CN113153196B - Stress-preserving coring intelligent rock core extraction system and method - Google Patents

Abstract

The invention relates to a stress-preserving coring intelligent core extraction system and a stress-preserving coring intelligent core extraction method, which at least comprise a core tube (2) capable of sampling a core sample, and are characterized in that the core tube (2) comprises a hydraulic adjusting assembly and a core acquisition assembly, when the hydraulic adjusting assembly injects hydraulic fluid into a high-pressure fluid chamber (41) of the core acquisition assembly axially below the hydraulic adjusting assembly, the high-pressure fluid chamber (41) provides radial pressure corresponding to pre-acquired ground stress data for a core entering a core accommodating chamber (42) in a mode of extruding the wall of the core accommodating chamber (42). The invention can automatically adjust the pressure of the high-pressure fluid chamber (41) to the core accommodating chamber (42) according to the stratum depth of the core barrel.

Description

Stress-preserving coring intelligent rock core extraction system and method

The invention relates to a pressurized coring system and a pressurized coring method, wherein the application number is 202110000627.7, the application date is 2021, 01 and 04, and the application type is the invention.

Technical Field

The invention relates to the technical field of rock mass drilling and sampling, in particular to a stress-preserving coring intelligent core extraction system and method.

Background

In the exploration process of oil and gas reservoir development and deep-buried underground engineering, because rock bodies in the deep stratum are usually in a high ground stress environment, the actual failure mechanism and mechanical property of stratum rock are obviously different from those of shallow rock, therefore, when the conventional drilling equipment is used for carrying out deep stratum rock core sampling operation, the rock core sample cannot maintain the original structure and form due to the change of pressure and self-weight stress applied to the rock core in the ascending process of a core barrel, so that the rock core pie phenomenon is generated, relevant operating personnel cannot acquire a complete and effective rock core sample, and subsequent exploration personnel cannot accurately make an actual data analysis result of a set stratum according to the acquired rock core, therefore, in order to be convenient for relevant technical personnel to efficiently and accurately acquire the intact rock core sample, a rock core acquisition assembly capable of adjusting the pressure applied to the rock core according to the initial environment is required to be designed in the core acquisition equipment, and the stable and unchanged rock core stress condition is ensured.

Chinese patent CN111335837a discloses a coal rock pressure-maintaining coring inner barrel, an inner rubber sleeve is inserted in a core holding barrel outer tube, a confining pressure cavity is formed between the inner rubber sleeve and an inner wall of the holding barrel outer tube, both ends of the inner rubber sleeve are provided with a sealing plug and a sealing ring, the sealing plug and the sealing ring at the upper end are used in a matching manner to seal an upper port of the confining pressure cavity, the sealing plug and the sealing ring at the lower end are used in a matching manner to seal a lower port of the confining pressure cavity, one end of an upper end connecting piece is connected with the upper end of the hollow core holding barrel in a sealing manner, the other end of the upper end connecting piece is connected with a pressure supply bin, the pressure supply bin is communicated with the confining pressure cavity through a pressure supply pipeline, a pressure supply valve is arranged on the pressure supply pipeline and used for controlling the supply of fluid at a reference pressure, one end of a lower end connecting piece is connected with the lower end of the hollow core holding barrel in a sealing manner, the other end of the core holding barrel is connected with a ball valve, an outlet pipeline is arranged at the upper end of the core holding barrel, and the upper end of the outlet pipeline is arranged at the upper end. The invention can ensure the accurate measurement of the gas content, and can realize the permeability test of the coal rock stratum without taking out the core. The pressure regulation can not be carried out according to the subsequent operation processes of lifting, taking out a sample and the like only after the initial pressurization to the set pressure, and the real-time regulation of the pressure borne by the core sample cannot be effectively realized. And the patent can not adjust the pressure of the rock core in real time according to the change of the stratum depth of the rock core pipe.

Chinese patent CN110552644A discloses an in-situ coal rock heat-preservation pressure-maintaining coring device and an application method thereof. The device comprises an upper joint, an outer cylinder and a coring bit, wherein the lower end of the upper joint is connected with the outer cylinder, and the lower end of the outer cylinder is connected with the coring bit; the inner wall of the lower end of the upper joint is connected with a connecting sleeve, the lower end of the connecting sleeve is designed to be a pressure ball seat matched and sealed with the starting ball, a communicating hole I is formed in the connecting sleeve at the upper end of the pressure ball seat, the differential sliding sleeve is hung on the pressure ball seat and blocks the communicating hole I, and a communicating hole II is formed in the differential sliding sleeve. The invention realizes that the temperature and the pressure of the original stratum of the taken coal rock sample are kept to the maximum extent, the original coal core entering the cylinder is coated by the flexible pressure film to avoid the pollution of drilling fluid and other external fluids, and high-pressure hydraulic liquid is isolated in the subsequent pressure maintaining stage, so that the original physical and chemical characteristics of the coal core are protected to the maximum extent, and the high-quality fidelity coal core sample is ensured to be obtained. Although this patent is provided with rock core pressurized and adjusts the structure, can make the integrality that can guarantee the rock core effectively through adjusting its pressure that receives, but the device structure is complicated, and the simple doing work of its pressure adjustment is adjusted, under the condition that is in deep stratum and degree of depth change, need a large amount of drive doing work for a long time to adjust the pressure that the rock core receives, greatly increased the device energy consume and the operating time of equipment, in addition the rock core access structure in this structure can't be dismantled fast alone, greatly reduced the efficiency that the rock core obtained.

Furthermore, on the one hand, due to the differences in understanding to the person skilled in the art; on the other hand, since the inventor has studied a lot of documents and patents when making the present invention, but the space is not limited to the details and contents listed in the above, however, the present invention is by no means free of the features of the prior art, but the present invention has been provided with all the features of the prior art, and the applicant reserves the right to increase the related prior art in the background.

Disclosure of Invention

To prior art not enough, a pressurization coring system is provided, the device can gather the pressure size of the rock core that rock core sample initial stress size and collection were preserved, and can hold the chamber to the rock core of system and adjust the pressure size that the rock core was applyed according to the rock core pressure data of gathering, make the rock core of gathering take out the initial stress size when the in-process keeps it to be in the rock mass all the time from the stratum, the high-pressure fluid through the micropump input is accomodate the chamber and is applyed the confining pressure to the rock core, and then guarantee to take out the stress fidelity of rock core in-process.

The invention relates to a pressurization coring system, which comprises a hydraulic adjusting assembly and a core collecting assembly, wherein the hydraulic adjusting assembly provides corresponding radial pressure for a core entering the core tube according to pre-acquired ground stress data, a chamber of a liquid storage bin of the hydraulic adjusting assembly is divided into a first liquid storage chamber positioned at a lower layer and a second liquid storage chamber positioned at an upper layer through an elastic membrane, and drilling fluid stored in the second liquid storage chamber can press the elastic membrane at the bottom of the chamber under the action of self gravity, so that the elastic membrane serving as the wall of the top chamber of the first liquid storage chamber is sunken towards the inside of the chamber of the first liquid storage chamber, the first liquid storage chamber storing the hydraulic fluid injects the hydraulic fluid stored in the high-pressure fluid chamber in a manner that the volume of the chamber is reduced, and the first radial pressure is applied to the core collected by the core collecting assembly; when the first radial pressure is different from the pre-acquired ground stress data, the hydraulic adjusting assembly further injects hydraulic liquid into the high-pressure fluid chamber through the driving of the driving part, so that the core in the core collecting assembly is pressurized for the second time, and the core can be subjected to the same radial pressure as the pre-acquired ground stress data in the core tube.

According to a preferred embodiment, when the hydraulic adjusting assembly injects hydraulic fluid into a high-pressure fluid chamber of a core collecting assembly axially below the hydraulic adjusting assembly, the high-pressure fluid chamber provides radial pressure corresponding to pre-collected ground stress data to a core entering the core accommodating chamber in a manner of pressing a chamber wall forming the core accommodating chamber.

According to a preferred embodiment, the hydraulic adjusting assembly injects hydraulic fluid into the high-pressure fluid cavity by performing space compression on a hydraulic fluid storage cavity in the fluid storage bin, so that a core entering the core accommodating cavity is subjected to a first radial pressure; according to the pressure difference between the collected first radial pressure and the pre-acquired ground stress data, the hydraulic adjusting assembly controls the driving part to drive the hydraulic liquid in the liquid storage bin to be continuously injected into the high-pressure fluid cavity, and therefore the radial pressure corresponding to the pre-collected ground stress data is provided for the core entering the core accommodating cavity.

According to a preferred embodiment, under the condition that a core is inserted into a core accommodating cavity and is subjected to the same radial pressure as the pre-collected ground stress, a core transfer system arranged at one end of the core tube lifts the hydraulic adjusting assembly and the core collecting assembly which are connected with each other upwards along the axial direction of the core tube, wherein a core claw assembly is further arranged at one end of the core tube far away from the core transfer system and can fix a collected core in the core accommodating cavity, so that the core rises along with the tubular axis and is separated from a rock body.

According to a preferred embodiment, the core collecting assembly capable of collecting pressure borne by the core and containing the core comprises a high-pressure fluid chamber and a core containing chamber, the high-pressure fluid chamber is connected with the core containing chamber in a mode that a core containing chamber is wrapped by a sleeve, so that a core pressurizing and containing structure with a double-chamber structure which is mutually separated and coaxial is formed, the core containing chamber and the high-pressure fluid chamber are mutually separated through an elastic chamber membrane, the high-pressure fluid chamber can apply acting force which is radially compressed along the elastic chamber membrane in a mode that hydraulic fluid is added into the chamber of the high-pressure fluid chamber, and accordingly pressure applied to the core of the inner chamber by the wall of the core containing chamber is adjusted.

According to a preferred embodiment, the stock solution storehouse can be divided into two adjacent and not communicating first stock solution chambeies and second stock solution chamber with its cavity, and wherein, the top terminal surface in first stock solution chamber and the bottom terminal surface in second stock solution chamber are same elastic membrane, and when the elastic membrane of its bottom was impressed according to the pressure variation that the drilling fluid in its inner chamber received in the second stock solution chamber, the deformation to the cavity inside recess of first stock solution chamber took place for the elastic membrane of first stock solution chamber top surface.

According to a preferred embodiment, the drill head comprises a bit tooth and a drill rod, the hydraulic adjustment assembly being received within the drill rod and rotationally decoupled from the drill rod when the drill rod is rotated for driving the bit tooth; the drill bit is provided with a plurality of diamond bit teeth along the circumference of the annular end surface, wherein the two adjacent bit teeth form a staggered drill bit lip surface in a mode of being arranged along different circumferential lines in the same annular surface.

According to a preferred embodiment, a driving part is further arranged on the conveying pipeline, which is connected with the high-pressure fluid chamber, of the first fluid storage chamber, and the driving part at least comprises a control chip and a driving pump, the driving pump can continuously charge hydraulic fluid into the high-pressure fluid chamber with the first radial pressure according to rock mass stress values collected by the end part of the rock core when the rock core pipe is inserted into a rock formation drilled by a drill bit to obtain the rock core, so that the high-pressure fluid chamber can pressurize the surface of the rock core collected into the rock core accommodating chamber, the collected rock core can keep a complete shape under the initial stress in the rock mass, the control chip can drive the driving pump to operate according to the actual pressure and the first radial pressure difference in the rock core accommodating chamber collected by a sensor arranged in the rock core pipe so as to further inject the hydraulic fluid into the high-pressure fluid chamber, and then the chamber membrane of the rock core accommodating chamber can apply the pressure which is the same as the pressure applied to the rock core collected in the initial state.

According to a preferred embodiment, the surface of the cavity wall of the core accommodating cavity facing to the core side is provided with a limiting module in a mode of avoiding the contact between the cavity wall and the core, and the limiting module with a triangular, quadrangular, pentagonal or other polygonal cross section is limited in a block shape and is connected with the cavity membrane of the core accommodating cavity in an integrated compression molding mode.

The application also provides a pressurizing coring method, wherein a core tube for taking a core is arranged on the radial inner side of the drill bit; arranging a hydraulic adjusting assembly and a core collecting assembly which are connected with each other in the core tube, and adjusting the radial pressure applied to the core entering the core tube by the hydraulic adjusting assembly according to pre-acquired ground stress data under the condition that a drill bit drills into a stratum with a set depth; the core collecting assembly can contain the collected core in a mode of maintaining unchanged pressure borne by the core.

The invention has the beneficial technical effects that:

1. according to the invention, the pressure applied to the rock core by the rock core containing structure can be adjusted in real time according to the pressure change, so that the collected rock core can be always kept in an environment with an initial stress, the damage to the form and structure of the rock core caused by the change of the pressure and the self-weight stress in the process of taking out the rock core is effectively avoided, and the integrity of the collected rock core sample and the accuracy of later data analysis are effectively improved;

2. the high-pressure fluid input in advance by the driving part is utilized to apply confining pressure equivalent to an initial stratum to the core wrapped in the wear-resistant rubber die sleeve, stress-preserving coring is carried out on the core, and a small amount of parts at the upper end and the lower end of the core are also wrapped by the wear-resistant rubber die sleeve, so that the core can be completely wrapped in the rubber die, and the appearance distribution of the in-situ stratum of the core is kept relatively completely; the magnitude of the stress retention provided by the static high-pressure fluid is relatively stable in the drill lifting process, the service life is relatively long, the stress retention range is relatively wide, the phenomenon of core caking can be effectively prevented, and the recovery ratio of stress retention coring can be remarkably improved;

3. the front end of the core tube is modified into a detachable component, the core tube is not required to be lifted by a rubber wire due to the characteristic of rope coring, when the core tube is lifted in a well, a ground worker can rapidly replace a detachable device at the front end of the core tube, the core drilling speed is greatly accelerated, and after high-pressure fluid is injected into the ground in advance, if sudden pressure drop of the high-pressure fluid is found, the high-pressure fluid can be judged to leak, whether the high-pressure fluid leaks before the core tube is taken down can be judged, if the high-pressure fluid leaks, the ground worker can rapidly replace the detachable device, and the sealing performance of the front end of the core tube can be greatly improved;

4. the wear-resistant rubber mold provided by the invention is characterized in that a plurality of rubber modules are poured on a common wear-resistant rubber mold, and the rubber modules are in direct contact with a rock core, so that the direct contact between a weaker outer layer rubber mold and the just drilled rock core is prevented from being damaged, and the success probability of stress-preserving coring can be greatly increased;

5. the drill bit at the front end uses an integral high-strength drill bit, is not an assembled drill bit, and has greatly different mechanical properties and normal states of rocks in a high ground stress environment stratum, so that when the assembled drill bit is drilled into rocks which are difficult to drill, the structure of the drill bit can be loosened, and more seriously, a drill rod can deviate from a preset track and the core sampling can fail; this is effectively avoided by using a high strength monolithic drill bit.

Drawings

FIG. 1 is a schematic diagram of the configuration of a preferred embodiment of a pressurized coring system of the present invention;

FIG. 2 is a schematic view of the stress retention portion of the pressurized coring system of the present invention;

FIG. 3 is a schematic view of a wall deployment of a core receiving chamber of the stress-preserving coring apparatus of the present invention;

FIG. 4 is a schematic view of the lip surface of the drill bit of the stress-maintaining core apparatus of the present invention.

List of reference numerals

1: a drill 2: the core barrel 3: core inner tube

4: stress retention section 5: a liquid storage bin 6: conveying pipeline

7: the driving section 8: power supply 9: core transfer system

11: bit teeth 12: the drill rod 41: high pressure fluid chamber

42: core accommodating chamber 43: core gripper assembly 51: first liquid storage cavity

52: second reservoir 53: elastic film 71: control chip

72: driving the pump 421: the limiting module 431: clamp base

432: clamp hoop

Detailed Description

Fig. 1 shows a pressure core-taking system comprising a drill bit 1 and a core barrel 2, wherein the drill bit 1 is provided with a through-going passage in the shank which can be inserted into the core barrel 2.

According to a specific embodiment, a hydraulic adjusting assembly capable of adjusting and containing the collected rock core is arranged in the core barrel 2, and the hydraulic adjusting assembly comprises a high-pressure fluid chamber 41, a rock core containing chamber 42 and a fluid storage bin 5 communicated with the high-pressure fluid chamber 41. The high-pressure fluid chamber 41 is connected with the core accommodating chamber 42 in a mode of sleeving and wrapping the core accommodating chamber 42, so that a core pressurizing structure with a double-chamber structure which is mutually separated and coaxial is formed. The core chamber 42 has its sealed end extended inside the chamber of the high pressure fluid chamber 41 in such a way as to constitute a one-way sealed chamber. The core accommodating cavity 42 and the high-pressure fluid cavity 41 are separated from each other through an elastic cavity membrane, so that the high-pressure fluid cavity 41 with a closed cavity can adjust the pressure applied to the core accommodating cavity 42 in a manner of pressurizing the cavity. The reservoir 5 is provided with a first reservoir 51 and a second reservoir 52 in such a manner that an elastic membrane 53 is provided in a main chamber thereof to divide the chamber into two sub-chambers which are not communicated with each other and store different liquids. The first reservoir chamber 51 can store hydraulic fluid which changes the hydraulic pressure in the high-pressure fluid chamber 41 according to requirements, and the second reservoir chamber 52 can store drilling fluid which can assist the drill bit 1 to drill in the stratum. Preferably, first stock solution chamber 51 sets up in 5 cavities of stock solution near the one end of bottom, and second stock solution chamber 52 sets up in 5 cavities of stock solution near the one end at top, wherein through can following the elastic membrane 53 that receives pressure and take place deformation between first stock solution chamber 51 and the second stock solution chamber 52. When the reservoir 5 goes deep into the ground layer along with the drill bit, the second reservoir 52 applies downward pressure to the elastic membrane 53 at the bottom thereof along with the change of the pressure applied to the elastic membrane 53, so that the elastic membrane 53 is recessed into the chamber of the first reservoir 51, the chamber volume of the first reservoir 51 is reduced, the hydraulic fluid in the chamber is conveyed to the high-pressure fluid chamber 41, and the initial adjustment of the pressure in the high-pressure fluid chamber 41 is realized. Further preferably, still be provided with the driving pump on the pipeline that first stock solution chamber 51 is connected with high-pressure fluid chamber 41, hydraulic pressure adjusting part can hold the chamber 42 to the rock core under the action of gravity and provide the transport of first radial pressure's basis on through the driving pump control hydraulic fluid, thereby further regulate and control the pressure that the chamber 42 chamber lateral wall received of rock core held, make the rock core that gets into in the rock core holds the chamber 42 can keep its stress that receives invariable all the time, the integrality of the rock core of taking has been guaranteed, it takes to conveniently protect the stress to the rock core sample, prevent that its stratum position and environmental change that is located and lead to taking place the sample and smash and the pie phenomenon.

The delivery pipe connecting the first reservoir chamber 51 and the high-pressure fluid chamber 41 is also provided with a driving part 7. The driving part 7 comprises a control chip 71 and a driving pump 72, the driving pump 72 can continuously charge hydraulic liquid into the high-pressure fluid chamber 42 with the first radial pressure according to the rock stress value acquired by the end part of the rock core pipe 2 when the rock core pipe 2 goes deep into the rock stratum drilled by the drill bit 1 to acquire the rock core, so that the high-pressure fluid chamber can pressurize the surface of the rock core acquired into the rock core accommodating chamber 42, and the acquired rock core can be ensured to be in a complete form under the initial stress in the rock mass. The control chip 71 can control the drive pump 72 to operate according to actual pressure in the core accommodating cavity 42 and initial core pressure acquired by a sensor arranged in the core barrel 2, so as to adjust the movement of hydraulic liquid in the high-pressure fluid cavity 41, and further enable a cavity membrane of the core accommodating cavity 42 to apply pressure, which is the same as the pressure in the initial state of the core, to the core acquired in the cavity membrane. Preferably, the core accommodating cavity 42 is further provided with a trigger sensor at the closed top of the core inner tube 3, so that when the drill bit continuously drills to take the core, the core gradually enters the core accommodating cavity 42, after the core contacts the trigger sensor arranged at the closed end, the control chip can control the drill bit to stop drilling, and prompt an operator to finish the related drilling sampling operation, so that the core inner tube 3 is manually controlled or automatically controlled by a program to lift up, and the connection between the core and the rock body is broken. The core barrel 2 is further provided with a core gripper assembly 43 at one end close to the drill bit 1, a through hole through which a core can pass and enter the core accommodating cavity 42 is formed in the core gripper assembly 43, and the core gripper assembly 43 comprises a gripper seat 431 and a gripper 432. Clip 432 is confined within the interior through cavity of clip seat 431 and can only move up and down along its axis and cannot be disengaged from within the clip seat. When the hole that drill bit 1 was bored is deepened at core barrel 2, the stress detection instrument that sets up at clamp 432 one end can insert the rock mass to obtain the initial stress of rock core to its stress size through gathering its probe pin, and then when the rock core entered into rock core and holds chamber 42, control chip 71 can control drive pump 72 work, thereby adjust the pressure that hydraulic fluid held the chamber 42 to the rock core in high-pressure fluid chamber 41 and exert, make the rock core that gets into can receive its stress that receives the size in the rock mass is the same.

Example 1

When this application carries out the rock core sample under to current high ground stress environment, because rock mass place stratum stress effect often can't acquire and preserve intact rock core sample, according to the ground stress grading standard that records in the geotechnical engineering reconnaissance standard will be originally ground stress and divide into following several grades:

1. maximum stress value of very high ground stress vertical axis: not less than 40MPa

Hard rock: rock burst occurs during the excavation process, rock blocks are popped out, rock masses on the wall of the tunnel are stripped, and more new cracks are generated; the foundation pit has a stripping phenomenon, and the formability is poor; the drilling core is mostly in the form of cake.

2. Maximum stress value of high ground stress vertical axis: 20 to 40MPa

Soft rock: the drilling core has a caking phenomenon, the wall rock body is stripped in the excavation process, the displacement is extremely obvious, even large displacement occurs, the duration is long, and the hole is not easy to form; the foundation pit rock mass has unloading resilience, obvious swelling or stripping and difficult forming;

hard rock: rock burst may occur in the excavation process, the rock mass of the cave wall has stripping and block falling phenomena, and more new cracks are generated; the stripping phenomenon exists in the foundation pit, and the formability is generally good; the phenomenon of caking exists when the core of the drill hole is drilled.

3. Maximum stress value of medium ground stress vertical axis: 10 to 20MPa

Soft rock: the drilling core has a cake phenomenon, the displacement of the rock mass on the wall of the hole is obvious in the excavation process, the duration is long, and the hole forming property is poor; the foundation pit has a bulging phenomenon, and the formability is poor;

hard rock: the phenomena of stripping and block dropping are generated on the part of the wall rock body in the excavation process, and the cave forming property is good; the local part of the foundation pit has a stripping phenomenon, and the formability is good.

4. Maximum stress value of low ground stress vertical axis: < 10MPa

Soft rock: in the excavation process, the wall rock mass of the hole has local displacement, and the hole forming property is good; the local part of the foundation pit has a bulging phenomenon, and the formability is generally good.

The core barrel of the existing coring bit is improved, the core adopted by the coring bit is sleeved into the one-way sealed high-wear-resistance rubber sleeve, wherein the core of the exposed part is subjected to stress fidelity by using certain pressure of underground slurry, and the core in the rubber sleeve is subjected to stress fidelity by working and transporting a micro pump inside a drill rod and high-pressure fluid with external equivalent pressure. This application is different from the spring stress fidelity structure among the prior art, utilizes high-pressure fluid to realize taking the stress fidelity of rock core to the extrusion force that holds the chamber cover to make the adjustability of device great, and the regulation of pressure size is accurate more accurate, and whole stress fidelity structure also has longer life for current spring structure.

The core barrel 2 is connected to the drill bit 1 in such a way that it can be inserted inside the drill rod 12 of the drill bit 1. The core tube 2 comprises a core inner tube 3 and a stress-maintaining part 4 which can be mutually connected in a threaded manner to form a closed high-pressure fluid chamber 41, wherein one end face of the core inner tube 3 is provided with an inner cavity forming part of the high-pressure fluid chamber 41 in a penetrating manner, and the end face of the core inner tube 3 can be mutually connected in a threaded manner with an outer ring opening of the stress-maintaining part 4 with an inverted U-shaped cavity, so that the high-pressure fluid chamber 41 is formed. And an external thread which is mutually matched with the internal thread on the pipe body of the core inner pipe 3 is arranged on the outer wall of one end of the outer ring opening of the stress-maintaining part 4. Before drilling and sampling, the core inner tube 3 and the stress-maintaining part 4 need to be connected with each other, and a certain amount of hydraulic fluid needs to be filled in advance into a high-pressure fluid chamber 41 formed by the core inner tube 3 and the stress-maintaining part. Preferably, the end face of the stress retention part 4 far away from the core inner tube 3 is also provided with a core accommodating cavity 42 which is sealed in a one-way mode and provided with an inner ring opening and is concave towards the inside of the end face. The cavity with the large-caliber outer ring opening and the core containing cavity 42 with the small-caliber inner ring opening are arranged at the bottom of the cavity with the outer ring opening and the cup-shaped end face of the columnar stress maintaining part 4 respectively, so that a reverse cavity with a coaxial line of two shared part cavity walls is formed, and the stress maintaining part 4 with the inverted U-shaped cavity is formed. Preferably, the cavity wall of the core accommodating cavity 42 is made of a material with certain elasticity, such as rubber, so that when the high-pressure fluid cavity 41 delivers hydraulic fluid to raise the hydraulic pressure in the cavity, an expansion force can be applied to the cavity wall of the core accommodating cavity 42, so that the cavity wall can press the columnar core in the cavity, and the core can always bear the pressure when the core is in a stratum rock mass. Preferably, the adopted core tube is slightly longer than the core length obtained every time, when the core slowly enters the core tube in the drilling process, the micro pump is correspondingly powered off when the drill bit temporarily stops downwards tunneling, and the input high-pressure fluid extrudes the high-wear-resistant rubber mold to wrap the core, so that the stress-preserving work of the core is completed. The rubber chamber wall with certain elasticity can enable the whole chamber wall to receive uniform confining pressure, so that the recovery ratio of stress-preserving coring is improved, and the phenomenon of core caking is prevented. When the core sample of the rock mass is collected, particularly for the rock in a high ground stress environment, due to the fact that the rock mass is located at different stratum positions, the initial pressure of the core in the rock mass is high, when the core is transported to the ground in the process of taking out the core, if the core sample cannot be enabled to always receive certain ambient pressure, the pressure around the environment where the core is located is suddenly reduced due to the change of the position of the core, so that the phenomenon of core caking of the core which is taken out of the rock mass in the transportation process can be caused, so that the collected sample brings great uncertain factors to subsequent core analysis work, because in order to obtain a complete core, an applying structure capable of applying pressure to the core is required to be arranged in core drilling equipment, the core which is taken out can always receive the same-size ambient pressure when the core is located at the initial position in the rock mass, and further according to the core taking requirement, technical personnel in the related fields design a high-protection stress core taking structure capable of applying confining pressure to the core taking process.

As shown in fig. 2, under the condition that the stress retention part 4 is in threaded connection with one end of the core inner tube 3, the core accommodating cavity 42 of the stress retention part 4 is inserted into the internal cavity of the core inner tube 3, and the surface of the rubber cavity wall of the core accommodating cavity 42 facing the core side is also provided with a limit module 421 capable of directly contacting with the surface of the core. As shown in fig. 3, the limiting module 421 is a rubber block integrally molded with the rubber cavity wall of the core accommodating cavity 42, and the rubber block may be in any shape such as triangle, quadrangle, pentagon, etc. Preferably, the limiting module 421 and the cavity wall of the core accommodating cavity 42 are made of rubber or other materials with high wear resistance and elasticity. Be provided with pressure sensor on spacing module 421 for control chip 71 can gather the actual pressure that receives after the rock core gets into rock core and holds chamber 42, thereby adjusts the size that the chamber wall of rock core holding chamber 42 applyed pressure to the rock core according to its actual pressure and rock core initial condition's stress. Preferably, the pressure sensor can collect pressure signals in real time in the lifting process, so that the collected abnormal signals are transmitted to the control chip under the condition of any pressure change in the lifting process, and the control chip controls the operation of the driving pump 72 to adjust the pressure of the hydraulic liquid in the high-pressure fluid chamber 41 on the wall of the core accommodating chamber. The limiting module 421 is uniformly arranged on the surface of the cavity wall according to a mode that the core is prevented from directly rubbing the rubber cavity wall to wear the cavity wall, so that the pressure applied by the high-pressure fluid chamber 41 on the cavity wall of the core accommodating chamber 42 can be uniformly transmitted to the limiting module 421, and the rubber module can apply confining pressure which is consistent with the surrounding stress received by the core when the core is in the rock mass. Through setting up the spacing module of rubber block formula, can improve the life on rubber cavity wall effectively, reduce the damaged risk that causes hydraulic fluid to reveal of chamber wall simultaneously.

Preferably, through the tip of connecting 4 detachably of the portion of guaranteeing stress at rock core inner tube 3 for can directly dismantle the portion of guaranteeing stress 4 that takes out from rock core inner tube 3 after accomplishing the rock mass and coring, make things convenient for the sample and the save of rock core. In addition, when sampling operation many times, only need to change other guarantor stress portion 4 again and be connected with rock core inner tube 3, can carry out rock core sample once more, improved the efficiency and the security of sample greatly, guarantee to take out the stress fidelity of rock core.

The device closely cooperates in the tunneling process through the loading stress-preserving coring system and the rock core transfer system, so that the recovery rate of stress-preserving coring is improved, and the occurrence of the phenomenon of rock core caking is prevented. And a liquid storage bin 5 and a driving part 7 which can convey pressurized hydraulic liquid into the high-pressure fluid cavity are further arranged at one end of the core inner tube 3, which is far away from the stress-maintaining part 4. Stock solution storehouse 5 communicates with each other through external pipeline 6 and high-pressure fluid chamber 41 to can carry the hydraulic fluid in the stock solution storehouse 5 to high-pressure fluid chamber 41 according to the demand, simultaneously, also can be when split rock core inner tube 3 and guarantor stress portion 4, can carry the surplus hydraulic fluid in the high-pressure fluid chamber 41 back to stock solution storehouse 5, thereby avoid hydraulic fluid from the kneck outflow. Preferably, the chamber volume of the reservoir 5 is greater than the difference between the volume of the inner tube 3 of the core and the volume of the core, so that after the core enters the core accommodating chamber 42, the volume of the hydraulic fluid which can enter the high-pressure fluid chamber 41 of the reservoir 5 is far greater than the volume of the high-pressure fluid chamber 41, and therefore the hydraulic fluid can exert expansion forces of different sizes on the elastic chamber wall of the high-pressure fluid chamber 41. The transfer duct 6 is also connected to a drive 7 which can provide drive for the hydraulic fluid in the circuit. The driving part 7 adopts a micro pump which can realize the conversion of the working state and the adjustment of the driving direction of the driving force provided by the micro pump by controlling the on-off of the electric power by an electromagnetic relay, thereby providing the driving force for the hydraulic liquid in the pipeline according to the requirement. In the process of core sampling, the driving part 7 controlled by the electromagnetic relay transmits high-pressure liquid flow to the high-pressure fluid chamber 41 according to requirements, so that the input high-pressure liquid flow exerts confining pressure on the wall of the core accommodating chamber 42. The driving part 7 is also electrically communicated with a power supply 8 which adopts rope power supply, mud pulse power generation and micro rechargeable storage battery power supply. The power supply 8 is also arranged at one end of the inner tube 3 of the rock core far away from the stress-maintaining part 4.

As shown in fig. 4, the ring-shaped end surface of the drill bit 1, which is provided with a through channel in the drill rod 12 thereof, is circumferentially provided with a plurality of diamond bit teeth 11, thereby forming a cutting and taking-in end of the drill bit. Wherein, two adjacent bit teeth 11 form the staggered bit lip surface according to the mode of setting on different circumferential lines in the same circular ring surface. Two bit teeth 11 with one bit tooth 11 in the middle are arranged on the same circumference of the annular end surface of the drill rod 12, so that the diamond bit teeth 11 which are arranged in a staggered mode and are circumferentially distributed in different circumferential sizes are formed on the annular end surface. The contact area of the drill bit and the rock mass surface can be effectively reduced by arranging the staggered drill bit lip faces, so that the pressure per unit area acting on the rock mass is increased, the volume of the rock mass can be more favorably crushed, the drill bit lip faces are partially left after being left, the volume of the cuttings is increased, the cuttings are remained at the bottom of the hole in the drilling process, the cuttings not taken away by the drilling fluid are also increased, the drill bit matrix can be effectively abraded, and the drill bit is enabled to be sharper. Preferably, the diamond bit teeth 11 are integrally sintered with the drill rod body of the drill bit 1 in a manner of filling the steel body mold layer by layer. Thereby avoiding the problem that the assembled drill bit is easy to loosen or fall off. The core barrel 2 is connected with a core transfer system 9 through a through channel in a drill rod 12 of the drill bit 1. Under the condition that the drill bit 1 drives the core barrel 2 to complete core taking, the core transfer system 9 can pull the core barrel 2 to move out of the drill rod 12, so that the core barrel 2 in the stratum is transferred to the ground. The core holding cavity 42 is provided with a core claw assembly 43 which can cut a core and support the cut core column on the wall of the drill bit end face. The core gripper assembly 43 includes at least a gripper seat 431 and a gripper 432. The clamp seat 431 is arranged at one end, far away from the core inner tube 3, of the stress maintaining part 4, the clamp 432 capable of sliding up and down on the inclined inner wall of the clamp seat 431 is arranged in the clamp seat 431 in a relative sliding mode, the clamp 432 with a side wall penetrating opening is limited by the clamp seat 431 in the up-and-down sliding process to change the size of the cross section of the clamp 432, and further the hollow ring diameter limited by the inner ring of the clamp 432 is reduced, so that the sliding friction force between the clamp 432 and the core is increased, and the core is separated from a rock body along with the lifting operation. The core gripper assembly 43 severs the connection between the core and the rock when the core is loaded into the core accommodating chamber 42. When the drill bit is used, a rock core slowly enters the core tube 2 in the drilling process, the drilling depth of each drilling is input in the drilling system, after the rock core is filled, the rock core is cut off by using the rock core claw assembly 43, the rock core is taken out through the rock core transfer system 9 under the condition that the drill bit is not lifted, another core tube 2 is put into the drill rod 12, the drilling is continued, the operation is carried out in a circulating mode until the drill bit is worn, the drill bit is lifted and replaced, and the reciprocating and circulating drilling is carried out according to the flow.

Example 2

The pressurized coring system is particularly suitable for performing stress-preserving coring work on rocks in a high ground stress environment. After the core is collected from the rock body by the coring device, the core is sleeved into a one-way sealed core accommodating cavity 42 formed by a high-wear-resistant rubber sleeve, wherein the core of the exposed part is subjected to stress fidelity by using certain pressure of underground slurry, and the core wrapped by the rubber sleeve is conveyed into a high-pressure fluid cavity 41 by using a micro pump arranged on a core pipe 2 and positioned in a drill rod 12, so that the high-pressure fluid cavity 41 applies equal pressure to the initial state of the core in the rock body to the core surface wrapped by the rubber sleeve by applying expansion pressure to the cavity wall, and the stress fidelity of the core is realized. Preferably, the micro pump supplies power through a rope or generates power through mud pulse (corresponding to the core abutting device), namely, the core completely enters the coring pipe and abuts against the device to be powered off. After the rock core completely enters the rock core accommodating cavity 42, the end part of the rock core can be abutted against the rock core abutting device arranged on the closed end face of the rock core accommodating cavity 42, so that the abutting signal transmitted by the device can control the disconnection of the circuit by the corresponding electromagnetic relay. Preferably, still install pressure sensor on brick 1 to can acquire the pressure size numerical value of the different degree of depth rock stratum position department of locating, thereby conveniently protect stress core structure and can control its hydraulic fluid of carrying different volumes in to high-pressure fluid chamber 41 to different stresses, make the rock core among the different pressure environment take the back homoenergetic and keep receiving the confined pressure unchangeable. After the core drilling is completed by the coring structure, the core in the coring pipe 2 is transported to the surface by wireline coring methods commonly used in the art.

Preferably, core pipe 2 sets up the integrated configuration for convenient dismantlement and equipment through the rubber die sleeve that will gather the parcel rock core with core inner tube 3 including the rock core inner tube 3 that can the mutual detachable connection and protect stress portion 4 to the convenience is at the coring in-process, only needs to change according to the demand and protects stress portion 4 and just can accomplish the rock core collection work of the different degree of depth in same drilling. And the rock core of this application shifts adopts rope coring technique, can be in the operation process of actually coring, only need utilize the rubber filament to propose coring pipe from the well, after coring pipe is proposed from the pit, constructor accomplishes the change of coring pipe front end subaerial, can improve the efficiency of well drilling coring and can reduce revealing of high-pressure fluid, can carry out the replacement work of rubber matrix with faster speed.

In the actual exploration process, well drilling and coring are important links in core analysis work, when rock is in some very environments, particularly high ground stress environments, the rock core is cracked into a cake shape along with the relief of the stress of a hole wall in the drilling process, and the thickness of the formed cake is smaller when the ground stress is larger; the invention provides a method for applying confining pressure by high-pressure fluid to prevent the occurrence of core caking phenomenon, ensure the core stress fidelity in a high ground stress environment and improve the sampling rate of stress-preserved coring. The stress-preserving system adopts the measures that the high-pressure fluid input in advance by the micro pump is utilized to apply confining pressure equivalent to an initial stratum to the core wrapped in the wear-resistant rubber die sleeve, stress-preserving coring is carried out on the core, a small amount of parts at the upper end and the lower end of the core are also wrapped by the wear-resistant rubber die sleeve, and compared with other patents, the method provided by the patent can completely wrap the core in the rubber die and completely preserve the appearance distribution of the in-situ stratum of the core; and the magnitude of the stress retention provided by the static high-pressure fluid is relatively stable in the process of drill lifting, the service life is relatively long, the range of the stress retention is relatively wide, the phenomenon of core caking can be effectively prevented, and the recovery ratio of stress retention coring can be obviously improved. By adopting the rope coring method, the advantages brought by the coring method are extremely obvious: the method can realize coring without drilling, save drilling time, increase drilling time, shorten construction time and reduce cost; the method that adopts the screw thread to link together the core pipe that combines this patent to provide, the speed of the coring of drilling that can be very big improvement, also very big improvement the rate of taking of rock core and can reduce the emergence probability of downthehole accident. This application will be got core tube front end repacking and be detachable component, owing to adopt the characteristics of rope coring, need not dig into, only need to mention core tube from the well with the rubber filament, mention the back in the core tube well, ground personnel can be fast with the detachable device replacement of coring tube front end, the speed that the rock core was got is bored in very big acceleration, and pour into high-pressure fluid into in advance subaerial after, if discover high-pressure fluid's sudden pressure drop, can judge that high-pressure fluid produces reveals, can judge before the coring tube under whether can take place to reveal, if take place to reveal, ground personnel can follow fast and trade detachable device, can greatly improve the sealing performance of coring tube front end. In addition, the drill bit at the front end of the device is an integral high-strength drill bit, the drill bit is not an assembled drill bit, the mechanical property and the normal state of rock are greatly different in a high ground stress environment stratum, when the assembled drill bit is drilled into rock which is difficult to drill, the structure of the drill bit can be loosened, and the drill rod can deviate from a preset track and the core sampling can fail to be caused seriously; this is effectively avoided by using a high strength one-piece drill bit.

It should be noted that the above-mentioned embodiments are exemplary, and that those skilled in the art, having benefit of this disclosure, may devise various solutions which are within the scope of this disclosure and are within the scope of the invention. It should be understood by those skilled in the art that the present specification and figures are illustrative only and are not limiting upon the claims. The scope of the invention is defined by the claims and their equivalents.

Claims (7)

1. The intelligent core extraction system capable of conducting stress-preserving coring at least comprises a core barrel (2) capable of taking a core sample, and is characterized in that the core barrel (2) comprises a hydraulic adjusting assembly and a core collecting assembly, when the hydraulic adjusting assembly injects hydraulic fluid into a high-pressure fluid cavity (41) of the core collecting assembly axially below the hydraulic adjusting assembly, the high-pressure fluid cavity (41) provides radial pressure corresponding to pre-collected ground stress data for a core entering a core accommodating cavity (42) in a mode of extruding the cavity wall of the core accommodating cavity (42); the sealed end of the core accommodating cavity (42) extends into the cavity of the high-pressure fluid cavity (41) in a mode of forming a one-way sealed cavity;

the hydraulic adjusting assembly provides corresponding radial pressure for a rock core entering a core barrel (2) according to pre-acquired ground stress data, wherein a chamber of a liquid storage bin (5) of the hydraulic adjusting assembly is divided into a first liquid storage cavity (51) positioned at a lower layer and a second liquid storage cavity (52) positioned at an upper layer through an elastic membrane (53);

when the second liquid storage cavity (52) applies pressure to the elastic membrane (53) according to the change of the gravity on the drilling fluid in the inner cavity of the second liquid storage cavity, the elastic membrane (53) serving as the top surface of the first liquid storage cavity (51) deforms to be sunken into the cavity of the first liquid storage cavity (51), so that the first liquid storage cavity (51) applies first radial pressure to the core collected by the core collecting assembly in a mode of injecting the stored hydraulic fluid into the high-pressure fluid cavity (41);

the core accommodating cavity (42) injects hydraulic fluid into the high-pressure fluid cavity (41) according to the fluid storage bin (5) to adjust first radial pressure applied to the core in the cavity; when the pressure difference exists between the acquired first radial pressure and the pre-acquired crustal stress value, the hydraulic adjusting assembly controls the driving part (7) to drive the hydraulic liquid of the liquid storage bin (5) to be continuously injected into the high-pressure fluid cavity (41), so that the radial pressure corresponding to the pre-acquired crustal stress data is provided for the rock core entering the rock core accommodating cavity (42).

2. The intelligent core extraction system with stress-maintaining coring function as claimed in claim 1, wherein the high-pressure fluid chamber (41) is connected with the core accommodating chamber (42) in a manner of covering and wrapping the chamber of the core accommodating chamber (42), so as to form a core pressurized accommodating structure with a mutually separated coaxial double-chamber structure.

3. The intelligent core extraction system with stress-preserving coring function as claimed in claim 2, wherein the core accommodating chamber (42) and the high-pressure fluid chamber (41) are separated from each other through an elastic chamber membrane, and the high-pressure fluid chamber (41) can apply a force compressed along the radial direction of the elastic chamber membrane in a manner of adding hydraulic fluid into the chamber of the high-pressure fluid chamber, so that the pressure applied by the chamber wall of the core accommodating chamber (42) to the core of the internal chamber of the high-pressure fluid chamber is adjusted.

4. The intelligent extraction system for stress-preserving coring, as set forth in claim 3, characterized in that the hydraulic adjustment assembly further injects hydraulic fluid into the high-pressure fluid chamber (41) by the driving of the driving part (7) when there is a difference between the first radial pressure and the pre-acquired ground stress data, so as to pressurize the core in the core collecting assembly a second time, so that the core can be subjected to the same radial pressure as the pre-acquired ground stress data in the core barrel (2).

5. The intelligent core extraction system capable of achieving stress-preserving coring as claimed in claim 4, wherein a core claw assembly (43) is further arranged at the axial lower end of the core tube (2), and the core claw assembly (43) can fix a core to be extracted in the core accommodating cavity (42) so that the core can be separated from a rock body along with the axial rising of the core tube (2).

6. The intelligent core extraction system with stress-preserving coring function as claimed in claim 5, wherein the driving part (7) at least comprises a control chip (71) and a driving pump (72), and the driving pump (72) can continuously charge hydraulic fluid into the high-pressure fluid chamber (41) with the first radial pressure according to rock stress values collected at the end part of the core tube (2) when the core tube (2) is deeply inserted into a rock formation drilled by the drill bit (1) for core acquisition, so that the high-pressure fluid chamber (41) can pressurize the core surface collected to the core accommodating chamber (42), and the collected core can maintain the complete form under the initial stress in the rock mass.

7. Intelligent core extraction system capable of guaranteeing stress coring according to claim 6, characterized in that the core barrel (2) is further sleeved with a drill bit (1) capable of drilling in the formation, and the hydraulic adjusting assembly is accommodated in a drill rod (12) of the drill bit (1) and is rotationally separated from the drill rod (12).

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