point of the AB arc, (°).

[0070] Then the contact pressure and axial force in the dogleg plane are corrected to:

[0071]

[0072]

[0073] Where △T is the axial force in the dogleg plane, N; f is the friction coefficient, dimensionless.

[0074] When the weight of the pipe string is greater than its critical buckling load, the pipe string will buckle in the wellbore. When the oil and gas well pipe string is in a spiral buckling state, the pipe string and the wellbore that constrains it will produce a large contact force, which will lead to serious pipe string friction and twisting, and even cause the pipe string to be "locked" and unable to perform normal downhole operations. The critical buckling load of the pipe string is calculated as follows:

[0075]

[0076] In the formula, F y is the critical load of tubing buckling, N; r is the gap between the outer wall of tubing and the wellbore wall, m; c1 is a constant, 2.0 for sinusoidal buckling and 3.657 for helical buckling.

[0077] When the actual load of the pipe string is greater than the critical buckling load, the pipe string buckles and generates additional contact force, which is calculated as follows:

[0078]

[0079] Where N ais the accessory contact force generated when the pipe string buckles, N; T is the axial force of the pipe string, N; c2 is a constant, which is 0.125 for sinusoidal buckling and 0.25 for helical buckling.

[0080] The contact pressure correction is:

[0081]

[0082] In this implementation, the measured data is used as the input parameter of the above model (i.e., equations (1)-(6), (8), and (10)-(11)) to calculate the force of the microelement segment of the tubing string. The above solution process is repeated multiple times to obtain the force of all microelement segments in the entire wellbore. The force is integrated to obtain the force of the entire tubing string. The force of the entire tubing string is then compared with the measured hanging weight. Specifically, the friction force on the tubing string can be obtained from the difference between the force on the tubing string in the well fluid and the hanging weight. Based on the friction force, the equivalent friction coefficient under the simulated measured data of the wellbore can be calculated.

[0083] In this embodiment, the equivalent friction coefficient of the entire wellbore is divided into the equivalent friction coefficient of the casing section and the equivalent friction coefficient of the open hole section. The equivalent friction coefficient of the casing section and the equivalent friction coefficient of the open hole section are obtained by respectively solving the above model.

[0084] An optional implementation method is to analyze whether the open hole segmented completion string can be lowered to the preset well depth based on the equivalent friction coefficient obtained by fitting. Specifically, based on the equivalent friction coefficient obtained by fitting, the friction resistance of the string is calculated using the friction torque mechanics theoretical model, and compared with the weight of the string in the mud in the wellbore. If the weight is greater than the friction resistance, the preset well depth can be reached and the completion string can be smoothly lowered. Otherwise, the preset well depth cannot be reached, and the wellbore operation is continued to make the wellbore more regular and smooth, thereby reducing the friction coefficient, and the analysis is performed again, that is, the feasibility analysis of the actual completion string lowering is completed.

[0085] An optional implementation manner, compared with the existing method of using empirical values ​​for the resistance encountered when simulating well clearance and lowering completion tubing, this embodiment sets different resistances from the resistance range value during the lowering of the tubing, and analyzes whether the tubing is bent and the buckling position during the lowering process. According to the analysis results, the critical value of the resistance can be determined, thereby providing more objective and accurate data support for the on-site construction of the completion operation, avoiding unreasonable and inaccurate setting of empirical values, improving the construction efficiency of the completion operation and ensuring the safety of the completion operation.

[0086] Based on the same technical concept, this embodiment also proposes a completion string running capability analysis system, specifically as follows: Figure 4 As shown, the system includes a data acquisition module, a fitting module, a feasibility analysis module and a resistance analysis module.

[0087] The data acquisition module is used to collect the measured data of the simulated well-drilling operation and process the measured data to obtain the measured data when the pipe string is normally raised and lowered.

[0088] The fitting module uses the processed measured data as the input parameters of the friction torque mechanics theoretical model to obtain the equivalent friction coefficient of the entire wellbore.

[0089] The feasibility analysis module analyzes the feasibility of running the completion string based on the fitted equivalent friction coefficient of the entire wellbore.

[0090] The resistance analysis module sets different resistances respectively, obtains the deformation state of the completion string under different resistances, and determines the critical resistance according to the deformation state of the completion string to guide the control of the completion string running process.

[0091] Embodiment 2:

[0092] This example uses the method proposed in the above example to analyze the running capability of a completion string in an ultra-deep and highly deviated well. The ultra-deep and highly deviated well has a completion depth of 8500m, an outer diameter of the reservoir casing of 196.85mm, a running depth of 7623m, and an open hole length of 977m. The basic data of the wellbore trajectory is collected and analyzed to obtain the following: Figure 3 The well inclination, dogleg and azimuth with well depth are shown. Figure 5 It can be seen that the maximum downhole angle of the well is 88.85° (well depth 8025m) and the maximum dogleg angle is 5.8° / 30m (well depth 7700m).

[0093] The specific process is as follows:

[0094] The structure of the horizontal well simulation string is: drill bit + weighted drill pipe + milling column + weighted drill pipe + milling column + weighted drill pipe + milling column + weighted drill pipe + drill pipe + thick-walled drill pipe. The time, hanging weight, and torque of the normal string tripping during the simulation of well driving are collected and screened, and the well depth-hanging weight analysis diagram is drawn, such as Figure 6 shown.

[0095] According to the friction torque mechanics theoretical model, the friction coefficient interval of the entire wellbore is divided into casing section and open hole section. Through multiple cycles of fitting, the equivalent friction coefficient that satisfies the simulated wellbore measured data is obtained: the friction coefficient of the casing section f c =0.25, equivalent friction coefficient of naked eye section f o =0.36, see Figure 7 shown.

[0096] The structure of the horizontal well open hole segmented completion string is: drill pipe + hanging packer + tubing + open hole packer + tubing + ball sleeve + tubing + open hole packer + ball sleeve + tubing + anchor packer + ball seat. Based on the equivalent friction coefficient obtained by fitting, the calculation and analysis of whether the open hole segmented completion string can be delivered to the scheduled well depth are as follows: Figure 8 From the hanging weight prediction trend chart, it can be seen that the pipe string can be lowered to the predetermined well depth, and no buckling behavior occurs when the pipe string is advanced in the horizontal section.

[0097] Different resistances were selected in the range of 0 to 50 kN to analyze the deformation state of the string. Fig. 9 The figure shows the axial load distribution of the entire well string when the resistance is 45kN. As the horizontal section increases, more suspended weight needs to be released at the top to overcome the friction and push the string forward. After encountering resistance, not only will the horizontal section string produce a certain micro-deformation (sinusoidal buckling state), but it will also cause the axial compression load on the upper part of the horizontal section to increase, and there is a risk of thread buckling. Therefore, the resistance encountered when the horizontal well string is lowered in the open hole segmented completion should not exceed 45kN, that is, the critical resistance is 45kN.

[0098] Embodiment 3:

[0099] This embodiment also proposes a computer device for executing the analysis method proposed in this embodiment 1.

[0100] Computer devices include processors, memory, and system buses; various device components, including memory and processors, are connected to the system bus. A processor is a piece of hardware used to execute computer program instructions through basic arithmetic and logical operations in a computer system. A memory is a physical device used to temporarily or permanently store computer programs or data (e.g., program state information). The system bus can be any of the following types of bus structures, including a memory bus or memory controller, a peripheral bus, and a local bus. The processor and memory can communicate data through the system bus. The memory includes read-only memory (ROM) or flash memory, and random access memory (RAM), RAM usually refers to the main memory loaded with the operating system and computer programs.

[0101] Computer equipment generally includes a storage device. The storage device can be selected from a variety of computer-readable media, which refers to any available media that can be accessed by the computer equipment, including both removable and fixed media. For example, computer-readable media include, but are not limited to, flash memory (micro SD card), CD-ROM, digital versatile disc (DVD) or other optical disk storage, magnetic tape cassette, magnetic tape, magnetic disk storage or other magnetic storage device, or any other medium that can be used to store the desired information and can be accessed by the computer equipment.

[0102] Computer devices can be logically connected to one or more network terminals in a network environment. Network terminals can be personal computers, servers, routers, smart phones, tablets, or other public network nodes. Computer devices are connected to network terminals through network interfaces (local area network LAN interfaces). Local area network (LAN) refers to a network of computers interconnected within a limited area, such as a home, school, computer laboratory, or office building using network media. WiFi and twisted pair cabling Ethernet are the two most commonly used technologies for building LANs.

[0103] It should be noted that other computer systems including more or fewer subsystems than a computer device may also be suitable for the invention.

[0104] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for analyzing the running capability of a completion string, characterized in that: The method includes: Collect the measured data of the simulated well-drilling operation and process the measured data to obtain the measured data of the normal tripping of the pipe string; The processed measured data are used as input parameters of the friction torque mechanics theoretical model to obtain the equivalent friction coefficient of the entire wellbore; According to the equivalent friction coefficient of the whole wellbore obtained by fitting, the feasibility of running the completion string is analyzed; Different resistances are set respectively, deformation states of the completion string under different resistances are obtained, and critical resistances are determined according to the deformation states of the completion string to guide the control of the completion string lowering process.

2. A completion string running capability analysis method according to claim 1, characterized in that: The measured data collected include the time, hanging weight, well depth, torque and mud performance parameters under the corresponding working conditions of the simulated well-drilling operation; The collected measured data are processed as follows: The collected measured data are processed to eliminate the measured data of abnormal pipe string conditions during the lifting and lowering of the pipe string, so as to obtain the measured data of normal pipe string tripping and lowering.

3. A completion string running capability analysis method according to claim 1, characterized in that: The friction torque mechanics theoretical model adopted is as follows: in the straight well section, the tubing is regarded as an ideal flexible body, and the stiffness effect of the tubing is not considered, that is, the soft rod model is used to calculate the contact force between the tubing and the well wall; in the curved well section, the tubing is regarded as a spring with stiffness, which produces additional pressure on the well wall, and the equivalent rigid rod model is used to calculate the friction resistance of the tubing.

4. A method for analyzing the running capability of a completion string according to claim 3, characterized in that: Based on the measured data, the friction torque mechanics theoretical model is used to solve the force of the micro-element segment of the pipe string. The force of each micro-element segment of the whole wellbore is integrated to get the force of the entire pipe string. Then, the force of the entire pipe string is compared with the suspended weight in the measured data to calculate the equivalent friction coefficient under the simulated measured data of the wellbore.

5. A method for analyzing the running capability of a completion string according to claim 4, characterized in that: Based on the measured data, the friction coefficient of the casing section and the equivalent friction coefficient of the open hole section were calculated using the friction torque mechanics theoretical model.

6. A completion string running capability analysis method according to claim 1, characterized in that: According to the equivalent friction coefficient obtained by fitting, it is analyzed whether the open hole segmented completion string can be lowered to the preset well depth. If yes, the completion string can be lowered smoothly. Otherwise, the well operation is continued to reduce the friction coefficient.

7. A method for analyzing the running capability of a completion string according to claim 1, characterized in that: Different resistances are set respectively, and whether the completion string buckles during the running process and the buckling position are analyzed. According to the analysis results, the critical value of the resistance is determined and output.

8. A method for analyzing the running capability of a completion string according to claim 7, characterized in that: Different resistance forces are distributed in the range of 0-50kN.

9. A completion string running capability analysis system, characterized in that: The system includes: The data acquisition module is used to collect the measured data of the simulated well-drilling operation and process the measured data to obtain the measured data of the normal tripping of the pipe string; The fitting module uses the processed measured data as the input parameters of the friction torque mechanics theoretical model to obtain the equivalent friction coefficient of the entire wellbore; The feasibility analysis module analyzes the feasibility of running the completion string based on the fitted equivalent friction coefficient of the entire wellbore; and The resistance analysis module sets different resistances respectively, obtains the deformation state of the completion string under different resistances, and determines the critical resistance according to the deformation state of the completion string to guide the control of the completion string running process.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

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