A method and system for dynamically monitoring the wear state of a PDC drill bit

Abstract

The application provides a PDC bit wear state while-drilling dynamic monitoring method and system, the method utilizes a designed optimization mechanical specific energy calculation model to monitor the mechanical specific energy of the bit drilling to each depth, further analyzes the deviation degree of the mechanical specific energy of different depth sections, judges the stability of the mechanical specific energy of each section, identifies the section where wear occurs, quantitatively calculates the PDC bit wear degree of a specific section based on the comprehensive PDC bit wear physical model, and further provides support for decision-making construction parameters; the method can overcome the problems of strong subjectivity, difficult quantification and limited applicability of the prior art, improve the applicability, reduce the complexity of calculation and construction cost, make the bit wear prediction more accurate, and provide a reliable basis for the on-site engineers to make decisions such as adjusting drilling parameters and tripping to replace the bit.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling construction optimization technology, and in particular to a method and system for dynamic monitoring of PDC drill bit wear status during drilling. Background Technology

[0002] As oilfield exploration and development expands from conventional oil and gas resources to unconventional resources such as low-permeability, deep and ultra-deep formations, deep-sea oil, shale oil, and shale gas, it faces challenges such as resource degradation, diversified exploration, complex development, and harsher environments. Drilling is a crucial link in the discovery, exploration, and exploitation of oil and gas resources. With increasingly complex geological environments and more demanding drilling conditions, there is an urgent need to develop a new generation of transformative drilling technologies to shorten drilling cycles and reduce drilling costs. PDC drill bits play a vital role in the oil and gas drilling field due to their high drilling speed and high rock-breaking efficiency. Currently, PDC drill bits are widely used in oil and gas drilling projects in soft to medium-hard formations. Statistics show that more than 70% of PDC drill bit failures are caused by damage to the cutting teeth, and the main form of damage to the cutting teeth is wear. Therefore, real-time monitoring of the wear level of PDC drill bits during drilling is particularly important for the smooth progress of drilling operations.

[0003] Currently, the wear assessment techniques for PDC drill bits mainly include the following categories: (1) empirical method; (2) physical method; and (3) data method. The empirical method is based on the accumulated experience of drilling engineers in familiarizing themselves with the working conditions of a specific operating area over many years. Given drilling parameters, formation characteristics, mechanical drilling speed, and other parameters, they then combine professional knowledge to make a reasonable judgment on the wear degree of the drill bit in the drilling process. This method lacks reliable theoretical guidance and is extremely dependent on experienced engineers in the operating area, and can only obtain a roughly reasonable wear assessment. The physical model method is based on the engineer's understanding of the factors affecting drill bit wear. After analyzing a large amount of data from drilled wells and laboratory tests, the relationship between these influencing factors and the degree of drill bit wear is derived and expressed in the form of a mathematical expression. The physical model drill bit wear prediction method is difficult to fully consider the factors affecting drill bit wear. The established physical model involves many unknown parameters, and the parameters vary greatly in different operating areas. Furthermore, with the development of complex oil and gas reservoirs and the application of new drilling tools and processes, the matching and applicability of the physical model face challenges. Data-driven methods typically utilize various sensors installed at the wellhead and bottom of the drilling platform to collect operating parameters of the drill bit during drilling, and then use mathematical algorithms to calculate drill bit wear. While data-driven methods overcome the weakness of physical models in terms of low adaptability to some extent, they have high requirements for equipment hardware and software, high investment costs, and are difficult to promote and popularize in the field.

[0004] The information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] To address the above problems, this invention provides a method for dynamic monitoring of PDC drill bit wear status while drilling. In one embodiment, the method includes:

[0006] The mechanical specific energy monitoring step, based on the characteristics of the drill string combination and operational intervention factors when the PDC drill bit is applied, determines the optimized mechanical specific energy calculation model corresponding to the PDC drill bit, and obtains the mechanical specific energy that characterizes the dynamic rock breaking efficiency of the drill bit under test at different working depths in real time.

[0007] The preliminary wear analysis steps are as follows: divide the analysis area according to the set range, calculate the corresponding mechanical specific energy deviation for each analysis area based on the obtained mechanical specific energy according to the set logic, and compare it with the set deviation standard value to determine the stability of the drill bit mechanical specific energy in the analysis area.

[0008] The quantitative wear analysis step involves selectively introducing the wear physical prediction model preset by the PDC drill bit to calculate the wear state data of the drill bit during operation for the analysis section where the mechanical specific energy stability meets the set conditions.

[0009] The drilling optimization steps, the stability of the overall drill bit mechanical energy, and the wear status data are used to determine the construction adjustment plan.

[0010] Preferably, as an improvement of the present invention, the process of determining the optimized mechanical specific energy calculation model corresponding to the PDC drill bit in the mechanical specific energy monitoring step includes:

[0011] Based on the fundamental mechanical specific energy model that integrates multiple drilling data such as drilling pressure, rotational speed, torque, drill bit size, mechanical drilling speed, and formation compressive strength, and combined with the hardware characteristics of the PDC drill bit + screw drill string combination, the model further introduces multiple influencing factors such as screw drilling speed, screw torque, threshold drilling pressure, and threshold drilling pressure to construct a corresponding optimized mechanical specific energy calculation model.

[0012] As a further improvement of the present invention, in the mechanical specific energy monitoring step, the mechanical specific energy data of the drill bit at each working depth are calculated according to the optimized mechanical specific energy calculation model described in the following formula:

[0013]

[0014] In the formula, E is the mechanical specific energy (MPa); W is the drilling pressure (kN); T is the surface torque (kN·m); N is the surface rotational speed (rpm); ROP is the mechanical drilling rate (m / h); d B Drill bit diameter, mm; Wbs Threshold drilling pressure, kN; T bs The threshold torque is expressed in kN·m; K N T is the drilling speed-to-flow ratio of the screw drill bit, r / L; Q is the total displacement, L / s; T m The maximum output torque of the screw drill bit is expressed in kN·m; Δp m The maximum pressure drop at the inlet and outlet of the screw drill bit, in MPa; Δp p The inlet and outlet pressures of the drill string assembly are in MPa.

[0015] As a further improvement of the present invention, the range of the analysis section is determined in advance based on the time of calculation of unit mechanical energy, geological characteristics, well type and construction working depth, and recorded. In the preliminary wear analysis step, the division is directly called according to the construction requirements.

[0016] As a further improvement of the present invention, in the preliminary wear analysis step, the deviation of the drill bit's mechanical specific energy is calculated by the following formula:

[0017]

[0018] Where i represents the i-th mechanical specific energy monitoring value in the current analysis section, and D represents the total number of mechanical specific energy monitoring values ​​in the analysis section.

[0019] As a further improvement of the present invention, in the quantitative wear analysis step, for the analysis section with a mechanical specific energy stability that meets the set conditions, the mechanical specific energy stability of the adjacent sections before and after it is further analyzed. If the difference in stability with the previous and / or subsequent sections is within the set range, the section is then regarded as a section that meets the wear conditions, and the subsequent wear state data is calculated to exclude the situation of sudden drilling encounters with abnormal geology.

[0020] As a further improvement of the present invention, in one embodiment, in the quantitative wear analysis step, the wear state data of the worn drill bit is quantitatively calculated according to the following wear physical prediction model:

[0021]

[0022] In the formula, ω is the dimensionless wear rate of the PDC drill bit; kN; A f The rock abrasiveness index, mg / cm³ 3 P is the normal force of the cutting tooth, kN; V is the cutting speed, m / s; h is the dimensionless wear height of the cutting tooth; a, b, d, k are parameters related to the shape of the cutting tooth and the formation characteristics.

[0023] As a further improvement of the present invention, in the drilling optimization step, for depth sections where the mechanical energy stability meets the wear conditions, if the wear status data does not reach the set threshold, it is determined to be light wear. The construction parameters are adjusted to ensure the drilling effect, and the original drill bit is used to continue drilling. If the wear status data is greater than or equal to the set threshold, it is determined to be heavy wear. The drill bit is replaced, and drilling continues based on the matching construction parameters.

[0024] Based on other aspects of the methods described in any one or more of the foregoing embodiments, the present invention also provides a storage medium storing program code that can implement the methods described in any one or more of the foregoing embodiments.

[0025] Based on the application improvements of the methods described in any one or more of the above embodiments, the present invention also provides a PDC drill bit wear condition dynamic monitoring system while drilling, which performs the methods described in any one or more of the above embodiments.

[0026] Compared with the closest prior art, the present invention also has the following beneficial effects:

[0027] This invention provides a dynamic monitoring method for PDC drill bit wear status during drilling. It utilizes an optimized mechanical specific energy calculation model to monitor the mechanical specific energy at various depths during drill bit operation, analyzes the deviation of mechanical specific energy in different depth sections, determines the stability of mechanical specific energy in each section, and identifies worn sections. Based on this, and leveraging the easily quantifiable characteristics of the PDC drill bit wear physical model, it quantitatively calculates the wear degree of PDC drill bits in specific formations. This method improves applicability, reduces computational complexity and field application costs, and simultaneously makes intelligent drill bit wear prediction more accurate. It provides a reliable basis for field engineers to make decisions such as adjusting drilling parameters and replacing drill bits during tripping. Furthermore, this invention avoids installing numerous sensors on the drilling platform and downhole tools, lowering the barrier to entry and possessing strong application value. It supports cost savings and improved economic efficiency in drilling projects.

[0028] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0029] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0030] Figure 1This is a schematic flowchart of a method for dynamic monitoring of PDC drill bit wear status during drilling, provided in an embodiment of the present invention.

[0031] Figure 2 This is a detailed diagram illustrating the operating principle of the PDC drill bit wear condition dynamic monitoring method provided in another embodiment of the present invention;

[0032] Figure 3 This is a monitoring graph of mechanical specific energy change in scenario 1 of the dynamic monitoring method for PDC drill bit wear status during drilling provided in this embodiment of the invention;

[0033] Figure 4 This is a mechanical specific energy change monitoring graph for scenario 2 of the PDC drill bit wear state dynamic monitoring method provided in this embodiment of the invention;

[0034] Figure 5 This is a monitoring graph of mechanical specific energy change in scenario 3 of the PDC drill bit wear state dynamic monitoring method provided in this embodiment of the invention;

[0035] Figure 6 This is a schematic diagram of the structure of the PDC drill bit wear status dynamic monitoring system provided in an embodiment of the present invention. Detailed Implementation

[0036] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples. Those skilled in the art will then fully understand how the present invention uses technical means to solve technical problems and achieve technical effects, and will be able to implement the present invention specifically based on the above-described implementation process. It should be noted that, as long as there is no conflict, the various embodiments and features of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0037] Although the flowchart describes the operations as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. The order of the operations can be rearranged. A process can terminate when its operation is complete, but it may also have additional steps not included in the diagram. A process can correspond to a method, function, procedure, subroutine, subroutine, etc.

[0038] Computer equipment includes user equipment and network equipment. User equipment or clients include, but are not limited to, computers, smartphones, PDAs, etc.; network equipment includes, but is not limited to, a single network server, a server group consisting of multiple network servers, or a cloud based on cloud computing consisting of a large number of computers or network servers. Computer equipment can operate independently to implement this invention, or it can connect to a network and implement this invention through interaction with other computer equipment in the network. The network in which the computer equipment is located includes, but is not limited to, the Internet, wide area networks, metropolitan area networks, local area networks, VPN networks, etc.

[0039] The terms “first,” “second,” etc., may be used herein to describe various units, but these units should not be limited by these terms; they are used merely to distinguish one unit from another. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. When a unit is referred to as “connected” or “coupled” to another unit, it may be directly connected or coupled to said other unit, or there may be intermediate units present.

[0040] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are also intended to include the plural. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components, and / or combinations thereof.

[0041] Currently, PDC drill bit wear assessment can be broadly categorized into two types: (1) empirical method; (2) physical method; and (3) data method. The empirical method is based on the accumulated experience of drilling engineers over many years regarding the working conditions of a specific operating area. Given drilling parameters, formation characteristics, and mechanical drilling rate, drilling engineers can make a general assessment of drill bit wear during drilling. This method lacks theoretical guidance and is highly dependent on experienced engineers in the operating area. The physical model method is based on engineers' understanding of factors affecting drill bit wear. Through analysis of a large amount of drilled field data and laboratory tests, the relationship between these influencing factors and the degree of drill bit wear is derived and expressed in the form of a mathematical expression. The physical model method for predicting drill bit wear is difficult to fully consider the factors affecting drill bit wear. The established physical model involves many unknown parameters, and the parameters vary greatly in different operating areas. Furthermore, with the development of complex oil and gas reservoirs and the application of new drilling tools and technologies, the applicability of the physical model faces challenges. Data-driven methods utilize various sensors installed at the wellhead and bottom of the drilling platform to collect parameters such as drilling pressure, torque, rotational speed, displacement, and vibration applied to the drill bit during drilling. Mathematical algorithms are then used to calculate drill bit wear. While data-driven methods overcome the limitations of physical models in terms of adaptability, they require sophisticated hardware and software, incur high costs, and are difficult to implement in the field. For example, document CN112983392A describes a method for determining drill bit efficiency in sedimentary rock formations using mechanical specific energy deviation from a trend line. This method first plots a scatter plot of the relationship between mechanical specific energy and drilling depth in a rectangular coordinate system. Then, it plots a mechanical specific energy trend line and a deviation trend line. Finally, it calculates the ratio α (slope of the deviation trend line to the trend line slope) and the ratio β (maximum mechanical specific energy to the average trend line value). When α and β exceed certain specified values, it can be determined that the drill bit efficiency has significantly decreased. This patent provides a qualitative assessment of drill bit efficiency, but it only applies to sedimentary rock formations and does not take into account the influence of complex geological factors. It is also prone to misjudgment, and the accuracy of the calculation results is difficult to meet engineering needs, thus having obvious application limitations.

[0042] To address the aforementioned issues, this invention provides a method and system for dynamic monitoring of PDC drill bit wear status during drilling. This method deeply integrates a data model based on mechanical specific energy and a physical model of PDC drill bit wear, optimizes the decision-making process and calculation principles, improves applicability, reduces field application costs, and makes drill bit wear prediction more accurate. It can provide a basis for field engineers to make decisions such as adjusting drilling parameters and replacing drill bits, thereby shortening drilling operation time and saving drilling costs.

[0043] The following describes the detailed flow of the method according to an embodiment of the present invention with reference to the accompanying drawings, the steps of which can be executed in a computer system containing, for example, a set of computer-executable instructions. Although the logical order of the steps is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that shown here.

[0044] Example 1

[0045] Figure 1 This diagram illustrates a flow chart of the PDC drill bit wear condition dynamic monitoring method provided in Embodiment 1 of the present invention. (Refer to...) Figure 1 As can be seen, the method includes the following steps.

[0046] The mechanical specific energy monitoring step, based on the characteristics of the drill string combination and operational intervention factors when the PDC drill bit is applied, determines the optimized mechanical specific energy calculation model corresponding to the PDC drill bit, and obtains the mechanical specific energy that characterizes the dynamic rock breaking efficiency of the drill bit under test at different working depths in real time.

[0047] The preliminary wear analysis steps are as follows: divide the analysis area according to the set range, calculate the corresponding mechanical specific energy deviation for each analysis area based on the obtained mechanical specific energy according to the set logic, and compare it with the set deviation standard value to determine the stability of the drill bit mechanical specific energy in the analysis area.

[0048] The quantitative wear analysis step involves selectively introducing the wear physical prediction model preset by the PDC drill bit to calculate the wear state data of the drill bit during operation for the analysis section where the mechanical specific energy stability meets the set conditions.

[0049] The drilling optimization steps, the stability of the overall drill bit mechanical energy, and the wear status data are used to determine the construction adjustment plan.

[0050] Based on the implementation logic provided in the above embodiments, the solution of the present invention adopts a unique strategy that integrates the data model based on mechanical specific energy and the physical model of PDC drill bit wear, taking the advantages of both methods, serving the monitoring of PDC drill bit wear status, improving applicability, reducing field application costs, and making drill bit wear prediction more accurate.

[0051] Furthermore, in actual drilling operations, mechanical specific energy, which is the work done by the drill bit to break a unit volume of rock, integrates numerous drilling-related data such as drilling pressure, rotational speed, torque, drill bit size, mechanical drilling speed, and formation compressive strength into a single indicator. This allows for qualitative monitoring of the drill bit's rock-breaking efficiency: When drilling in homogeneous formations, mechanical specific energy increases slowly with drill bit wear and drilling time; however, it increases sharply when encountering sudden changes in formation lithology or when the drill bit wears down and fails. The traditional mechanical specific energy model is as follows:

[0052]

[0053] In the formula, E is the mechanical specific energy (MPa); W is the drilling pressure (kN); T is the surface torque (kN·m); N is the surface rotational speed (rpm); ROP is the mechanical drilling rate (m / h); d B The value is the drill bit diameter, in mm.

[0054] The researchers of this invention considered that traditional mechanical energy specificity models only take into account the work done by non-PDC drill bits in breaking a unit volume of rock under the action of drilling pressure and torque. When a modern drilling tool combination of PDC drill bit + screw drill string is used downhole, the hydraulic energy contained in the drilling fluid ejected from the water nozzle of the PDC drill bit also plays an auxiliary role in rock breaking. In addition, screw drilling speed, screw torque, threshold drilling pressure, and threshold drilling pressure also affect the work used for dynamic rock breaking during the operation of the PDC drill bit. Therefore, in a preferred embodiment, the process of determining the optimized mechanical energy specificity calculation model corresponding to the PDC drill bit in the mechanical energy specificity monitoring step includes:

[0055] Based on the fundamental mechanical specific energy model that integrates multiple drilling data such as drilling pressure, rotational speed, torque, drill bit size, mechanical drilling speed, and formation compressive strength, and combined with the hardware characteristics of the PDC drill bit + screw drill string combination, the model further introduces multiple influencing factors such as screw drilling speed, screw torque, threshold drilling pressure, and threshold drilling pressure to construct a corresponding optimized mechanical specific energy calculation model.

[0056] Figure 2 The diagram illustrates the detailed operating principle of the PDC drill bit wear condition dynamic monitoring method provided in this embodiment of the invention, as shown below. Figure 2 As shown, specifically, in one embodiment, in the mechanical energy specificity monitoring step, the mechanical energy specificity data of the drill bit at each working depth is calculated according to the optimized mechanical energy specificity calculation model described in the following formula:

[0057]

[0058] In the formula, E is the mechanical specific energy of the PDC drill bit, MPa; W is the drilling pressure, kN; T is the surface torque, kN·m; N is the surface rotation speed, rpm; ROP is the mechanical drilling speed, m / h; d B Drill bit diameter, mm; W bs Threshold drilling pressure, kN; T bs The threshold torque is expressed in kN·m; K N T is the drilling speed-to-flow ratio of the screw drill bit, r / L; Q is the total displacement, L / s; T m The maximum output torque of the screw drill bit is expressed in kN·m; Δp m The maximum pressure drop at the inlet and outlet of the screw drill bit, in MPa; Δp p The inlet and outlet pressures of the drill string assembly are in MPa.

[0059] When the mechanical specific energy monitoring value of the drill bit in a certain depth segment (section) is stable and the deviation from the mechanical specific energy baseline is small, the drill bit is basically without wear. Therefore, this invention determines the stability of the drill bit's mechanical specific energy by analyzing the deviation of the mechanical specific energy for each depth segment. Specifically, in one embodiment, in the preliminary wear analysis step, the deviation of the drill bit's mechanical specific energy is calculated by the following formula:

[0060]

[0061] Where i represents the i-th mechanical specific energy monitoring value in the current analysis section, and D represents the total number of mechanical specific energy monitoring values ​​in the analysis section.

[0062] The mechanical specific energy at each depth during PDC drilling can be accurately obtained using the above formula (2), and then a further judgment can be made for each depth segment. In an optional embodiment, before calculating the mechanical specific energy or before calculating the deviation of the drill bit's mechanical specific energy, the analysis segment range is determined and recorded in advance based on the time required to calculate the unit mechanical specific energy, geological characteristics, well type, and construction working depth. The segment is then directly called upon in the preliminary wear analysis step according to the construction requirements to achieve the division.

[0063] When a sharp increase in mechanical specific energy is detected in a certain section, the mechanical drilling efficiency of the corresponding drill bit decreases, and the PDC drill bit may wear out. However, researchers have considered that when encountering sudden abnormal geological conditions, even if the drill bit does not wear out significantly, there may be a sharp increase in mechanical specific energy during the drilling process in a short period of time. In order to avoid treating such a situation as a wear occurrence section and performing unnecessary calculations, in a preferred embodiment, in the wear quantitative analysis step, for the analysis section with a mechanical specific energy stability that meets the set conditions, the mechanical specific energy stability of its adjacent sections is further analyzed. If the difference in stability between the section and the previous and / or subsequent section is within the set range, the section is then regarded as a section that meets the wear conditions, and the subsequent wear state data calculation continues. Otherwise, it is determined that the current change in mechanical specific energy is caused by encountering abnormal geological conditions. This can effectively exclude the situation of encountering sudden abnormal geological conditions.

[0064] When the mechanical specific energy deviates from the set value, it indicates that the drilling efficiency has decreased. This is not necessarily due to drill bit wear; it could also be caused by sudden changes in formation conditions, drill string vibration, or other factors. To quantitatively determine the wear degree of the PDC drill bit, further quantitative calculations based on the rock-breaking mechanism of the PDC drill bit are required. Therefore, in one embodiment, in the wear quantitative analysis step, the wear state data of the worn drill bit is quantitatively calculated according to the following wear physical prediction model:

[0065]

[0066] In the formula, ω is the dimensionless wear rate of the PDC drill bit; kN; A f The rock abrasiveness index, mg / cm³ 3 P is the normal force on the cutting tooth, kN; V is the cutting speed, m / s; h is the dimensionless wear height of the cutting tooth; k is related to the formation conditions and the state of the cutting tooth; a, b, and d are related to the back slope angle and outcrop height of the cutting tooth, and can be obtained by multiple linear regression after measuring a large amount of data in the laboratory. Generally, k is between 1*10 -5 Up to 3*10 -5 Between, a is between 1.2 and 2.4, b is between 1.2 and 1.4, and d is between 1.5 and 1.9.

[0067] Using the implementation concept of this invention, before performing quantitative calculation of wear status, the depth range where the mechanical energy deviation meets the set requirements is identified, and further quantitative calculation of wear status is carried out in a targeted manner. Since the calculation model for PDC drill bit wear prediction involves many unknown parameters and complex parameter fitting, it can be seen that this invention only needs to perform calculations at the formation depth where the mechanical energy deviation meets the wear conditions during application, without needing to perform fitting across the entire well section. This significantly reduces the computational load on the processor and improves computational efficiency while ensuring the accuracy of monitoring results.

[0068] After calculating the wear status data of the drill bit, if the calculated PDC drill bit wear rate is greater than a certain threshold, the wear of the drill bit is intensifying, and it is recommended to stop drilling, pull out the drill bit, and replace it; if the calculated PDC drill bit wear rate is less than the certain threshold, the drill bit is slightly worn, but the wear is acceptable, and it is recommended to adjust the construction parameters and continue drilling, while monitoring the change in mechanical specific energy.

[0069] Therefore, in one embodiment, in the drilling optimization step, for depth sections where the mechanical energy stability meets the wear conditions, if the wear status data does not reach the set threshold, it is determined to be light wear. The drilling parameters are adjusted to ensure the drilling effect, and the original drill bit is used to continue drilling. If the wear status data is greater than or equal to the set threshold, it is determined to be heavy wear. The drill bit is replaced, and drilling continues based on the matching drilling parameters.

[0070] In practical applications, to ensure a stable drilling progress, once partial wear of the drill bit is confirmed, drilling parameters can be adjusted according to operational needs. After continuing drilling for a period of time, the wear of the drill bit may be monitored to reach a predetermined severity. At this point, after pulling out the well and replacing the drill bit, the drilling parameters can be adjusted to reasonable values ​​according to operational needs, thereby controlling the wear rate of the drill bit while achieving optimal drilling results.

[0071] For example, different series of construction parameters can be pre-set according to the current well type and geological characteristics data, corresponding to the scenarios of no drill bit wear and partial wear. These parameters can be retrieved and used when needed to maintain the stability of drilling operations when the drill bit is partially worn, and to control the wear rate of the drill bit to a minimum while ensuring drilling efficiency.

[0072] Implementation Case:

[0073] Taking the 2000-2500m section of Well 4-8 in Northwest China as an example, the wear condition monitoring of the PDC drill bit during operation is achieved by following these steps:

[0074] Scenario Case 1:

[0075] Collect relevant parameters of PDC drill bits and screw drill tools; collect logging data to obtain data such as rock compressive strength, drilling pressure, rotation speed, torque, and hydraulic parameters in the 2000-2500m section.

[0076] The mechanical specific energy baseline can be calculated and approximated by the rock compressive strength according to the basic theory of rock mechanics.

[0077] The mechanical specific energy of the PDC drill bit during drilling is obtained using formula (2). The curve of mechanical specific energy changing with depth is plotted in a rectangular coordinate system, with the X-axis representing mechanical specific energy and the Y-axis representing depth.

[0078] Monitor the change in mechanical specific energy and calculate the mechanical specific energy deviation using formula (3). If the mechanical specific energy deviation is less than the threshold of 10%, it indicates that the mechanical specific energy is relatively stable.

[0079] In this case, the mechanical specific energy deviation was 3.6%, which is relatively stable. Figure 3 As shown. Based on this, it can be determined that the drill bit is not worn, and it is recommended to continue drilling.

[0080] Scenario Case 2:

[0081] Collect relevant parameters of PDC drill bits and screw drill tools; collect logging data to obtain data such as rock compressive strength, drilling pressure, rotation speed, torque, and hydraulic parameters in the 2000-2500m section.

[0082] The mechanical specific energy baseline can be calculated and approximated by the rock compressive strength according to the basic theory of rock mechanics.

[0083] The mechanical specific energy of the PDC drill bit during drilling is obtained using formula (2). The curve of mechanical specific energy changing with depth is plotted in a rectangular coordinate system, with the X-axis representing mechanical specific energy and the Y-axis representing depth.

[0084] Monitor the change in mechanical specific energy and calculate the deviation of mechanical specific energy using formula (3). In this case, the deviation of mechanical specific energy is 54%, which is greater than the threshold of 10%. The deviation is large and may cause drill bit wear.

[0085] Using formula (4), the dimensionless wear rate of the PDC drill bit in the 2250-2350m section is calculated to be 0.0024. The calculated value is less than the threshold of 0.005. Figure 4 As shown. Based on this, it can be determined that the drill bit has experienced slight wear, but the degree of wear is minor, and drilling can continue.

[0086] Scenario Case 3:

[0087] Collect relevant parameters of PDC drill bits and screw drill tools; collect logging data to obtain data such as rock compressive strength, drilling pressure, rotation speed, torque, and hydraulic parameters in the 2000-2500m section.

[0088] The mechanical specific energy baseline can be calculated and approximated by the rock compressive strength according to the basic theory of rock mechanics.

[0089] The mechanical specific energy of the PDC drill bit during drilling is obtained using formula (2). The curve of mechanical specific energy changing with depth is plotted in a rectangular coordinate system, with the X-axis representing mechanical specific energy and the Y-axis representing depth.

[0090] Monitor the change in mechanical specific energy and calculate the deviation of mechanical specific energy using formula (3). In this case, the deviation of mechanical specific energy is 72%, which is greater than the threshold of 10%. The deviation is large and may cause drill bit wear.

[0091] Using formula (4), the dimensionless wear rate of the PDC drill bit in the 2250-2350m section is calculated to be 0.0065. The calculated value is greater than the threshold of 0.005. Figure 5 As shown in the image. Based on this, it is determined that the drill bit has experienced severe wear, and it is recommended to stop drilling, pull out the drill bit, and replace it.

[0092] To address the problems of strong subjectivity, difficulty in quantification, and poor adaptability in traditional PDC drill bit wear prediction methods, the above embodiments of this invention propose a dynamic monitoring method for PDC drill bit wear status while drilling. This method employs an optimized mechanical energy density algorithm for rapid quantitative determination of whether drill bit wear has occurred in a specific formation. It also leverages the easily quantifiable characteristics of the PDC drill bit wear physical model to quantitatively calculate the wear degree of PDC drill bits in specific formations. This method enables real-time monitoring of PDC drill bit wear while drilling, providing a basis for field engineers to make decisions such as adjusting drilling parameters and replacing drill bits during tripping. Furthermore, it can be implemented using only existing drilling logging parameters and related tool parameters, avoiding the need to install numerous sensors on the drilling platform and downhole tools, thus lowering the barrier to entry and demonstrating significant application value.

[0093] While improving applicability and reducing the complexity of calculations and the cost of field applications, it also makes drill bit wear prediction more accurate. Accurate understanding of wear can provide a basis for making the next decision on the drilling site, and can also support the optimization of drilling parameters, guidance on drill bit selection, optimization of drill bit design, saving drilling costs, and improving economic efficiency.

[0094] For the foregoing method embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0095] It should be noted that, in other embodiments of the present invention, the method can also combine one or more of the above embodiments to obtain a new method for dynamic monitoring of PDC drill bit wear status while drilling, so as to achieve optimized control of the operating parameters of modern drilling tools.

[0096] It should be noted that, based on the methods in any one or more embodiments of the present invention described above, the present invention also provides a storage medium storing program code that can implement the methods described in any one or more embodiments. When the program code is executed by the operating system, it can implement the PDC drill bit wear state dynamic monitoring method as described above.

[0097] Example 2

[0098] The methods described in detail in the above-disclosed embodiments of the present invention can be implemented using various forms of devices or systems. Therefore, based on other aspects of the methods described in any one or more of the above embodiments, the present invention also provides a PDC drill bit wear condition dynamic monitoring system for drilling. This system is used to execute the PDC drill bit wear condition dynamic monitoring method for drilling described in any one or more of the above embodiments. Specific embodiments are given below for detailed description.

[0099] Specifically, Figure 6 The figure shows a schematic diagram of the PDC drill bit wear condition dynamic monitoring system provided in an embodiment of the present invention. As shown in the figure, the system includes:

[0100] The mechanical energy specificity monitoring module is configured to determine the optimized mechanical energy specificity calculation model corresponding to the PDC drill bit based on the drill string combination characteristics and operational intervention factors during PDC drill bit application, and obtain the mechanical energy specificity that characterizes the dynamic rock breaking efficiency of the drill bit under test at different working depths in real time.

[0101] The wear preliminary analysis module is configured to divide the analysis area according to a set range, and for each analysis area, calculate the corresponding mechanical specific energy deviation based on the obtained mechanical specific energy according to the set logic, and compare it with the set deviation standard value to determine the stability of the drill bit mechanical specific energy in the analysis area.

[0102] The wear quantitative analysis module is configured to selectively introduce the wear physical prediction model preset by the PDC drill bit to calculate the wear state data of the drill bit during operation for the analysis section where the mechanical specific energy stability meets the set conditions.

[0103] The drilling optimization module is configured to make decisions and match construction adjustment schemes based on the stability of the drill bit's mechanical specific energy and wear status data.

[0104] Furthermore, in one embodiment, the mechanical specific energy monitoring module determines the optimized mechanical specific energy calculation model corresponding to the PDC drill bit through the following operation:

[0105] Based on the fundamental mechanical specific energy model that integrates multiple drilling data such as drilling pressure, rotational speed, torque, drill bit size, mechanical drilling speed, and formation compressive strength, and combined with the hardware characteristics of the PDC drill bit + screw drill string combination, the model further introduces multiple influencing factors such as screw drilling speed, screw torque, threshold drilling pressure, and threshold drilling pressure to construct a corresponding optimized mechanical specific energy calculation model.

[0106] In an optional embodiment, the mechanical specific energy monitoring module is configured to calculate the mechanical specific energy data of the drill bit at each working depth according to the optimized mechanical specific energy calculation model described in the following formula:

[0107]

[0108] In the formula, E is the mechanical specific energy (MPa); W is the drilling pressure (kN); T is the surface torque (kN·m); N is the surface rotational speed (rpm); ROP is the mechanical drilling rate (m / h); d B Drill bit diameter, mm; W bs Threshold drilling pressure, kN; T bs The threshold torque is expressed in kN·m; K N T is the drilling speed-to-flow ratio of the screw drill bit, r / L; Q is the total displacement, L / s; T m The maximum output torque of the screw drill bit is expressed in kN·m; Δp m The maximum pressure drop at the inlet and outlet of the screw drill bit, in MPa; Δp p The inlet and outlet pressures of the drill string assembly are in MPa.

[0109] Furthermore, in one embodiment, the system also includes a section range setting module, which is configured to pre-determine and record the analysis section range matched based on the time of calculating the unit mechanical energy, geological characteristics, well type, and construction working depth. In this way, during the application monitoring process, the wear preliminary analysis module can directly call to realize the division according to the construction needs.

[0110] In an optional embodiment, the wear preliminary analysis module calculates the mechanical specific energy deviation of the drill bit using the following formula:

[0111]

[0112] Where i represents the i-th mechanical specific energy monitoring value in the current analysis section, and D represents the total number of mechanical specific energy monitoring values ​​in the analysis section.

[0113] Preferably, in one embodiment, the wear quantitative analysis module is specifically configured as follows: for analysis sections that meet the set conditions for mechanical energy stability, the mechanical energy stability of adjacent sections before and after it is further analyzed. If the difference in stability between the section and the previous and / or subsequent section is within the set range, the section is regarded as a section that meets the wear conditions, and the subsequent wear state data is calculated to exclude the situation of sudden drilling encounters with abnormal geology.

[0114] Furthermore, in one embodiment, the wear quantitative analysis module is further configured to: quantitatively calculate the wear state data of the worn drill bit according to the following wear physical prediction model:

[0115]

[0116] In the formula, ω is the dimensionless wear rate of the PDC drill bit; kN; A f The rock abrasiveness index, mg / cm³ 3 P is the normal force of the cutting tooth, kN; V is the cutting speed, m / s; h is the dimensionless wear height of the cutting tooth; a, b, d, and k are parameters related to the shape of the cutting tooth and the formation characteristics.

[0117] In an optional embodiment, the drilling optimization module is configured as follows: for depth sections where the mechanical energy stability meets the wear conditions, if the wear status data does not reach the set threshold, it is determined to be light wear, and the construction parameters are adjusted to ensure drilling effect before continuing drilling with the original drill bit; if the wear status data is greater than or equal to the set threshold, it is determined to be heavy wear, and the drill bit is replaced before continuing drilling based on the matched construction parameters.

[0118] In the PDC drill bit wear condition dynamic monitoring system provided in this embodiment of the invention, each module or unit structure can operate independently or in combination according to actual judgment and calculation needs to achieve the corresponding technical effects.

[0119] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0120] The phrase "an embodiment" in the specification means that a specific feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0121] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A method for dynamic monitoring of PDC drill bit wear condition during drilling, characterized in that, The method includes: Mechanical specific energy monitoring steps: Based on the drill string combination characteristics and operational intervention factors when the PDC drill bit is applied, determine the optimized mechanical specific energy calculation model corresponding to the PDC drill bit, and obtain the mechanical specific energy that characterizes the dynamic rock breaking efficiency of the drill bit under test at different working depths in real time; Preliminary wear analysis steps: Divide the analysis area into sections according to the set range, calculate the corresponding mechanical specific energy deviation for each analysis section based on the obtained mechanical specific energy according to the set logic, and compare it with the set deviation standard value to determine the stability of the drill bit's mechanical specific energy in the analysis section; Wear quantitative analysis steps: For the analysis section where the mechanical specific energy stability meets the set conditions, the wear physical prediction model preset by PDC drill bit is selectively introduced to calculate the wear state data of the drill bit during operation; Drilling optimization steps: Determine the matching construction adjustment plan based on the stability of the drill bit's mechanical specific energy and wear status data; In the mechanical specific energy monitoring step, the mechanical specific energy data of the drill bit at each working depth are calculated according to the optimized mechanical specific energy calculation model described in the following formula: In the formula, For mechanical specific energy, ; For drilling pressure, ; For ground torque, ; For ground rotation speed, ; For mechanical drilling speed, ; The diameter of the drill bit. ; Threshold drilling pressure, ; For threshold torque, ; This refers to the drilling speed-to-flow ratio of the screw drill bit. ; For total displacement, ; This is the maximum output torque of the screw drill bit. ; This represents the maximum pressure drop at the inlet and outlet of the screw drill bit. ; For the inlet and outlet pressures of the drill string assembly, ; In the preliminary wear analysis step, the deviation of the drill bit's mechanical specific energy is calculated using the following formula: Where i represents the i-th mechanical specific energy monitoring value in the current analysis section, and D represents the total number of mechanical specific energy monitoring values ​​in this analysis section; In the quantitative wear analysis step, the wear state data of the worn drill bit are quantitatively calculated according to the following wear physical prediction model: In the formula, The dimensionless wear rate of the PDC drill bit; As an index of rock abrasiveness, ; For cutting teeth, ; For cutting speed, ; The dimensionless wear height of the cutting teeth; These are parameters related to the shape of the cutting teeth and formation characteristics.

2. The method according to claim 1, characterized in that, In the mechanical specific energy monitoring step, the process of determining the optimized mechanical specific energy calculation model corresponding to the PDC drill bit includes: Based on the fundamental mechanical energy specificity model that integrates multiple drilling data such as drilling pressure, rotational speed, torque, drill bit size, mechanical drilling speed, and formation compressive strength, and combined with the hardware characteristics of the PDC drill bit + screw drill string combination, multiple influencing factors such as screw drilling speed, screw torque, threshold drilling pressure, and threshold torque are further introduced to construct a corresponding optimized mechanical energy specificity calculation model.

3. The method according to claim 1, characterized in that, The analysis section range is determined in advance based on the time, geological characteristics, well type, and construction depth of the unit mechanical energy calculation and is recorded. In the preliminary wear analysis step, the division is directly called upon according to the construction requirements.

4. The method according to claim 1, characterized in that, In the quantitative wear analysis step, for analysis sections with mechanical specific energy stability that meet the set conditions, the mechanical specific energy stability of the adjacent sections before and after it is further analyzed. If the difference in stability with the previous and / or subsequent sections is within the set range, the section is then regarded as a section that meets the wear conditions, and the subsequent wear state data is calculated to exclude the situation of sudden drilling encounters with abnormal geological conditions.

5. The method according to claim 1, characterized in that, In the drilling optimization process, for depth sections where the mechanical energy stability meets the wear conditions, if the wear status data does not reach the set threshold, it is determined to be light wear. The drilling parameters are adjusted to ensure drilling results, and the original drill bit is used to continue drilling. If the wear status data is greater than or equal to the set threshold, it is determined to be heavy wear. The drill bit is replaced, and drilling continues based on the matched drilling parameters.

6. A storage medium, characterized in that, The storage medium stores program code capable of implementing the method as described in any one of claims 1 to 5.

7. A dynamic monitoring system for wear condition of PDC drill bits during drilling, characterized in that, The system performs the method as described in any one of claims 1 to 5.

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