Experimental device and method for researching rock crushing characteristics

Abstract

The invention relates to an experimental device and method for researching rock crushing characteristics. The experimental device comprises an experimental kettle, a base for mounting the experimental kettle and a crusher mounted on the base. The experiment kettle comprises a kettle body and a kettle cover arranged on the kettle body, and the kettle body and the kettle cover jointly define a closed cavity used for containing a rock sample. A drill rod extending into the experiment kettle is arranged on the crusher, and a drill bit propped against the rock sample is mounted at the end part of the drill rod. Wherein the kettle body is configured to enable the temperature and the pressure in the cavity to reach preset values respectively before the drill bit crushes the rock sample. Therefore, the experimental research on the rock crushing characteristic can be ensured to be carried out under the preset temperature and pressure conditions, so that the obtained experimental data is more practical, and reliable support is provided for the research on deep and ultra-deep drilling rock crushing technologies and tools.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rock breaking experiment, and particularly relates to an experimental device and method for studying rock breaking characteristics. BACKGROUND

[0002] In the process of exploring and developing deep and ultra-deep drilling, with the increase of drilling depth, the temperature and pressure under the well are continuously improved. The increase of temperature and pressure has a great influence on the characteristics of the formation rock. Therefore, it is necessary to study and analyze the breaking characteristics of the formation rock under high temperature and high pressure environment, to provide experimental and theoretical support for the research and development of drilling tools for deep and ultra-deep drilling, so as to improve the efficiency of deep and ultra-deep drilling.

[0003] In the prior art, the rock breaking characteristics under high temperature and high pressure environment are analyzed by numerical simulation, or the rock breaking experiment is carried out under the conventional environment. Due to the lack of simulation of high temperature and high pressure environment under the well, the numerical simulation and the rock breaking experiment under the conventional environment lack pertinence, and the related research data is insufficient to provide effective basis for the rock breaking technology research under high temperature and high pressure environment.

[0004] Therefore, it is necessary to provide an experimental device for studying the breaking characteristics of rock under high temperature and high pressure conditions, which can more truly simulate the drilling rock breaking under high temperature and high pressure conditions at the bottom of the well, so as to provide reliable support for the research of rock breaking technology and tools for deep and ultra-deep drilling. SUMMARY

[0005] Based on the above problems existing in the prior art, the present application provides an experimental device and method for studying the breaking characteristics of rock, which can be used to study the breaking characteristics of rock under high temperature and high pressure environment.

[0006] In a first aspect of the present application, an experimental device for studying the breaking characteristics of rock is provided, comprising,

[0007] An experimental kettle comprising a kettle body and a kettle cover arranged on the kettle body, the kettle body and the kettle cover jointly defining a closed cavity for accommodating a rock sample;

[0008] A base for mounting the experimental kettle; and

[0009] A breaker mounted in the base, the breaker being provided with a drill rod extending into the experimental kettle, and a drill bit for breaking the rock sample being mounted at an end of the drill rod,

[0010] The kettle body is configured to enable the temperature and pressure in the cavity to reach predetermined values before the drill bit breaks the rock sample.

[0011] Further, the kettle body comprises an inner shell and an outer shell arranged outside the inner shell, and a heating coil is arranged between the inner shell and the outer shell, so that the temperature in the cavity can reach a predetermined value.

[0012] Further, the kettle body is further connected with a booster pump in fluid communication with the cavity, so as to pump fluid into the cavity to make the pressure in the cavity reach a predetermined value.

[0013] Further, the booster pump is configured to sequentially pressurize and maintain pressure of the experimental kettle in stages before the pressure in the cavity reaches the predetermined value.

[0014] Further, the kettle body is provided with a bracket for placing the rock sample, and the bracket is provided with an opening for the drill bit to pass through, and the drill rod extends upward into the cavity, so that the drill bit can abut against the lower surface of the rock sample.

[0015] Further, the upper surface of the rock sample abuts against the lower surface of the kettle cover, so that the force exerted on the rock sample by the kettle cover and the weight of the rock sample can balance the force exerted on the rock sample by the drill bit.

[0016] Further, the kettle body is further provided with a pressure sensor and a temperature sensor for real-time monitoring of the pressure and temperature in the cavity.

[0017] Further, the experimental device further comprises a control console electrically connected with the pressure sensor, the temperature sensor and the crusher, and the drill rod is further provided with an integrated sensor electrically connected with the control console for monitoring the drilling pressure, rotational speed, torque and vibration parameters of the drill bit.

[0018] In a second aspect, the present application provides an experimental method for studying the rock breaking characteristics, using any of the above experimental devices, comprising the following steps,

[0019] Step S1: After placing a rock sample of a predetermined size in the experimental kettle, the experimental kettle is pressurized and maintained in stages for sealing test;

[0020] Step S2: The experimental kettle after completing the sealing test is depressurized to reduce the pressure in the experimental kettle to a predetermined pressure value;

[0021] Step S3: The experimental kettle is heated to raise the temperature in the experimental kettle to a predetermined temperature value, and then a drill bit of a predetermined specification and size is used to break the rock sample;

[0022] Step S4: Monitor and collect the drilling pressure, rotational speed, torque and vibration parameters of the drill bit, and then study the breaking characteristics of the rock sample in combination with the rock debris generated in the breaking process.

[0023] Further, in the step S3, the drill bit breaks the rock sample from the lower surface of the rock sample.

[0024] The beneficial effects of the present application are: the experimental device for studying rock breaking characteristics provided by the present application comprises an experimental kettle, a base for mounting the experimental kettle, and a breaker mounted on the base. The experimental kettle comprises a kettle body and a kettle cover arranged on the kettle body, and the kettle body and the kettle cover jointly define a sealed cavity for accommodating a rock sample. The breaker is provided with a drill rod extending into the experimental kettle, and the end of the drill rod is provided with a drill bit abutting against the rock sample. The kettle body is configured to enable the temperature and pressure in the cavity to reach predetermined values before the drill bit breaks the rock sample. In this way, it is ensured that the experimental study of rock breaking characteristics can be carried out under predetermined temperature and pressure conditions, so that the obtained experimental data is more in line with the actual situation, thereby providing reliable support for the research of deep and ultra-deep drilling rock breaking technology and tools.

[0025] In addition, in the present application, the breaker is mounted below the experimental kettle, so that the drill bit can act on the lower surface of the rock sample. In this way, on the one hand, the weight of the rock sample is fully utilized, so that the drill bit can act on the rock sample with sufficient drilling pressure. On the other hand, the force of the rock sample acting on the experimental kettle is also reduced, so as to reduce the strength requirement of the experimental kettle. BRIEF DESCRIPTION OF DRAWINGS

[0026] The present application will be further described below in conjunction with the drawings and examples.

[0027] Figure 1 The structure of an experimental device for studying rock breaking characteristics is shown.

[0028] In the drawings, the reference signs are as follows: 10, experimental kettle; 11, kettle body; 111, inner shell; 112, outer shell; 113, cavity; 114, heating coil; 12, kettle cover; 121, bolt; 13, booster pump; 14, bracket; 20, base; 30, breaker; 31, drill rod; 32, drill bit; 40, rock sample; 50, control console. DETAILED DESCRIPTION

[0029] In order to make the technical problems to be solved by the present application, the technical solutions and the beneficial effects clearer, the present application will be described in detail in conjunction with the drawings. The present drawing is a simplified schematic diagram, which only schematically illustrates the basic structure of the present application, and therefore only shows the structures related to the present application. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] Reference Figure 1 As shown in the drawings, the present application provides an experimental device for studying rock breaking characteristics, which comprises a base 20, an experimental kettle 10 mounted on the base 20, and a breaker 30 arranged in the base 20. The experimental kettle 10 can be filled with fluid under pressure to immerse a rock sample 40 placed in the experimental kettle 10, so that the rock sample 40 is in a high-pressure environment. The breaker 30 is provided with a drill rod 31 in sealing connection with the experimental kettle 10, and the drill rod 31 extends to the experimental kettle 10 and is provided with a drill bit 32 at an end away from the breaker 30. The breaker 30 can rotate the drill bit 32 to apply pressure to the rock sample 40 through the drill rod 31, so as to break the rock sample 40. It should be noted that the breaker 30 is well known to those skilled in the art, and will not be described in detail in this application.

[0031] In some embodiments, the experimental kettle 10 comprises a kettle body 11 with an open top, and a kettle cover 12 mounted at the opening of the kettle body 11. The kettle body 11 and the kettle cover 12 together define a closed cavity 113 for accommodating the rock sample 40. The kettle body 11 is designed in a double-layer structure, comprising an inner shell 111 and an outer shell 112 sleeved outside the inner shell 111. A heating coil 114 is arranged between the inner shell 111 and the outer shell 112 for heating the fluid under pressure filled in the cavity 113, so that the rock sample 40 in the cavity 113 is in a high-temperature and high-pressure environment. The heating coil 114 can be a resistance heating coil. The heating coil 114 is electrically connected to an external power source to generate heat by using the heat effect of electric current. The inner shell 111 transmits the heat generated by the heating coil 114 to the fluid under pressure in the experimental kettle 10, so that the temperature in the experimental kettle 10 reaches a predetermined temperature.

[0032] In some preferred embodiments, the heating coil 114 can also be an electromagnetic heating coil. The heating coil 114 is electrically connected to an external high-frequency device (not shown). The high-frequency device is electrically driven by an external power source to make a high-frequency and high-voltage current flow through the heating coil 114, so that a high-speed alternating magnetic field is generated in the heating coil 114. The inner shell 111 made of ferromagnetic material generates eddy current in the alternating magnetic field, so that the carriers in the inner shell 111 move at high speed in a random manner and collide and rub against each other, thereby generating heat in the inner shell 111. The heat generated by the inner shell 111 is directly transmitted to the fluid under pressure in the kettle body 11, thereby effectively improving the heating efficiency and accelerating the speed of conducting experiments.

[0033] In some other embodiments not shown, the kettle body 11 is further wrapped with heat insulation cotton. On the one hand, the temperature in the kettle body 11 can quickly reach a predetermined temperature, and on the other hand, the safety of the experiment can be improved by avoiding the experimental personnel from touching the kettle body 11 by mistake. The heat insulation cotton can also be removed after the experiment is completed, so that the kettle body 11 can be quickly cooled down.

[0034] In some embodiments, the kettle cover 12 is fastened to the kettle body 11 by bolts 121, so that the sealing member (not shown) mounted on the kettle cover 12 is in interference fit with the kettle body 11, thereby achieving sealing between the kettle cover 12 and the kettle body 11 to define a closed cavity 113. In this way, the experimental kettle 10 can withstand the pressure of the fluid inside it, ensuring the stability of the pressure environment of the rock sample 40.

[0035] Reference Figure 1 As shown, in some embodiments, the experimental kettle 10 is in fluid communication with the booster pump 13 through a pipe, so that the pressure of the fluid in the experimental kettle 10 can reach a predetermined pressure. The experimental kettle 10 can also be subjected to a sealing test by the booster pump 13. In some embodiments, the booster pump 13 sequentially pressurizes the experimental kettle 10 to 10 MPa, 20 MPa, 30 MPa, 40 MPa, and 50 MPa. Upon reaching each pressure stage, the booster pump 13 stops pressurizing for a period of time to maintain pressure, while the pressure drop in the experimental kettle 10 is monitored by a pressure sensor (not shown) in the experimental kettle 10. If the pressure drop value is not higher than 0.1 MPa, it means that the sealing of the experimental kettle 10 meets the experimental requirements. The pressure maintaining time can be determined according to the experimental requirements. In some embodiments, the pressure maintaining time can be 5 min.

[0036] In some embodiments, a bracket 14 for placing the rock sample 40 is provided in the experimental kettle 10, and the bracket 14 is provided with an opening for the drill bit 32 to pass through, so that the lower surface of the rock sample 40 can abut against the drill bit 32 on the drill rod 31. In this way, the force of the drill bit 32 on the rock sample 40 can be easily balanced by the gravity of the rock sample 40 itself. By providing the bracket 14, the upper surface of the rock sample 40 can also abut against the lower surface of the kettle cover 12, thereby reducing the force exerted by the rock sample 40 on the experimental kettle 10 due to the action of the drill bit 32, while fully utilizing the self-weight of the rock sample 40. Therefore, in addition to bearing the pressure of the fluid inside it, the experimental kettle 10 only needs to bear a small amount of force from the rock sample 40, thereby effectively reducing the strength requirement of the experimental kettle 10 and in turn reducing the requirement for the experimental device. The rock cuttings produced by the drill bit 32 breaking the rock sample 40 can fall through the bracket 14 to the bottom of the kettle body 11 for cleaning after the experiment is completed. Due to the support and separation effect of the bracket 14, the generated rock cuttings will not affect the drilling of the rock sample 40 by the drill rod 31 and the drill bit 32.

[0037] In some embodiments, the rock sample 40 can be selected to have a size of 0.5m x 0.5m x 0.5m, or other sizes according to specific experimental conditions. The drill bit 32 can be selected to be a toothed drill bit 32 with a diameter of 152.4mm, and the drill teeth on the drill bit 32 can be round teeth, tapered teeth, ridge teeth, chisel teeth. The experimenter can select a drill bit 32 with a predetermined size and specific drill teeth according to the experimental requirements.

[0038] Again in combination Figure 1 As shown, in some embodiments, the experimental device provided by the present application further comprises a control console 50 electrically connected with the crusher 30 and the booster pump 13. Through the control console 50, relevant instructions can be sent to the crusher 30 and the booster pump 13, so that the booster pump 13 pressurizes the fluid in the experimental kettle 10 or the crusher 30 drives the drill rod 31 to crush the rock sample 40 through the drill bit 32. The control console 50 is also electrically connected with the pressure sensor and the temperature sensor (not shown in the figure) arranged in the experimental kettle 10, and the integrated sensor (not shown in the figure) arranged on the crusher 30 for monitoring the drilling pressure, rotating speed, torque and vibration parameters of the drill bit 32. Through the pressure sensor, the pressure of the fluid in the experimental kettle 10 can be monitored in real time, so that the experimenter controls the output of the booster pump 13 through the control console 50, and ensures that the rock sample 40 is always in an environment with a predetermined pressure. Through the temperature sensor, the temperature in the experimental kettle 10 can be monitored in real time, so that the experimenter controls the output of the heating coil 114 through the control console 50, and ensures that the rock sample 40 is always in an environment with a predetermined temperature. Through the integrated sensor, the drilling pressure, rotating speed, torque and vibration parameters of the drill bit 32 can be monitored in real time, so that the analysis and evaluation can be carried out after the experiment is completed. The control console 50 is a prior art known to those skilled in the art, and will not be described in the present application.

[0039] In combination Figure 1As shown, the use process of the experimental device for researching rock breaking characteristics provided by the present application is as follows. According to the pre-designed experimental scheme, the experimental personnel installs the predetermined drill bit 32 on the drill rod 31, then places the rock sample 40 on the bracket 14, and fastens the kettle cover 12 to the kettle body 11 through the bolt 121. The control console 50 sends a command to the booster pump 13, so that the booster pump 13 injects the fluid with pressure into the experimental kettle 10 to perform the sealing test. After the sealing test is completed, the pressure is released to make the pressure in the experimental kettle 10 reach the predetermined pressure. The control console 50 makes the heating coil 114 heat the experimental kettle 10, so that the temperature in the experimental kettle 10 reaches the predetermined temperature. Then the control console 50 sends a command to the breaker 30, so that the breaker 30 drives the drill bit 32 through the drill rod 31 to break the rock sample 40 at the predetermined rotating speed and drilling distance. During the breaking process, the integrated sensor monitors the drilling pressure, rotating speed, torque and vibration parameters of the drill bit 32 in real time, and sends these parameters to the control console 50 for storage. The rock cuttings generated during the breaking process naturally settle at the bottom of the experimental kettle 10, and are collected after the experiment is completed, so as to comprehensively evaluate the breaking effect and breaking efficiency on the rock sample 40 in combination with the drilling pressure, rotating speed, torque and vibration parameters of the drill bit 32.

[0040] When the rock sample 40 no longer has the experimental conditions, the experimental kettle 10 is depressurized and cooled to make the inside of the experimental kettle 10 reach the normal temperature and pressure conditions. The experimental kettle 10 is opened, and the residual rock sample 40 and the generated rock cuttings are taken out, and then the next new rock sample 40 is placed to perform the next experiment.

[0041] Based on the above experimental device for researching rock breaking characteristics, the present application further provides an experimental method for researching rock breaking characteristics, comprising the following steps.

[0042] In step S1, the experimental personnel places the rock sample 40 of a predetermined size in the experimental kettle 10, and then performs the sealing test by the booster pump 13 to the experimental kettle 10 in stages. The booster pump 13 can sequentially perform the stage pressurization to the experimental kettle 10 at the pressures of 10 MPa, 20 MPa, 30 MPa, 40 MPa and 50 MPa. When each pressure stage is reached, the booster pump 13 stops pressurizing for a period of time to perform the pressure maintaining. At the same time, the pressure drop in the experimental kettle 10 is monitored by the pressure sensor in the experimental kettle 10. If the pressure drop value is not higher than 0.1 MPa, it indicates that the sealing property of the experimental kettle 10 reaches the experimental requirement.

[0043] In step S2, the experimental personnel depressurizes the experimental kettle 10 after the sealing test is completed, so that the pressure in the experimental kettle 10 is reduced to the predetermined pressure value.

[0044] In step S3, the experimenter heats the experimental kettle 10 through the heating coil 114 to raise the temperature in the experimental kettle 10 to a predetermined temperature value. Then the controller 50 sends a command to the breaker 30 to drive the drill bit 32 through the drill rod 31 at a predetermined rotation speed and drilling distance to break the rock sample 40. In this step, the drill bit 32 preferably breaks the rock sample 40 perpendicularly to the lower surface of the rock sample 40 to facilitate the full use of the weight of the rock sample 40, thereby reducing the force exerted on the experimental kettle 10 by the rock sample 40 due to the action of the drill bit 32.

[0045] In step S4, the drilling pressure, rotation speed, torque and vibration parameters of the drill bit 32 are monitored in real time through the integrated sensor and sent to the controller 50 for storage. After the experiment is completed, the experimenter evaluates the breaking effect and breaking efficiency of the rock sample 40 in combination with the drilling pressure, rotation speed, torque and vibration parameters of the drill bit 32 and the rock debris generated during the breaking process to facilitate the study of the breaking characteristics of the rock sample 40.

[0046] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, it can be fixed connection, it can also be detachable connection or integral connection, it can be mechanical connection, it can be direct connection or indirect connection through intermediate medium, it can be internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0047] It should be understood that the terms "length", "width", "upper", "lower", "front and back", "left and right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0048] The above is based on the ideal embodiment of the present application, and through the above description, relevant personnel can make various changes and modifications without deviating from the scope of the present application. The technical scope of the present application is not limited to the content of the specification, and must be determined by the scope of the claims.

Claims

1. An experimental device for studying rock breaking characteristics, comprising, an experimental kettle (10) including a kettle body (11) and a kettle cover (12) arranged on the kettle body (11), the kettle body (11) and the kettle cover (12) together defining a closed cavity (113) for accommodating a rock sample (40); a base (20) for mounting the experimental kettle (10); and a breaker (30) mounted on the base (20), the breaker (30) being provided with a drill rod (31) extending into the experimental kettle (10), an end of the drill rod (31) being mounted with a drill bit (32) for breaking the rock sample (40), wherein the kettle body (11) being configured to enable the temperature and pressure in the cavity (113) to reach predetermined values before the drill bit (32) breaks the rock sample (40).

2. The experimental apparatus for investigating rock breakage characteristics according to claim 1, wherein, the kettle body (11) includes an inner shell (111) and an outer shell (112) arranged outside the inner shell (111), a heating coil (114) being arranged between the inner shell (111) and the outer shell (112) to enable the temperature in the cavity (113) to reach a predetermined value.

3. The experimental apparatus for investigating rock breakage characteristics according to claim 1, wherein, The kettle body (11) is further connected to a booster pump (13) in fluid communication with the cavity (113) to pump fluid into the cavity (113) to enable the pressure in the cavity (113) to reach a predetermined value.

4. The experimental apparatus for investigating rock breakage characteristics according to claim 3, wherein, The booster pump (13) is configured to sequentially pressurize and maintain pressure of the experimental kettle (10) in stages before the pressure in the cavity (113) reaches the predetermined value.

5. The experimental apparatus for studying rock breakage characteristics according to claim 1, wherein, The kettle body (11) is provided with a cradle (14) for placing the rock sample (40), the cradle (14) being provided with an opening for the drill bit (32) to pass through, the drill rod (31) extending upwardly into the cavity (113) so that the drill bit (32) can abut against a lower surface of the rock sample (40).

6. The experimental apparatus for investigating rock breakage characteristics according to claim 5, wherein, The upper surface of the rock sample (40) abuts against the lower surface of the kettle cover (12), so that the force exerted by the kettle cover (12) on the rock sample (40) and the weight of the rock sample (40) can balance the force exerted by the drill bit (32) on the rock sample (40).

7. The experimental apparatus for investigating rock breakage characteristics according to any one of claims 1-6, wherein, The kettle body (11) is further provided with a pressure sensor and a temperature sensor to monitor the pressure and temperature in the cavity (113) in real time.

8. The experimental apparatus for investigating rock breakage characteristics according to claim 7, wherein, The experimental device further comprises a control console (50) electrically connected to the pressure sensor, the temperature sensor and the breaker (30), the drill rod (31) being further provided with an integrated sensor electrically connected to the control console (50) for monitoring the drilling pressure, rotational speed, torque and vibration parameters of the drill bit (32).

9. An experimental method for investigating rock breakage characteristics using the experimental apparatus according to any one of claims 1 to 8, characterized by, comprising the following steps, step S1: after placing a rock sample of a predetermined size in the experimental kettle, the experimental kettle is pressurized and maintained in stages for sealing test; step S2: depressurizing the experimental kettle after the sealing test is completed to reduce the pressure in the experimental kettle to a predetermined pressure value; Step S3: heating the experimental furnace to raise the temperature in the experimental furnace to a predetermined temperature value, and then using a drill bit of a predetermined specification and size to break the rock sample; Step S4: monitoring and collecting the drilling pressure, rotation speed, torque and vibration parameters of the drill bit, and then combining the rock debris generated in the breaking process to study the breaking characteristics of the rock sample.

10. The experimental method for investigating rock breakage characteristics according to claim 9, wherein, In the step S3, the drill bit breaks the rock sample from the lower surface of the rock sample.

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