Rock coring device

Abstract

The invention provides a rock coring device. The rock coring device comprises an outer cylinder, an inner cylinder, a coring drill bit, a core catcher, a columnar air bag, a linear telescopic device, a flow control valve and a controller. The coring drill bit is connected to the bottom of the outer cylinder and internally provided with a core catcher. The inner cylinder is rotationally connected into the outer cylinder. The columnar air bag is slidably arranged in the inner cylinder in a penetrating mode, and the linear telescopic device is arranged between the columnar air bag and the top of the inner cylinder. And the flow control valve is connected with the columnar air bag. During working, the outer barrel drives the coring drill bit to rotate to drill a rock stratum, and a core column generated by drilling penetrates through the core catcher and then abuts against the bottom end of the columnar air bag. And the core column pushes the bottom end of the columnar air bag to move towards the interior of the columnar air bag. Meanwhile, the controller controls the flow control valve to continuously exhaust gas in the columnar air bag and controls the linear telescopic device to continuously push the columnar air bag downwards. The core column is wrapped by the columnar air bag and then inserted into the inner cylinder, the core column can be rapidly isolated from the outside, and the core column is prevented from being polluted by drilling fluid.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas exploration, and in particular to a rock coring device. Background Art

[0002] In the process of oilfield exploration, cores are important data for discovering oil and gas layers and studying strata, source layers, reservoirs, caprocks, structures, etc. After the oilfield is put into development, cores are used to further study and understand the sedimentary characteristics of the oil layers, the physical properties, pore structure, wettability, relative permeability, lithofacies characteristics of the reservoirs, physical simulation of the oil layers and the laws of oil layer flooding; to understand and master the characteristics of oil layer flooding at different development stages and different water-containing stages, to clarify the distribution of remaining oil, and to provide a scientific basis for the design of oilfield development plans, strata, well network adjustments and infill wells. Coring is the process of using special coring tools to bring underground rocks to the ground in blocks during the drilling process. This block of rock is called a core, through which various properties of rocks can be measured, underground structures and rock deposition environments can be studied intuitively, and the properties of fluids therein can be understood.

[0003] During conventional coring, the filtrate of the drilling fluid intrudes into the core, causing the oil and gas saturation of the oil layer core to change and making it impossible to obtain accurate data. Closed coring is a coring technology that uses sealing fluid to quickly protect the drilled core, which can prevent the drilling fluid from contaminating the core. In the prior art, closed coring only protects the drilled core column with sealing fluid. In this method, the sealing fluid is easily penetrated or even penetrated by the continuously flowing drilling fluid during the flushing process, thereby eroding the internal core. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a rock coring device, which aims to solve the problem that the coring method in the related art easily causes the filtrate of the drilling fluid to invade the core.

[0005] The present invention provides a rock coring device, comprising: outer cylinder; A coring drill bit, the coring drill bit being detachably connected to the bottom end of the outer cylinder; A core claw, the core claw being arranged inside the coring drill bit; An inner cylinder, the inner cylinder is inserted into the outer cylinder, and the inner cylinder is rotatably connected to the outer cylinder, the bottom end of the inner cylinder is open, and the bottom end of the inner cylinder extends downward to the top of the core claw; A columnar airbag, wherein the columnar airbag is inserted into the inner tube, and the outer side wall of the columnar airbag is in sliding contact with the inner side wall of the inner tube, and the bottom end of the columnar airbag is used to bend toward the inside of the columnar airbag under the drive of the core column, and the part of the columnar airbag bent to the inside of the columnar airbag is used to cover the outside of the core column; A linear telescopic device, which is arranged on the inner side of the inner cylinder and between the top of the inner cylinder and the top of the cylindrical airbag, and is used to drive the cylindrical airbag to move in the inner cylinder; A flow control valve, the flow control valve being connected to the columnar airbag; A controller, wherein the controller is electrically connected to the linear telescopic device and the flow control valve, and the controller is used to control the linear telescopic device to drive the columnar airbag to move in the inner tube so that the bending position of the columnar airbag is located at a position flush with the bottom end of the inner tube, and the controller is used to control the exhaust flow of the flow control valve so that the air pressure in the columnar airbag is within a preset pressure range.

[0006] According to the rock coring device provided by the present invention, the columnar airbag includes a non-elastic mesh layer and a plurality of elastic strips, the plurality of elastic strips are distributed on the inner side of the non-elastic mesh layer along the circumference of the non-elastic mesh layer, and each of the elastic strips extends along the axial direction of the columnar airbag, leaving a gap between two adjacent elastic strips.

[0007] According to the rock coring device provided by the present invention, a locking ring is sleeved on the outside of the columnar airbag and near the bending position, the locking ring is made of magnetic or ferrous material, and a strong magnetic positioning ring is provided at the inner bottom end of the inner tube to limit the axial and radial position of the locking ring, and the distance between the inner wall of the locking ring and the outer wall of the core column is less than the wall thickness of the columnar airbag.

[0008] The rock coring device provided by the present invention further includes a pressure stabilizing assembly, the pressure stabilizing assembly including: A gas storage tank, the gas storage tank is arranged in the outer cylinder; A two-way air pump, which is arranged between the gas storage tank and the cylindrical airbag, and is used to transport the gas in the gas storage tank to the cylindrical airbag, or to transport the gas in the cylindrical airbag to the gas storage tank; A pressure sensor, the pressure sensor is used to detect the air pressure in the cylindrical airbag; The pressure sensor and the bidirectional air pump are both electrically connected to the controller. The controller controls the operation of the bidirectional air pump based on the pressure value detected by the pressure sensor and the preset pressure range so that the pressure in the cylindrical airbag is within the preset pressure range.

[0009] According to the rock coring device provided by the present invention, the gas storage tank includes a tank body, a piston and a back-pressure elastic member, the piston is arranged in the tank body, and the outer wall of the piston is in sliding and sealing contact with the inner wall of the tank body, the piston divides the internal space of the tank body into a first cavity and a second cavity, and the back-pressure elastic member is arranged in the first cavity to drive the piston to compress the space of the second cavity.

[0010] The rock coring device provided by the present invention further comprises a compression bag, wherein the compression bag comprises: A bladder body, the bladder body is arranged on the inner top of the part of the columnar airbag bent to the inside of the columnar airbag, the bladder body is used to contain the sealing liquid, and the bottom of the bladder body is provided with a drainage hole; An elastic support member is disposed in the capsule, and the elastic force range provided by the elastic support member is within the preset pressure range.

[0011] According to the rock coring device provided by the present invention, the elastic support member is a spring, and the elastic coefficient of each wire diameter of the spring gradually increases or decreases.

[0012] According to the rock coring device provided by the present invention, a bearing is provided between the inner cylinder and the outer cylinder.

[0013] According to the rock coring device provided by the present invention, at least two bearings are provided, and the plurality of bearings are distributed along the axial direction of the inner cylinder.

[0014] According to the rock coring device provided by the present invention, a push plate is provided between the linear telescopic device and the columnar airbag.

[0015] The present invention adopts the above technical solution, which has the following advantages: The rock coring device provided by the present invention comprises an outer cylinder, an inner cylinder, a coring drill bit, a core claw, a columnar airbag, a linear telescopic device, a flow control valve and a controller. The coring drill bit is detachably connected to the bottom of the outer cylinder, and the core claw is arranged inside the coring drill bit. The inner cylinder is rotatably connected to the inside of the outer cylinder, and the bottom end of the inner cylinder extends downward to the top of the core claw. The columnar airbag is penetrated in the inner cylinder and is in sliding contact with the inner cylinder. The linear telescopic device is arranged in the inner cylinder and is located between the columnar airbag and the top of the inner cylinder. The bottom end of the columnar airbag is used to bend toward the inside of the columnar airbag under the drive of the core and move upward, and the part of the columnar airbag bent into the inside of the columnar airbag is used to wrap around the outside of the core column. The flow control valve is connected to the columnar airbag. The flow control valve and the linear telescopic device are both electrically connected to the controller. During operation, the outer cylinder drives the core drill bit to rotate and drill the rock formation. The core column produced by drilling passes through the middle of the drill bit and hits the bottom end of the columnar airbag after passing through the core claw. As the core drill bit continues to drill downward, the core column also pushes the bottom end of the columnar airbag to continuously move into the inside of the columnar airbag. During the drilling process, the controller controls the flow control valve to continuously discharge the gas in the columnar airbag, and controls the displacement of the flow control valve per unit time to be equal to the volume occupied by the core column inserted into the columnar airbag, so that the columnar airbag is always in a filled state during the squeezing process, so that it can support the columnar airbag to be continuously inserted from the lower end by the core column. At the same time, due to the process of the core column being inserted into the columnar airbag, the bending position of the columnar airbag will also continuously move upward. At this time, the controller controls the linear telescopic device to continuously push the columnar airbag downward, and the pushing length of the linear telescopic device per unit time is equal to the feed amount of the core drill bit, so as to compensate for the length of the upward movement of the bending position of the columnar airbag. The core column obtained by drilling is wrapped by a columnar air bag and then inserted into the inner tube. The columnar air bag that follows the core column to fold into the inner tube can not only provide shock-absorbing protection for the core column to prevent it from breaking due to drilling impact during the drilling process, but also the columnar air bag that follows the core column to fold into the inner tube tightly wraps the surface of the core column, which can quickly isolate the core column from the outside world and prevent the core column from being contaminated by drilling fluid, thereby ensuring the accuracy of the core composition and characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 is a cross-sectional view of a rock coring device provided by one embodiment of the present invention; Figure 2 yes Figure 1The enlarged view of point A in the middle; Figure 3 yes Figure 2 The enlarged view of point B in the middle; Figure 4 is a cross-sectional view of a compression bladder provided by an embodiment of the present invention; Figure 5 is a cross-sectional view of a cylindrical airbag provided in one embodiment of the present invention.

[0018] Reference numerals: 110: outer cylinder; 120: inner cylinder; 130: coring drill bit; 140: core claw; 150: bearing; 200: columnar air bag; 210: non-elastic mesh layer; 220: elastic inflatable strip; 230: extrusion part; 300: linear telescopic device; 410: locking ring; 420: strong magnetic positioning ring; 510: tank body; 520: piston; 530: back pressure elastic part; 610: bladder body; 620: elastic support part; 630: drainage hole; 640: baffle plate; 700: push plate. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0024] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0025] The rock coring device provided by the present invention comprises an outer cylinder, an inner cylinder, a coring drill bit, a core claw, a columnar airbag, a linear telescopic device, a flow control valve and a controller. The coring drill bit is detachably connected to the bottom of the outer cylinder, and the core claw is arranged inside the coring drill bit. The inner cylinder is rotatably connected to the inside of the outer cylinder, and the bottom end of the inner cylinder extends downward to the top of the core claw. The columnar airbag is penetrated in the inner cylinder and is in sliding contact with the inner cylinder. The linear telescopic device is arranged in the inner cylinder and is located between the columnar airbag and the top of the inner cylinder. The bottom end of the columnar airbag is used to bend toward the inside of the columnar airbag under the drive of the core and move upward, and the part of the columnar airbag bent into the inside of the columnar airbag is used to wrap around the outside of the core column. The flow control valve is connected to the columnar airbag. The flow control valve and the linear telescopic device are both electrically connected to the controller. During operation, the outer cylinder drives the core drill bit to rotate and drill the rock formation. The core column produced by drilling passes through the middle of the drill bit and hits the bottom end of the columnar airbag after passing through the core claw. As the core drill bit continues to drill downward, the core column also pushes the bottom end of the columnar airbag to continuously move into the inside of the columnar airbag. During the drilling process, the controller controls the flow control valve to continuously discharge the gas in the columnar airbag, and controls the displacement of the flow control valve per unit time to be equal to the volume occupied by the core column inserted into the columnar airbag, so that the columnar airbag is always in a filled state during the squeezing process, so that it can support the columnar airbag to be continuously inserted from the lower end by the core column. At the same time, due to the process of the core column being inserted into the columnar airbag, the bending position of the columnar airbag will also continuously move upward. At this time, the controller controls the linear telescopic device to continuously push the columnar airbag downward, and the pushing length of the linear telescopic device per unit time is equal to the feed amount of the core drill bit, so as to compensate for the length of the upward movement of the bending position of the columnar airbag. The core column obtained by drilling is wrapped by a columnar air bag and then inserted into the inner tube. The columnar air bag that follows the core column to fold into the inner tube can not only provide shock-absorbing protection for the core column to prevent it from breaking due to drilling impact during the drilling process, but also the columnar air bag that follows the core column to fold into the inner tube tightly wraps the surface of the core column, which can quickly isolate the core column from the outside world and prevent the core column from being contaminated by drilling fluid, thereby ensuring the accuracy of the core composition and characteristics.

[0026] Combine the following Figures 1 to 5 The rock coring device provided by the present invention is described.

[0027] An embodiment of the present invention provides a rock coring device, including an outer cylinder 110, an inner cylinder 120, a coring drill bit 130, a core claw 140, a columnar air bag 200, a linear telescopic device 300, a flow control valve and a controller.

[0028] The core drill bit 130 is connected to the bottom end of the outer cylinder 110 through a tapered thread, and the core drill bit 130 is driven to rotate by the rotation of the outer cylinder 110. The core claw 140 is installed inside the core drill bit 130. The core claw 140 is used to cut the core and support the cut core column. Commonly used core claws 140 have several structures such as clamp type, clamp plate type, slip type, etc.

[0029] The upper end of the inner cylinder 120 is closed and the lower end is open. The outer side of the upper end of the inner cylinder 120 is rotatably connected to the outer cylinder 110. The axis of the inner cylinder 120, the axis of the outer cylinder 110 and the axis of relative rotation of the two are collinear.

[0030] The linear telescopic device 300 and the cylindrical airbag 200 are arranged inside the inner cylinder 120, and the cylindrical airbag 200 is arranged at the bottom of the inner cylinder 120, and the linear telescopic device 300 is arranged between the top of the cylindrical airbag 200 and the top of the inner cylinder 120. The linear telescopic device 300 is connected to the controller through an electrical signal, and the linear telescopic device 300 is used to drive the cylindrical airbag 200 to move downward along the axial direction of the inner cylinder 120 under the control of the controller.

[0031] The linear telescopic device 300 may be a linear motor, which can better control the telescopic amount, and thus can more accurately control the displacement of the cylindrical airbag 200 .

[0032] The columnar airbag 200 is a closed columnar structure, and the bottom end of the columnar airbag 200 is used to contact the top of the core. When the core column moves upward relative to the inner tube 120, the top of the core column drives the bottom end of the columnar airbag 200 to bend toward the inside of the columnar airbag 200 and move upward. The part of the columnar airbag 200 bent into the inside of the columnar airbag 200 is covered on the outside of the core column.

[0033] The flow control valve is connected to the columnar airbag 200 and is electrically connected to the controller. The flow control valve is used to control the displacement of the gas in the columnar airbag 200 under the control of the controller so that the air pressure in the columnar airbag 200 is within a preset pressure range.

[0034] During operation, when the rock coring device reaches the rock formation to be sampled, the outer cylinder 110 rotates to drive the coring drill bit 130 below to drill the rock formation, and the core column produced by the drilling passes through the middle of the drill bit, and after passing through the core claw 140, it hits the bottom end of the columnar airbag 200. As the coring drill bit 130 continues to drill downward, the produced core column also pushes the bottom end of the columnar airbag 200 to continuously squeeze into the inside of the columnar airbag 200.

[0035] During the drilling process, the core column squeezes the columnar airbag 200, causing the internal space of the columnar airbag 200 to become smaller and smaller. The controller controls the flow control valve to continuously discharge the gas in the columnar airbag 200, and controls the flow control valve to discharge the gas per unit time equal to the volume occupied by the core column inserted into the columnar airbag 200, so that the columnar airbag 200 is always in a filled state during the squeezing process, so that it can support the columnar airbag 200 to be continuously inserted from the lower end by the core column.

[0036] During the process of inserting the core column into the columnar airbag 200, the bending position of the columnar airbag 200 will also continuously move upward. At this time, it is necessary to push the columnar airbag 200 downward continuously through the linear telescopic device 300 arranged above the columnar airbag 200. The controller controls the pushing length of the linear telescopic device 300 per unit time to be equal to the feed amount of the coring drill bit 130, that is, the length of the core column inserted into the columnar airbag 200, so as to compensate for the length of the upward movement of the bending position of the columnar airbag 200, ensure that the columnar airbag 200 is always in a squeezed state, and keep the columnar airbag 200 full, so that it can support the columnar airbag 200 to be continuously inserted from the lower end by the core column.

[0037] The core column obtained by drilling is wrapped by the columnar airbag 200 and then inserted into the inner cylinder 120. The columnar airbag 200 that follows the core column to fold into the inner cylinder 120 can not only provide shock-absorbing protection for the core column to prevent it from breaking due to drilling impact during the drilling process, but also the columnar airbag 200 that follows the core column to fold into the inner cylinder 120 tightly wraps the surface of the core column, which can quickly isolate the core column from the outside world and prevent the core column from being contaminated by drilling fluid, thereby ensuring the accuracy of the core composition and characteristics.

[0038] In some embodiments, the cylindrical airbag 200 is composed of an outer non-elastic mesh layer 210 and a plurality of inner elastic strips.

[0039] The inelastic mesh layer 210 is used to limit the maximum diameter of the cylindrical airbag 200, thereby leaving a gap between the cylindrical airbag 200 and the inner tube 120, so that the friction of the cylindrical airbag 200 sliding in the inner tube 120 is small, so that the linear telescopic device 300 can drive the cylindrical airbag 200 to move in the inner tube 120.

[0040] The elastic strip may be an elastic inflatable strip 220, which can be compressed and deformed, thereby enabling the cylindrical airbag 200 to be bent and folded. A plurality of elastic inflatable strips 220 are provided, and the plurality of elastic inflatable strips 220 are spaced apart along the circumference of the non-elastic mesh layer 210, and each elastic inflatable strip 220 extends along the axial direction of the non-elastic mesh layer 210. Nitrogen or other gases with a small volume that are affected by temperature may be introduced into the cylindrical airbag 200.

[0041] In addition, an extrusion portion 230 is disposed at the bottom end of the cylindrical airbag 200 . The extrusion portion 230 is obtained by thickening the cylindrical airbag 200 inwardly. The extrusion portion 230 is used to be folded into the interior of the cylindrical airbag 200 .

[0042] like Figure 5 As shown, since the outer diameter of the folded portion of the columnar airbag 200 becomes smaller, the outer non-elastic mesh layer 210 will produce longitudinal wrinkles. As a result, a gap can be left between adjacent elastic inflatable strips 220, so that the non-elastic mesh layer 210 on the columnar airbag 200 folded inside can be accommodated in the gap. In order to ensure that the columnar airbag 200 folded inside is more tightly wrapped with the surface of the core column, the gap can be controlled as small as possible during the implementation process, and the adjacent elastic inflatable strips 220 are brought closer to each other as much as possible when the wrinkled non-elastic mesh layer 210 can be accommodated, and when the non-elastic mesh layer 210 can be accommodated in the gap, the elastic inflatable strips 220 on the columnar airbag 200 cover more on the core column, thereby ensuring that the columnar airbag 200 protects the core column.

[0043] In some embodiments, a locking ring 410 is further provided at the folded portion of the cylindrical airbag 200. The cross section of the locking ring 410 is preferably elliptical or circular, thereby reducing the resistance of the cylindrical airbag 200 when it is folded. The locking ring 410 is sleeved on the cylindrical airbag 200 that is folded into the interior. A strong magnetic positioning ring 420 is provided at the position corresponding to the locking ring 410 on the inner cylinder 120. The magnetic attraction of the strong magnetic positioning ring 420 to the locking ring 410 keeps the locking ring 410 at the folded portion of the cylindrical airbag 200. If the locking ring 410 also has its own magnetism, it is necessary to set the locking ring 410 and the strong magnetic positioning ring 420 to attract opposite sexes.

[0044] By setting a locking ring 410 at the folded part of the columnar airbag 200, the locking ring 410 squeezes the columnar airbag 200 wrapped on the core column after the folding, so that the columnar airbag 200 wrapped on the core column after the folding fits more closely with the core column, thereby enabling the columnar airbag 200 to better protect the core column, thereby increasing the probability of the core column not being contaminated by drilling fluid, and further improving the accuracy of the core composition and characteristics.

[0045] In some embodiments, the rock coring device further comprises a pressure stabilizing assembly, which comprises an air storage tank, a bidirectional air pump and a pressure sensor.

[0046] The pressure sensor is used to detect the pressure value inside the cylindrical airbag 200. The air tank is connected to the cylindrical airbag 200 through a two-way air pump, and the two-way air pump is connected to the cylindrical airbag 200 through a flow control valve. The pressure sensor and the two-way air pump are both connected to the controller through electrical signals.

[0047] When there is a slight deviation in the coordination between the flow control valve and the linear telescopic device 300, the pressure value detected by the pressure sensor will deviate from the normal value. A high pressure value will cause the columnar airbag 200 to be under excessive pressure and accelerate damage. A low pressure value will cause the columnar airbag 200 to become soft, thereby preventing the core column from being inserted normally.

[0048] This embodiment detects the pressure value in the columnar airbag 200 in real time through a pressure sensor. When the pressure value detected by the sensor is lower than the preset pressure range, the controller controls the two-way air pump to start, and the gas in the gas storage tank is pumped into the columnar airbag 200 through the two-way air pump to compensate for the pressure value; when the pressure value detected by the sensor exceeds the preset pressure range, the controller increases the opening of the flow control valve, and the gas in the columnar airbag 200 is sucked into the gas storage tank through the two-way air pump to compensate for the pressure value. In this way, the pressure value in the columnar airbag 200 can float within the preset pressure range, ensuring that the columnar airbag 200 is always in a filled state, so that it can support the columnar airbag 200 to be normally inserted into the core column.

[0049] The cooperation of the pressure sensor and the bidirectional air pump compensates for the deviation in the cooperation between the flow control valve and the linear telescopic device 300, thereby making the process of folding and wrapping the core column by the columnar air bag 200 more stable and reliable, improving the stability and reliability of the core extraction process, and also ensuring the accuracy of the composition and characteristics of the core.

[0050] In some embodiments, the gas storage tank includes a tank body 510, a piston 520, and a back-pressure elastic member 530. The piston 520 is disposed in the tank body 510, and the outer side wall of the piston 520 is in sliding and sealing contact with the inner side wall of the tank body 510, so as to divide the internal space of the tank body 510 into a first cavity and a second cavity. In this embodiment, the first cavity is located above the piston 520, and the second cavity is located below the piston 520. The back-pressure elastic member 530 is disposed in the first cavity, one end of the back-pressure elastic member 530 is in contact with the inner top of the tank body 510, and the other end is connected to the top of the piston 520, and the back-pressure elastic member 530 is squeezed between the piston 520 and the tank body 510, so that the back-pressure elastic member 530 can always provide a force for the piston 520 to compress the space of the second cavity.

[0051] If a conventional air tank is used, when the two-way air pump continuously pumps the gas in the columnar air bag 200 into the air tank, the pumping will become increasingly difficult due to the gradual increase of gas in the air tank. This problem will not only cause the two-way air pump to gradually increase its power to work, resulting in a reduced life of the two-way air pump, but also cause the displacement of the two-way air pump to be uncontrollable due to excessive back pressure, resulting in unstable pressure value in the columnar air bag 200, making it impossible for the columnar air bag 200 to remain filled and even the core column cannot be inserted into the columnar air bag 200 normally.

[0052] In order to solve this problem, this embodiment supports the piston 520 by the back pressure elastic member 530, so that the gas entering the gas storage tank can squeeze the back pressure elastic member 530 by pushing the piston 520, so that the two-way air pump is only subjected to the stable elastic force provided by the back pressure elastic member 530 during the process of pumping gas into the gas storage tank, so that the two-way air pump is more stable when working, and the pressure value in the columnar air bag 200 is more stable, so that the columnar air bag 200 remains filled, and the core column can be normally and stably inserted into the columnar air bag 200 for protection.

[0053] In some embodiments, a compression bag is provided at the inner top of the part of the cylindrical airbag 200 that is folded into the inside of the cylindrical airbag 200, and the compression bag includes a bag body 610 and an elastic support member 620 provided in the bag body 610. The bag body 610 is used to contain sealing liquid, and a drainage hole 630 is provided at the bottom edge of the bag body 610.

[0054] The elastic support member 620 may be a spring, and the elastic coefficient of each wire diameter of the spring gradually increases or decreases.

[0055] For example, the elastic coefficient of each wire diameter section on the spring gradually increases or decreases linearly.

[0056] Alternatively, the elastic coefficient of each wire diameter on the spring can be gradually increased or decreased in a gradient to meet the use requirements. Figure 4 The elastic coefficients of segments a, b and c gradually increase or decrease, and can be divided into different amounts of gradient changes according to actual needs.

[0057] The capsule 610 is filled with a sealing liquid, which is a polymer liquid with high viscosity, good fluidity, strong adhesion and good waterproofness that is pre-placed in the capsule 610 .

[0058] The core column produced by drilling is against the bottom end of the capsule 610, or a baffle 640 can be set at the bottom end of the capsule 610 so that the top of the core column contacts the baffle 640. As the process of drilling the core column continues, the gas pumped into the columnar airbag 200 by the controller through the two-way air pump gradually increases, thereby gradually increasing the pressure in the columnar airbag 200, and then the spring force that acts on the extrusion part 230 as a balancing force with the columnar airbag 200 also gradually increases. Because the elastic coefficient of each wire diameter on the spring gradually changes, and the range of change of the elastic force is within the preset pressure range of the columnar airbag 200, the spring is gradually compressed, and then the sealing liquid in the compression bag is gradually squeezed out from the drainage hole 630, and the sealing liquid is evenly squeezed between the core column and the columnar airbag 200, so that the columnar airbag 200 can better seal and protect the core column, increase the probability that the core column is not contaminated by drilling fluid, and further improve the accuracy of the core composition and characteristics.

[0059] In this embodiment, as the core column is gradually inserted into the columnar airbag 200, the sealing liquid in the compression bag is gradually squeezed between the inserted core column and the folded columnar airbag 200, thereby ensuring that the surface of the core column inserted into the columnar airbag 200 is covered with a layer of sealing liquid, so that the drilled core column can be protected in a timely and effective manner, ensuring the accuracy of the core composition and characteristics.

[0060] The deviation of the displacement caused by the compression of the spring can be compensated by the controller controlling the linear telescopic device 300 to shorten the feed amount.

[0061] In some embodiments, the inner cylinder 120 and the outer cylinder 110 can be rotatably connected by setting a rotating member. The rotating member can be a bearing 150. Two upper and lower circles of balls can be set in the bearing 150, or two bearings 150 can be set along the axial direction of the inner cylinder 120. In this way, the stability of the inner cylinder 120 can be guaranteed to the maximum extent.

[0062] In some embodiments, a push plate 700 can be set between the bottom end of the linear telescopic device 300 and the top end of the cylindrical airbag 200, so that the linear telescopic device 300 and the cylindrical airbag 200 are connected through the push plate 700 to increase the force-bearing area and make the top end of the cylindrical airbag 200 more evenly stressed.

[0063] In addition, a lubricant may be provided on the inner wall of the inner cylinder 120 , which reduces the friction of the cylindrical airbag 200 sliding in the inner cylinder 120 , thereby facilitating the pushing of the linear telescopic device 300 and improving the controllability and accuracy of the linear telescopic device 300 .

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A rock coring device, characterized in that: include: outer cylinder (110); a coring drill bit (130), the coring drill bit (130) being detachably connected to the bottom end of the outer cylinder (110); A core claw (140), the core claw (140) being arranged inside the coring drill bit (130); an inner cylinder (120), the inner cylinder (120) being inserted into the outer cylinder (110), the inner cylinder (120) being rotatably connected to the outer cylinder (110), the bottom end of the inner cylinder (120) being open, and the bottom end of the inner cylinder (120) extending downward to the top of the core claw (140); a columnar airbag (200), the columnar airbag (200) being inserted into the inner cylinder (120), and the outer wall of the columnar airbag (200) being in sliding contact with the inner wall of the inner cylinder (120), the bottom end of the columnar airbag (200) being used to bend toward the inside of the columnar airbag (200) under the drive of the core column, and the portion of the columnar airbag (200) bent toward the inside of the columnar airbag (200) being used to cover the outside of the core column; a linear telescopic device (300), the linear telescopic device (300) being arranged on the inner side of the inner cylinder (120) and located between the top of the inner cylinder (120) and the top of the columnar airbag (200), the linear telescopic device (300) being used to drive the columnar airbag (200) to move within the inner cylinder (120); A flow control valve, the flow control valve being connected to the columnar airbag (200); A controller, the controller being electrically connected to the linear telescopic device (300) and the flow control valve, the controller being used to control the linear telescopic device (300) to drive the columnar airbag (200) to move within the inner tube (120), so that the bending position of the columnar airbag (200) is located at a position flush with the bottom end of the inner tube (120), and the controller being used to control the exhaust flow of the flow control valve, so that the air pressure within the columnar airbag (200) is within a preset pressure range.

2. The rock coring device according to claim 1, characterized in that: The columnar airbag (200) comprises a non-elastic mesh layer (210) and a plurality of elastic strips, wherein the plurality of elastic strips are distributed on the inner side of the non-elastic mesh layer (210) along the circumference of the non-elastic mesh layer (210), and each of the elastic strips extends along the axial direction of the columnar airbag (200), with a gap being left between two adjacent elastic strips.

3. The rock coring device according to claim 1 or 2, characterized in that: A locking ring (410) is sleeved on the outside of the columnar airbag (200) and near the bending position. The locking ring (410) is made of a magnetic or ferrous material. A strong magnetic positioning ring (420) is provided at the inner bottom end of the inner tube (120) for limiting the axial and radial position of the locking ring (410). The distance between the inner wall of the locking ring (410) and the outer wall of the core column is less than the wall thickness of the columnar airbag (200).

4. The rock coring device according to claim 1, characterized in that: It also includes a voltage stabilizing component, the voltage stabilizing component includes: A gas storage tank, the gas storage tank being arranged in the outer cylinder (110); a bidirectional air pump, the bidirectional air pump being arranged between the air storage tank and the columnar air bag (200) and being used for conveying the gas in the air storage tank into the columnar air bag (200), or for conveying the gas in the columnar air bag (200) into the air storage tank; a pressure sensor, the pressure sensor being used to detect the air pressure in the cylindrical airbag (200); The pressure sensor and the bidirectional air pump are both electrically connected to the controller, and the controller controls the operation of the bidirectional air pump based on the pressure value detected by the pressure sensor and the preset pressure range, so that the pressure in the cylindrical airbag (200) is within the preset pressure range.

5. The rock coring device according to claim 4, characterized in that: The gas storage tank comprises a tank body (510), a piston (520) and a back-pressure elastic member (530); the piston (520) is arranged in the tank body (510), and the outer wall of the piston (520) is in sliding and sealing contact with the inner wall of the tank body (510); the piston (520) divides the internal space of the tank body (510) into a first cavity and a second cavity; the back-pressure elastic member (530) is arranged in the first cavity and is used to drive the piston (520) to compress the space of the second cavity.

6. The rock coring device according to claim 1, characterized in that: Also included is a compression sac, the compression sac comprising: a capsule (610), the capsule (610) being arranged at the inner top of the portion of the columnar airbag (200) bent to the inside of the columnar airbag (200), the capsule (610) being used to contain a sealing liquid, and a liquid drainage hole (630) being arranged at the bottom of the capsule (610); An elastic support member (620), wherein the elastic support member (620) is arranged in the capsule (610), and the elastic force range provided by the elastic support member (620) is within the preset pressure range.

7. The rock coring device according to claim 6, characterized in that: The elastic support member (620) is a spring, and the elastic coefficient of each wire diameter of the spring gradually increases or decreases.

8. The rock coring device according to claim 1, characterized in that: A bearing (150) is provided between the inner cylinder (120) and the outer cylinder (110).

9. The rock coring device according to claim 8, characterized in that: At least two bearings (150) are provided, and a plurality of the bearings (150) are distributed along the axial direction of the inner cylinder (120).

10. The rock coring device according to claim 1, characterized in that: A push plate (700) is provided between the linear telescopic device (300) and the columnar airbag (200).

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