Drill rod flow dividing short section, method for adjusting opening and closing of flow dividing holes and tail pipe tripping-in pipe string

Abstract

The invention provides a drill rod shunting short section which comprises a sleeve, at least one through shunting hole formed in the sleeve, a throttling mechanism comprising a valve seat and a throttling valve, an adjusting mechanism comprising a first connecting cylinder arranged at the downstream of the valve seat and forming an annulus with the sleeve, and a second connecting cylinder arranged at the downstream of the first connecting cylinder, the throttling valve is arranged in the mode that throttling can be formed to drive the adjusting mechanism to move upwards when upward-returning fluid in a shaft passes through the throttling valve, and therefore the flow dividing hole is opened for flow dividing; the reset mechanism is configured to enable the adjusting mechanism to move downwards to close the flow dividing holes when no upward-returning fluid passes through the shaft. According to the device, internal upward-returning fluid can be shunted in the tripping-in process of a tail pipe tripping-in pipe string, so that the excitation pressure on a stratum during tripping-in is reduced, and it can be guaranteed that drilling fluid can be circulated in the forward direction at any time.

Description

Technical Field

[0001] The invention relates to the field of downhole tools for petroleum well completion, and in particular to a drill pipe diversion nipple, a method for adjusting the opening and closing of a diversion hole, and a tail pipe lowering pipe string. Background Art

[0002] At present, the liner cementing technology is to use the liner hanger to connect the liner string, and lower the liner hanger and the liner string to the designed position through the drilling tool, and then perform cementing operations. Its operation pipe string generally includes: feeding drilling tools, liner hangers, ball seats, floating collars, floating shoes, etc. When the liner string is lowered into the wellbore, the fluid in the wellbore needs to return along the liner annulus, and at the same time generate agitation pressure on the formation, which may induce formation leakage; at the same time, it is necessary to intermittently grout from the wellhead during the lowering process to ensure the pressure balance inside and outside the pipe string, which will greatly increase the operation time. The automatic grouting liner lowering technology uses a normally open floating collar to achieve the simultaneous return of fluid through the inside of the liner and the annulus during the liner lowering process, thereby reducing the agitation pressure. However, since the inner diameter of the liner is generally larger than the inner diameter of the drilling tool, a certain agitation pressure will still be generated when the internal fluid returns to the feeding drilling tool. To this end, a drill pipe diverter nipple (SPE135178) was developed. It is connected to the upper part of the liner hanger so that the fluid inside the pipe string can be returned to the drill bit through the large channel in the drill bit annulus, thereby greatly reducing the agitation pressure during the liner running process and ensuring the safety, reliability and running speed of the liner in the formation prone to leakage.

[0003] Drill pipe diversion nipples are generally divided into two types: diversion hole normally open type and normally closed type. Among them, although the normally open diversion nipples have a simple structure, they cannot meet the process requirements of mid-circulation forward circulation of drilling fluid. Usually, it is necessary to close the diversion hole by throwing a ball to hold the pressure after it is in place. The normally closed diversion nipples use a reverse throttling mechanism to open the diversion hole by using the pressure difference generated by the return fluid at the throttling mechanism, and then use a spring to automatically close the diversion hole. This nipple can not only realize the diversion of the return fluid inside the pipe string at the upper part of the tail pipe hanger, but also realize the forward circulation at any time during the tail pipe lowering process.

[0004] However, the sliding parts inside the normally closed drill pipe diversion nipple and the sealing tube for closing the diversion hole need to be installed with multiple sets of sealing rings. The sliding resistance of opening and closing the diversion hole in the downhole environment is relatively large. There is a risk that the diversion hole cannot be completely closed only by the reset force of the spring, which may lead to problems such as the inability to hang the tail pipe hanger and cementing in the later stage. In addition, if the closing reliability is ensured by increasing the spring reset force, it is very easy to cause the diversion hole opening pressure to increase, thereby failing to achieve the purpose of reducing the exciting pressure. Therefore, it is necessary to improve the drill pipe diversion nipple to improve the reliability of the diversion hole closure.

[0005] Therefore, it is desired in the art to provide a drill pipe diverter nipple to solve the above technical problems. Summary of the invention

[0006] The purpose of the present invention is to provide a drill pipe diversion short joint, which can not only realize the diversion of internal upward return fluid during the lowering of the tail pipe, thereby reducing the exciting pressure on the formation during lowering, but also ensure that the drilling fluid can be circulated forward at any time.

[0007] According to a first aspect of the present invention, there is provided a drill pipe flow diverter nipple, comprising a sleeve, wherein at least one diverter hole is provided through the sleeve.

[0008] A throttling mechanism is concentrically arranged in the sleeve, comprising a valve seat and a throttling valve arranged on the valve seat,

[0009] The regulating mechanism comprises a first connecting tube arranged downstream of the valve seat and forming an annulus with the sleeve, a second connecting tube arranged downstream of the first connecting tube, and a petal ball seat arranged in the second connecting tube and abutting against the sleeve, wherein in an initial state, the first connecting tube is fixedly connected to the second connecting tube by a pin,

[0010] a reset mechanism disposed in the annulus, and

[0011] A pressure-holding ball is put into the sleeve,

[0012] The throttle valve is configured to form throttling when upward return fluid passes through the wellbore to drive the regulating mechanism upward, thereby opening the diversion hole for diversion; the reset mechanism is configured to force the regulating mechanism downward to close the diversion hole when no upward return fluid passes through the wellbore;

[0013] The petal ball seat is configured to form a pressure holding function with the pressure holding ball when the diverter hole is not completely closed, so as to force the second connecting tube to move further downward, thereby completely closing the diverter hole.

[0014] In one embodiment, the sleeve includes a first sleeve portion and a second sleeve portion disposed downstream of the first sleeve portion, wherein the diverter hole is radially disposed on the second sleeve portion, and the annulus is formed between the first connecting sleeve and the second sleeve portion.

[0015] In one embodiment, an expansion groove extending radially outward and used to receive the split ball seat is formed on the inner wall of the second sleeve portion, and the expansion groove is radially within the range of the second connecting tube.

[0016] Among them, when the diverter hole is not completely closed, the petal ball seat is constructed to be able to expand and enter the expansion groove after descending under the pressure formed by the pressure-holding ball, thereby prompting the second connecting tube to close the diverter hole and allow the petal ball seat to pass.

[0017] In one embodiment, a plurality of supports and ball seat grooves are alternately arranged along the circumference of the second connecting tube, and the petal ball seat is radially arranged in the ball seat groove.

[0018] In one embodiment, the split-flange ball seat includes a main body portion configured in a partial fan-shaped form, and a guide portion extending radially inward and downward from the main body portion into the second connecting tube, wherein a plurality of the guide portions are enclosed in the second connecting tube to form a round hole ball seat for receiving the pressure-holding ball.

[0019] In one embodiment, the split-petal ball seat further includes a first engaging portion and a second engaging portion extending axially outward from both sides of the main body portion.

[0020] A recessed portion extending radially inward and respectively cooperating with the first engaging portion and the second engaging portion is formed on the outer wall surface of the ball seat groove.

[0021] In one embodiment, a radially outwardly extending guide slope is formed at the junction of the expansion groove and the first engaging portion to allow the petal ball seat to move upward and exit the expansion groove under the action of the throttle valve or to move downward and enter the expansion groove under the action of the ball pitching pressure.

[0022] In one embodiment, the reset mechanism comprises a spring seat and a spring arranged at the lower end surface of the first connecting cylinder, wherein a first end of the spring is axially abutted against the spring seat, and a second end of the spring is axially abutted against the second connecting cylinder.

[0023] In one embodiment, a groove extending radially inward and used to accommodate an expandable clamping ring is formed on the outer wall of the first connecting tube.

[0024] The spring seat includes a seat body portion configured in an annular shape, and a boss extending axially upward from the seat body portion and connected to the second sleeve portion, wherein a limiting cavity for receiving the clamping ring is formed between the seat body portion and the first sleeve portion.

[0025] In one embodiment, the drill pipe diverter nipple also includes a first joint arranged at the upstream end of the first sleeve portion and used to connect to the upper pipe string, and a second joint arranged at the downstream end of the second sleeve portion and used to connect to the tail pipe hanger, wherein a step extending radially inward and downwardly inclined is formed at the upper end surface of the second joint.

[0026] According to a second aspect of the present invention, there is provided a method for adjusting the opening and closing of a diversion hole by using the diversion sub of a drill pipe as described above, comprising the following steps:

[0027] S1. When the upward return fluid passes through the wellbore, throttling is formed through the throttle valve to drive the regulating mechanism upward, thereby opening the diversion hole;

[0028] S2. When there is no upward return fluid passing through the wellbore, the adjusting mechanism is urged to move downward by the reset mechanism to reclose the diversion hole.

[0029] In one embodiment, the step of completely closing the diverter hole comprises:

[0030] When the diverter hole is not completely closed, a pressure-holding ball is put into the sleeve, and the petal ball seat can expand and enter the expansion groove after descending under the pressure formed by the pressure-holding ball, thereby prompting the second connecting tube to close the diverter hole and allow the petal ball seat to pass through.

[0031] According to a third aspect of the present invention, there is provided a liner lowering pipe string, comprising:

[0032] The tail pipe string has a guide shoe connected to its end.

[0033] a liner hanger disposed upstream of the liner string, and

[0034] A drill pipe flow diverter nipple as described above is connected to the upper end of the liner hanger via a lifting joint.

[0035] Compared with the prior art, the advantages of the present invention are:

[0036] First, the present invention is provided with an expandable petal ball seat and a matching expansion slot. Therefore, when the second connecting tube cannot rely on the elastic force of the spring to re-block the diverter hole, the present invention can achieve the purpose of completely closing the diverter hole by throwing the ball to hold the pressure, and also achieve the purpose of allowing the holding pressure ball to pass through the drill pipe diverter nipple.

[0037] On the one hand, the petal ball seat can drive the second connecting tube to move downward synchronously under the action of holding pressure, and when the petal ball seat expands and enters the expansion groove, it can prompt the second connecting tube to completely close the diversion hole, thereby eliminating the problem of being unable to hang the tail pipe hanger and cementing in the later stage due to the inability to close the diversion hole; on the other hand, because the petal ball seat can expand and enter the expansion groove after moving downward under the action of holding pressure, the inner diameter of the round hole ball seat is enlarged to allow the holding pressure ball to pass through the drill pipe diversion short section.

[0038] Secondly, the present invention provides a diversion hole on the sleeve, which not only realizes the diversion effect on the internal fluid during the lowering of the tail pipe, thereby reducing the exciting pressure when lowering the tail pipe; but also ensures that the drilling fluid can be positively circulated at any time, thereby effectively improving the lowering efficiency and safety of the tail pipe lowering string. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be described in detail below with reference to the accompanying drawings:

[0040] Figure 1 The structure of the drill pipe flow dividing nipple according to the present invention is schematically shown;

[0041] Figure 2 The structure of the second connecting tube in the drill pipe flow dividing nipple according to the present invention is schematically shown;

[0042] Figure 3 for Figure 2 A partial cross-sectional view showing the positional relationship between the support and the ball seat groove;

[0043] Figure 4 It is a structural schematic diagram of a petal ball seat in a drill pipe flow splitting nipple according to the present invention;

[0044] Figure 5 A partial cross-sectional view of a drill pipe flow dividing nipple according to the present invention, which shows the positional relationship between the petal ball seat and the expansion groove in the initial state;

[0045] Figure 6 The schematic diagram shows the working state of normal fluid circulation when the diversion hole of the drill pipe diversion short joint is closed;

[0046] Figure 7 The schematic diagram shows the working state of fluid throttling back when the diversion hole of the drill pipe diversion short section is opened;

[0047] Figure 8 The schematic diagram shows the working state of the fluid when the diversion hole of the drill pipe diversion short joint is not completely closed;

[0048] Fig. 9 The schematic diagram shows the process of completely closing the diverter hole by throwing a ball to hold the pressure;

[0049] Fig.10 The structure of the tail pipe lowering pipe string according to the present invention is schematically shown.

[0050] In the drawings, the same reference numerals are used for the same components. The drawings are not drawn to scale. DETAILED DESCRIPTION

[0051] In order to make the technical solutions and advantages of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0052] The directional terms "upstream" or "above" or similar terms refer to the direction closer to the wellhead, i.e. Figure 1 The directional terms "downstream" or "below" or similar terms refer to the direction away from the wellhead, i.e. Figure 1 The bottom direction in .

[0053] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0054] In the present invention, unless otherwise clearly stipulated and limited, terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal connection of two elements.

[0055] For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] The present invention will be further described below in conjunction with the accompanying drawings.

[0057] Figure 1 The structure of a drill pipe flow dividing sub 100 according to the present invention is schematically shown.

[0058] like Figure 1 As shown, according to a first aspect of the present invention, a drill pipe flow dividing nipple 100 is provided, which mainly includes a sleeve 10, a throttling mechanism, an adjusting mechanism and a resetting mechanism.

[0059] In one embodiment, Figure 1As shown, the sleeve 10 includes a first sleeve portion 11 and a second sleeve portion 12 disposed downstream of the first sleeve portion 11. At least one through-flow diversion hole 101 is disposed on the second sleeve portion 12. The diversion hole 101 is configured to effectively and reasonably divert the upward return fluid during the lowering of the tail pipe lowering pipe string 200 (described below), thereby reducing the agitation pressure when lowering the tail pipe. The content is described below.

[0060] Preferably, a threaded connection is formed between the first sleeve portion 11 and the second sleeve portion 12 .

[0061] In one embodiment, Figure 1 As shown, the regulating mechanism includes a first connecting cylinder 31 and a second connecting cylinder 32 which are arranged in sequence. The first connecting cylinder 31 is arranged downstream of the valve seat 21 (described below), and forms an annulus 301 for accommodating the reset mechanism between the first connecting cylinder 31 and the first sleeve portion 11. The second connecting cylinder 32 is arranged downstream of the first connecting cylinder 31, and forms a sealed connection with the inner circumferential surface of the second sleeve portion 12.

[0062] Preferably, in the initial state, the first connecting cylinder 31 is fixedly connected to the second connecting cylinder 32 via the pin 35 .

[0063] In one embodiment, Figure 1 As shown, the reset mechanism is arranged in the annulus 301 formed by the first connecting cylinder 31 and the first sleeve part 11, and includes a spring seat 51 and a spring 52. The spring 52 is sleeved outside the first connecting cylinder 31, and the spring seat 51 is arranged at the junction of the first sleeve part 11 and the spring 52.

[0064] Preferably, the first end of the spring 52 is axially abutted against the spring seat 51 , and the second end of the spring 52 is axially abutted against the upper end surface of the second connecting tube 32 .

[0065] According to the present invention, Figure 1 As shown, the adjustment mechanism further includes a split ball seat 4. The split ball seat 4 is disposed in the second connecting cylinder 32 and abuts against the second sleeve portion 12 in radial direction.

[0066] In one embodiment, Figure 1 As shown, the throttle mechanism is concentrically arranged in the sleeve 10, and includes a valve seat 21 and a throttle valve 22. The valve seat 21 is installed in the first sleeve portion 11, and the throttle valve 22 is installed in the valve seat 21. Preferably, the valve seat 21 and the throttle valve 22 are both located upstream of the first connecting cylinder 31.

[0067] Preferably, the throttle valve 22 is a gate-type one-way valve, which can allow forward circulation (flow in the wellbore downward circulation) and can also achieve a throttling effect during reverse circulation.

[0068] Preferably, the valve seat 21 and the first connecting cylinder 31 are fixedly connected via threads, and the outer diameter of the valve seat 21 is greater than the outer diameter of the first connecting cylinder 31 , thereby facilitating shearing of the pin 35 .

[0069] During the lowering of the tail pipe entry pipe string 200, the upward return fluid in the wellbore can flow into the drill pipe diversion short joint 100, and the throttle valve 22 can form a throttling pressure difference in the sleeve 10 to prompt the second connecting tube 32 to squeeze the spring 52 and move upward, thereby opening the diversion hole 101 to allow the upward return fluid to be reasonably diverted to the external annulus through the diversion hole 101, thereby effectively reducing the exciting pressure when the tail pipe is lowered to achieve the purpose of preventing formation leakage.

[0070] When the tail pipe lowering pipe string 100 stops being lowered and the fluid stops returning upward, the regulating mechanism can move downward under the elastic force of the spring 52 and re-block the diverter hole 101 through the second connecting tube 32 .

[0071] Figure 2 The structure of the second connecting tube 32 in the drill pipe flow dividing nipple 100 according to the present invention is schematically shown.

[0072] Figure 3 for Figure 2 A partial cross-sectional view showing the positional relationship between the support 33 and the ball seat groove 34.

[0073] Figure 4 Schematic diagram of the structure of the split ball seat 4 in the drill pipe splitter sub 100 according to the present invention.

[0074] Figure 5 It is a partial cross-sectional view of the drill pipe flow dividing nipple 100 according to the present invention, which shows the positional relationship between the petal ball seat 4 and the expansion groove 13 in the initial state.

[0075] In one embodiment, Figures 2 to 5 As shown, a plurality of seats 33 and ball seat grooves 34 are alternately arranged along the circumference of the second connecting tube 32, and the petal ball seat 4 is radially arranged in the ball seat groove 34. In combination with the above, when the second connecting tube 32 moves upward under the throttling pressure difference formed by the throttle valve 22, the petal ball seat 4 can be contracted into the ball seat groove 34 of the second connecting tube 32 under the squeezing action of the second sleeve part 12.

[0076] In a specific embodiment, Figure 4As shown, the split ball seat 4 includes a main body portion 41 and a guide portion 42. The main body portion 41 is configured as a partial fan-shaped structure. The guide portion 42 extends radially inward and downward from the main body portion 41 into the second connecting tube 32. A plurality of guide portions 42 can be enclosed in the second connecting tube 32 to form a round hole ball seat for receiving the pressure-holding ball 7.

[0077] Preferably, the inner diameter of the round-hole ball seat is smaller than the outer diameter of the pressure-holding ball 7 , whereby the petal ball seat 4 can form pressure holding by abutting against the pressure-holding ball 7 through the round-hole ball seat.

[0078] It is easy to understand that in the subsequent ball throwing and pressure holding operation, the pressure holding ball 7 can form an axial abutment with the round hole ball seat, thereby forming a pressure holding with the petal ball seat 4 in the sleeve 10.

[0079] In one embodiment, Figure 1 and 5 As shown, a radially outwardly extending expansion groove 13 is formed on the inner wall of the second sleeve portion 12. Preferably, the expansion groove 13 is radially within the range of the second connecting tube 32, and when the petal ball seat 4 is expanded, the expansion groove 13 can receive the petal ball seat 4, thereby allowing the pressure holding ball 7 to pass through the drill pipe diverter nipple 100 and go down, the content of which is introduced below.

[0080] When the second connecting tube 32 cannot rely on the elastic force of the spring 52 to re-seal the diverter hole 101, the present invention can not only determine whether the diverter hole 101 is completely closed by throwing a ball to hold the pressure, but also prompt the second connecting tube 32 to completely close the diverter hole 101 and allow the holding ball 7 to pass through.

[0081] It is easy to understand that when the diverter hole 101 is completely closed, the petal ball seat 4 has expanded and entered into the expanded groove 13. At this time, the pressure-holding ball 7 thrown in will directly pass through the drill pipe diverter short section 100 and move downstream; when the diverter hole 101 is not completely closed, the petal ball seat 4 shrinks in the ball seat groove 34 of the second connecting tube 32. At this time, the pressure-holding ball 7 thrown in will not pass directly, but will abut against the petal ball seat 4 to form pressure holding.

[0082] Specifically, a pressure-holding ball 7 is put into the sleeve 10. The pressure-holding ball 7 forms an axial abutment with the round hole ball seat surrounded by a plurality of guide portions 42, thereby forming a pressure holding with the petal ball seat 4 in the second connecting tube 32. The petal ball seat 4 can drive the second connecting tube 32 to move downward synchronously under the pressure holding, and when the petal ball seat 4 is aligned with the expansion groove 13 in the radial direction, the petal ball seat 4 can expand and enter the expansion groove 13, thereby prompting the second connecting tube 32 to completely close the diverter hole 101, so as to improve the safety of the drill pipe diverter nipple 100.

[0083] It is easy to understand that when the petal ball seat 4 enters the expansion groove 13, the petal ball seat 4 (round hole ball seat) will gain a larger passage to allow the pressure-holding ball 7 to smoothly pass through the drill pipe diverter nipple 100 and move downstream.

[0084] It is worth noting that when the petal ball seat 4 is contracted into the second connecting tube 32 under the action of the second sleeve portion 12, the petal ball seat 4 (round hole ball seat) will have a smaller inner diameter. Therefore, when the pressure-holding ball 7 is put into the drill pipe diversion short joint 100, the pressure-holding ball 7 can abut against the petal ball seat 4 to form pressure holding. When the petal ball seat 4 enters the expansion groove 13, the petal ball seat 4 will have a larger inner diameter, thereby allowing the pressure-holding ball 7 and the drill pipe capsule (not shown) to pass through.

[0085] In one embodiment, Figure 1 , 4 As shown in Figures 5 and 6, the split-petal ball seat 4 further includes a first engaging portion 43 and a second engaging portion 44 extending axially outward from both sides of the main body 41. In addition, a recessed portion 341 extending radially inward is formed on the outer wall surface of the ball seat groove 34. It is easy to understand that the recessed portion 341 can form an effective matching relationship with the first engaging portion 43 and the second engaging portion 34, respectively, so as to prevent the split-petal ball seat 4 from falling off from the ball seat groove 34.

[0086] In a preferred embodiment, Figure 1 and 5 As shown, a guide slope 131 extending radially outward is formed at the junction of the expansion groove 13 and the first engaging portion 43. It is easy to understand that the guide slope 131 can allow the first ball seat petal 20 to move upward and exit the expansion groove 13 under the throttling pressure difference formed by the throttle valve 22, and can also allow the petal ball seat 4 to expand under the pressure formed by the pressure ball 7 and enter the expansion groove 13.

[0087] In one embodiment, Figure 1 As shown, a groove 311 extending radially inward and used to accommodate an expandable clamping ring 312 is formed on the outer wall of the first connecting cylinder 31. In the initial state, the clamping ring 312 shrinks into the groove 311 under the action of the first sleeve part 11.

[0088] Preferably, if Figure 1 As shown, the spring seat 51 includes a seat body portion 511 configured in an annular shape, and a boss 512 extending axially upward from the seat body portion 511. The boss 512 is fixedly connected to the lower end surface of the second sleeve portion 12. Thus, a limiting cavity 513 for receiving the retaining ring 312 is formed between the seat body portion 511, the first sleeve portion 11 and the boss 512.

[0089] During the process of ball pitching and pressure holding, if the pressure formed by the pressure holding ball 7 and the petal ball seat 4 is greater than the shear stress of the pin 35, the first connecting tube 31 and the second connecting tube 32 will separate, and the retaining ring 312 will follow the first connecting tube 31 downward until it is radially aligned with the limiting cavity 513, and the retaining ring 312 pops out from the retaining groove 311 and enters into the limiting cavity 513 to achieve axial locking of the first connecting tube 31, thereby permanently closing the diversion hole 101.

[0090] During the ball pitching and pressure holding process, if the pressure holding pressure formed by the pressure holding ball 7 and the petal ball seat 4 is not enough to shear off the pin 35, it can also be sheared off in the subsequent pressure holding process, thereby achieving the purpose of closing the diversion hole 101.

[0091] According to the present invention, Figure 1 As shown, the drill pipe flow dividing nipple 100 also includes a first joint 61 and a second joint 62. The first joint 61 is arranged at the upstream end of the first sleeve portion 11 and is used to connect with the upper pipe string (not shown in the drawings). The second joint 62 is arranged at the downstream end of the second sleeve portion 12 and is used to connect with the liner hanger 203 (described below).

[0092] In one embodiment, Figure 1 As shown, a step 621 extending radially inward and downward is formed on the upper end surface of the second joint 62. It is easy to understand that when the petal ball seat 4 expands and enters the expansion groove 13, the second connecting tube 32 can axially abut against the step 621.

[0093] Fig.10 The structure of the liner lowering pipe string 200 according to the present invention is schematically shown.

[0094] According to a second aspect of the present invention, a tail pipe lowering pipe string 200 is provided. Fig.10 As shown, the liner running string 200 includes a liner string 201, a guide shoe 202 connected to the end of which, a liner hanger 203 arranged upstream of the liner string 201, and a drill pipe diverter nipple 100 as described above connected to the upper end of the liner hanger 203 through a lifting joint 204.

[0095] During the lowering process of the liner entry pipe string 200, the fluid in the well can enter the liner entry pipe string 200 through the through hole on the guide shoe 202, and then return to the drill pipe diversion short joint 100 through the liner hanger 203 and the pulling joint 204 in sequence, and then the returned fluid goes up through the throttle valve 22 in the drill pipe diversion short joint 100 to open the diversion hole 101, so as to continue to return to the external annulus through the diversion hole 101 to reduce the excitation pressure when the liner is lowered.

[0096] Figure 6The schematic diagram shows the working state of normal fluid circulation when the diversion hole 101 of the drill pipe diversion short sub 100 is closed;

[0097] Figure 7 The schematic diagram shows the working state of fluid throttling back when the diversion hole 101 of the drill pipe diversion short sub 100 is opened;

[0098] Figure 8 The schematic diagram shows the working state of the fluid when the diversion hole 101 of the drill pipe diversion sub 100 is not completely closed;

[0099] Fig. 9 The schematic diagram shows the process of completely closing the diverter hole 101 by ball-throwing and pressure-holding;

[0100] According to a third aspect of the present invention, a method for adjusting the opening and closing of the diversion hole 101 by using the drill pipe diversion short section 100 as described above is provided. Figures 6 to 9 Give a detailed introduction.

[0101] First, when the upward return fluid passes through the wellbore, throttling is formed through the throttle valve 22 to drive the regulating mechanism upward, thereby opening the diversion hole 101.

[0102] Then, when there is no upward return fluid passing through the wellbore, the adjustment mechanism is urged downward by the reset mechanism to reclose the diversion hole 101 .

[0103] Specifically, during the lowering of the liner entry pipe string 200, the fluid in the wellbore returns to the drill pipe diversion short section 100 through the guide shoe 202. The first connecting tube 31 presses the spring 52 and moves upward under the throttling pressure difference formed by the throttle valve 22, thereby opening the diversion hole 101 to allow the fluid to be reasonably diverted to the external annulus through the diversion hole 101. After the liner entry pipe string 200 reaches the designed position, the second connecting tube 32 moves downward under the action of the spring 52 and closes the diversion hole 101.

[0104] In one embodiment, the regulating method as described above further comprises the step of completely closing the diversion hole:

[0105] When the diverter hole 101 is not completely closed, the pressure-holding ball 7 is put into the sleeve 10, and the petal ball seat 4 can expand and enter the expansion groove 13 after descending under the pressure formed by the pressure-holding ball 7, thereby prompting the second connecting tube 32 to close the diverter hole 101 and allow the petal ball seat 4 to pass through.

[0106] Compared with the prior art, the advantages of the present invention are:

[0107] First, the present invention is provided with an expandable petal ball seat 4 and a matching expansion slot 13. Therefore, when the second connecting tube 32 cannot rely on the elastic force of the spring 52 to re-block the diverter hole 101, the present invention can achieve the purpose of completely closing the diverter hole 101 and allowing the pressure-holding ball 7 to pass through the drill pipe diverter nipple 100 by throwing the ball to hold the pressure.

[0108] On the one hand, the petal ball seat 4 can drive the second connecting tube 32 to move downward synchronously under the action of pressure holding, and when the petal ball seat 4 expands and enters the expansion groove 13, it can prompt the second connecting tube 32 to completely close the diversion hole 101, thereby eliminating the problem of being unable to sit the tail pipe hanger 203 and cement the well in the later stage due to the inability to close the diversion hole 101; on the other hand, since the petal ball seat 4 can expand and enter the expansion groove 13 after moving downward under the action of pressure holding, the inner diameter of the round hole ball seat is enlarged to allow the pressure holding ball 7 to pass through the drill pipe diversion short section 100.

[0109] Secondly, the present invention provides the diversion hole 101 on the sleeve 10, which can not only realize the diversion effect on the internal fluid during the lowering of the tail pipe string 200, thereby reducing the exciting pressure when lowering the tail pipe; but also ensure that the drilling fluid can be positively circulated at any time, thereby effectively improving the lowering efficiency and safety of the tail pipe string 200.

[0110] The above are only preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art can easily make changes or modifications within the disclosure scope of the present invention, and such changes or modifications should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A drill pipe diverter nipple, comprising: A sleeve (10), wherein at least one through-flow hole (101) is provided on the sleeve (10), A throttling mechanism is concentrically arranged in the sleeve (10), comprising a valve seat (21) and a throttling valve (22) arranged on the valve seat (21). The regulating mechanism comprises a first connecting tube (31) arranged downstream of the valve seat (21) and forming an annulus (301) with the sleeve (10), a second connecting tube (32) arranged downstream of the first connecting tube (31), and a petal ball seat (4) arranged in the second connecting tube (32) and abutting against the sleeve (10), wherein in an initial state, the first connecting tube (31) is fixedly connected to the second connecting tube (32) by a pin (35), a reset mechanism disposed in the annulus (301), and A pressure-holding ball (7) is used to be put into the sleeve (10), The throttle valve (22) is configured to form throttling when upward return fluid passes through the wellbore to drive the regulating mechanism upward, thereby opening the diversion hole (101) for diversion; the reset mechanism is configured to force the regulating mechanism downward to close the diversion hole (101) when no upward return fluid passes through the wellbore; The petal ball seat (4) is configured to form a pressure-holding ball (7) when the diverter hole (101) is not completely closed, so as to force the second connecting tube (32) to move further downward, thereby completely closing the diverter hole (101).

2. The drill pipe flow diverter sub according to claim 1, characterized in that: The sleeve (10) comprises a first sleeve portion (11) and a second sleeve portion (12) arranged downstream of the first sleeve portion (11), wherein the diversion hole (101) is radially arranged on the second sleeve portion (12), and the annulus (301) is formed between the first connecting sleeve (31) and the second sleeve portion (12).

3. The drill pipe flow diverter sub according to claim 2, characterized in that: An expansion groove (13) is formed on the inner wall of the second sleeve portion (12) and extends radially outward and is used to receive the petal ball seat (4). The expansion groove (13) is located within the range of the second connecting tube (32) in the radial direction. Wherein, when the diverter hole (101) is not completely closed, the petal ball seat (4) is constructed to be able to expand and enter into the expansion groove (13) after descending under the pressure formed by the pressure-holding ball (7), thereby prompting the second connecting tube (32) to close the diverter hole (101) and allow the petal ball seat (4) to pass through.

4. The drill pipe flow diverter sub according to claim 3, characterized in that: A plurality of supports (33) and ball seat grooves (34) are alternately arranged along the circumference of the second connecting tube (32), and the petal ball seat (4) is radially arranged in the ball seat groove (34).

5. The drill pipe flow diverter sub according to claim 4, characterized in that: The split ball seat (4) comprises a main body portion (41) configured in a partially fan-shaped form, and a guide portion (42) extending radially inward and downwardly from the main body portion (41) into the second connecting tube (32), wherein a plurality of the guide portions (42) are enclosed in the second connecting tube (32) to form a round hole ball seat for receiving the pressure-holding ball (7).

6. The drill pipe flow diverter sub according to claim 5, characterized in that: The petal ball seat (4) further comprises a first engaging portion (43) and a second engaging portion (44) extending axially outward from both sides of the main body portion (41). A recessed portion (341) is formed on the outer wall surface of the ball seat groove (34) and extends radially inwardly and cooperates with the first engaging portion (43) and the second engaging portion (44) respectively.

7. The drill pipe flow diverter sub according to claim 6, characterized in that: A radially outwardly extending guiding inclined surface (131) is formed at the junction of the expansion groove (13) and the first engaging portion (43) to allow the petal ball seat (4) to move upward and exit the expansion groove (13) under the action of the throttle valve (22) or to move downward and enter the expansion groove (13) under the action of the ball pitching pressure.

8. The drill pipe flow diverter sub according to claim 7, characterized in that: The reset mechanism comprises a spring seat (51) and a spring (52) arranged at the lower end surface of the first connecting tube (31), wherein a first end of the spring (52) is axially abutted against the spring seat (51), and a second end is axially abutted against the second connecting tube (32).

9. The drill pipe flow diverter sub according to claim 8, characterized in that: A clamping groove (311) is formed on the outer wall of the first connecting tube (31) and extends radially inwardly and is used to accommodate an expandable clamping ring (312). The spring seat (51) comprises a seat body portion (511) configured in an annular shape, and a boss (512) extending axially upward from the seat body portion (511) and connected to the second sleeve portion (12), wherein a limiting cavity (513) for receiving the retaining ring (312) is formed between the seat body portion (511) and the first sleeve portion (11).

10. The drill pipe flow diverter sub according to claim 9, characterized in that: The drill pipe diversion nipple also includes a first joint (61) arranged at the upstream end of the first sleeve portion (11) and used to connect the upper pipe string, and a second joint (62) arranged at the downstream end of the second sleeve portion (12) and used to connect the tail pipe hanger (203), wherein a step (621) extending radially inward and downwardly inclined is formed at the upper end surface of the second joint (62).

11. A method for adjusting the opening and closing of a diversion hole by using a drill pipe diversion nipple according to any one of claims 1 to 10, comprising the following steps: S1. When the upward return fluid passes through the wellbore, throttling is formed through the throttle valve (22) to drive the regulating mechanism upward, thereby opening the diversion hole (101); S2. When there is no upward return fluid passing through the wellbore, the adjustment mechanism is urged downward by the reset mechanism to reclose the diversion hole (101).

12. The method according to claim 11, characterized in that Completely close the orifice including the following steps: When the diverter hole (101) is not completely closed, a pressure-holding ball (7) is inserted into the sleeve (10), and the petal ball seat (4) can expand and enter the expansion groove (13) after descending under the pressure formed by the pressure-holding ball (7), thereby prompting the second connecting tube (32) to close the diverter hole (101) and allow the petal ball seat (4) to pass through.

13. A tail pipe lowering pipe string, comprising: The tail pipe string (201) has a guide shoe (202) connected to its end. a liner hanger (203) disposed upstream of the liner string (201), and A drill pipe flow dividing nipple according to any one of claims 1 to 10 connected to the upper end of the liner hanger (203) via a lifting joint (204).

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