CN108005603B - flexible closed coring tool - Google Patents

Abstract

the application discloses flexible airtight coring tool includes: the core drill bit mechanism and the flexible drill rod are connected in sequence; a core inner barrel penetrates through the flexible drill rod; the front end of the core inner cylinder is supported in the coring bit mechanism; the coring bit mechanism comprises a coring bit, a sealing head and a core claw; at least part of the obturator head is located within the coring bit; the core claw is positioned in the coring bit and sleeved outside the sealing head; the core gripper is arranged to only allow the sealing head to move backwards when subjected to a backward external force, and is arranged to fix the position of the sealing head when the sealing head is subjected to an external force in other directions or no external force; the flexible drill pipe comprises a first drill pipe joint, a second drill pipe joint and a plurality of drill pipe short sections which are connected end to end and located between the first drill pipe joint and the second drill pipe joint.

Description

Flexible airtight coring tool

technical field

The application relates to the field of oilfield exploration and development, in particular to a flexible airtight coring tool.

Background technique

Oilfield exploration and development requires accurate acquisition of important geological data such as original oil saturation and formation porosity in order to formulate a reasonable exploration and development plan. In the middle and late stages of oilfield development, it is necessary to check the water injection effect, quantitatively analyze the oil-water dynamics of the reservoir, the situation of the water-flooded reservoir and the effect of water flooding, so as to formulate effective measures to tap potential, increase efficiency and increase production, and improve the development plan. Coring and core analysis, as one of the most direct and important methods to obtain oil and gas data and understand reservoirs, can provide an important basis for the formulation and adjustment of development plans.

According to the purpose and operation method of coring, drilling and coring can be divided into conventional coring and special coring. Sealed coring belongs to special coring, which refers to the use of sealed coring tools and sealing fluid to take out cores that are hardly polluted by the free water of drilling fluid under the condition of water-based drilling fluid.

At present, the size of conventional airtight coring tools is large, and the requirements for wellbore trajectory and drilling quality are relatively high when coring in horizontal well drilling. All kinds of sealed coring tools for horizontal wells used cannot be used in ultra-short-radius horizontal wells or highly-inclined wells with a sidetracking radius of less than 3m, and cannot achieve fixed-point and azimuth coring. In addition, the installation of the sealing head of the existing sealing coring tool needs positioning pins to be fixed, the installation structure is complicated, and the manufacturing is difficult.

Contents of the invention

The technical problem to be solved by the present invention is to provide a flexible airtight coring tool suitable for solving at least one of the above problems.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows:

A flexible airtight coring tool, comprising: a coring bit mechanism connected in sequence, and a flexible drill rod; a core inner cylinder is pierced in the flexible drill rod; the front end of the core inner cylinder is supported by the core bit within the institution;

The core bit mechanism includes a core bit, a sealing head, and a core claw; at least part of the sealing head is located in the core bit; the core claw is located in the core bit and sleeved on the sealing head outside; the core jaws are set to only allow the sealing head to move backwards when subjected to a backward external force, and are set to allow the sealing head to move backwards when the sealing head is subjected to an external force in other directions or no external force fixing the position of the sealing head;

The flexible drill pipe includes a first tool joint, a second tool joint, and a plurality of end-to-end tool subs between the first tool joint and the second tool joint; the The flexible drill rod is connected to the core bit mechanism through the first drill rod joint; two adjacent drill rod sub-joints can be bent at a predetermined angle.

As a preferred embodiment, the inner wall of the core jaw is provided with a first locking tooth inclined backward, and the outer wall of the sealing head is provided with a second locking tooth matched with the first locking tooth; The second locking teeth are tilted forward; the core jaws can expand radially and reset.

As a preferred embodiment, the cross section of the core claw is an open ring.

As a preferred embodiment, the rear end of the core inner cylinder is also fixed with a fixing piece; the fixing piece is used to maintain the position of the sealing head when the sealing head enters the core inner cylinder.

As a preferred embodiment, the fixing member includes a permanent magnet block arranged at the rear end of the core inner cylinder; the sealing head is made of a material that can be attracted by a magnet.

As a preferred embodiment, a first annular channel is provided between the core inner barrel and the flexible drill rod; the core bit is provided with a fluid flow channel communicating with the first annular channel.

As a preferred embodiment, the rear end of the core inner cylinder is also provided with a pressure balance mechanism, and the pressure balance mechanism is used to balance the pressure inside the core inner cylinder; There is a water jacket; the wall of the water jacket is provided with a water passage.

As a preferred embodiment, the pressure balance mechanism includes a discharge nut and an inner cylinder pressure balance piston; the fixing member is installed on the front end of the inner cylinder pressure balance piston; the relief nut covers the The rear end of the inner cylinder of the rock core; the front end of the pressure balance piston of the inner cylinder is located in the inner cylinder of the rock core and is in sealing fit with the wall of the inner cylinder of the rock core, and the rear end of the pressure balance piston of the inner cylinder passes through the Drain nut.

As a preferred embodiment, the drill pipe pup joint includes:

A ball-tooth mechanism extending lengthwise, a first connecting portion is arranged on the side wall of the button-tooth mechanism; a ball head structure is arranged on one end of the ball-tooth mechanism, and a plurality of ball-tooth structures are arranged on the side wall The transmission teeth are arranged at intervals along its circumference; the rear of the transmission teeth is provided with a first sealing outer spherical surface; the front of the transmission teeth is provided with a second sealing outer spherical surface;

A toothed sleeve mechanism that is movably connected with the ball and tooth mechanism; the toothed sleeve mechanism has an activity space for accommodating the ball head structure; the rear end of the toothed sleeve mechanism is sleeved outside the ball and tooth mechanism and is located on the The rear of the ball head structure; the lower part of the activity space is provided with a first sealing inner spherical surface that matches the second sealing outer spherical surface, and the upper part of the activity space is provided with a sealing outer spherical surface that matches the first sealing outer spherical surface. The second sealed inner spherical surface; the wall of the activity space is provided with a plurality of track grooves corresponding to the transmission teeth one by one; the transmission teeth partially extend into the track grooves; the transmission teeth and the track The bottom surfaces of the grooves are in contact; the tooth sleeve mechanism is provided with a second connecting portion capable of being connected with the first connecting portion.

As a preferred embodiment, the transmission tooth and the ball head structure are integrally formed; the transmission tooth extends along an arc or an envelope from top to bottom; and the track groove is an arc groove.

As a preferred embodiment, the outer contour of the cross-section of the transmission tooth is a partial arc; the diameter of the outer contour of the cross-section of the transmission tooth first increases and then decreases from top to bottom.

As a preferred embodiment, the position of the maximum diameter of the outer contour of the cross-section of the transmission tooth is closer to the rear end of the transmission tooth than the front end of the transmission tooth; The two sealing outer spherical surfaces are located on the same sphere; the position of the maximum diameter and the center of the sphere are located on the same cross section.

As a preferred embodiment, at least one of the first sealing outer spherical surface and the first sealing inner spherical surface, and/or at least one of the second sealing outer spherical surface and the second sealing inner spherical surface There is an annular lubricating oil groove; the lubricating oil groove is filled with high temperature resistant lubricating grease.

As a preferred embodiment, the gear sleeve mechanism includes a gear sleeve and an end cover; the gear sleeve is fixedly connected to the front end of the end cover to form the movable space; the outer wall of the gear sleeve has a first spherical surface Structure; the rear end of the gear sleeve is connected to the end cover; the first sealing inner spherical surface and the track groove are arranged on the inner wall of the gear sleeve; the second sealing inner spherical surface is arranged on the end cover The front end of the end cover is provided with the second connecting portion; the rear end of the end cover is sleeved outside the front end of the button mechanism and is provided with a second spherical structure matched with the first spherical structure.

Beneficial effect:

It can be seen from the above description that the flexible airtight coring tool of the present invention only allows the sealing head to move backward when the sealing head is subjected to a backward external force by setting the core jaws, and is set to When the head is subjected to external force in other directions or no external force, the position of the sealing head is fixed, so that the sealing head can be positioned at the front end of the flexible airtight coring tool without positioning by only matching the core jaws with the sealing head Pins and pin holes are provided, and the installation is relatively simple.

With reference to the following description and accompanying drawings, there are disclosed in detail specific embodiments of the invention, indicating the manner in which the principles of the invention may be employed. It should be understood that embodiments of the invention are not limited thereby in scope. Embodiments of the invention encompass many changes, modifications and equivalents within the spirit and scope of the appended claims.

Features described and/or illustrated with respect to one embodiment can be used in the same or similar manner in one or more other embodiments, in combination with, or instead of features in other embodiments .

It should be emphasized that the term "comprising/comprising" when used herein refers to the presence of a feature, integer, step or component, but does not exclude the presence or addition of one or more other features, integers, steps or components.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings on the premise of not paying creative efforts.

Fig. 1 is a schematic structural diagram of a flexible airtight coring tool provided by an embodiment of the present application;

Fig. 2 is a sectional view of Fig. 1;

Fig. 3 is an enlarged view of the structure of the core claw and part of the sealing head in Fig. 1 .

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described The embodiments are only some of the embodiments of the present application, but not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

It should be noted that when an element is referred to as being “disposed on” another element, it may be directly on the other element or there may also be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and similar expressions are used herein for purposes of illustration only and are not intended to represent the only embodiments.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terminology used herein in the description of the present invention is only for the purpose of describing specific embodiments, and is not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Please refer to FIG. 1 to FIG. 3 , which are flexible airtight coring tools provided in an embodiment of the present application. The flexible airtight coring tools are applied but not limited to drilling operations of ultra-short-radius sidetracking horizontal wells. In this embodiment, the flexible airtight coring tool includes a coring bit mechanism and a flexible drill rod connected in sequence; a core inner cylinder 7 is pierced in the flexible drill rod; the front end of the core inner cylinder 7 is supported in the core bit mechanism.

The core bit mechanism includes a core bit 1, a sealing head 3, and a core claw 4; at least part of the sealing head 3 is located in the core bit 1; the core claw 4 is located in the core bit 1 and Sleeved outside the sealing head 3; the core claws 4 are set to only allow the sealing head 3 to move backwards when subjected to a backward external force, and are set to move backward when the sealing head 3 is subjected to other forces The position of the sealing head 3 is fixed when there is an external force in the direction or when there is no external force.

The flexible drill pipe comprises: a first drill pipe joint 5, a second drill pipe joint 11, and a plurality of end-to-end connected drill pipes between the first drill pipe joint 5 and the second drill pipe joint 11 short section. The flexible drill pipe is connected to the core bit mechanism through the first drill pipe joint 5; two adjacent drill pipe nipples can be bent at a predetermined angle.

It can be seen from the above description that the flexible airtight coring tool of this embodiment only allows the airtight head 3 to move backward when the core claw 4 is subjected to a backward external force, and is set to The position of the sealing head 3 is fixed when the sealing head 3 is subjected to external forces in other directions or when there is no external force, so that the sealing head 3 can be positioned in a flexible airtight position only by cooperating with the core claw 4 and the sealing head 3. The front end of the coring tool does not need positioning pins and pin holes, so the installation is relatively simple.

At the same time, the flexible airtight coring tool is provided with a flexible drill pipe, and the flexible drill pipe can be bent at a predetermined angle between two adjacent drill pipe nipples, and the bending formed by multiple drill pipe nipples is superimposed so that the The flexible airtight coring tool is capable of drilling ultra-short radius sidetracked horizontal wells.

Wherein, the maximum bendable angle between two adjacent drill pipe pup joints can be 8 degrees. Specifically, the drill pipe pup joint includes: a button mechanism 8 extending lengthwise, a first connecting portion is provided on the side wall of the button mechanism 8; a ball head structure is arranged at one end of the button mechanism 8 24, the side wall of the ball head structure 24 is provided with a plurality of transmission teeth 21 arranged at intervals along its circumference; the rear of the transmission teeth 21 is provided with a first sealed outer spherical surface; the front of the transmission teeth 21 (Bottom) is provided with the second sealing outer spherical surface 19; the tooth sleeve mechanism that is movably connected with the described button gear mechanism 8; the tooth sleeve mechanism has an activity space for accommodating the ball head structure 24; The end sleeve is set outside the button mechanism 8 and is located behind the ball head structure 24; the lower part of the movable space is provided with a first sealed inner spherical surface matched with the second sealed outer spherical surface 19, the The upper part of the movable space is provided with a second sealed inner spherical surface matched with the first sealed outer spherical surface; the wall of the movable space is provided with a plurality of track grooves 20 corresponding to the transmission teeth 21 one by one; The transmission tooth 21 partially extends into the track groove 20; the transmission tooth 21 is in contact with the bottom surface of the track groove 20; the tooth sleeve mechanism is provided with a second connection part that can be connected with the first connection part .

When a plurality of drill pipe nipples are connected end to end to form a flexible drill pipe, as shown in Figure 1, the button mechanism 8 of a drill pipe nipple extends from the front end of the previous drill pipe nipple into its sleeve mechanism, so that a drill pipe nipple The first connection part of the sub-joint is matched with the second connection part of the previous drill pipe sub-joint for transmission; The ball tooth mechanism 8 extends from the front end of the drill pipe sub-joint into the tooth sleeve mechanism, so that the first connection part of the next drill pipe sub-joint cooperates with the second connection part of the drill pipe sub-joint, thereby carrying out transmission.

It can be seen from the above description that the drill pipe pup joint forms a bendable structure through the active cooperation of the ball tooth mechanism 8 and the tooth sleeve mechanism, so that it can bend itself, and the bending formed by multiple drill pipe pup joints is superimposed to perform ultra-short Drilling operations for radius sidetracked horizontal wells. At the same time, the drive tooth 21 of the drill pipe nipple provided by this embodiment is a fixed structure of the ball tooth mechanism 8, and the transmission is carried out through the cooperation of the drive tooth 21 and the track groove 20, which can reduce stress concentration and improve the reliability of the equipment.

A whole flexible chain is formed through the flexible drill pipe and the drill bit which is connected with the flexible drill pipe in a universal way, which is different from the traditional spaced pipe, including the guide pipe composed of multiple trapezoidal pipes. The traditional spaced elbow can only be bent in one direction to become a similar elbow, and after bending, it no longer shows flexibility, but becomes a section of steel elbow. Once the outer edge of the steel elbow meets the inner side of the well wall If there is no friction, the steel elbow will not be able to arch inward by itself to avoid obstacles.

In contrast to the flexible drill pipe in this embodiment, since each section of the drill pipe subsection is universally movably connected with the tooth sleeve mechanism through the ball tooth mechanism 8, when any section of the drill pipe subsection collides with the well wall At this time, the short joints of the drill pipe in this section can be properly bent, so as to avoid obstacles, so that the drill pipe bit can travel unimpeded. As for the flexible casing used for well cementing, the two adjacent flexible casings are flexibly connected by hinged telescopic tubes, which can also ensure that the flexible casing can smoothly go down the well to the required position.

It should be noted that the front and rear directions and the up and down directions in the present invention refer to the first drill pipe joint 5, and the parts close to the first drill pipe joint 5 of the two parts are at the front or below, away from the first drill pipe joint 5. The rear or upper direction of the drill joint 5; for example, the direction from the first drill joint 5 to the second drill joint 11 is from front to rear or from bottom to top.

Please continue to refer to FIG. 1 , the ball tooth mechanism 8 extends lengthwise, and its overall structure is a tube body. The first connecting portion is roughly arranged from the rear end (or rear end) of the button mechanism 8 in the longitudinal direction to the position of the ball head. (When the reader faces FIG. 1 ), the ball head structure 24 is located behind (or in front of) the first connecting portion. A plurality of transmission teeth 21 arranged at intervals along the circumference of the ball head structure 24 are provided on the side wall. The rear of the transmission tooth 21 is provided with a first sealing outer spherical surface; the front of the transmission tooth 21 is provided with a second sealing outer spherical surface 19 .

In order to effectively improve the structural strength, the transmission gear 21 and the ball head structure 24 are integrally formed. Of course, the transmission teeth 21 can also be fixed on the outer surface of the ball head structure 24 by means of welding or the like. The transmission teeth 21 extend along an arc or an envelope from top to bottom; the track groove 20 is an arc groove. The outer contour of the cross section of the transmission tooth 21 is a partial arc; the diameter of the outer contour of the cross section of the transmission tooth 21 first increases and then decreases from top to bottom.

By setting such a structure, the transmission tooth 21 forms an arc-shaped envelope structure with a small diameter at the upper and lower ends and a large diameter in the middle, and the transmission tooth 21 can still transmit a large torque when it is bent at a large angle under the action of an axial force , and will not produce obvious stress concentration, and has better structural reliability. At the same time, the transmission gear 21 with arc-shaped structure cooperates with the arc-shaped groove to form a transmission pair, which can realize that the force-bearing area of the transmission pair of the flexible drill pipe remains unchanged at any angle, and can effectively reduce fatigue wear of structural parts.

Further, the maximum diameter position of the outer contour of the cross section of the transmission tooth 21 is closer to the rear end of the transmission tooth 21 than the front end of the transmission tooth 21 . Specifically, the first sealing outer spherical surface and the second sealing outer spherical surface 19 are located on the same sphere; the position of the maximum diameter is located on the same cross section as the center of the sphere.

In this embodiment, the movable space of the tooth sleeve mechanism can accommodate the button mechanism 8 . Wherein, the movable space and the ball head structure 24 can be arranged concentrically, so that the button mechanism 8 can swing universally, thereby forming a bending angle. The outer surface of the ball head structure 24 is in contact with the inner surface of the activity space.

In order to facilitate sealing and prevent drilling fluid from leaking, the lower part of the movable space is provided with a first sealed inner spherical surface matched with the second sealed outer spherical surface 19, and the upper part of the described movable space is provided with a first sealed outer spherical surface matched with the first sealed outer spherical surface. The second sealing inner spherical surface matched with the spherical surface. Further, in order to ensure the flexibility of the drill pipe to rotate and bend, at least one of the first sealing outer spherical surface and the first sealing inner spherical surface, and/or, the second sealing outer spherical surface 19 and the second sealing outer spherical surface At least one of the inner spherical surfaces is provided with an annular lubricating oil groove 22; the lubricating oil groove 22 is filled with high temperature resistant lubricating grease. As shown in FIG. 1 , the annular lubricating oil groove 22 has two (also called two) coaxially arranged.

As shown in Fig. 1 and Fig. 2, the transmission teeth 21 and the bottom surface of the track groove 20 arranged on the outer wall of the ball head structure 24 are all along the extension direction of the button mechanism 8 (it can also be from top to bottom as shown in Fig. 1 ). (down or from bottom to top) extending in an arc shape, and the arc along which the transmission teeth 21, track grooves 20 and their bottom surfaces are matched with the outline of the ball head structure 24 (for example, different diameters but concentric arrangement). As shown in FIG. 1 , the contour line of the bottom surface of the transmission tooth 21 and the outer contour line of the ball head structure 24 are concentric circles.

As shown in FIG. 1 , one end of the transmission tooth 21 extends into the track groove 20 and contacts the bottom surface of the track groove 20 . When the ball head structure 24 rotates in the activity space, the drive tooth 21 slides relative to the track groove 20. During the sliding process, the drive tooth 21 is always in contact with the bottom surface of the track groove 20, thereby ensuring that the ball head structure 24 and the activity space are arranged concentrically . Specifically, the number of the transmission teeth 21 is uniformly distributed along the circumferential direction; the number of the track grooves 20 is six.

Specifically, the gear sleeve mechanism may include a gear sleeve 9 and an end cover 10 . The tooth sleeve 9 is fixedly connected to the front end of the end cover 10 and forms the movable space. The outer wall of the tooth sleeve 9 has a first spherical structure 23 . The rear end of the tooth sleeve 9 is connected to the end cap 10; the end cap 10 is provided with the second connecting portion. The rear end of the end cap 10 is provided with a second spherical structure 18 matched with the first spherical structure 23 . In order to facilitate the rotation of the button mechanism 8, the rear end of the end cover 10 is provided with a tapered hole leading into the activity space; the end cover 10 is sleeved outside the button mechanism 8 through the tapered hole; The tapered hole gradually increases in diameter from bottom to top. Preferably, the inclination angle of the tapered hole is 8 degrees.

Wherein, the tooth sleeve 9 and the end cover 10 are both sleeve-type structures or tubular structures as shown in FIG. 1 , so that the drill pipe pup joint formed with the button mechanism 8 has a central flow channel. As shown in Fig. 1, the gear sleeve 9 and the end cover 10 are arranged from top to bottom. The gear sleeve 9 cooperates with the end cover 10 to form a movable space, and the inner wall of the gear sleeve 9 is provided with the first sealing inner spherical surface and the track groove 20 . The gear sleeve 9 is screwed to the end cap 10 . As shown in Figure 1, the second sealed inner spherical surface is arranged on the front end of the end cover 10; The structure 23 cooperates with the second spherical structure 18 .

As shown in Figure 1, the ball head structure 24 is sandwiched between the tooth sleeve 9 and the end cap 10, and the upper surface of a diameter-reducing protrusion of the end cap 10 forms the second sealed inner spherical surface, and the diameter-reducing protrusion The raised lower surface forms a step for the rear end of the button mechanism 8 to abut against. The second spherical structure 18 is disposed on the rear end of the end cover 10 and is an inner spherical surface. The first spherical surface structure 23 is disposed on the outer wall of the tooth sleeve 9 and is an outer spherical surface. The first spherical structure 23 and the second spherical structure 18 are in contact with each other, providing guidance and assistance for the relative swing between the button mechanism 8 and the tooth sleeve mechanism, and at the same time, preventing dirt from entering between the end cover 10 and the ball structure 24 active sphere.

As shown in FIG. 1 , the end cap 10 is provided with a second connecting portion, and both the second connecting portion and the first connecting portion can be threaded and connected with threads (of the next drill pipe pup joint). Wherein, the second connecting portion is located behind the movable space and behind the diameter-reducing protrusion. The ball tooth mechanism 8 and the tooth sleeve mechanism are connected by threads, which can stably maintain the transmission of torque, thus facilitating bending between two adjacent drill pipe sub-joints.

Further, the gear sleeve 9 is screwed to the end cap 10 . The track grooves 20 are evenly distributed along the circumference of the ball head structure 24 . One transmission tooth 21 is disposed in each track groove 20 and pin hole. All the transmission teeth 21 are located on the same plane, so that the bending of the drill pipe pup joint can be satisfied, and the torque can be better transmitted at the same time. The number of the track grooves 20 is no less than four. As shown in FIG. 2 , the number of track grooves 20 is six, and the number of transmission teeth 21 is also six. The first connecting portion is an external thread, and the second connecting portion is an internal thread.

In one embodiment, the first drill pipe joint 5 is also movably connected to the drill pipe sub-joint, and the second drill pipe joint 11 is also movably connected to the drill pipe sub-joint. Specifically, as shown in FIG. 1 , one end of the first drill pipe joint 5 is provided with a drill pipe pin. The rear end of the first drill joint 5 is sheathed outside the front end of the button mechanism 8 and is provided with the second spherical structure 18 . Further, as shown in FIG. 1 , the rear end of the second drill joint 11 is provided with a drill box box, and the front end of the second drill joint 11 receives the ball joint structure 24 .

In this embodiment, the drill pipe pup joint can be bent, that is, a relative swing occurs between the sleeve mechanism and the button mechanism 8 . Preferably, the bendable degree of the drill pipe pup joint is 100 degrees. With such settings, the ultra-short-radius sidetracking horizontal well or highly-deviated well drilling operation with a build-up radius of no more than 1.8 meters can be successfully completed in a 5 1/2" (5.5-inch) well.

In this embodiment, the material of the core inner cylinder 7 may be titanium alloy. In this way, the core inner cylinder 7 has high elasticity, and its inner diameter is greater than 32 mm. Based on the resilience performance of titanium alloy, the core inner cylinder 7 can bend when passing through the build-up section, and can rebound naturally when entering the horizontal section, ensuring that all Get the rock core and enter the rock core inner cylinder 7 smoothly. At the end of coring, when the drilling tool is lifted up and passes through the build-up section and the window, the core inner barrel 7 can bend into the main wellbore and rebound, reducing the lifting resistance and potential damage to the flexible and airtight coring tool. By providing the core inner cylinder 7 with such a structure, the length of a single core can be greater than 0.8m, and the diameter of the core can be greater than 32mm.

Please continue to refer to FIG. 1 , at least part of the sealing head 3 is inside the core bit 1 . The drill joint connects the rear end of the core bit 1 with the first drill joint 5 . The core bit 1 has a tubular structure as a whole, and the transition from the outer wall to the inner wall can be a circular arc, so as to facilitate drilling. The sealing head 3 is inserted into the core bit 1 . The sealing head 3 may be hollow in order to guide the drilled core.

In this embodiment, as shown in FIG. 3 , the inner wall of the core claw 4 is provided with a first locking tooth 41 inclined backward, and the outer wall of the sealing head 3 is provided with a tooth corresponding to the first locking tooth 41 . The matched second locking teeth 31; the second locking teeth 31 are inclined forward; the core jaws 4 can expand radially and reset. Wherein, the first locking tooth 41 of the core claw 4 can also anchor the core, so that the core can be sheared and separated from the formation when the core is taken.

Further, the cross section of the core claw 4 is an open ring. Specifically, the core claw 4 has a split sleeve structure, so that it can expand, shrink and reset in the radial direction. When the sealing head 3 is subjected to a backward force (when the core is drilled, it is pushed by the core), the first latch 41 of the core claw 4 is inclined backward, and in cooperation with the second latch 31, only the airtight seal is allowed. Head 3 moves backwards. During the backward movement of the sealing head 3 , every time the first locking tooth 41 passes through in the moving direction, the core claw 4 will undergo expansion and reset until the sealing head 3 enters the rear core inner cylinder 7 .

A first annular passage is provided between the inner core barrel 7 and the flexible drill pipe. The core bit 1 is provided with a liquid flow channel communicating with the first annular channel. Specifically, the fluid flow channels are arranged on the walls of the core bit 1 and the bit joint, so as to facilitate the flow of drilling fluid. As shown in Figure 1, the front end of the drill joint is provided with external threads and internal threads. The front end of the drill joint extends into the core bit 1 and is threadedly connected with the core bit 1 . In order to prevent drilling fluid from entering the core inner cylinder 7, a sealing gasket 2 is sheathed outside the sealing head 3.

In this embodiment, the core bit mechanism may further include a suspension mechanism supporting the front end of the core inner cylinder 7 . The suspension mechanism is located in the core bit mechanism; one end of the sealing head 3 extends into one end of the suspension mechanism, and the other end of the suspension mechanism is connected to the core inner cylinder; the sealing head 3 can Sliding into the coring inner barrel; the suspension mechanism can prevent the rotation of the core bit mechanism from being transmitted to the coring inner barrel. Specifically, the suspension mechanism includes a bearing assembly 6 .

In this embodiment, the bearing assembly 6 may include a bearing (such as a tapered roller bearing) and a bearing sleeve. The bearing is fixed in the bearing sleeve, and the bearing sleeve is sleeved in the drill joint (coring bit 1), and is sleeved on the outside of the front end of the core inner cylinder 7.

Further, in order to prevent the airtight head 3 from falling under the action of external force or gravity in the process of lifting the drilling tool, causing impact on the mined rock core, even the core inner cylinder 7 of the core foundation, the rear end of the core inner cylinder 7 is also fixed with a Fixing piece 12 ; the fixing piece 12 is used to maintain the position of the sealing head 3 when the sealing head 3 enters the core inner cylinder 7 .

Specifically, the fixing member 12 includes a permanent magnet block arranged at the rear end of the core inner cylinder 7; the sealing head 3 is made of a material that can be attracted by a magnet. The permanent magnet block is adsorbed on the permanent magnet block due to the magnetic force of the permanent magnet block after the sealing head 3 enters the inner cylinder 7 of the rock core, so that the position of the sealing head 3 is relatively fixed, and the rock core will not be pushed during the lifting process .

As shown in Figure 1, the rear end of the core inner cylinder 7 is also provided with a pressure balance mechanism, and the pressure balance mechanism is used to balance the pressure inside the core inner cylinder 7; A water jacket 14 is provided; a water passage is provided on the wall of the water jacket 14 . The water jacket 14 can effectively filter circulating drilling fluid. A sliding bearing 15 may also be provided between the water jacket 14 and the inner core cylinder 7, so that the inner cylinder 7 of the rock core can be supported by the sliding bearing 15.

Specifically, the pressure balance mechanism includes a discharge nut 16 and an inner cylinder pressure balance piston 13 . The fixing member 12 is installed on the front end of the inner cylinder pressure balance piston 13; the discharge nut 16 is covered on the rear end of the core inner cylinder 7; the front end of the inner cylinder pressure balance piston 13 is located on the The core inner cylinder 7 is in close contact with the wall of the core inner cylinder 7 , and the rear end of the pressure balance piston 13 of the inner cylinder passes through the discharge nut 16 . In order to further balance the pressure of the core inner cylinder 7, an overflow valve 17 is provided at the rear end of the pressure balance piston 13 (the accompanying drawing 1 is only schematic).

The coring process of the flexible airtight coring tool of the above-mentioned embodiment will be described in detail below: (1) sidetracking is opened at the design position of the wellbore, and drilled to the designed coring position; (2) the flexible airtight coring tool of the present embodiment The coring tool is lowered to the coring position; (3) The drilling fluid is circulated outside the well, and the rotating power is slowly started, and the drilling fluid passes through the first annular channel and the liquid flow channel to wash away the debris deposited at the bottom of the well; (4) The drilling fluid outside the well Increase the drilling pressure, and the coring bit mechanism starts to drill the core; (5) the sealing head 3 is pushed into the core inner cylinder 7 by the core; (6) the core enters the core inner cylinder 7 under the guidance of the sealing head 3, and at the same time, The sealing head 3 will squeeze the sealing liquid in the inner cylinder 7 of the rock core, and the sealing liquid overflows to the position of the rock core through the sealing head 3, and wraps the rock core; The fluid wraps the core continuously until a long enough core is drilled; (8) The drilling tool is lifted up at the wellhead, and the entire flexible and airtight coring tool is separated from the working face of the drill bit. At this time, the core claw 4 will hold the core tightly , the first locking tooth 41 (barb structure) of the rock core claw 4 is tightened by tension, and the rock core is pulled tighter and tighter, until the rock core breaks, and the core is cut; (9) continue to lift the drilling tool, and the rock core is put out of the wellhead; (10) ) Take out the core inner tube 7 filled with the core, and pack the core for subsequent use.

Any numerical value cited herein includes all values from the lower value to the upper value in increments of one unit for the lower and upper values, with a separation of at least two units between any lower value and any higher value That's it. For example, if it is stated that a component quantity or process variable (such as temperature, pressure, time, etc.) has a value from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose Values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32, etc. are also explicitly listed in the specification. For values less than 1, one unit is considered to be 0.0001, 0.001, 0.01, 0.1, as appropriate. These are merely examples intended to be expressly stated, and it is considered that all possible combinations of numerical values recited between the lowest value and the highest value are expressly set forth in this specification in a similar manner.

Unless otherwise indicated, all ranges include the endpoints and all numbers between the endpoints. "About" or "approximately" used with a range applies to both endpoints of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30", inclusive of at least the indicated endpoints.

All articles and references disclosed, including patent applications and publications, are hereby incorporated by reference for all purposes. The term "consisting essentially of" describing a combination shall include the identified elements, ingredients, parts or steps as well as other elements, ingredients, parts or steps that do not substantially affect the basic novel characteristics of the combination. Use of the terms "comprising" or "comprising" to describe a combination of elements, ingredients, parts or steps herein also contemplates an embodiment that consists essentially of these elements, ingredients, parts or steps. By using the term "may" herein, it is intended that inclusion of "may" in any of the described attributes is optional.

Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step may be divided into separate plural elements, ingredients, parts or steps. The disclosure of "a" or "an" to describe an element, ingredient, component or step is not meant to exclude other elements, ingredients, components or steps.

It should be understood that the foregoing description is for purposes of illustration and not limitation. Many implementations and many applications other than the examples provided will be apparent to those of skill in the art from reading the above description. The scope of the present teachings, therefore, should be determined not with reference to the above description, but should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are hereby incorporated by reference for completeness. The omission from the preceding claims of any aspect of the subject matter disclosed herein is not intended to be a disclaimer of such subject matter, nor should it be considered that the inventors did not consider the subject matter to be part of the disclosed inventive subject matter.

Claims (13)

1. A flexible airtight coring tool, characterized in that it comprises: a coring bit mechanism and a flexible drill rod connected in sequence; the flexible drill rod is provided with a core inner cylinder; the front end of the core inner cylinder is supported within said core bit mechanism; The core bit mechanism includes a core bit, a sealing head, and a core claw; at least part of the sealing head is located in the core bit; the core claw is located in the core bit and sleeved on the sealing head outside; the core jaws are set to only allow the sealing head to move backwards when subjected to a backward external force, and are set to allow the sealing head to move backwards when the sealing head is subjected to an external force in other directions or no external force fixing the position of the sealing head; The flexible drill pipe includes a first tool joint, a second tool joint, and a plurality of end-to-end tool subs between the first tool joint and the second tool joint; the The flexible drill pipe is connected to the core bit mechanism through the first drill pipe joint; a predetermined angle can be bent between two adjacent drill pipe nipples; the inner wall of the core claw is provided with a first locking tooth inclined backward , the outer wall of the sealing head is provided with a second locking tooth matched with the first locking tooth; the second locking tooth is inclined forward; the core claw can be expanded radially and reset. 2. The flexible airtight coring tool according to claim 1, wherein the cross section of the core claw is an open ring. 3. The flexible airtight coring tool as claimed in claim 1, characterized in that: the rear end of the inner cylinder of the rock core is also fixed with a fixing piece; the fixing piece is used for when the sealing head enters the inner cylinder of the rock core Keep the closed head in place. 4. The flexible airtight coring tool according to claim 3, characterized in that: said fixing member comprises a permanent magnet block arranged at the rear end of said rock core inner cylinder; said airtight head is made of a material that can be attracted by a magnet . 5. The flexible airtight coring tool according to claim 1, characterized in that: a first annular passage is provided between the core inner cylinder and the flexible drill rod; the core bit is provided with the The liquid flow channel communicated with the first annular channel. 6. The flexible airtight coring tool according to claim 4, characterized in that: the rear end of the core inner cylinder is also provided with a pressure balance mechanism, and the pressure balance mechanism is used to balance the pressure inside the core inner cylinder ; The rear end of the inner cylinder of the core is provided with a water jacket; the wall of the water jacket is provided with a water channel. 7. The flexible and airtight coring tool according to claim 6, characterized in that: the pressure balance mechanism includes a relief nut and an inner cylinder pressure balance piston; the fixing member is installed on the front end of the inner cylinder pressure balance piston The discharge nut covers the rear end of the inner cylinder of the rock core; the front end of the pressure balance piston of the inner cylinder is located in the inner cylinder of the rock core and is tightly attached to the wall of the inner cylinder of the rock core, and the inner cylinder The rear end of the barrel pressure balance piston passes through the relief nut. 8. The flexible airtight coring tool according to any one of claims 1-7, wherein the drill pipe nipple comprises: A ball-tooth mechanism extending lengthwise, a first connecting portion is arranged on the side wall of the button-tooth mechanism; a ball head structure is arranged on one end of the ball-tooth mechanism, and a plurality of ball-tooth structures are arranged on the side wall The transmission teeth are arranged at intervals along its circumference; the rear of the transmission teeth is provided with a first sealing outer spherical surface; the front of the transmission teeth is provided with a second sealing outer spherical surface; A toothed sleeve mechanism that is movably connected with the ball and tooth mechanism; the toothed sleeve mechanism has an activity space for accommodating the ball head structure; the rear end of the toothed sleeve mechanism is sleeved outside the ball and tooth mechanism and is located on the The rear of the ball head structure; the lower part of the activity space is provided with a first sealing inner spherical surface that matches the second sealing outer spherical surface, and the upper part of the activity space is provided with a sealing outer spherical surface that matches the first sealing outer spherical surface. The second sealed inner spherical surface; the wall of the activity space is provided with a plurality of track grooves corresponding to the transmission teeth one by one; the transmission teeth partially extend into the track grooves; the transmission teeth and the track The bottom surfaces of the grooves are in contact; the tooth sleeve mechanism is provided with a second connecting portion capable of connecting with the first connecting portion. 9. The flexible airtight coring tool according to claim 8, characterized in that, the transmission teeth and the ball head structure are integrally formed; the transmission teeth extend along an arc or an envelope from top to bottom ; The track groove is an arc groove. 10. The flexible airtight coring tool as claimed in claim 9, wherein the outer contour of the cross-section of the transmission tooth is a partial arc; the diameter of the outer contour of the cross-section of the transmission tooth is first from top to bottom. Decrease after increasing. 11. The flexible airtight coring tool according to claim 10, wherein the position of the maximum diameter of the outer contour of the cross-section of the transmission tooth is closer to the rear end of the transmission tooth than the front end of the transmission tooth; The first sealing outer spherical surface and the second sealing outer spherical surface are located on the same sphere; the position of the maximum diameter is located on the same cross section as the center of the sphere. 12. The flexible airtight coring tool according to claim 11, characterized in that, at least one of the first sealed outer spherical surface and the first sealed inner spherical surface, and/or, the second sealed outer spherical surface and At least one of the second sealed inner spherical surfaces is provided with an annular lubricating oil groove; the lubricating oil groove is filled with high temperature resistant lubricating grease. 13. The flexible and airtight coring tool according to claim 8, wherein the tooth sleeve mechanism comprises a tooth sleeve and an end cover; the tooth sleeve is fixedly connected to the front end of the end cover and forms the movable space; The outer wall of the gear sleeve has a first spherical structure; the rear end of the gear sleeve is connected to the end cover; the first sealing inner spherical surface and the track groove are arranged on the inner wall of the gear sleeve; the The second sealed inner spherical surface is arranged on the front end of the end cap; the end cap is provided with the second connecting part; the rear end of the end cap is sleeved outside the front end of the button mechanism and is provided with the second connecting part. One spherical structure cooperates with a second spherical structure.