Experimental device for researching temperature change of hydrate sample during rotary drilling

Abstract

The invention belongs to the technical field of natural gas hydrates, and discloses an experimental device for researching the temperature change of a hydrate sample during rotary drilling, which comprises a hydrate synthesis kettle, a temperature detection mechanism and a movable drilling mechanism. The hydrate synthesis kettle is used for containing a hydrate sample, the temperature detection mechanism is arranged on the hydrate synthesis kettle and is configured to detect the temperature of the hydrate sample in the hydrate synthesis kettle, the movable drilling mechanism comprises a pressure maintaining bin, a movable driver, a rotary driver and a coring bit, and the pressure maintaining bin selectively communicates with the hydrate synthesis kettle; the movable driver is arranged in the pressure maintaining bin and can drive the coring bit to stretch into a hydrate sample in the hydrate synthesis kettle, and when the coring bit stretches into the hydrate sample, the rotary driver can drive the coring bit to rotate. By means of the arrangement, the experimental device can conveniently monitor the temperature change of the hydrate sample under the rotary drilling disturbance condition.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas hydrates, and particularly to an experimental device for studying the temperature change of hydrate samples during rotary drilling. Background Art

[0002] Natural gas hydrates are crystalline solid substances formed by hydrocarbon gas molecules (mainly methane) and water under certain temperature and pressure conditions. They are mainly stored under the permafrost in high-latitude regions and under the continental shelf extending from the continent to the ocean. Due to their rich reserves, cleanliness, and high energy density, they have high resource value. Moreover, hydrates are also very important for studying global greenhouse effects, marine geological disasters, and marine engineering safety. To better study natural gas hydrates, researchers need to obtain complete and undisturbed in-situ samples of natural gas hydrates from the seabed through core drilling and conduct further experimental analysis.

[0003] However, due to the special properties of natural gas hydrates themselves, there are significant differences in their occurrence states, failure mechanisms, and changes in physical and mechanical properties compared with conventional submarine sediments. During the core drilling process in natural gas hydrate formations, when the formation is disturbed by drilling, it is prone to squeezing, deformation, and dislocation like a soil body under stress, which will cause changes in important formation parameters such as porosity, permeability, and saturation of in-situ samples. Moreover, the disturbances generated during the drilling process will cause local temperature and pressure changes in natural gas hydrates, which will cause the hydrates to decompose. This will not only result in poor integrity of the hydrate samples and reduce their research value, but also cause changes in reservoir strength and stress state, leading to engineering problems such as sand production in the reservoir, wellbore collapse, formation settlement, and landslides. In addition, the temperature and pressure changes generated by the disturbances will also bring large errors to the results of wave velocity logging, unable to correctly reflect the occurrence state of hydrates in the formation, and thus affecting the exploration and exploitation results of natural gas hydrates.

[0004] Currently, in order to study the temperature change law of natural gas hydrates under the disturbance of rotary drilling, researchers need to design and build an experimental device for detecting the temperature change of hydrate samples during the core drilling process of rotary drilling, so as to better monitor the temperature change of natural gas hydrate samples during the disturbance process. Summary of the Invention

[0005] The purpose of the present invention is to provide an experimental device for studying the temperature change of hydrate samples during rotary drilling, which can facilitate the monitoring of the temperature change of hydrate samples under the disturbance condition of rotary drilling.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] An experimental device for studying the temperature change of hydrate samples during rotary drilling, comprising:

[0008] A hydrate synthesis kettle for accommodating hydrate samples;

[0009] A temperature detection mechanism is arranged in the hydrate synthesis kettle and is configured to detect the temperature of the hydrate samples in the hydrate synthesis kettle;

[0010] A mobile drilling mechanism includes a pressure-holding chamber, a mobile driver, a rotary driver, and a core bit. The pressure-holding chamber is selectively connected to the hydrate synthesis kettle. The mobile driver is arranged in the pressure-holding chamber and can drive the core bit to extend into the hydrate samples in the hydrate synthesis kettle. When the core bit extends into the hydrate samples, the rotary driver can drive the core bit to rotate.

[0011] Optionally, the temperature detection mechanism includes a first temperature detection component and a second temperature detection component. The first temperature detection component is arranged along the extension direction of the hydrate synthesis kettle. When the core bit extends into the hydrate samples, the core bit is sleeved on the first temperature detection component, and the second temperature detection component is arranged around the circumference of the hydrate synthesis kettle.

[0012] Optionally, the first temperature detection component includes a plurality of first temperature sensors and a plurality of first fixing frames that are detachably connected in sequence. The plurality of first fixing frames are arranged in sequence along the axial direction of the hydrate synthesis kettle, and one first temperature sensor is arranged between every two adjacent first fixing frames.

[0013] Optionally, an installation groove is arranged in the first fixing frame. The first fixing frame includes a connection end for connecting the installation groove. Among two adjacent first fixing frames, the connection end of one first fixing frame is connected to the installation groove of the other first fixing frame, and an accommodation groove for accommodating the first temperature sensor is formed between the connection end and the installation groove.

[0014] Optionally, the first fixing frame is provided with a through hole, the accommodation groove communicates with the inside of the hydrate synthesis kettle through the through hole, and the sensing end of the first temperature sensor is arranged towards the through hole.

[0015] Optionally, an assembly groove communicating with the installation groove is further arranged in the first fixing frame, and the assembly groove is used for accommodating the signal wire of the first temperature sensor.

[0016] Optionally, the second temperature detection assembly includes a second fixing bracket and a plurality of second temperature sensors. The second fixing bracket is disposed around the hydrate synthesis reactor and extends along the axial direction of the hydrate synthesis reactor. A plurality of the second temperature sensors form a group and are spaced along the circumferential direction of the second fixing bracket on the second fixing bracket. Multiple groups of the second temperature sensors are spaced along the extending direction of the second fixing bracket.

[0017] Optionally, the orientation of the sensing end of the second temperature sensor is perpendicular to the axis direction of the hydrate synthesis reactor.

[0018] Optionally, each group of the second temperature sensors is correspondingly provided with one of the first temperature sensors, and the sensing ends of the first temperature sensor and the corresponding second temperature sensor are both located on the same horizontal plane.

[0019] Optionally, the experimental device for studying the temperature change of the hydrate sample during rotary drilling further includes a pressure maintaining mechanism. The pressure maintaining mechanism is disposed between the hydrate synthesis reactor and the mobile drilling mechanism and is configured to control the on-off between the hydrate synthesis reactor and the pressure maintaining chamber.

[0020] Advantages of the present invention:

[0021] The present invention provides an experimental device for studying the temperature change of a hydrate sample during rotary drilling, which includes a hydrate synthesis reactor, a temperature detection mechanism, and a mobile drilling mechanism. The hydrate synthesis reactor is used to accommodate the hydrate sample. The temperature detection mechanism is disposed in the hydrate synthesis reactor, and the temperature of the hydrate sample in the hydrate synthesis reactor is detected by the temperature detection mechanism, so as to facilitate the operator to study the temperature change law of the hydrate under the disturbance condition of rotary drilling. The mobile drilling mechanism includes a pressure maintaining chamber, a mobile driver, a rotary driver, and a coring bit. The pressure maintaining chamber is selectively connected to the hydrate synthesis reactor, which is beneficial to ensuring that the temperature and pressure in the pressure maintaining chamber and the hydrate synthesis reactor are basically the same, so as to maintain the in-situ pressure condition of the hydrate sample during the drilling process and reduce the problem of hydrate decomposition caused by temperature and pressure changes. The mobile driver is disposed in the pressure maintaining chamber and can drive the coring bit to extend into the hydrate sample in the hydrate synthesis reactor. When the coring bit extends into the hydrate sample, the rotary driver can drive the coring bit to rotate, so as to realize the rotary coring operation of the hydrate sample and reproduce the disturbance process. Through the above settings, the experimental device for studying the temperature change of the hydrate sample during rotary drilling of the present application can facilitate the monitoring of the temperature change of the hydrate sample under the disturbance condition of rotary drilling. Description of the Drawings

[0022] Figure 1 is a schematic diagram of the experimental device for studying the temperature change of the hydrate sample during rotary drilling provided by an embodiment of the present invention;

[0023] Figure 2 is Figure 1 The sectional view at A - A in

[0024] Figure 3 is Figure 1 The enlarged partial view at B in

[0025] In the figure:

[0026] 1. Hydrate synthesis kettle; 2. Temperature detection mechanism; 21. First temperature detection component; 211. First temperature sensor; 212. First fixing bracket; 2121. Installation groove; 21211. Accommodation groove; 2122. Connection end; 2123. Assembly groove; 22. Second temperature detection component; 221. Second fixing bracket; 222. Second temperature sensor; 3. Mobile drilling mechanism; 31. Pressure - maintaining chamber; 32. Mobile driver; 33. Rotary driver; 34. Core - taking bit; 4. Pressure - maintaining mechanism. Specific embodiments

[0027] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention are shown in the drawings, rather than all structures.

[0028] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above - mentioned terms in the present invention can be understood according to specific circumstances.

[0029] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0030] In the description of this embodiment, the orientation or positional relationships such as "upper", "lower", "right", etc. are based on the orientation or positional relationships shown in the drawings. They are only for convenience of description and simplifying the operations, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0031] Natural gas hydrate is a crystalline solid substance formed by hydrocarbon gas molecules (mainly methane) and water under certain temperature and pressure conditions. It mainly exists under the permafrost in high-latitude regions and under the continental shelf extending from the continent to the ocean. Due to its rich reserves, cleanliness and high energy density, it has high resource value. Moreover, hydrates are also very important for studying global greenhouse effects, marine geological disasters, and marine engineering safety, etc. In order to better study natural gas hydrates, researchers need to obtain complete and undisturbed in-situ samples of natural gas hydrates from the seabed by means of drilling and coring and conduct further experimental analysis.

[0032] However, due to the special properties of natural gas hydrates themselves, there are significant differences in their occurrence states, failure mechanisms, and changes in physical and mechanical properties compared with conventional submarine sediments. During the drilling and coring process of natural gas hydrate formations, when the formation is disturbed by drilling, it is very easy to be squeezed, deformed and displaced like a soil body under stress, which will in turn cause changes in important formation parameters such as porosity, permeability and saturation of the in-situ samples. Moreover, the disturbance generated during the drilling process will cause local temperature and pressure changes in natural gas hydrates, which will in turn cause the hydrates to decompose. This will not only result in poor integrity of the hydrate samples and reduce their research value, but also cause changes in reservoir strength and stress state, leading to engineering problems such as sand production in the reservoir, wellbore collapse, formation settlement, and landslides. In addition, the temperature and pressure changes generated by the disturbance will also bring large errors to the results of wave velocity logging, unable to correctly reflect the occurrence state of hydrates in the formation, and thus affecting the exploration and exploitation results of natural gas hydrates.

[0033] Currently, in order to study the temperature change law of natural gas hydrates under the condition of rotary drilling disturbance, researchers need to design and build a temperature change detection experimental device for hydrate samples during the rotary drilling and coring disturbance process to better monitor the temperature change of natural gas hydrate samples during the disturbance process.

[0034] Such as Figures 1-3As shown in the figure, this embodiment provides an experimental device for studying the temperature change of hydrate samples during rotary drilling, which includes a hydrate synthesis kettle 1, a temperature detection mechanism 2, and a mobile drilling mechanism 3. The hydrate synthesis kettle 1 is used to accommodate hydrate samples. The temperature detection mechanism 2 is arranged in the hydrate synthesis kettle 1 and is configured to detect the temperature of the hydrate samples in the hydrate synthesis kettle 1. The mobile drilling mechanism 3 includes a pressure-holding chamber 31, a mobile drive 32, a rotary drive 33, and a core bit 34. The pressure-holding chamber 31 is selectively connected to the hydrate synthesis kettle 1. The mobile drive 32 is arranged in the pressure-holding chamber 31 and can drive the core bit 34 to extend into the hydrate samples in the hydrate synthesis kettle 1. When the core bit 34 extends into the hydrate samples, the rotary drive 33 can drive the core bit 34 to rotate.

[0035] In this embodiment, the hydrate synthesis kettle 1 is used to accommodate hydrate samples. The temperature detection mechanism 2 is arranged in the hydrate synthesis kettle 1. The temperature of the hydrate samples in the hydrate synthesis kettle 1 is detected through the temperature detection mechanism 2, which is convenient for operators to study the temperature change law of hydrates under the disturbance of rotary drilling. The mobile drilling mechanism 3 includes a pressure-holding chamber 31, a mobile drive 32, a rotary drive 33, and a core bit 34. The pressure-holding chamber 31 is selectively connected to the hydrate synthesis kettle 1, which is beneficial to ensuring that the temperature and pressure in the pressure-holding chamber 31 and the hydrate synthesis kettle 1 are basically the same, thereby maintaining the in-situ pressure conditions of the hydrate samples during the drilling process and reducing the problem of hydrate decomposition caused by temperature and pressure changes. The mobile drive 32 is arranged in the pressure-holding chamber 31 and can drive the core bit 34 to extend into the hydrate samples in the hydrate synthesis kettle 1. When the core bit 34 extends into the hydrate samples, the rotary drive 33 can drive the core bit 34 to rotate, thereby realizing the rotary coring operation of the hydrate samples and reproducing the disturbance process. Through the above settings, the experimental device for studying the temperature change of hydrate samples during rotary drilling in this embodiment can facilitate the monitoring of the temperature change of hydrate samples under the disturbance of rotary drilling.

[0036] It should be noted that in this embodiment, the mobile drive 32 can drive the core bit 34 to move up and down, and then cooperate with the rotary drive 33 to drive the core bit 34 to rotate around its own axis, thereby realizing the rotary sampling of hydrate samples. In other embodiments, in order to simulate the actual sampling situation of natural gas hydrates, the mobile drive 32 can also drive the core bit 34 to move in an inclined direction, and the moving direction of the core bit 34 forms an angle with the vertical direction. The specific direction of the core bit 34 extending into the hydrate synthesis kettle 1 is not limited too much here.

[0037] The following describes the specific structure of the experimental device for studying the temperature change of hydrate samples during rotary drilling:

[0038] Specifically, asFigures 1-3 As shown in Figures 1-3 , the mobile drive 32 is arranged in the pressure-holding chamber 31. A rotary drive 33 is provided at the output end of the mobile drive 32, and the output end of the rotary drive 33 is connected to the core bit 34. The mobile drive 32 can drive the rotary drive 33 and the core bit 34 to perform lifting operations, so that the core bit 34 can extend into the hydrate sample in the hydrate synthesis reactor 1 or be withdrawn from the hydrate sample. When the core bit 34 extends into the hydrate sample, the rotary drive 33 can drive the core bit 34 to rotate, thereby realizing the rotary coring operation of the hydrate sample and further reproducing the disturbance process.

[0039] More specifically, the mobile drive 32 includes a rotary motor, a turbine, and a worm. The output end of the rotary motor is connected to the turbine, and the turbine is meshed with the worm. The rotary drive 33 includes a servo motor and a speed reducer. The servo motor is arranged on the worm, and the output shaft of the servo motor is connected to the core bit 34 through the speed reducer. By driving the turbine to rotate with the rotary motor, the worm, the servo motor, the speed reducer, and the core bit 34 are driven to realize the lifting movement. The servo motor can drive the core bit 34 to rotate through the speed reducer, thereby realizing the rotary coring operation of the hydrate sample. In other embodiments, the mobile drive 32 includes an electric cylinder, and the core bit 34 is driven by the electric cylinder to realize lifting. The rotary drive 33 includes a stepping motor, and the core bit 34 is driven by the stepping motor to rotate and core. Here, the specific structures of the mobile drive 32 and the rotary drive 33 are not overly limited, as long as the above functions can be achieved.

[0040] Specifically, the temperature detection mechanism 2 includes a first temperature detection component 21 and a second temperature detection component 22. The first temperature detection component 21 is arranged along the extension direction of the hydrate synthesis reactor 1, and thus monitors the temperature change of the hydrate sample along the movement path of the core bit 34. When the core bit 34 extends into the hydrate sample, the core bit 34 is sleeved on the first temperature detection component 21, ensuring that the core bit 34 will not collide with the first temperature detection component 21, thereby improving the safety of the operation. The second temperature detection component 22 is arranged circumferentially around the hydrate synthesis reactor 1, and thus monitors the temperature of the hydrate on the rotation path of the core bit 34. Compared with the traditional point-type monitoring, the above setting adopts three-dimensional temperature monitoring, which can better reflect the overall temperature gradient change inside the hydrate sample.

[0041] More specifically, the first temperature detection component 21 includes a plurality of first temperature sensors 211 and a plurality of first fixing frames 212 that are detachably connected in sequence. The plurality of first fixing frames 212 are arranged in sequence along the axial direction of the hydrate synthesis kettle 1. A first temperature sensor 211 is provided between every two adjacent first fixing frames 212. Such an arrangement enables the plurality of first temperature sensors 211 to be spaced apart along the axial direction of the hydrate synthesis kettle 1, and can monitor the instantaneous temperature changes at different depth positions during the movement of the coring bit 34. Moreover, through the detachable connection between adjacent first fixing frames 212, it is possible to facilitate the adjustment of the spacing between the first temperature sensors 211 or the replacement of damaged components, thereby improving the flexibility of the experimental device.

[0042] More specifically, in this embodiment, the adjacent two first fixing frames 212 are connected by threads to improve the convenience of assembly and maintenance. In other embodiments, the detachable connection can also be achieved between the adjacent two first fixing frames 212 by means of plugging or clamping, etc., and no more limitations are made here.

[0043] Moreover, a stop washer is clamped between the adjacent two first fixing frames 212, thereby preventing the loosening between the first fixing frames 212 connected by threads and improving the stability and connection strength of the overall structure. Among them, the stop washer is made of a rubber pad or a silicone pad, and no more limitations are made here.

[0044] Specifically, an installation groove 2121 is provided inside the first fixing frame 212. The first fixing frame 212 includes a connection end 2122 for connecting the installation groove 2121, so that the connection end 2122 can be threadedly connected to the installation groove 2121, thereby realizing the detachable connection between the plurality of first fixing frames 212. Among the adjacent two first fixing frames 212, the connection end 2122 of one first fixing frame 212 is connected to the installation groove 2121 of the other first fixing frame 212. An accommodation groove 21211 for accommodating the first temperature sensor 211 is formed between the connection end 2122 and the installation groove 2121, thereby saving the installation space of the first temperature sensor 211 and improving the space utilization rate and structural compactness of the first temperature detection component 21.

[0045] More specifically, the first fixing frame 212 is provided with a through hole. The accommodation groove 21211 communicates with the inside of the hydrate synthesis kettle 1 through the through hole, and the sensing end of the first temperature sensor 211 faces the through hole. By providing the through hole, the first temperature sensor 211 can directly contact the hydrate sample inside the hydrate synthesis kettle 1, thereby avoiding the temperature measurement error caused by the heat insulation of the first fixing frame 212.

[0046] More specifically, an assembly groove 2123 communicating with the installation groove 2121 is further provided inside the first fixing frame 212. The assembly groove 2123 is used to accommodate the signal wire of the first temperature sensing element 211, which can play a role in storing and protecting the signal wire, preventing the signal wire from being entangled, and avoiding it being damaged by the core bit 34 during the core drilling process.

[0047] Specifically, the second temperature detection assembly 22 includes a second fixing frame 221 and a plurality of second temperature sensing elements 222. The second fixing frame 221 is arranged around the hydrate synthesis reactor 1 and extends along the axial direction of the hydrate synthesis reactor 1, so as to ensure that the second temperature detection assembly 22 can comprehensively cover the hydrate sample along the circumferential direction of the hydrate synthesis reactor 1, improving the accuracy and comprehensiveness of the monitoring of the temperature change of the hydrate sample. The plurality of second temperature sensing elements 222 are in a group and are arranged at intervals along the circumferential direction of the second fixing frame 221. Multiple groups of second temperature sensing elements 222 are arranged at intervals along the extending direction of the second fixing frame 221, and can cooperate with the first temperature sensing element 211 to monitor the temperature change of the hydrate sample at different depths in the hydrate synthesis reactor 1, so as to construct temperature monitoring data in a three-dimensional space.

[0048] Specifically, the orientation of the sensing end of the second temperature sensing element 222 is perpendicular to the axis direction of the hydrate synthesis reactor 1, which can not only ensure that the second temperature sensing element 222 can monitor the temperature of the hydrate sample along the radial direction of the hydrate synthesis reactor 1, but also avoid large differences in the temperature of the hydrate sample on its radial path caused by heat generation due to friction of the core bit 34, thereby improving the accuracy of temperature monitoring.

[0049] Specifically, each group of second temperature sensing elements 222 is correspondingly provided with a first temperature sensing element 211, and the sensing ends of the first temperature sensing element 211 and the corresponding second temperature sensing element 222 are both located on the same horizontal plane. Such a setting ensures that at the same depth layer of the hydrate sample, the temperature differences and changes of the hydrate sample at different radial distances are measured, thereby ensuring the rationality of the experimental data.

[0050] It should be noted that the first temperature sensing element 211 and the second temperature sensing element 222 in this embodiment can both adopt a thermocouple sensor or a thermistor sensor. No excessive limitations are imposed on the specific structures of the above components here, as long as the above functions can be realized. It can be understood that the sensing ends of the first temperature sensing element 211 and the second temperature sensing element 222 are both the temperature sensing probes in the temperature sensor for directly contacting the medium, and those skilled in the art are clear about the specific structures of the temperature sensing probes, so they will not be elaborated here.

[0051] Specifically, the experimental device for studying the temperature change of hydrate samples during rotary drilling further includes a pressure maintaining mechanism 4. The pressure maintaining mechanism 4 is arranged between the hydrate synthesis kettle 1 and the mobile drilling mechanism 3 and is configured to control the on-off between the hydrate synthesis kettle 1 and the pressure maintaining chamber 31. By setting the pressure maintaining mechanism 4, the pressure inside the hydrate synthesis kettle 1 can be maintained constant during the drilling process, thereby inhibiting the decomposition of the hydrate samples, avoiding the influence of pressure changes on the experimental data, and improving the accuracy of the experimental results.

[0052] More specifically, in this embodiment, the pressure maintaining mechanism 4 includes a sphere and a valve rod. The hydrate synthesis kettle 1 is connected to the pressure maintaining chamber 31 through the sphere in a switchable manner. The sphere is driven to rotate by the valve rod, thereby realizing the cutting off and distribution of the medium between the hydrate synthesis kettle 1 and the pressure maintaining chamber 31. Moreover, the sphere is detachably arranged between the hydrate synthesis kettle 1 and the pressure maintaining chamber 31, so as to facilitate the operation personnel to disassemble and replace the above components and ensure that the phase state of the hydrate samples does not change, which is beneficial to ensuring the normal progress of the experiment. In other embodiments, the pressure maintaining mechanism 4 is selected as a globe valve or a butterfly valve, and the specific structure of the pressure maintaining mechanism 4 is not limited too much here.

[0053] Specifically, the hydrate synthesis kettle 1 and the pressure maintaining chamber 31 are respectively provided with an openable and closable air inlet, an exhaust port, a water inlet and a drain port, and the on-off of the above ports is respectively controlled by solenoid valves, thereby realizing the independent pressurization, pressure relief, water inlet and drainage operations of the hydrate synthesis kettle 1 and the pressure maintaining chamber 31, so as to facilitate the simulation of the actual situation of natural gas hydrates and is beneficial to improving the accuracy of the experimental data.

[0054] More specifically, the experimental device for studying the temperature change of hydrate samples during rotary drilling further includes a pressure sensor. The pressure sensor is arranged on the hydrate synthesis kettle 1 and the pressure maintaining chamber 31, and can monitor the experimental data of the pressure in the hydrate synthesis kettle 1 and the pressure maintaining chamber 31 in real time, and cooperate with the corresponding air inlet and exhaust port operations to meet the experimental requirements.

[0055] It should be noted that the experimental device for studying the temperature change of hydrate samples during rotary drilling in this embodiment can construct a cross-type temperature monitoring chain layer by setting the first temperature detection component 21 and the second temperature detection component 22, and can perform a three-dimensional and all-round monitoring on the temperature change of the surrounding hydrates during the synthesis and core drilling of the hydrate samples. Moreover, the data detected by the temperature sensor and the pressure sensor can be transmitted to the corresponding software of the computer, so as to study the law of temperature change of natural gas hydrates under the condition of rotary disturbance.

[0056] The following describes the usage process of the experimental device for studying the temperature change of hydrate samples during rotary drilling:

[0057] Install the hydrate synthesis kettle 1 on the test bench. Arrange the first temperature detection component 21 and the second temperature detection component 22 inside the hydrate synthesis kettle 1. For the first temperature detection component 21, vertically install the first fixing frame 212 at the central position of the bottom of the hydrate reaction kettle, and install the first temperature sensor 211 between two adjacent first fixing frames 212. That is, after installing each first fixing frame 212, install a first temperature sensor 211. By setting the first temperature detection component 21, monitor the temperature change of the hydrate at the axis during the synthesis and coring of the hydrate sample; for the second temperature detection component 22, first arrange the annular second fixing frame 221 inside the hydrate synthesis kettle 1, and install multiple groups of second temperature sensors 222 at intervals in the vertical direction. At the same time, make the sensing end of the second temperature sensor 222 perpendicular to the axis direction of the hydrate synthesis kettle 1, and the sensing ends of the first temperature sensor 211 and the corresponding second temperature sensor 222 are on the same horizontal plane. By setting the second temperature detection component 22, comprehensively monitor the temperature change of the surrounding hydrate during the synthesis and coring of the hydrate sample;

[0058] Then install the hydrate synthesis kettle 1, the pressure maintaining mechanism 4 and the mobile drilling mechanism 3 from bottom to top in sequence;

[0059] Fill the hydrate synthesis kettle 1 with water, gradually increase the pressure inside the hydrate synthesis kettle 1 to the required pressure through an air compressor, and then open the inlet and outlet of the hydrate synthesis kettle 1 to make natural gas form a cycle inside the hydrate synthesis kettle 1, and reduce the temperature inside the hydrate synthesis kettle 1 to around 2°C through a temperature regulating mechanism (such as a heat exchanger or a temperature control valve);

[0060] After the natural gas hydrate is synthesized, gradually pressurize the pressure maintaining chamber 31 so that the pressure inside the pressure maintaining chamber 31 is basically the same as the pressure inside the lower hydrate synthesis kettle 1. At this time, make the pressure maintaining chamber 31 and the hydrate synthesis kettle 1 communicate with each other through the pressure maintaining mechanism 4;

[0061] Drive the coring bit 34 to extend into the hydrate sample in the hydrate synthesis kettle 1 through the mobile driver 32. When the coring bit 34 extends into the hydrate sample, drive the coring bit 34 to rotate through the rotary driver 33 to perform rotary coring operation on the hydrate sample, and control the rotation speed of the coring bit 34 to accurately reproduce the disturbance process;

[0062] During the rotation of the coring bit 34, its disturbance will cause the temperature inside the hydrate sample to change. The temperature in the hydrate sample is detected by the first temperature sensor 211 and the second temperature sensor 222, and the monitored data is transmitted to the data collector through the signal line for collection, and then the data is further transmitted to the corresponding software of the computer, so as to draw the corresponding chart for researchers to study the temperature change law of natural gas hydrate under rotational disturbance conditions;

[0063] After the hydrate drilling experiment is completed, the coring bit 34 is lifted into the pressure maintaining chamber 31 by the moving driver 32, and the pressure maintaining mechanism 4 is closed to disconnect the connection between the pressure maintaining chamber 31 and the hydrate synthesis kettle 1. Then, the pressure in the pressure maintaining chamber 31 is released. After the pressure is released, the mobile drilling mechanism 3 is disassembled and replaced with other experimental instruments to be tested, so as to complete the mode switching of the hydrate synthesis kettle 1 under the pressure maintaining state.

[0064] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. An experimental device for studying the temperature change of hydrate samples during rotary drilling, characterized in that: include: A hydrate synthesis reactor (1), used for containing a hydrate sample; a temperature detection mechanism (2), disposed in the hydrate synthesis reactor (1), and configured to detect the temperature of the hydrate sample in the hydrate synthesis reactor (1); The mobile drilling mechanism (3) comprises a pressure-maintaining chamber (31), a mobile driver (32), a rotary driver (33) and a coring drill bit (34); the pressure-maintaining chamber (31) can be selectively connected to the hydrate synthesis reactor (1); the mobile driver (32) is arranged in the pressure-maintaining chamber (31) and can drive the coring drill bit (34) to extend into the hydrate sample in the hydrate synthesis reactor (1); when the coring drill bit (34) extends into the hydrate sample, the rotary driver (33) can drive the coring drill bit (34) to rotate.

2. The experimental device for studying the temperature change of hydrate samples during rotary drilling according to claim 1, characterized in that: The temperature detection mechanism (2) comprises a first temperature detection component (21) and a second temperature detection component (22); the first temperature detection component (21) is arranged along the extension direction of the hydrate synthesis reactor (1); when the coring drill bit (34) extends into the hydrate sample, the coring drill bit (34) is sleeved on the first temperature detection component (21); and the second temperature detection component (22) is arranged in a circumferential direction of the hydrate synthesis reactor (1).

3. The experimental device for studying the temperature change of hydrate samples during rotary drilling according to claim 2, characterized in that: The first temperature detection assembly (21) comprises a plurality of first temperature sensing components (211) and a plurality of first fixing frames (212) which are detachably connected in sequence, wherein the plurality of first fixing frames (212) are arranged in sequence along the axial direction of the hydrate synthesis reactor (1), and a first temperature sensing component (211) is provided between each two adjacent first fixing frames (212).

4. The experimental device for studying the temperature change of hydrate samples during rotary drilling according to claim 3, characterized in that: A mounting groove (2121) is provided in the first fixing frame (212), and the first fixing frame (212) comprises a connecting end (2122) for connecting to the mounting groove (2121); among two adjacent first fixing frames (212), the connecting end (2122) of one of the first fixing frames (212) is connected to the mounting groove (2121) of the other first fixing frame (212), and an accommodating groove (21211) for accommodating the first temperature sensor (211) is formed between the connecting end (2122) and the mounting groove (2121).

5. The experimental device for studying the temperature change of hydrate samples during rotary drilling according to claim 4, characterized in that: The first fixing frame (212) is provided with a through hole, the containing groove (21211) is connected to the interior of the hydrate synthesis reactor (1) through the through hole, and the sensing end of the first temperature sensor (211) is arranged toward the through hole.

6. The experimental device for studying the temperature change of hydrate samples during rotary drilling according to claim 4, characterized in that: The first fixing frame (212) is further provided with an assembly groove (2123) connected to the installation groove (2121), and the assembly groove (2123) is used to accommodate a signal line of the first temperature sensor (211).

7. The experimental device for studying the temperature change of hydrate samples during rotary drilling according to claim 3, characterized in that: The second temperature detection assembly (22) comprises a second fixing frame (221) and a plurality of second temperature sensing elements (222); the second fixing frame (221) is arranged in a circle inside the hydrate synthesis reactor (1) and is extended along the axial direction of the hydrate synthesis reactor (1); the plurality of second temperature sensing elements (222) form a group and are arranged on the second fixing frame (221) at intervals along the circumferential direction of the second fixing frame (221); and the plurality of groups of second temperature sensing elements (222) are arranged at intervals along the extension direction of the second fixing frame (221).

8. The experimental device for studying the temperature change of hydrate samples during rotary drilling according to claim 7, characterized in that: The direction of the sensing end of the second temperature sensor (222) is perpendicular to the axial direction of the hydrate synthesis reactor (1).

9. The experimental device for studying the temperature change of hydrate samples during rotary drilling according to claim 7, characterized in that: Each group of the second temperature sensing elements (222) is provided with a corresponding first temperature sensing element (211), and the sensing end of the first temperature sensing element (211) and the corresponding sensing end of the second temperature sensing element (222) are both located on the same horizontal plane.

10. The experimental device for studying the temperature change of hydrate samples during rotary drilling according to any one of claims 1 to 9, characterized in that: The experimental device for studying the temperature change of the hydrate sample during rotary drilling also includes a pressure maintaining mechanism (4), which is arranged between the hydrate synthesis reactor (1) and the mobile drilling mechanism (3) and is configured to control the connection between the hydrate synthesis reactor (1) and the pressure maintaining chamber (31).

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