System and method for measuring temperature rise rule of well bottom drill bit in drilling process

Abstract

The invention provides a system and method for measuring the temperature rise rule of a shaft bottom drill bit in the drilling process, and relates to the technical field of petroleum and natural gas drilling, and the system comprises a simulation drilling device which comprises a simulation shaft, a simulation drill rod and a rock breaking drill bit, the rock breaking drill bit is installed at one end of the simulation drill rod and can stretch into the simulation wellbore along with the simulation drill rod, a shale sample is arranged in the simulation wellbore, and a plurality of temperature measuring elements are arranged in the simulation wellbore, the simulation drill rod, the rock breaking drill bit and the shale sample respectively; the drilling machine rotating device is connected with the other end of the simulation drill rod and drives the simulation drill rod to rotate, and the simulation drill rod drives the rock breaking drill bit to drill the shale sample; and the data acquisition unit is respectively connected with the plurality of temperature measuring elements and is used for receiving the temperature data acquired by the temperature measuring elements. The system and method for measuring the temperature rise rule of the well bottom drill bit in the drilling process can more accurately predict the temperature rise rule of a well bottom temperature field in the rock breaking process of the drill bit.

Description

Technical Field

[0001] The invention relates to the technical field of oil and natural gas drilling, and in particular to a measuring system and a measuring method for a temperature rise law of a bottom hole drill bit during drilling. Background Art

[0002] Unconventional natural gas such as shale gas has become the main force for increasing reserves and production, and the safe and efficient development of shale gas is an important demand for energy development. As an important successor energy source in the future, the exploration and development of unconventional oil and gas resources such as shale gas has gradually moved from shallow formations to deep formations. At present, the long horizontal well development mode is mainly adopted, and the bottom hole circulation temperature is high. During the drilling process, the technical difficulties of high failure rate of rotary steering instruments under high temperature conditions and difficulty in rapid drilling of long horizontal sections under high-density drilling fluid conditions will be faced. In particular, when hard rock formations are frequently encountered, PDC drill bit wear and failure of downhole tool components such as rotary steering caused by high bottom hole temperature are frequent, which is not conducive to the safe and effective development of shale gas long horizontal wells.

[0003] During the drilling process, different wellbore heat transfer conditions can have an important impact on the change law of the PDC drill bit and the bottom hole temperature field. At present, the research methods for wellbore heat transfer problems can be summarized into two categories: semi-transient method and full transient method. The semi-transient method and the full transient method have their own advantages and disadvantages. When the semi-transient method analyzes the wellbore heat transfer problem, since the wellbore is regarded as an infinitely long linear heat source extending along the axis of the wellbore, the calculation of the heat exchange between the wellbore and the formation does not require grid division in the formation, but relies on a dimensionless time function. Therefore, the application of the semi-transient method is not limited by the geometric shape of the wellbore trajectory and has a wide range of applications. However, its prediction accuracy depends largely on the dimensionless time function. Inappropriate functions may lead to large errors in the calculation results of the wellbore temperature in the early heat exchange stage. The full transient method makes full use of modern computer technology and numerical calculation technology, and strictly solves the entire temperature field according to the energy conservation equation and the essence of heat exchange between the heat exchange objects. The accuracy of the calculation results is independent of the length of the heat exchange time. However, this method requires grid division in the formation when applied, and is more suitable for vertical wells. It is very difficult to apply this method to inclined wells, large displacement wells and horizontal wells.

[0004] During the rock breaking process of the PDC drill bit, the cutting teeth drill at high speed and rub against the rock violently. More than half of the energy supplied to the drill bit is converted into friction heat. The superposition effect of high temperature formation temperature and cutting friction heat causes the temperature of the drill bit to rise sharply. However, the existing research objects of wellbore heat transfer mainly include heat transfer in the wellbore and heat transfer in the formation. The influence of heat generated by the bottom hole drill bit on the wellbore temperature field is not fully considered. The calculation of the wellbore temperature field is not accurate enough, which is far from the actual drilling process.

[0005] In view of this, the inventor, based on many years of production design experience in this field and related fields, has designed a measurement system and method for the temperature rise law of the bottom hole drill bit during drilling after repeated experiments, in order to solve the problems existing in the prior art. Summary of the invention

[0006] The purpose of the present invention is to provide a system and method for measuring the temperature rise law of a bottom hole drill bit during drilling, which can more accurately predict the temperature rise law of the bottom hole temperature field during the rock breaking process of the drill bit.

[0007] In order to achieve the above object, the present invention proposes a measurement system for the temperature rise law of a bottom hole drill bit during drilling, wherein the measurement system comprises:

[0008] A simulated drilling device, comprising a simulated wellbore, a simulated drill rod and a rock-breaking drill bit, wherein the rock-breaking drill bit is mounted at one end of the simulated drill rod and can extend into the simulated wellbore along with the simulated drill rod, a shale sample is arranged in the simulated wellbore, and a plurality of temperature measuring elements are respectively arranged in the simulated wellbore, the simulated drill rod, the rock-breaking drill bit and the shale sample;

[0009] A drilling rig rotating device, connected to the other end of the simulated drill rod and driving the simulated drill rod to rotate, and the simulated drill rod drives the rock breaking drill bit to drill the shale sample;

[0010] The data acquisition unit is respectively connected to the plurality of temperature measuring elements and receives the temperature data acquired by each of the temperature measuring elements.

[0011] The present invention also proposes a method for measuring the temperature rise law of a bottom hole drill bit during drilling. Using the measurement system as described above, the measurement method comprises:

[0012] The simulated drill rod is driven to rotate by the drilling rig rotating device, and the simulated drill rod drives the rock breaking drill bit to drill the shale sample;

[0013] A plurality of temperature measuring elements respectively detect temperature data of a simulated wellbore, a simulated drill pipe, a rock breaking drill bit and a shale sample and transmit the temperature data to a data acquisition unit;

[0014] The data acquisition unit collects temperature data and calculates the temperature rise law of the bottom hole temperature field during the drilling process of the rock breaking drill bit based on the temperature data.

[0015] Compared with the prior art, the present invention has the following characteristics and advantages:

[0016] The present invention proposes a measurement system and method for the temperature rise law of the bottom hole drill bit during drilling. The drilling rig drilling device drives the rock breaking drill bit to drill the shale sample through the simulated drill rod to conduct the bottom hole drill bit breaking shale experiment. At the same time, multiple temperature measuring elements arranged in the simulated wellbore, simulated drill rod, rock breaking drill bit and shale sample collect temperature data in real time and transmit the temperature data to the data acquisition unit. As a result, the data acquisition unit can obtain the temperature rise law of the entire bottom hole temperature field such as the drill bit, drill rod, shale inside and wellbore annulus during the bottom hole drill bit breaking shale experiment, fully considering the influence of the heat generated by the bottom hole drill bit on the temperature field of the whole wellbore, and can provide data support for establishing a more accurate prediction model of the temperature field of the whole wellbore of the drill bit breaking rock drilling, and finally greatly improve the accuracy of the wellbore temperature field prediction model. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the figures are only schematic, used to help understand the present invention, and are not specifically limited to the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to the teachings of the present invention.

[0018] Figure 1 It is a structural schematic diagram of the measurement system proposed by the present invention;

[0019] Figure 2 It is a schematic diagram of the structure of the experimental frame in the present invention;

[0020] Figure 3 It is a structural schematic diagram of the drilling rig rotating device in the present invention;

[0021] Figure 4 It is a working schematic diagram of the data collection unit in the present invention;

[0022] Figure 5 It is a schematic diagram of the installation of multiple temperature detection elements in the present invention;

[0023] Figure 6 for Figure 5 A partial enlarged view of (a);

[0024] Figure 7 for Figure 5 A partial enlarged view of (II);

[0025] Figure 8 for Figure 5 A partial enlarged view of (c).

[0026] Description of Reference Numerals

[0027] 100. Measurement system; 10. Simulation drilling device;

[0028] 11. Simulate wellbore; 12. Simulate drill pipe;

[0029] 13. Rock breaking drill bit; 131. Drill bit body;

[0030] 132. Cutting tooth composite piece; 133. Temperature thermocouple channel;

[0031] 134. Thermal grease; 135. Sealant;

[0032] 20. Drilling rig rotating device; 21. Driving motor;

[0033] 22. Coupling; 23. Drill pipe joint;

[0034] 24. Water inlet joint; 25. Conductive slip ring;

[0035] 26. Torque sensor; 30. Data acquisition unit;

[0036] 40. Shale sample; 50. Temperature measuring element;

[0037] 51. a first temperature thermocouple; 52. a second temperature thermocouple;

[0038] 53. a third temperature thermocouple; 54. a fourth temperature thermocouple;

[0039] 55. Signal transmission line; 60. Infrared thermal imager;

[0040] 70. Experimental rack; 71. Experimental rack top plate;

[0041] 72. Experimental stand base; 73. Column;

[0042] 74. Installation box; 80. Lifting mechanism;

[0043] 81. Displacement plate; 82. Hydraulic cylinder;

[0044] 83. Hydraulic rod; 84. Hydraulic device;

[0045] 841, first oil inlet pipeline; 842, first oil return pipeline;

[0046] 843. Second oil inlet pipeline; 844. Second oil return pipeline;

[0047] 85. Electronic control device; 90. Drilling fluid mixing device;

[0048] 91. Drilling fluid low-pressure pipeline; 92. Drilling fluid booster pump;

[0049] 93. Drilling fluid high-pressure pipeline; 94. Drilling fluid normal-pressure drainage pipeline. DETAILED DESCRIPTION

[0050] The details of the present invention can be more clearly understood with reference to the accompanying drawings and the description of the specific embodiments of the present invention. However, the specific embodiments of the present invention described herein are only used for the purpose of explaining the present invention and cannot be understood as limiting the present invention in any way. Under the guidance of the present invention, technicians can conceive of any possible variations based on the present invention, which should all be considered to belong to the scope of the present invention.

[0051] like Figures 1 to 8 As shown, the present invention proposes a measurement system 100 for measuring the temperature rise law of a bottom hole drill bit during drilling, and the measurement system 100 includes:

[0052] The simulated drilling device 10 includes a simulated wellbore 11, a simulated drill rod 12 and a rock breaking drill bit 13. The rock breaking drill bit 13 is installed at one end of the simulated drill rod 12 and can be extended into the simulated wellbore 11 along with the simulated drill rod 12. A shale sample 40 is arranged in the simulated wellbore 11. A plurality of temperature measuring elements 50 are respectively arranged in the simulated wellbore 11, the simulated drill rod 12, the rock breaking drill bit 13 and the shale sample 40.

[0053] The drilling rig rotating device 20 is connected to the other end of the simulated drill rod 12 and drives the simulated drill rod 12 to rotate, and the simulated drill rod 12 drives the rock breaking drill bit 13 to drill the shale sample 40;

[0054] The data acquisition unit 30 is connected to the plurality of temperature measuring elements 50 respectively and receives the temperature data acquired by each temperature measuring element 50 .

[0055] The present invention proposes a measuring system 100 for measuring the temperature rise law of a bottom hole drill bit during drilling. The drilling rig rotating device 20 drives the rock breaking drill bit 13 to drill the shale sample 40 through the simulated drill rod 12 to perform a bottom hole drill bit shale breaking experiment. At the same time, a plurality of temperature measuring elements 50 arranged in the simulated wellbore 11, the simulated drill rod 12, the rock breaking drill bit 13 and the shale sample 40 collect temperature data in real time and transmit the temperature data to the data acquisition unit 30. Thus, the data acquisition unit 30 can obtain the temperature rise law of the entire bottom hole temperature field such as the drill bit, the drill rod, the inside of the shale and the wellbore annulus during the bottom hole drill bit shale breaking experiment, fully considers the influence of the heat generated by the bottom hole drill bit on the temperature field of the whole wellbore, and can provide data support for establishing a more accurate prediction model of the temperature field of the whole wellbore of the drill bit rock breaking drilling, and finally greatly improves the accuracy of the wellbore temperature field prediction model.

[0056] The measuring system 100 for the temperature rise law of the bottom hole drill bit during drilling proposed in the present invention can accurately obtain the temperature rise performance of the bottom hole drill tool during the drilling of a long horizontal section shale gas well. It is also suitable for other horizontal wells and deep well and ultra-deep well operation scenarios where the drill bit is severely worn and the bottom hole circulates at high temperature, and has a relatively broad prospect for promotion and application.

[0057] In an optional embodiment of the present invention, a shale clamping device (not shown in the figure) is provided in the simulated wellbore 11, and the shale sample 40 is detachably fixed in the simulated wellbore 11 through the shale clamping device. With the above structure, the type of the shale sample 40 can be changed to simulate different formation environments. For example, the shale sample 40 can be changed to a highly abrasive formation and hard formation rock that can cause severe wear of the drill bit and high temperature circulation at the bottom of the well, so that the bottom temperature rise law of horizontal wells and deep wells and ultra-deep wells drilling in other formations can be analyzed.

[0058] In the present invention, the temperature measuring element 50 is built into the simulated wellbore 11, the simulated drill pipe 12, the rock breaking drill bit 13 and the shale sample 40, and can directly measure the temperature of the simulated wellbore 11, the simulated drill pipe 12, the rock breaking drill bit 13 and the shale sample 40, which is more realistic and accurate.

[0059] In an optional embodiment of the present invention, the temperature measuring element 50 is a temperature thermocouple, and each temperature thermocouple is electrically connected to the data acquisition unit 30 through a signal transmission line 55. The above method of directly measuring temperature by contact with a built-in temperature thermocouple measures the temperature of the rock breaking drill bit 13 during drilling by using a plurality of first temperature thermocouples 51 built into the rock breaking drill bit 13, measures the temperature of the simulated drill pipe 12 during drilling by using a plurality of second temperature thermocouples 52 built into the simulated drill pipe 12, measures the annular temperature during the return of drilling fluid by using a plurality of third temperature thermocouples 53 built into different positions of the simulated wellbore 11, and measures the internal temperature of the shale sample 40 during drilling by using a plurality of fourth temperature thermocouples 54 built into the shale sample 40.

[0060] In an optional embodiment of the present invention, the rock breaking drill bit 13 includes a drill bit body 131 and a plurality of cutting tooth composite pieces 132 arranged on the drill bit body 131, and temperature measuring elements 50 are respectively arranged in the drill bit body 131 and the cutting tooth composite pieces 132. With the above structure, the temperatures of the cutting tooth composite pieces 132 and the drill bit body 131 during the drilling process are measured by the first temperature thermocouple 51 and the second temperature thermocouple 52 built into the rock breaking drill bit 13.

[0061] Furthermore, the specific process of measuring temperature is as follows: first, a 2 mm temperature thermocouple hole 133 is drilled on the cutting tooth composite piece 132 and the drill bit body 131, and the probes of the first temperature thermocouple 51 and the second temperature thermocouple 52 are placed in the corresponding temperature thermocouple hole 133; secondly, in order to better ensure close contact between the drill bit body 131 (cutting tooth composite piece 132) and the probe of the first temperature thermocouple 51 (the probe of the second temperature thermocouple 52), the temperature thermocouple hole 133 is densely filled with thermal conductive silicone grease 134; finally, in order to prevent the drilling fluid from entering the temperature thermocouple hole 133 and affecting the measurement result, the temperature thermocouple hole 133 is filled again with sealant 135.

[0062] In an optional embodiment of the present invention, the rock breaking drill bit 13 is a PDC drill bit.

[0063] In an optional embodiment of the present invention, the measurement system 100 further includes an infrared thermal imager 60 capable of contactlessly measuring the simulated wellbore 11, and the infrared thermal imager 60 is electrically connected to the data acquisition unit 30. With the above structure, the infrared thermal imager 60 is connected to the data acquisition unit 30 (such as a computer) through a data line, so that the data acquisition unit 30 obtains an infrared dynamic temperature measurement image of the rock breaking drill bit 13 during the drilling process. Furthermore, the data acquisition unit 30 can also display a mark in a designated bottom well area to directly obtain the surface temperature distribution law of the bottom well drill bit.

[0064] In the present invention, the measurement system 100 adopts a method combining the built-in temperature thermocouple contact direct measurement with the infrared thermal imager 60 indirect non-contact measurement to test the temperature of the cutting tooth composite piece 132 of the rock breaking drill bit 13, the temperature of the drill bit body 131, the temperature of the simulated drill pipe 12, the internal temperature of the shale sample 40, and the increase in the annulus return temperature.

[0065] In an optional embodiment of the present invention, the measurement system 100 further includes an experimental frame 70, on which the simulated drilling device 10 and the drilling rig rotating device 20 are respectively arranged, and a lifting mechanism 80 for driving the drilling rig rotating device 20 to move is arranged on the experimental frame 70. By driving the drilling rig rotating device 20 and the simulated drill rod 12 to be lowered and lifted by the lifting mechanism 80, not only can the drilling process of the drill bit be simulated more realistically, but also the disassembly and replacement of the rock breaking drill bit 13 and the shale sample 40 are facilitated.

[0066] In an optional example of this embodiment, the experimental rack 70 includes an experimental rack top plate 71, an experimental rack base 72 and a plurality of columns 73, wherein the plurality of columns 73 are respectively arranged between the experimental rack top plate 71 and the experimental rack base 72, and each column 73 is detachably fixedly connected to the experimental rack top plate 71 and the experimental rack base 72 by a nut, thereby forming a complete structure.

[0067] Furthermore, the lifting mechanism 80 includes a displacement plate 81, a hydraulic cylinder 82 and a hydraulic rod 83. The displacement plate 81 is arranged between the experimental frame top plate 71 and the experimental frame base 72. Each column 73 passes through the displacement plate 81 and slides with the displacement plate 81. The hydraulic cylinder 82 is fixedly connected to the top of the experimental frame top plate 71 by bolts. The bottom end of the hydraulic rod 83 passes through the experimental frame top plate 71 and is fixedly connected to the displacement plate 81. After applying hydraulic pressure, the hydraulic cylinder 82 drives the hydraulic rod 83 to extend or retract, thereby applying or removing drilling pressure on the displacement plate 81, and the displacement plate 81 moves downward or upward. The drilling rig rotating device 20 is installed on the displacement plate 81, thereby realizing the lowering or lifting of the simulated drill rod 12.

[0068] In an optional embodiment of the present invention, the drilling rig rotating device 20 includes a driving motor 21, a coupling 22 and a drill rod joint 23 connected in series, and the drill rod joint 23 is detachably connected to the simulated drill rod 12. With the above structure, the driving motor 21 drives the drill rod joint 23 to rotate through the coupling 22, and then the drill rod joint 23 drives the simulated drill rod 12 to rotate synchronously. The coupling 22 transmits torque while reducing vibration and buffering, driving the simulated drill rod 12 to rotate.

[0069] In an optional example of this embodiment, the drive motor 21 is fixedly connected above the displacement plate 81 by bolts, and the output end of the drive motor 21 passes downward through the displacement plate 81 and is connected to the coupling 22 .

[0070] In an optional example of this embodiment, the drive motor 21 is a hydraulic motor.

[0071] In an optional example, the lifting mechanism 80 further includes a hydraulic device 84, which is connected to the hydraulic cylinder 82 via a first oil inlet line 841 and a first oil return line 842 to provide hydraulic oil to the hydraulic cylinder 82. Furthermore, the hydraulic device is also connected to the hydraulic motor via a second oil inlet line 843 and a second oil return line 844 to provide hydraulic oil to the hydraulic motor.

[0072] Furthermore, the lifting mechanism 80 also includes an electric control device 85 , and the hydraulic device 84 is controlled by the electric control device 85 .

[0073] In an optional embodiment of this embodiment, an axially through-going drill pipe passage is provided in the simulated drill pipe 12, a diversion passage is provided in the drill pipe joint 23, a water inlet joint 24 is provided on the outer shell of the drill pipe joint 23, the water inlet joint 24 is in sealing and rotational cooperation with the drill pipe joint 23, and the drill pipe joint 23 is connected to the drilling fluid mixing device 90 through the water inlet joint 24. With the above device, when the rock breaking drill bit 13 drills the shale sample 40, the drilling fluid provided by the drilling fluid mixing device 90 enters the rock breaking drill bit 13 through the water inlet joint 24, the drill pipe joint 23, and the simulated drill pipe 12, so as to more realistically simulate the actual drilling condition of the PDC drill bit.

[0074] The present invention has a driving circuit for the lifting mechanism 80, a driving circuit for the drilling rig rotating device 20 and a circuit for the drilling fluid (i.e., a circuit for jet impact). The above three flow paths are independently arranged and can also be independently controlled and adjusted, so that the rotation speed, drilling pressure, drilling fluid displacement and jet pressure during the drilling process are continuously adjustable. Through similar principles, multiple parameters of shale drilling can be designed to simulate various processes of drilling long horizontal sections of shale gas wells at the drilling site, so that the test conditions are more consistent with the temperature rise law under actual conditions on site.

[0075] In an optional example, the water inlet joint 24 has a joint body and a water inlet pipe, the joint body has an axially through-mounting cavity, the water inlet pipe is fixedly connected to the outer wall of the joint body, a water inlet channel is provided in the water inlet pipe, the water inlet channel is connected to the mounting cavity, the joint body is sleeved outside the drill pipe joint 23 and is sealed and rotated with the drill pipe joint 23, one end of the guide cavity of the drill pipe joint 23 passes through the bottom end of the drill pipe joint 23 and is connected to the drill pipe channel of the simulated drill pipe 12, the other end of the guide cavity opens on the outer wall of the drill pipe joint 23, a guide ring groove is provided in the water inlet joint 24, the guide ring groove is aligned with the opening of the other end of the guide cavity, and the water inlet channel of the water inlet pipe is connected to the guide ring groove. With the above structure, the drilling fluid provided by the drilling fluid mixing device 90 enters the guide ring groove from the water inlet channel, then enters the guide cavity from the guide ring groove, and finally enters the drill pipe channel from the guide cavity for drilling operation of the rock breaking drill bit 13.

[0076] In an optional example, the drilling fluid mixing device 90 is a low-pressure drilling fluid mixing device, and a drilling fluid low-pressure pipeline 91, a drilling fluid booster pump 92 and a drilling fluid high-pressure pipeline 93 are sequentially arranged between the drilling fluid mixing device and the water inlet joint 24.

[0077] Furthermore, an installation box 74 for installing the simulated wellbore 11 is provided on the test frame base 72. A receiving chamber is provided in the installation box 74, and the simulated wellbore 11 is provided in the receiving chamber. A drilling fluid normal pressure drainage pipeline 94 is connected to the outside of the installation box 74, and the drilling fluid normal pressure drainage pipeline 94 is connected to the drilling fluid mixing device 90. With the above structure, the drilling fluid discharged from the simulated wellbore 11 flows back to the drilling fluid mixing device 90 via the receiving chamber and the drilling fluid normal pressure drainage pipeline 94.

[0078] In an optional example of this embodiment, a conductive slip ring 25 is installed on the drill pipe joint 23, and the signal transmission lines 55 of each temperature measuring element 50 in the simulated drill pipe 12 and the signal transmission lines 55 of each temperature measuring element 50 in the rock breaking drill bit 13 are electrically connected to the data acquisition unit 30 through the conductive slip ring 25 to ensure high-speed rotation of the drill pipe joint 23 and the rock breaking drill bit 13.

[0079] In an optional example, the conductive slip ring 25 is a through-hole conductive slip ring, and the signal transmission line 55 of each temperature measuring element 50 extends through the channel in the simulated drill pipe 12 and slides in contact with the lower part of the through-hole conductive slip ring, thereby avoiding the wire entanglement problem caused by the rotation of the signal transmission line 55. It can rotate 360° continuously without limit along with the simulated drill pipe and rock breaking drill bit, thereby realizing uninterrupted transmission of thermocouple signals.

[0080] In an optional embodiment of this embodiment, a torque sensor 26 is installed on the drill rod joint 23, and the torque sensor 26 is electrically connected to the data acquisition unit 30. With the above mechanism, the data acquisition unit 30 can obtain the rotation speed data of the simulated drill rod 12 in real time through the torque sensor 26.

[0081] The present invention also proposes a method for measuring the temperature rise law of a bottom hole drill bit during drilling. Using the measurement system as described above, the measurement method comprises:

[0082] The simulated drill rod 12 is driven to rotate by the drilling rig rotating device 20, and the simulated drill rod 12 drives the rock breaking drill bit 13 to drill the shale sample 40;

[0083] The plurality of temperature measuring elements 50 respectively detect the temperature data of the simulated wellbore 11, the simulated drill pipe 12, the rock breaking drill bit 13 and the shale sample 40 and transmit the temperature data to the data acquisition unit 30;

[0084] The data acquisition unit 30 collects temperature data and calculates the temperature rise law of the bottom hole temperature field during the drilling process of the rock breaking drill bit 13 according to the temperature data.

[0085] The present invention proposes a method for measuring the temperature rise law of the bottom hole drill bit during drilling, and based on the test results of drill bit rock breaking heat generation that simulates the downhole environment, establishes a long horizontal section drilling heat exchange model and a numerical calculation method, analyzes the response law of the drill bit and bottom hole temperature field and drilling parameters during the rock breaking process, reveals the flow heat exchange mechanism of long horizontal section shale gas well drilling, clarifies the distribution characteristics of the wellbore temperature field under the influence of drill bit heat generation, and explores the temperature control method in the long horizontal section drilling process, which is of great significance for guiding drill bit design and optimizing the wellbore temperature control method of long horizontal section shale gas wells.

[0086] The specific working process of the measuring system 100 and the measuring method of the temperature rise law of the bottom hole drill bit during drilling proposed by the present invention is as follows:

[0087] The drilling fluid mixing device 90 pumps the prepared drilling fluid into the drilling fluid booster pump 92 through the drilling fluid low-pressure pipeline 91. After being pressurized by the drilling fluid booster pump 92, the drilling fluid enters the simulated drill pipe 12 through the drilling fluid high-pressure pipeline 93, and finally reaches the rock-breaking drill bit 13 connected below it. A jet is formed through the nozzle on the rock-breaking drill bit 13 to impact the surface of the shale sample 40 clamped by the shale clamping device. The fluid after the experiment is filtered and discharged through the drilling fluid normal pressure drainage pipeline 94; the hydraulic device 84 is connected to the drilling rig lifting mechanism and the drilling rig rotating device 20 through the hydraulic pipeline, and controls the simulated drill pipe 12 and the rock-breaking drill bit 13 to rise and fall and rotate up and down through the electronic control device 85, so as to form a certain drilling pressure and speed to rotate and drill the shale sample 40 clamped by the shale clamping device; the data acquisition unit 30 collects data such as temperature, drilling pressure, speed, torque, mechanical drilling speed and jet pressure in real time through the infrared thermal imager 60 and various types of temperature measuring elements 50 and torque sensor 26. Based on the above data, we can establish a long horizontal section drilling heat transfer model and numerical calculation method, analyze the response law of the drill bit and bottom hole temperature field and drilling parameters during the rock breaking process, reveal the flow heat transfer mechanism of long horizontal section shale gas well drilling, clarify the distribution characteristics of the wellbore temperature field under the influence of drill bit heat generation, and explore the temperature control method in the long horizontal section drilling process, which is of great significance for guiding drill bit design and optimizing the wellbore temperature control method of long horizontal section shale gas wells.

[0088] The detailed explanation of the above-mentioned embodiments is only intended to explain the present invention so as to facilitate a better understanding of the present invention. However, these descriptions cannot be interpreted as limitations on the present invention for any reason. In particular, the various features described in different embodiments may also be arbitrarily combined with each other to form other embodiments. Unless there is a clear description to the contrary, these features should be understood to be applicable to any embodiment and are not limited to the described embodiments.

Claims

1. A system for measuring the temperature rise of a bottom hole drill bit during drilling, characterized in that: The measurement system comprises: A simulated drilling device, comprising a simulated wellbore, a simulated drill rod and a rock-breaking drill bit, wherein the rock-breaking drill bit is mounted at one end of the simulated drill rod and can extend into the simulated wellbore along with the simulated drill rod, a shale sample is arranged in the simulated wellbore, and a plurality of temperature measuring elements are respectively arranged in the simulated wellbore, the simulated drill rod, the rock-breaking drill bit and the shale sample; A drilling rig rotating device, connected to the other end of the simulated drill rod and driving the simulated drill rod to rotate, and the simulated drill rod drives the rock breaking drill bit to drill the shale sample; The data acquisition unit is respectively connected to the plurality of temperature measuring elements and receives the temperature data acquired by each of the temperature measuring elements.

2. The system for measuring the temperature rise law of the bottom hole drill bit during drilling as claimed in claim 1, characterized in that: The temperature measuring elements are thermocouples, and each of the thermocouples is electrically connected to the data acquisition unit via a signal transmission line.

3. The system for measuring the temperature rise law of the bottom hole drill bit during drilling as claimed in claim 1 or 2, characterized in that: The rock breaking drill bit comprises a drill bit body and a plurality of cutting tooth composite pieces arranged on the drill bit body, and the temperature measuring elements are respectively arranged in the drill bit body and in the cutting tooth composite pieces.

4. The system for measuring the temperature rise law of the bottom hole drill bit during drilling as claimed in claim 1, characterized in that: The measurement system further comprises an infrared thermal imager capable of measuring the temperature of the simulated wellbore in a non-contact manner, and the infrared thermal imager is electrically connected to the data acquisition unit.

5. The system for measuring the temperature rise law of the bottom hole drill bit during drilling as claimed in claim 1, characterized in that: The measurement system further comprises an experimental frame, on which the simulated drilling device and the drilling rig rotating device are respectively arranged, and a lifting mechanism for driving the drilling rig rotating device to move is arranged on the experimental frame.

6. The system for measuring the temperature rise law of the bottom hole drill bit during drilling as claimed in claim 1, characterized in that: The drilling rig rotating device comprises a driving motor, a coupling and a drill rod joint which are connected in series in sequence, and the drill rod joint is detachably connected to the simulated drill rod.

7. The system for measuring the temperature rise law of the bottom hole drill bit during drilling as claimed in claim 6, characterized in that: An axially penetrating drill rod channel is provided in the simulated drill rod, a diversion cavity connected to the drill rod channel is provided in the drill rod joint, a water inlet joint is provided on the outer shell of the drill rod joint, the diversion cavity is connected to a drilling fluid mixing device through the water inlet joint, and the drilling fluid mixing device is used to supply drilling fluid to the diversion cavity.

8. The system for measuring the temperature rise law of the bottom hole drill bit during drilling as claimed in claim 6, characterized in that: A conductive slip ring is installed on the drill rod joint, and each of the temperature measuring elements in the simulated drill rod and each of the temperature measuring elements in the rock breaking drill bit are electrically connected to the data acquisition unit through the conductive slip ring.

9. The system for measuring the temperature rise law of the bottom hole drill bit during drilling as claimed in claim 6, characterized in that: A torque sensor is installed on the drill pipe joint, and the torque sensor is electrically connected to the data acquisition unit.

10. A method for measuring the temperature rise of a bottom hole drill bit during drilling, using the measurement system as claimed in any one of claims 1 to 9, characterized in that: The measurement method includes: The simulated drill rod is driven to rotate by the drilling rig rotating device, and the simulated drill rod drives the rock breaking drill bit to drill the shale sample; A plurality of temperature measuring elements respectively detect temperature data of a simulated wellbore, a simulated drill pipe, a rock breaking drill bit and a shale sample and transmit the temperature data to a data acquisition unit; The data acquisition unit collects temperature data and calculates the temperature rise law of the bottom hole temperature field during the drilling process of the rock breaking drill bit based on the temperature data.

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