CN107989563B - Downhole circulating well washing tool and use method thereof - Google Patents

Abstract

The invention discloses an underground circulating well-flushing tool and a use method thereof, comprising a circulating well-flushing tool body, a pressure relief nipple and a switch container which are connected in sequence, wherein the circulating well-flushing tool body comprises a hollow circulating jacket, a hollow mandrel sleeved in the circulating jacket and a switch assembly; the pressure relief nipple is of a hollow cavity structure connected to the bottom of the circulating jacket, wherein the hollow cavity is communicated with a drilling fluid circulation channel in the circulating jacket, an opening is formed in the side wall of the pressure relief nipple, and a pressure relief valve is arranged in the opening; the switch storage device comprises a storage jacket and an inner cylinder arranged in the storage jacket, the storage jacket is connected to the bottom of the pressure relief nipple, the switch body and Guan Faqiu are stored in the inner cylinder, and the inner cylinder is of a hollow structure. The automatic pressure relief nipple can realize free switching of circulating well flushing and normal well drilling operation, and can timely open a circulating channel when a drilling tool is blocked by adopting the setting of the pressure relief nipple, and has the characteristics of automatic liquid discharge, automatic grouting, work efficiency improvement and the like.

Description

Downhole circulating well washing tool and use method thereof

Technical Field

The invention relates to an underground circulating well-flushing tool and a using method thereof, in particular to a tool capable of realizing underground circulating well-flushing operation in horizontal well drilling and completion and well repairing and well-flushing operation and a using method thereof, belonging to the technical field of petroleum and natural gas drilling and well-flushing processes and tools.

Background

In the process of drilling a horizontal well and a large-displacement well, because rock fragments of a shaft in the horizontal direction cannot circulate out of the ground in time due to the influence of gravity, a large amount of rock fragment deposits are generated in the horizontal section well to form a rock fragment bed, and then a sleeve with a preset depth cannot be smoothly put in during well completion, so that non-production time is increased, and well drilling efficiency and well completion quality are reduced. In general, a mode of increasing pumping of a slurry pump is required to generate a certain turbulence, which is helpful for cleaning a shaft. However, the pump speed requirements required to achieve turbulent flow are not met for small bore mud motors and Measurement While Drilling (MWD) tools, and particularly efficient well bore cleaning is rendered extremely difficult when drilling highly deviated and horizontal wells. Drilling operators typically employ short trips, well cleanout, bit replacement, and other cleaning operations to address such issues. These methods may have some effect, but require a lot of time to drill, reducing production efficiency. In addition, if the lower drilling tool or the drill bit water hole is blocked and the circulation operation cannot be performed in time, underground complex accidents such as well wall collapse and the like are easily caused, and the risk of blowout accidents is increased.

The prior patent document CN203594377U (a coiled tubing gravity drilling tool, 2014.05.14) discloses a drilling tool structure capable of reducing the scaling and necking conditions of oil pipes in oil, gas and water wells, in which, in the structure, through a water spraying hole formed in the middle of the inner cavity of a drill bit, during construction, a coiled tubing is passed through a blowout preventer and a blowout preventer, a coiled tubing joint is inserted and tightened by a cone nut, and then the whole device is taken into the blowout preventer, and then the blowout preventer and the blowout preventer are connected with an oil production wellhead to open a well. And slowly lowering the gravity drilling tool into the well, stopping the drilling tool from advancing when the drilling bit in the well encounters resistance, and still affecting the upper part of the working cylinder by downward gravity of the continuous oil pipe, and converting the downward motion of the continuous oil pipe into spiral rotation by the spiral shaft and the spiral transmission nut to drive the drilling bit to rotate and scrape the drilling bit. After one stroke is completed, the second downward pressurizing drilling is completed, the high-pressure well-flushing liquid in the continuous oil pipe is used for flushing sand and flushing the well at the same time, the well wall dirt and attachments are cleaned, and the process is repeated until completion.

Besides, the prior patent document CN204113158U (2015.01.21) also discloses a well flushing device capable of effectively reducing the times of tripping a screw drill, tripping a well flushing pipe column and flushing a well, and the well flushing device is matched with the screw drill, so that repeated forward drilling and reverse flushing reciprocating construction of one trip can be realized, normal drilling and plugging can be realized, and dust can be backwashed out of the ground in time. When the drilling is carried out, drilling plug liquid is injected from an oil pipe, enters the cylinder body through the upper joint, enters the central sieve tube through sieve mesh filtration, enters the screw drill through the central through hole of the reversing joint, and pushes the screw drill rotor to drive the lower end drill bit to rotate so as to realize the drilling plug. When backwashing is started, drilling plug fluid carrying dust in the annular space of the oil and the sleeve is changed from ascending to descending, enters the side hole of the switching joint of the well flushing device, opens a valve, enters the annular space of the central screen pipe and the cylinder body, enters the oil pipe through the upper joint, and finally returns out of the ground to finish well flushing.

Disclosure of Invention

The invention aims to provide a downhole circulating well-flushing tool, which adopts a circulating well-flushing tool body, a pressure relief nipple and a switch container to form a part of a drilling tool in a matched mode, through the input and use of a switch assembly, not only can the free switching of circulating well-flushing and normal well-drilling operation be realized, but also the circulation channel can be timely opened when the drilling tool is blocked by adopting the pressure relief nipple, the occurrence of complex underground accidents caused by stopping circulation can be avoided, the drilling fluid in the drilling tool can be automatically discharged through the tool when the drilling tool is started, the drilling fluid is prevented from splashing outside a drilling platform, the automatic grouting function is realized when the drilling tool is in a down-hole state, and the working efficiency is improved.

The invention aims to provide a using method of a downhole circulating well-flushing tool, which is simple, can realize free switching between circulating well-flushing and normal well-drilling operation, can solve the problem that a circulating channel is opened in time when a drilling tool is blocked, does not need to take off the drilling tool, replace a drill bit or the well-flushing tool in the whole operation state switching process, can reduce non-production time, and has the characteristics of improving well-drilling efficiency and well-cleaning degree and well-completion quality.

The invention is realized by the following technical scheme: an underground circulating well-flushing tool comprises a circulating well-flushing tool body, a pressure relief nipple and a switch container which are connected in sequence,

The circulating well-flushing tool body comprises a hollow circulating jacket, a hollow mandrel and a switch assembly, wherein the hollow mandrel and the switch assembly are sleeved in the circulating jacket, the hollow structures of the circulating jacket and the mandrel are matched to form a drilling fluid circulation channel, a jacket through hole is formed in the middle shell of the circulating jacket, and a nozzle is arranged in the jacket through hole; the mandrel axially slides in the circulating jacket, a mandrel through hole is formed in a shell of the mandrel, a valve seat is arranged in the mandrel below the mandrel through hole, an inner hole of the valve seat is communicated with a drilling fluid circulation channel in the mandrel, an elastic locking mechanism which is clamped with the upper shell of the circulating jacket is arranged at the top of the mandrel, an elastic reset mechanism is arranged at the bottom of the mandrel, and the mandrel through hole and the jacket through hole are arranged in a staggered manner when the mandrel is locked through the elastic locking mechanism; the switch assembly comprises a switch body, a valve closing ball and a locking ball, wherein an elastic part of the switch body is seated in an inner hole of a valve seat and drives a mandrel to slide downwards along a circulating sleeve until the mandrel through hole is communicated with a sleeve through hole, the diameter of the locking ball is smaller than the inner diameters of the mandrel through hole and a nozzle through hole, a locker for clamping the locking ball is arranged in the nozzle, an annular groove is arranged on the inner wall of a shell of the circulating sleeve along the position of the sleeve through hole, the width of the annular groove is larger than the inner diameter of the nozzle through hole, the diameter of the valve closing ball is larger than the inner diameter of the mandrel through hole and smaller than the inner diameter of the inner hole of the valve seat, guan Faqiu acts on the locking ball,

The pressure relief nipple is a hollow cavity structure connected to the bottom of the circulating jacket, wherein the hollow cavity is communicated with a drilling fluid circulation channel in the circulating jacket, an opening is arranged on the side wall of the pressure relief nipple, a pressure relief valve is arranged in the opening,

the switch storage device comprises a storage jacket and an inner cylinder arranged in the storage jacket, the storage jacket is connected to the bottom of the pressure relief nipple, the switch body and Guan Faqiu are stored in the inner cylinder, and the inner cylinder is of a hollow structure.

The lower end part of the elastic locking mechanism is sleeved at the top of the mandrel, the upper end part of the elastic locking mechanism is a variable-diameter elastic tube with a slotted structure, the outer diameter of the upper end part of the elastic locking mechanism is larger than that of the lower end part of the elastic locking mechanism, the middle end part of the elastic locking mechanism, which is connected with the upper end part of the elastic locking mechanism, is of an inclined structure, and the inner wall of the circulating jacket is provided with an inclined structure for restraining the upper end part of the elastic locking mechanism.

The bottom of the mandrel is downwards extended with a hollow mandrel extension section, the mandrel extension section is equal to the inner diameter of the mandrel, the outer diameter of the mandrel extension section is smaller than the outer diameter of the mandrel, an annular cavity is formed between the outer wall of the mandrel extension section and the circulating jacket, and the elastic reset mechanism is sleeved in the annular cavity.

And a communication hole for communicating the annular cavity is formed in the side wall of the mandrel extension section.

And a sealing mechanism is arranged between the circulating jacket and the mandrel, and the sealing mechanism is correspondingly arranged on the upper side and the lower side of the circulating through hole.

The switch body comprises a sphere part, a cone part arranged at the upper part of the sphere part and a weighted short handle arranged at the lower part of the sphere part, wherein the sphere part is an elastic part of the switch body, the outer diameter of the sphere part is larger than the inner diameter of an inner hole of the valve seat, and the maximum outer diameters of the cone part and the weighted short handle are smaller than the inner diameter of the inner hole of the valve seat.

And boss structures distributed in an annular mode are arranged in the inner hole of the valve seat.

And a sealing groove is arranged on the outer wall of the valve seat, which is contacted with the mandrel, and a sealing surface is arranged on the valve seat, which is contacted with the sphere part.

The locking device comprises a rotary slip and a spring assembly which are arranged in the nozzle, the rotary slip comprises a bidirectional latch which rotates along with a rotating shaft, and the rotating shaft is fixed in the nozzle; the spring assembly comprises a sleeve arranged in the nozzle, a spring is arranged in the sleeve, a piston is arranged at the top of the spring, and inner clamping teeth of the bidirectional clamping teeth act on the piston.

The pressure relief valve is characterized in that the pressure relief valve comprises a pressure relief valve seat sleeved in the opening, one end of an inner hole of the pressure relief valve seat is a pressure relief through hole, a valve core is arranged in the inner hole of the pressure relief valve seat, the top of the valve core is a spherical part for sealing the pressure relief through hole, an adjusting bolt is sleeved between the lower part of the valve core and the inner hole of the pressure relief valve seat, a nut sleeved in the adjusting bolt is arranged at the bottom of the valve core, a lower through hole communicated with the outside is arranged in the lower part of the valve core, an annular space is formed between the outer wall of the middle part of the valve core and the inner hole of the pressure relief valve seat, a middle through hole perpendicular to the lower through hole is arranged in the middle part of the valve core, the middle through hole is communicated with the annular space and the lower through hole, and a spring mechanism is sleeved outside the valve core in the annular space.

The contact surface of the pressure relief through hole and the sphere part is a conical sealing surface.

And a sealing part is arranged between the pressure relief valve seat and the inner wall of the opening.

And a radial counter bore structure is arranged on the outer side end surface of the pressure relief valve seat.

The inner barrel is cut apart through the baffle and is formed the main passageway of drilling fluid circulation and accomodate the switch ware body and close the passageway of accomodating of valve ball, upwards extends along the main passageway and establishes the inclined plane boss of direction, the main passageway all is hollow out construction with accomodating the passageway, and the backup pad is established to the inner barrel bottom, accomodates the passageway bottom and is equipped with the through-hole that restriction switch ware body and close the valve ball and pass through.

The partition plate is eccentrically arranged in the inner cylinder.

The application method of the downhole circulating well flushing tool comprises the following steps of:

(1) During normal operation: the mandrel is locked through an elastic locking mechanism;

(2) During cyclic well flushing:

(2.1) sequentially throwing a switch body and a locking ball into the circulating jacket, wherein after an elastic part of the switch body is seated in an inner hole of the valve seat, the locking ball reaches the nozzle and is locked by the locking device;

(2.2) the slurry in the well flows into the annular groove of the outer sleeve through hole through the nozzle, so that the automatic grouting of the tool is realized;

(2.3) after grouting, throwing a valve closing ball into the circulation jacket, and after Guan Faqiu acts on the locking ball to unlock the locking ball, the elastic part of the switch body deforms under pressure and penetrates through the inner hole of the valve seat, the switch body and the valve closing ball fall into the inner cylinder, and the mandrel is restored to a locking state for the next well flushing operation;

(3) And (3) performing circulating well flushing when the downhole instrument is blocked:

and (3) sequentially throwing the switch body and the locking ball into the circulation jacket, when the downhole instrument is judged to be blocked, increasing the pressure in the pressure relief nipple until the pressure relief valve is opened, simultaneously controlling the pressure in the pressure relief nipple to be lower than the deformation pressure of the elastic component of the switch body, enabling the locking ball to reach the nozzle and be locked by the locker, and repeating the steps (2.2) and (2.3) to finish one-time well flushing operation when the downhole instrument is blocked.

In the step (2.1), after the switch body and the locking ball are sequentially thrown into the circulation jacket, the drilling pump is started to circulate, the pressure is increased firstly and then reduced, the discharge capacity is increased simultaneously, and after the elastic component of the switch body is judged to be seated in the inner hole of the valve seat, the mandrel descends, and the locking ball reaches the nozzle and is locked by the locking device.

In the step (3), after the switch body and the locking ball are sequentially thrown into the circulation jacket, the drilling pump is started to circulate, the pressure is increased and then is decreased, and meanwhile, the displacement is not increased, so that the blockage of the downhole instrument at the moment is judged.

Compared with the prior art, the invention has the following advantages:

(1) The invention has reasonable structural design, the circulating jacket and the mandrel adopt a sliding fit mode, the switch assembly is used as a state change switch, when the mandrel is locked, the circulating channel is closed to realize normal drilling operation, after the switch body and the locking ball are put into the well, the circulating channel is opened to perform automatic grouting so as to realize automatic well flushing operation, the operation steps are simple, the normal drilling operation and the well flushing operation can be switched by adopting the mode of throwing the switch assembly, the production time consumed by tripping during the existing well flushing operation is effectively overcome, and the improvement of the well drilling efficiency is facilitated.

(2) The circulating well-flushing tool body can be matched with a drill rod or a drilling tool to form a part of the drilling tool, when the circulating well-flushing tool is used, an upper joint can be arranged on a circulating jacket of the circulating well-flushing tool body, the upper joint is connected with the lower part of the drill rod or the drilling tool, and when a circulating channel is opened or locked, only a switch assembly is needed to be put into the drilling tool at a ground inlet, so that one-time well-flushing operation can be realized, and the circulating well-flushing tool is convenient to use.

(3) The elastic reset mechanism is designed at the lower part of the mandrel and can be made of springs or other elastic materials, and the mechanism such as a shear pin is not used, so that the elastic reset mechanism has the following functions: after the valve closing ball is thrown in, the mandrel can slide upwards under the elastic action and restore the locking state, so that the next throwing of the switch assembly is facilitated, and the operation of circulating well flushing is realized.

(4) The elastic reset mechanism is sleeved in an annular cavity formed between the mandrel extension section and the circulating jacket, and when the elastic reset mechanism is used, a communication hole can be formed in the mandrel extension section, so that the mandrel can conveniently slide up and down, and the up and down pressure is balanced.

(5) The elastic locking mechanism is arranged on the mandrel, and is limited by the inclined surface structure on the circulating jacket, so that the mandrel is locked on the circulating jacket, the mandrel and the valve seat can be prevented from sliding due to thrust during normal drilling, and tools can be prevented from being opened in a circulating way.

(6) The special rotary slip structure is designed in the nozzle, and after the locking ball is put into the nozzle, the locking ball is locked in the nozzle by the rotary slip structure, so that the tool is in a locking and opening state, on one hand, the mandrel is limited to slide due to the locking of the locking ball, and particularly after the ground drilling pump is stopped, the elastic locking mechanism is reset to drive the mandrel to slide upwards; on the other hand, because the locking of locking ball can open the circulation channel inside and outside the instrument, because the ring channel that the circulation overcoat inner wall set up, because of U type pipe effect, when the locking of locking ball, can realize the connection of the inside and outside fluid channel of instrument, not only can carry out automatic grouting, reduce the grouting link on well head ground, in the process of taking out the drill, the liquid in the drilling tool receives the action of gravity can also be discharged through this passageway is automatic, avoided the liquid of drilling platform face to splash outward, have the characteristics that improve down the efficiency of boring, satisfy the safety environmental protection requirement.

(7) The invention relates to a circulating well-flushing tool body which adopts a specially designed switch assembly, comprising a switch body which consists of a sphere part, a cone part, a weighted short handle and the like, wherein the sphere part can adopt an elastic part made of a deformable material, and the three parts can be made into an integral structure or can be connected and fixed through threads and the like. The switch operation of the tool is realized, and meanwhile, the tool can be thrown in place faster than a common spherical tool, and the switch operation of a horizontal well section tool is facilitated, for example, the design of a heavy short handle can be adopted, a material or metal with a specific gravity larger than that of a deformation material can be adopted, the descending speed of the switch body can be accelerated, and the operation efficiency is improved; the bevel on the cone portion will help support the valve ball in a better setting.

(8) According to the invention, through the design of the valve seat, the ball body part of the switch body is used for being seated in the inner hole of the valve seat, so that the mandrel can slide downwards to open the circulating channel, and when the valve seat is used, an annular boss structure can be designed in the inner hole of the valve seat, so that the switch body is prevented from being impacted by gravity and inertia to prematurely break down the valve seat and lose the opening capacity, and meanwhile, in order not to influence the sealing of the valve seat, a sealing groove and a sealing surface are also designed on the valve seat, so that the sealing isolation of the space of the upper drilling tool and the lower drilling tool of the valve seat is ensured after the ball body part is seated, and the effective use of the switch assembly is facilitated.

In normal drilling, if the lower drilling tool or the bit water hole is blocked, the conventional circulating tool forms a sealing surface after ball throwing, but the upper part and the lower part of the sealing surface form sealing cavities, so that the tool cannot be opened in time by utilizing pressure difference, and thus, the down-hole complex and even production accidents can be caused.

(10) According to the invention, the switch container is designed under the pressure relief nipple, and the inner barrel of the switch container is divided into a main channel and a containing channel for drilling fluid circulation by adopting the eccentrically arranged partition plate, so that the blockage of the internal flow channel of the drilling tool, which is filled with the switch component, is avoided; the main channel and the storage channel are of hollow structures, so that the flow area of the drilling tool is conveniently increased, the problem of blockage of tools due to impurities in liquid is avoided, the integral pressure consumption of the tools is reduced, and the influence on the normal drilling process is reduced; the hollowed-out parts can adopt strip-shaped holes, so that the liquid can conveniently stagger the flow channels, and the area of the fluid can be increased.

Drawings

FIG. 1 is a schematic cross-sectional view of a downhole circulating flushing tool of the present invention in a downhole in-situ configuration.

FIG. 2 is a schematic cross-sectional view of the downhole circulating flushing tool of the present invention in an open state.

FIG. 3 is a schematic cross-sectional block diagram of the resilient latch mechanism of the present invention.

FIG. 4 is a schematic cross-sectional view of the locking ball of the present invention in an unlocked state when it enters the nozzle.

Fig. 5 is a schematic cross-sectional view showing a locked state of the locking ball of the present invention when it enters the nozzle.

Fig. 6 is a schematic structural diagram of the switch body according to the present invention.

Fig. 7 is a schematic diagram of a closing operation of the switch body according to the present invention.

Fig. 8 is a schematic diagram of the switch body of the present invention after the switch body is turned off.

Fig. 9 is a schematic view of a valve seat according to the present invention.

Fig. 10 is a schematic structural diagram of the pressure release valve according to the present invention.

FIG. 11 is a schematic structural view of the inner barrel of the present invention.

FIG. 12 is a top view of the inner barrel of the present invention.

FIG. 13 is a schematic diagram (a) of a method of using a downhole circulation logging tool according to the present invention.

FIG. 14 is a schematic diagram (b) of a method of using a downhole circulation logging tool according to the present invention.

FIG. 15 is a schematic diagram (c) of a method of using a downhole circulation logging tool according to the present invention.

FIG. 16 is a schematic diagram (d) of a method of using a downhole circulation logging tool according to the present invention.

FIG. 17 is a schematic diagram (e) of a method of using a downhole circulation logging tool according to the present invention.

FIG. 18 is a schematic diagram (f) of a method of using a downhole circulation logging tool according to the present invention.

FIG. 19 is a schematic diagram (g) of a method of using a downhole circulation logging tool according to the present invention.

FIG. 20 is a schematic diagram (h) of a method of using a downhole circulation logging tool according to the present invention.

FIG. 21 is a schematic diagram (i) of a method of using a downhole circulation logging tool according to the present invention.

The device comprises a 1-circulation well-flushing tool body, a 1-circulation jacket, a 1-101-jacket through hole, a 1-102-nozzle, a 1-103-annular groove, a 1-104-inclined plane structure, a 1-2-mandrel, a 1-201-mandrel through hole, a 1-202-mandrel extension section, a 1-3-switch assembly, a 1-301-switch body, a 1-301 a-sphere part, a 1-301 b-cone part, a 1-301 c-weighted short handle, a 1-302-Guan Faqiu and a 1-303-locking ball, wherein the first part is a circular well-flushing tool body; 1-4 parts of valve seat, 1-401 parts of boss structure, 1-402 parts of sealing groove, 1-403 parts of sealing surface, 1-5 parts of elastic locking mechanism, 1-501 parts of elastic tube, 1-6 parts of elastic resetting mechanism,

2-pressure relief nipple, 2-1-pressure relief valve, 2-101-pressure relief valve seat, 2-102-pressure relief through hole, 2-103-valve core, 2-103 a-ball component, 2-103 b-lower through hole, 2-103 c-middle through hole, 2-104-adjusting bolt, 2-105-nut, 2-106-annular space, 2-107-spring mechanism, 2-109-sealing component, 2-110-radial counter bore structure,

3-switch container, 3-1-containing jacket, 3-2-inner cylinder, 3-partition, 3-4-main channel, 3-5-containing channel, 3-6-inclined boss, 3-7-through hole, 3-8-supporting plate,

4-annular cavity, 5-sealing mechanism, 6-locker, 6-1-rotary slip, 6-2-spring assembly, 6-3-pivot, 6-201-sleeve, 6-202-spring, 6-203-piston, 7-upper joint, 8-counter bore.

Detailed Description

The present invention will be described in further detail with reference to examples, but embodiments of the present invention are not limited thereto.

Example 1:

the embodiment relates to an underground circulating well-flushing tool, as shown in the structure of fig. 1, which mainly comprises a circulating well-flushing tool body 1, a pressure relief nipple 2 and a switch container 3 which are connected in sequence, and the concrete structure of the underground circulating well-flushing tool can be summarized as follows:

the circulating well-flushing tool body 1 comprises a hollow circulating jacket 1-1, a hollow mandrel 1-2 sleeved in the circulating jacket 1-1 and a switch assembly 1-3, wherein the top of the circulating jacket 1-1 can be connected with an upper joint 7, the upper joint 7 is connected with the lower part of a drill collar or a drill rod to form a part of a drilling tool, the circulating jacket 1-1 and the upper joint 7 are of hollow structures, the hollow structures are communicated with the drill collar or the drill rod and form a drilling fluid circulation channel, a jacket through hole 1-101 is formed in the middle shell of the circulating jacket 1-1, a replaceable nozzle 1-102 is arranged in the jacket through hole 1-101 and used as a fluid channel in circulating well flushing, an annular groove 1-103 is formed in the inner wall of the shell of the circulating jacket 1-1 along the position of the jacket through hole 1-101, and the width of the annular groove 1-103 is larger than the inner diameter of the through hole of the nozzle 1-102. The mandrel 1-2 axially slides in the circulating jacket 1-1, the hollow structure of the mandrel 1-2 is consistent with a drilling fluid circulation channel, a mandrel through hole 1-201 is arranged on the shell of the mandrel 1-2, and the size and the position of the through hole are consistent with those of the nozzle 1-102 of the circulating jacket 1-1. In use, the number of the outer sleeve through holes 1-101 and the mandrel through holes 1-201 can be appropriately adjusted according to the construction process, for example, as shown in fig. 1, the number of the outer sleeve through holes 1-101 and the mandrel through holes 1-201 is two.

As shown in FIG. 1, a valve seat 1-4 is arranged in a mandrel 1-2 below a mandrel through hole 1-201, an inner hole of the valve seat 1-4 is communicated with a drilling fluid circulation channel in the mandrel 1-2, an elastic locking mechanism 1-5 which is clamped with a shell at the upper part of a circulating jacket 1-1 is arranged at the top of the mandrel 1-2, an elastic reset mechanism 1-6 is arranged at the bottom of the mandrel 1-2, and when the mandrel 1-2 is locked by the elastic locking mechanism 1-5, the mandrel through hole 1-201 and the jacket through hole 1-101 are arranged in a staggered manner.

The switch of the downhole circulation well flushing tool adopts a switch assembly 1-3, and comprises a switch body 1-301, a valve closing ball 1-302 and a locking ball 1-303, wherein an elastic part of the switch body 1-301 is seated in an inner hole of a valve seat 1-4 and drives a mandrel 1-2 to slide downwards along a circulation jacket 1-1 until a mandrel through hole 1-201 is communicated with a jacket through hole 1-101, the diameter of the locking ball 1-303 is smaller than the inner diameters of the mandrel through hole 1-201 and a nozzle 1-102 through hole, a locker 6 for clamping the locking ball 1-303 is arranged in the nozzle 1-102, the diameter of the valve closing ball 1-302 is larger than the inner diameter of the mandrel through hole 1-201 and smaller than the inner diameter of the inner hole of the valve seat 1-4, and the valve closing ball 1-302 acts on the locking ball 1-303.

In this embodiment, the pressure relief nipple 2 is a hollow cavity structure connected to the bottom of the circulation casing 1-1, wherein the hollow cavity is communicated with a drilling fluid circulation channel in the circulation casing 1-1, an opening is formed in the side wall of the pressure relief nipple 2, and a pressure relief valve 2-1 is arranged in the opening. The switch container 3 comprises a container sleeve 3-1 and an inner cylinder 3-2 arranged in the container sleeve 3-1, wherein the container sleeve 3-1 is connected to the bottom of the pressure relief nipple 2, the switch body 1-301 and the valve closing ball 1-302 are contained in the inner cylinder 3-2, and the inner cylinder 3-2 is of a hollow structure.

Example 2:

this example relates to a method of using the downhole circulation logging tool of example 1.

As described in embodiment 1, the downhole circulating flushing tool according to this embodiment is used with a drilling tool, the upper joint 7 of the circulating casing 1-1 is connected to a drill pipe or drill collar, and the bottom of the switch container 3 is connected to a downhole tool.

The specific methods of use can be summarized as follows:

(1) During normal operation: in the state shown in fig. 1, the mandrel 1-2 is locked by the elastic locking mechanism 1-5, at this time, the through hole of the mandrel 1-2 and the through hole of the outer sleeve 1-101 are arranged in a staggered manner up and down, and the circulating channel of the tool is closed.

(2) During cyclic well flushing:

(2.1) sequentially throwing the switch body 1-301 and the locking ball 1-303 into the circulation jacket 1-1 at the wellhead on the ground, starting the drilling pump to circulate, after the elastic component of the switch body 1-301 is seated in the inner hole of the valve seat 1-4, the drilling pump pressure is increased and then reduced, the displacement is increased simultaneously, at the moment, the mandrel 1-2 slides downwards along the circulation jacket 1-1 to the mandrel through hole 1-201 to be communicated with the jacket through hole 1-101, the circulation channel is opened, the locking ball 1-303 moves downwards to the circulation channel in the state shown in fig. 2, and enters the circulation channel under the suction force of the fluid low-pressure area, and after the locking ball 1-303 reaches the nozzle 1-102, the locking ball is locked by the locking device 6.

(2.2) the well slurry flows into the annular grooves 1-103 of the outer sleeve through holes 1-101 through the nozzles 1-102, so that the automatic grouting of the tool is realized.

(2.3) after grouting, throwing valve closing balls 1-302 with the same number as the mandrel through holes 1-201 into the circulating jacket 1-1 at the surface wellhead, and when the valve closing balls 1-302 descend to the mandrel through holes 1-201, adsorbing the valve closing balls at the positions of the mandrel through holes 1-201 under the suction action of a fluid low pressure area, sealing the valve closing balls by plugging, simultaneously acting on the locking balls 1-303 to unlock the locking balls 1-303, discharging the unlocked locking balls 1-303 out of the tool, and lifting the valve closing balls to the wellhead along the annular space of a well hole for recovery; after the pressure of the upper space of the valve seat 1-4 rises to a certain value, the elastic component of the switch body 1-301 is deformed by pressure and penetrates through the inner hole of the valve seat 1-4, the switch body 1-301 and the valve closing ball 1-302 fall into the inner cylinder 3-2, and the mandrel 1-2 moves upwards to be restored to a locking state under the action of the elastic reset mechanism 1-6 so as to be subjected to the next well flushing operation.

(3) And (3) performing circulating well flushing when the downhole instrument is blocked:

sequentially throwing the switch body 1-301 and the locking ball 1-303 into the circulation jacket 1-1, starting the drilling pump circulation, reducing the drilling pump after the pressure is increased, judging that the underground instrument is blocked while the discharge capacity is not increased, continuously increasing the drilling pump pressure at the moment to increase the pressure in the pressure relief nipple 2 until the pressure relief valve 2-1 is opened, simultaneously controlling the pressure in the pressure relief nipple 2 to be lower than the deformation pressure of the elastic component of the switch body 1-301, enabling the mandrel 1-2 to slide downwards until the circulation channel is opened, enabling the locking ball 1-303 to reach the nozzle 1-102 and be locked by the locking device 6, and repeating the steps (2.2) and (2.3) to finish one-time well flushing operation when the underground instrument is blocked.

Example 3:

the present embodiment defines the structure of the circulating well-flushing tool body 1 on the basis of embodiment 1, and specifically includes the following:

as shown in fig. 3, the lower end portion of the elastic locking mechanism 1-5 according to this embodiment is sleeved on the top of the mandrel 1-2, the upper end portion of the elastic locking mechanism 1-5 is a variable-diameter elastic tube 1-501 with a slit structure, the outer diameter of the upper end portion is larger than that of the lower end portion, the middle end portion connecting the upper end portion and the lower end portion of the elastic locking mechanism 1-5 is in an inclined structure, and the inner wall of the circulating jacket 1-1 is provided with an inclined structure 1-104 for restraining the upper end portion of the elastic locking mechanism 1-5.

When the circulation channel is required to be opened, the mandrel 1-2 is stressed to slide downwards along the axis, meanwhile, the elastic locking mechanism 1-5 is driven to slide downwards, when the elastic locking mechanism 1-5 slides downwards, the inclined structure of the terminal part of the elastic locking mechanism is matched with the inclined surface structure 1-104 to slide, the upper end part of the elastic locking mechanism is provided with the variable-diameter elastic tube 1-501, the outer diameter of the variable-diameter elastic tube is limited by the inclined surface structure 1-104 at the inner side of the circulation jacket 1-1, the outer diameter of the elastic tube 1-501 is reduced, and the elastic tube is folded to slide downwards continuously, so that the mandrel 1-2 is separated from a locking state. When the tool needs to be closed, the mandrel 1-2 slides upwards, the elastic tube 1-501 slides upwards along the inner inclined surface structure 1-104 of the circulating jacket 1-1, the elastic tube 1-501 expands in diameter under the action of elasticity, and at the moment, the mandrel 1-2 is in a locking state. The locking state of the mandrel 1-2 is beneficial to preventing the tool from sliding and opening in advance during axial circulation, and ensures the reliability of normal operation.

In this embodiment, as shown in fig. 1, a hollow mandrel extension section 1-202 is extended downward along the bottom of the mandrel 1-2, the mandrel extension section 1-202 is equal to the inner diameter of the mandrel 1-2, the outer diameter of the mandrel extension section 1-202 is smaller than the outer diameter of the mandrel 1-2, an annular cavity 4 is formed between the outer wall of the mandrel extension section 1-202 and the circulating jacket 1-1, an elastic reset mechanism 1-6 is sleeved in the annular cavity 4, a spring or other elastic mechanism can be adopted, and the switch of the circulating well-flushing tool body 1 is realized by virtue of axial sliding of the mandrel 1-2 and pushing compression or extension of the elastic reset mechanism 1-6. In order to facilitate the balance of the up-down pressure when the mandrel 1-2 slides, the side wall of the mandrel extension section 1-202 is also provided with a communication hole which is communicated with the annular cavity 4.

As shown in fig. 4 and 5, the locking device 6 according to the present embodiment includes a rotary slip 6-1 and a spring assembly 6-2 provided in a nozzle 1-102, the rotary slip 6-1 includes a bi-directional latch rotating with a rotary shaft 6-3, and the rotary shaft 6-3 is fixed in the nozzle 1-102; the spring assembly 6-2 comprises a sleeve 6-201 arranged in the nozzle 1-102, a spring 6-202 is arranged in the sleeve 6-201, a piston 6-203 is arranged at the top of the spring 6-202, and inner clamping teeth of the bidirectional clamping teeth act on the piston 6-203.

In this embodiment, the nozzles 1-102 may be screwed or otherwise connected in the through holes 1-101, and as a fluid passage during circulation well flushing, the nozzles 1-102 may be replaced by a counter bore 8 provided on the end surface thereof in combination with a special tool for disassembly. The rotary slips 6-1 in the nozzle 1-102 can be used to lock the tool open after a ball is thrown. The working principle of the mechanism is as follows: after the insertion of the switch body 1-301 into the tool, an opening operation of the tool (circulation channel) is effected, after which a locking ball 1-303, which is also a deformable material, is inserted into the tool. After the locking balls 1-303 have descended to the circulation through holes, they will enter the radial circulation channels by suction from the low pressure area, as shown in fig. 4. When the locking ball 1-303 enters the nozzle 1-102, its radially outward working force will push the outer shoes of the rotary slips 6-1 to rotate and in turn push the piston 6-203 to compress with the spring 6-202. While the rotary slips 6-1 are rotated, the inner slips are engaged from the other side of the locking balls 1-303, and at this time, the locking balls 1-303 are in a locked state due to the elasticity of the springs 6-202 and the double gripping force of the slips, as shown in fig. 5.

In the present embodiment, as shown in fig. 1, a sealing mechanism 5 is provided between the circulation casing 1-1 and the mandrel 1-2, and the sealing mechanism 5 is provided on the upper and lower sides of the circulation through hole.

Example 4:

the present embodiment defines the structure of the switch body 1-301 and the associated valve seat 1-4 on the basis of embodiment 3, and specifically includes the following:

as shown in fig. 6, 7 and 8, the switch body 1-301 according to this embodiment includes a spherical portion 1-301a, a cone portion 1-301b provided on an upper portion of the spherical portion 1-301a, and a weighted stub shaft 1-301c provided on a lower portion of the spherical portion 1-301a, the spherical portion 1-301a is an elastic member of the switch body 1-301, an outer diameter of the elastic member is larger than an inner diameter of an inner hole of the valve seat 1-4, and a maximum outer diameter of the cone portion 1-301b and the weighted stub shaft 1-301c is smaller than the inner diameter of the inner hole of the valve seat 1-4.

As shown in FIG. 9, in the embodiment, boss structures 1-401 distributed in an annular shape are arranged in the inner holes of valve seats 1-4; a sealing groove 1-402 is arranged on the outer wall of the valve seat 1-4 contacted with the mandrel 1-2, and a sealing surface 1-403 is arranged on the valve seat 1-4 contacted with the sphere part 1-301 a.

The three parts of the switch body 1-301 according to this embodiment may be formed as an integral structure or may be connected by means of threads or the like. The ball portion 1-301a is an elastic member composed of a deformable material, and the weighted stub shaft 1-301c may be a material or metal having a larger specific gravity than the deformable material. When the tool needs to be opened, the switch body 1-301 is put into the drilling tool at the ground wellhead, the gravity of the weighted short handle 1-301c is increased, the descending speed of the switch is accelerated, the working efficiency is improved, the outer diameter of the weighted short handle 1-301c is smaller than the inner diameter of the valve seat 1-4, the outer diameter of the sphere part 1-301a is larger than the inner diameter of the valve seat 1-4, therefore, the weighted short handle 1-301c can pass through the valve seat 1-4, and the sphere part 1-301a is seated on the inner hole of the valve seat 1-4, so that the space in the drilling tool above and below the valve seat 1-4 is isolated. With the gradual increase of the pressure at the upper part of the valve seat 1-4, after overcoming the supporting force of the elastic restoring mechanism 1-6 and the acting force of the elastic locking mechanism 1-5, the mandrel 1-2 compresses the elastic restoring mechanism to slide downwards until the circulating channel is opened. The tool in the open state is shown in fig. 2. When the tool needs to be closed, valve closing balls 1-302 with the same number as the through holes on the mandrel 1-2 are thrown into the drilling tool at the wellhead of the ground. Guan Faqiu 1-302, when descending to the mandrel through hole 1-201, will be sucked at the mandrel through hole 1-201 and seal it off due to the suction force of the fluid low pressure area. The slope of the taper on the switch body 1-301 will help support the shutoff ball 1-302 in place. The space in the upper drilling tool of the valve seat 1-4 is closed again, the pressure is increased, the mandrel 1-2 is lowered to the lowest position, the switch body 1-301 is forced to deform by the increase of the upper pressure, the ball body 1-301a is forced to deform, the pressure is increased to a certain set pressure, the ball body 1-301a deforms completely to pass through the inner hole of the valve seat 1-4, the channels in the drilling tool are communicated again, the elastic reset mechanism is reset, the mandrel 1-2 is pushed to be in an up-to-lock state, the tool body is closed, and the tool in the closed state is shown in fig. 1. After the valve closing ball 1-302 loses the support of the cone portion 1-301b as the pressure in the drilling tool decreases, the valve closing ball will drop to the inner cylinder 3-2 along with the switch body 1-301 because the outer diameter is smaller than the inner diameter of the inner hole of the valve seat 1-4.

In addition, the boss structure 1-401 designed in the inner hole of the valve seat 1-4 in the embodiment has the function of preventing the valve seat 1-4 from being broken down prematurely due to gravity and inertia in the descending process of the switch body 1-301, losing the opening capability and not affecting the sealing of the valve seat 1-4. The sealing groove 1-402 can also seal and isolate the drilling tool space above and below the valve seat 1-4 when the switch body 1-301 is seated on the sealing surface 1-403 on the inner hole of the valve seat 1-4.

Example 5:

the present embodiment defines the structure of the relief valve 2-1 on the basis of embodiment 4, and specifically includes the following:

as shown in fig. 10, the relief valve 2-1 according to this embodiment includes a relief valve seat 2-101 sleeved in the opening, one end of the inner hole of the relief valve seat 2-101 is a relief through hole 2-102, a valve core 2-103 is provided in the inner hole of the relief valve seat 2-101, a ball member 2-103a (such as a hemispherical solid structure) sealing the relief through hole 2-102 is provided at the top of the valve core 2-103, an adjusting bolt 2-104 is sleeved between the lower part of the valve core 2-103 and the inner hole of the relief valve seat 2-101, a nut 2-105 such as a hexagon nut is provided at the bottom of the valve core 2-103 and sleeved in the adjusting bolt 2-104, a lower through hole 2-103b communicating with the outside is provided in the lower part of the valve core 2-103, an annular space 2-106 is formed between the outer wall of the middle part of the valve core 2-103 and the inner hole of the relief valve seat 2-101, a middle through hole 2-103c perpendicular to the lower through hole 2-103b is provided in the middle of the valve core 2-103, the middle through hole 2-103c communicates with the annular space 2-106 and the lower through hole 2-103b, and a spring mechanism 2-107 is provided outside the valve core 2-107 in the annular space 2-103. The contact surface of the pressure relief through hole 2-102 and the sphere part 2-103a is a conical sealing surface. A sealing part 2-109 is arranged between the pressure relief valve seat 2-101 and the inner wall of the opening. The outer side end surface of the pressure relief valve seat 2-101 is provided with a radial counter bore structure 2-110 which can be conveniently disassembled, assembled and replaced.

The working principle of the pressure relief nipple 2 is as follows: after the high-pressure liquid in the pressure relief nipple 2 pushes the ball part 2-103a on the valve core 2-103 through the pressure relief through hole 2-102, the high-pressure liquid enters the middle through hole 2-103c and the lower through hole 2-103b of the valve core 2-103 through the annular space 2-106 and leaks to the outside of the pressure relief nipple 2 to form a pressure relief channel. Before installation and use, the compression amount of the spring mechanism 2-107 can be adjusted by adjusting the displacement amount of the adjusting screw plug, so that the sealing pressure of the valve core 2-103 can be adjusted.

The pressure relief nipple 2 has the functions that: in the circulating well flushing process, when the lower drilling tool or the drill bit is blocked by mercury, after the lower drilling tool or the drill bit is plugged, the upper sealing pressure and the lower sealing pressure of the valve seat 1-4 are equal, the mandrel 1-2 cannot be pushed to downwards compress the elastic reset mechanism, after the pressure is increased to the deformation pressure of the ball body part 1-301a, the valve seat 1-4 is deformed by the switch body 1-301, and the tool is still in a closed state. After the pressure relief nipple 2 is installed, even if the water hole of the lower drilling tool is blocked, when the pressure in the lower drilling tool of the valve seat 1-4 rises to a certain pressure value (the pressure value is lower than the deformation pressure of the ball body part 1-301 a), the valve core 2-103 moves against the force of the spring mechanism 2-107 to form a pressure relief channel, so that after the pressure of the lower space of the valve seat 1-4 is reduced, the switch body 1-301 can push the mandrel 1-2 to move downwards and open a circulation channel. Therefore, the pressure relief nipple 2 ensures that the tool is smoothly opened when the water hole of the drilling tool is blocked.

Example 6:

the structure of the opening Guan Shouna device 3 is limited on the basis of embodiment 5, and the containing jacket 3-1 of the opening/closing container 3 is connected to the lower part of the pressure relief nipple 2 through threads, so that the opening/closing device is used for receiving the mechanisms such as the opening/closing device body 1-301 and the valve closing ball 1-302 for operating the tool switch, and meanwhile, the drilling fluid channel is kept smooth. The method specifically comprises the following steps:

as shown in fig. 11 and 12, an inner cylinder 3-2 according to this embodiment is divided by a partition plate 3-3 to form a main channel 3-4 through which drilling fluid circulates and a receiving channel 3-5 for receiving a switch body 1-301 and a valve closing ball 1-302, a guiding inclined boss 3-6 extends upward along the main channel 3-4, the main channel 3-4 and the receiving channel 3-5 are hollow structures, a supporting plate 3-8 is arranged at the bottom of the inner cylinder 3-2, and a through hole 3-7 for limiting the passage of the switch body 1-301 and the valve closing ball 1-302 is arranged at the bottom of the receiving channel 3-5. In the embodiment, the partition plate 3-3 is eccentrically arranged in the inner cylinder 3-2, so that the blockage of the flow passage in the drilling tool is avoided when the switch body 1-301 and the valve closing ball 1-302 are filled.

Example 7:

this example relates to a method of using the downhole circulation logging tool of example 6. The specific contents are summarized as follows:

Before the tool is drilled, a switch body 1-301 is put into the drilling tool (figure 13), then a locking ball 1-303 is put into the drilling tool, the drilling pump circulation is started, the switch body 1-301 is judged to be in place through pressure drop, the displacement is increased and then reduced, and the locking ball 1-303 is locked to the nozzle 1-102 (figure 14). The tool can realize automatic grouting of the drilling tool when the drilling tool is drilled down. After the drill is put in place, the valve closing ball 1-302 is put in, the valve closing ball 1-302 is put to the position of the mandrel through hole 1-201 and the locking ball 1-303 is unlocked (figure 15), the locking ball 1-303 is removed from the outside of the tool, and the valve closing ball rises to the wellhead along the annular space of the well hole for recovery. The upper pressure of the valve seat 1-4 rises to a certain value, the ball portion 1-301a of the switch body 1-301 deforms, and the valve closing ball 1-302 falls down while losing support through the valve seat 1-4 (fig. 16). The switch body 1-301 and the valve closing ball 1-302 drop to the lower special receiving tool, and the tool mandrel 1-2 goes up to return to the locking state (fig. 17), so that normal operation cycle is performed. When the tool needs to be opened, a switch body 1-301 is put into the drilling tool. And (3) starting the drilling pump for circulation, judging that the switch is in place through pressure drop (figure 18), increasing the displacement after the tool is opened, and carrying out special operations such as circulating well flushing. If the pressure increases after the switch body 1-301 is put into the valve body (lower than the deformation pressure of the ball portion 1-301a of the switch body 1-301), but there is no pressure drop thereafter, the displacement is not increased either, and it is judged that the lower drill or the bit water hole is clogged. At the moment, pumping is continuously increased, after the pumping pressure rises to the sealing pressure value of the pressure relief nipple 2 (still lower than the deformation pressure of the switch), the pressure relief valve 2-1 is opened, the pressure at the lower part of the valve seat 1-4 is reduced, the pressure difference is formed between the upper part and the lower part of the valve seat 1-4, the mandrel 1-2 descends, and the tool can still be normally opened. After the lower pressure is reduced, the pressure relief valve 2-1 of the pressure relief nipple 2 is automatically closed. When the tool needs to be closed, the valve closing ball 1-302 is thrown into the drilling tool, and after the valve closing ball 1-302 reaches the position 1-201 of the mandrel through hole (figure 19), the pump pressure is raised. After the pump pressure increases to the trigger deformation pressure value, the trigger begins to deform and pass through the ball seat, and the valve closing ball 1-302 falls off while losing support (fig. 20). The switch and the valve closing ball 1-302 drop to a special storage tool (storage channel 3-5) at the lower part of the pressure relief nipple 2, and the mandrel 1-2 goes up to return to a locking state (figure 21) to perform normal operation circulation.

In this embodiment, the components of the switch body 1-301, the valve closing ball 1-302, the locking ball 1-303, etc. may be made of degradable materials, and automatically degrade in the downhole storage tool after the operation is completed, so as to prolong the working time of the tool in the downhole and reduce the design length of the tool.

The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and any simple modification, equivalent variation, etc. of the above embodiment according to the technical matter of the present invention fall within the scope of the present invention.

Claims (15)

1. A downhole circulation well cleanup tool, characterized by: comprises a circulating well-flushing tool body (1), a pressure relief nipple (2) and a switch container (3) which are connected in sequence,

the circulating well-flushing tool body (1) comprises a hollow circulating jacket (1-1), a hollow mandrel (1-2) sleeved in the circulating jacket (1-1) and a switch assembly (1-3), wherein hollow structures of the circulating jacket (1-1) and the mandrel (1-2) are matched to form a drilling fluid circulation channel, a jacket through hole (1-101) is formed in a middle shell of the circulating jacket (1-1), and a nozzle (1-102) is arranged in the jacket through hole (1-101); the mandrel (1-2) axially slides in the circulating jacket (1-1), a mandrel through hole (1-201) is formed in a shell of the mandrel (1-2), a valve seat (1-4) is arranged in the mandrel (1-2) below the mandrel through hole (1-201), an inner hole of the valve seat (1-4) is communicated with a drilling fluid circulation channel in the mandrel (1-2), an elastic locking mechanism (1-5) which is clamped with the upper shell of the circulating jacket (1-1) is arranged at the top of the mandrel (1-2), an elastic reset mechanism (1-6) is arranged at the bottom of the mandrel (1-2), and when the mandrel (1-2) is locked through the elastic locking mechanism (1-5), the mandrel through hole (1-201) and the jacket through hole (1-101) are arranged in a staggered mode; the switch assembly (1-3) comprises a switch body (1-301), guan Faqiu (1-302) and a locking ball (1-303), wherein an elastic part of the switch body (1-301) is set in an inner hole of a valve seat (1-4) and drives a mandrel (1-2) to slide downwards along a circulating jacket (1-1) until a mandrel through hole (1-201) is communicated with a jacket through hole (1-101), the diameter of the locking ball (1-303) is smaller than the inner diameter of the mandrel through hole (1-201) and a nozzle (1-102) through hole, a locker (6) for clamping the locking ball (1-303) is arranged in the nozzle (1-102), an annular groove (1-103) is arranged on the inner wall of a shell of the circulating jacket (1-1) along the position of the jacket through hole (1-101), the width of the annular groove (1-103) is larger than the inner diameter of the nozzle (1-102) through hole, the diameter of the Guan Faqiu (1-302) is larger than the inner diameter of the mandrel through hole (1-201) and smaller than the inner diameter of the inner hole of the valve seat (1-102) through hole, a Guan Faqiu (1-302) acts on the locking ball (1-303),

The lower end part of the elastic locking mechanism (1-5) is sleeved at the top of the mandrel (1-2), the upper end part of the elastic locking mechanism (1-5) is a variable-diameter elastic tube (1-501) with a slot structure, the outer diameter of the upper end part of the elastic tube is larger than that of the lower end part of the elastic tube, the middle end part connecting the upper end part of the elastic locking mechanism (1-5) and the lower end part of the elastic tube is in an inclined structure, the inner wall of the circulating jacket (1-1) is provided with an inclined surface structure (1-104) restraining the upper end part of the elastic locking mechanism (1-5),

the pressure relief nipple (2) is of a hollow cavity structure connected to the bottom of the circulating jacket (1-1), wherein the hollow cavity is communicated with a drilling fluid circulation channel in the circulating jacket (1-1), an opening is arranged on the side wall of the pressure relief nipple (2), a pressure relief valve (2-1) is arranged in the opening,

the switch container (3) comprises a container jacket (3-1) and an inner cylinder (3-2) arranged in the container jacket (3-1), the container jacket (3-1) is connected to the bottom of the pressure relief nipple (2), the switch bodies (1-301) and Guan Faqiu (1-302) are contained in the inner cylinder (3-2), the inner cylinder (3-2) is of a hollow structure, the switch body (1-301) comprises a sphere part (1-301 a), a cone part (1-301 b) arranged on the upper part of the sphere part (1-301 a) and a weighted short handle (1-301 c) arranged on the lower part of the sphere part (1-301 a), the sphere part (1-301 a) is an elastic part of the switch body (1-301), the outer diameter of the elastic part is larger than the inner diameter of an inner hole of the valve seat (1-4), and the maximum outer diameters of the cone part (1-301 b) and the weighted short handle (1-301 c) are smaller than the inner diameter of the inner hole of the valve seat (1-4).

2. A downhole circulating flushing tool as set forth in claim 1, wherein: the hollow mandrel extension section (1-202) is arranged along the bottom of the mandrel (1-2) in a downward extending mode, the inner diameter of the mandrel extension section (1-202) is equal to that of the mandrel (1-2), the outer diameter of the mandrel extension section (1-202) is smaller than that of the mandrel (1-2), an annular cavity (4) is formed between the outer wall of the mandrel extension section (1-202) and the circulating jacket (1-1), and the elastic reset mechanism (1-6) is sleeved in the annular cavity (4).

3. A downhole circulation well-flushing tool as set forth in claim 2, wherein: the side wall of the mandrel extension section (1-202) is provided with a communication hole which is communicated with the annular cavity (4).

4. A downhole circulating flushing tool as set forth in claim 1, wherein: a sealing mechanism (5) is arranged between the circulating jacket (1-1) and the mandrel (1-2), and the sealing mechanism (5) is correspondingly arranged at the upper side and the lower side of the jacket through hole (1-101).

5. A downhole circulating flushing tool as set forth in claim 1, wherein: and boss structures (1-401) distributed in an annular mode are arranged in the inner holes of the valve seats (1-4).

6. A downhole circulating flushing tool as set forth in claim 1, wherein: a sealing groove (1-402) is arranged on the outer wall of the valve seat (1-4) contacted with the mandrel (1-2), and a sealing surface (1-403) is arranged on the valve seat (1-4) contacted with the sphere part (1-301 a).

7. A downhole circulating flushing tool as set forth in claim 1, wherein: the locking device (6) comprises a rotary slip (6-1) and a spring assembly (6-2), wherein the rotary slip (6-1) is arranged in the nozzle (1-102), the rotary slip (6-1) comprises bidirectional clamping teeth which rotate along with a rotating shaft (6-3), and the rotating shaft (6-3) is fixed in the nozzle (1-102); the spring assembly (6-2) comprises a sleeve (6-201) arranged in the nozzle (1-102), a spring (6-202) is arranged in the sleeve (6-201), a piston (6-203) is arranged at the top of the spring (6-202), and inner clamping teeth of the bidirectional clamping teeth act on the piston (6-203).

8. A downhole circulating flushing tool as set forth in claim 1, wherein: the pressure relief valve (2-1) comprises a pressure relief valve seat (2-101) sleeved in the opening, one end of an inner hole of the pressure relief valve seat (2-101) is a pressure relief through hole (2-102), a valve core (2-103) is arranged in the inner hole of the pressure relief valve seat (2-101), the top of the valve core (2-103) is a spherical part (2-103 a) for sealing the pressure relief through hole (2-102), an adjusting bolt (2-104) is sleeved between the lower part of the valve core (2-103) and the inner hole of the pressure relief valve seat (2-101), a nut (2-105) sleeved in the adjusting bolt (2-104) is arranged at the bottom of the valve core (2-103), a lower through hole (2-103 b) communicated with the outside is arranged in the lower part of the valve core (2-103), an annular space (2-106) is formed by the outer wall of the middle part of the valve core (2-103) and the inner hole of the pressure relief valve seat (2-101), a middle through hole (2-103 c) perpendicular to the lower through hole (2-103 b) is arranged in the middle part of the valve core (2-103), the middle through hole (2-103 c) is communicated with the annular space (2-103) and the lower through hole (2-106), a spring mechanism (2-107) is sleeved outside the valve core (2-103) in the annular space (2-106).

9. A downhole circulating flushing tool as set forth in claim 8, wherein: the contact surface of the pressure relief through hole (2-102) and the sphere part (2-103 a) is a conical sealing surface.

10. A downhole circulating flushing tool as set forth in claim 8, wherein: a sealing part (2-109) is arranged between the pressure relief valve seat (2-101) and the inner wall of the opening.

11. A downhole circulating flushing tool as set forth in claim 8, wherein: the outer side end face of the pressure relief valve seat (2-101) is provided with a radial counter bore structure (2-110).

12. A downhole circulating flushing tool as set forth in claim 1, wherein: the inner barrel (3-2) is divided into a main channel (3-4) for drilling fluid circulation and a containing channel (3-5) for containing the switch bodies (1-301) and Guan Faqiu (1-302) through the partition plate (3-3), a guided inclined boss (3-6) is arranged along the main channel (3-4) in an upward extending mode, the main channel (3-4) and the containing channel (3-5) are of hollow structures, the bottom of the inner barrel (3-2) is provided with a supporting plate (3-8), and the bottom of the containing channel (3-5) is provided with a through hole (3-7) for limiting the switch bodies (1-301) and Guan Faqiu (1-302) to pass through.

13. A downhole circulating flushing tool as set forth in claim 12, wherein: the partition plate (3-3) is eccentrically arranged in the inner cylinder (3-2).

14. A method of using the downhole circulating flushing tool of claim 1, wherein: the underground circulating well-flushing tool is used together with a drilling tool, the top of the circulating jacket (1-1) is connected with a drill rod or a drill collar, the bottom of the switch container (3) is connected with an underground instrument, and the underground circulating well-flushing tool comprises the following using method:

(1) During normal operation: the mandrel (1-2) is locked by an elastic locking mechanism (1-5);

(2) During cyclic well flushing:

(2.1) after the switch body (1-301) and the locking ball (1-303) are sequentially put into the circulation jacket (1-1), starting the drilling pump to circulate, increasing the pressure and then reducing the pressure, increasing the displacement simultaneously, judging that after the elastic part of the switch body (1-301) is seated in the inner hole of the valve seat (1-4), the mandrel (1-2) descends, and the locking ball (1-303) reaches the nozzle (1-102) and is locked by the locker (6);

(2.2) the well slurry flows into the annular groove (1-103) of the outer sleeve through hole (1-101) through the nozzle (1-102), so as to realize automatic grouting of the tool;

After grouting is finished (2.3), a valve closing ball (1-302) is thrown into the circulation jacket (1-1), guan Faqiu (1-302) acts on the locking ball (1-303) to unlock the locking ball (1-303), an elastic part of the switch body (1-301) deforms under pressure to penetrate through an inner hole of the valve seat (1-4), the switch bodies (1-301) and Guan Faqiu (1-302) fall into the inner barrel (3-2), and the mandrel (1-2) is restored to a locking state for the next well flushing operation;

(3) And (3) performing circulating well flushing when the downhole instrument is blocked:

and sequentially throwing the switch body (1-301) and the locking ball (1-303) into the circulation jacket (1-1), increasing the pressure in the pressure relief nipple (2) until the pressure relief valve (2-1) is opened when the underground instrument is judged to be blocked, simultaneously controlling the pressure in the pressure relief nipple (2) to be lower than the deformation pressure of the elastic component of the switch body (1-301), and enabling the mandrel (1-2) to slide downwards, so that the locking ball (1-303) reaches the nozzle (1-102) and is locked by the locker (6), and repeating the steps (2.2) and (2.3) to finish one-time well flushing operation when the underground instrument is blocked.

15. A method of using a downhole circulating flushing tool of claim 14, wherein: in the step (3), after the switch body (1-301) and the locking ball (1-303) are sequentially put into the circulation jacket (1-1), the drilling pump is started for circulation, the pressure is increased and then the pressure is decreased, and meanwhile, the displacement is not increased, so that the plugging of the downhole instrument at the moment is judged.