WO2015089897A1

WO2015089897A1 - Airtight casing joint

Info

Publication number: WO2015089897A1
Application number: PCT/CN2014/000646
Authority: WO
Inventors: 罗蒙; 王琍; 张忠铧
Original assignee: 宝山钢铁股份有限公司
Priority date: 2013-12-18
Filing date: 2014-07-07
Publication date: 2015-06-25
Also published as: CN104453738A; EA031841B1; EA201691250A1

Abstract

An airtight casing joint (10) comprises a male casing end (1) and a female casing end (2). The male casing end is provided with an external thread (3) and the female casing end is provided with an internal thread (4). The external thread of the male casing end meshes with the internal thread of the female casing end. The tooth profiles of the external and the internal thread are both buttress. The rear of the external thread of the male casing end is provided with a first sealing surface (5) and a first stop shoulder (7) connecting with the first sealing surface along the feed direction of the external thread. The first stop shoulder is located at the far end of the male casing end. The female casing end has a second sealing surface (6) matching with the first sealing surface with an interference fit and a second stop shoulder (8) matching with the first stop shoulder. The second sealing surface also connects with the second stop shoulder. There is a clearance (11) between the internal thread and the external thread. The airtight casing joint has advantages of good resistance to tension, compression and torsion, better anti-galling performance and excellent airtight performance.

Description

Air sealing sleeve joint technical field

The invention relates to a petroleum casing joint, in particular to a partial trapezoidal casing joint. Background technique

At present, the existing casing joints can be roughly divided into two categories, one is a standard API series, which includes Long Thread Casing (LTC) or Short Thread Casing (STC) and a trapezoidal trapezoid. Threaded joints (Buttress Thread Casing, BTC), the other is a non-standard series of joints, the series are collectively referred to as special threaded joints.

Standard API series joints can be divided into two types: round threaded joints and partial trapezoidal threaded joints. Among them, round threaded joints include long round threaded joints and short round threaded joints. The advantage of the former is that the processing cost is low, the disadvantage is that slippage is easy, the tensile strength is not high, and the torsion resistance and compression resistance are insufficient, and the utility model is mainly applicable to oil and gas well operations with low connection strength requirements such as shallow wells and low pressure wells; The advantage is that the connection strength is high, and it can be applied to deep wells and deep well operations, and the disadvantages are poor resistance to torsion and compression. The common disadvantage of both is that they do not have a hermetic performance.

The announcement number is CN201391239Y, and the announcement date is January 27, 2010. The Chinese patent document entitled "A Torque Shoulder Surfacing Welding Alloy and Sealing Ring Sealing Coupling" discloses a seal with a seal ring. The connecting coupling comprises a steel coupling base body disposed on the pipe body, wherein the steel coupling base body is provided with a torque shoulder of a stack of corrosion resistant alloy layers, and a welding resistance is provided at the outer root of the torque shoulder An undercut of the etched alloy layer, and a sealing ring is placed in the undercut. The connecting coupling disclosed in the patent document has the advantages of simple structure and convenient operation, and the sealing effect is achieved by stacking the corrosion resistant alloy plus the sealing ring, and can be used for the corrosion protection integrity and sealing integrity connection of the composite oil pipe and the casing, but Cannot be interchanged with standard casing or fitting products.

The announcement number is CN2409331Y, and the announcement date is December 6, 2000. The Chinese patent document entitled "Oil, casing and trapezoidal threaded joint" relates to an oil-and-sleeve trapezoidal threaded joint suitable for oil field drilling. It consists of the pipe body and the pipe coupling through the taper thread of the trapezoidal pipe. The taper of the taper pipe thread of the pipe body and the pipe coupling is 1: T, and the pipe coupling is trapezoidal. Tube The tip taper of an effective length at the beginning of the taper thread is slightly increased to 1: (Τ-ζ:), and ζ is 4 to 9. The technical solution involved in the patent document achieves the limit action by changing the processing technology or the thread shape to reduce the risk of joint sticking, but it has certain processing difficulty.

The publication number is CN202125257U, and the publication date is December 22, 2004. The Chinese patent document entitled "High anti-torque, high-sealing, anti-adhesive oil-sleeve joint" discloses a high torque resistance and sealing property. Strong, anti-sticking effect oil casing joint. The oil casing joint is formed by a pipe body with an external thread at the end and a coupling with an internal thread. The pipe body is provided with a pipe body shoulder, a pipe body sealing surface and a pipe body right angle shoulder. The coupling is provided with a coupling shoulder, a coupling sealing surface and a right angle shoulder of the coupling. After the external internal thread connection, the sealing surface of the pipe body and the sealing surface of the coupling body, the shoulder of the pipe body and the shoulder of the coupling, and the right angle of the pipe body The shoulder and the right angle shoulder of the coupling respectively form a three-way sealing structure, and the external internal thread is a trapezoidal thread with an unequal height.

In the drilling process, for ordinary drilling, the general API standard threaded joint can complete the drilling task, but for the more severe working conditions, the three super gas wells (ie ultra-deep, ultra-high temperature, ultra-high corrosion gas wells) In terms of the mechanical properties of the API standard threaded joints, the working environment of the three super gas wells cannot be fully satisfied, especially the high pressure gas and harmful gas in the drilling process cannot be prevented. Therefore, in actual production, a joint having both tensile strength, compression resistance, torque resistance, and good gas sealing performance is required. Summary of the invention

The object of the present invention is to provide a gas-sealed casing joint which has good tensile strength, compression resistance and torque resistance, excellent gas sealing performance and good anti-sticking property, and can be adapted to the three super gas fields ( Work environment for ultra-deep, ultra-high temperature, ultra-high corrosion gas wells.

In order to achieve the above object, the present invention provides a hermetic sleeve joint comprising a sleeve male end and a sleeve female end, the sleeve male end having an external thread, the sleeve female end having an internal thread, and the sleeve male end The external thread is engaged with the internal thread of the female end of the sleeve, and the external thread and the internal thread have a trapezoidal shape; and - in the feeding direction of the external thread, a first seal is provided at the rear of the male thread on the male end of the sleeve a first stop shoulder that is coupled to the first sealing surface, the first retaining shoulder is located at an end of the male end of the sleeve; the female end of the sleeve has a second sealing surface that is in an interference fit with the first sealing surface And a second stop shoulder that matches the first stop shoulder, the second seal surface also engaging the second stop shoulder; There is a gap between the internal thread and the external thread. .

In the technical solution of the present invention, a first stop shoulder is provided at the end of the male end of the sleeve, and a second stop shoulder matched with the first stop shoulder is provided on the female end of the sleeve, thereby ensuring The airtight casing joint is resistant to torque and compression.

At the same time, the hermetic sleeve joint of the present invention is provided with a first sealing surface behind the male thread on the male end of the sleeve and a second sealing surface on the female end of the sleeve with an interference fit with the first sealing surface. This ensures the hermetic performance of the joint. On the basis of this, there is a certain gap between the internal thread and the external thread in the hermetic sleeve joint of the present invention, which makes the external thread of the male end of the sleeve and the internal thread of the female end of the sleeve not completely contact, which greatly reduces the The risk of sticking between the sleeve joints due to screwing.

It should be noted that in order to better improve the gas sealing performance of the joint, the thread grease can be filled between the gaps to achieve the function of the auxiliary gas seal.

Further, in the hermetic sleeve joint of the present invention, the external thread has a tooth height range of 1.0 2.5 mm.

Further, in the hermetic sleeve joint of the present invention, the gap between the internal thread and the external thread includes a first gap in the direction of the tooth height, and the tooth height of the external thread is lower than the tooth height of the internal thread .

Further, in the hermetic sleeve joint of the present invention, the first gap has a range of 0.1 0.8

Further, in the hermetic sleeve joint of the present invention, the gap between the internal thread and the external thread further includes a second gap in the tooth width direction.

Further, in the hermetic sleeve joint of the present invention, the second gap has a range of -0.04 0.08 mm

In the technical solution of the present invention, the second gap is a distance between the internal thread and the external thread in the tooth width direction, and a negative value indicates a distance between the internal and external threads in the tooth width direction, and a positive value indicates The distance between the internal and external threads in the tooth width direction. Within the above range of distances, the value of the second gap is preferably as small as possible to increase the tensile and compressive resistance of the hermetic sleeve joint.

Further, in the hermetic sleeve joint of the present invention, 1.0 tan a 10, where α is the bearing angle of the internal and external threads.

The bearing angle α is the main cause of the tensile and compression resistance of the hermetic sleeve joint of the present invention. Prime, when 1.0 taii a 10, is beneficial to the compensation of the hermetic casing joint processing.

Further, in the hermetic sleeve joint of the present invention, the first sealing surface and the second sealing surface are both inclined sealing surfaces, and the inclined sealing surface is inclined in the feeding direction along the external thread. Next, the inclination angle β of the first sealing surface is the same as the inclination angle β of the second sealing surface.

Furthermore, when 0.1 t _an P 1.8, it is advantageous to obtain a hermetic sleeve joint with higher topography accuracy.

Further, the length of the first sealing surface and the second sealing surface in the hermetic sleeve joint of the present invention in the thread feeding direction is 0.5 to 8.0 mm. The contact length of the sealing surface is one of the important parameters that affect the sealing effect of the joint.

Further, in the hermetic sleeve joint of the present invention, the first sealing surface and the second sealing surface have an interference fit with a depth in the tooth height direction of 0.1 to 1.8 mm. The contact depth of the sealing surface is also one of the important parameters that affect the gas sealing effect of the joint.

It should be noted that those skilled in the art can adjust the contact length and depth of the sealing surface according to the steel pipes of different specifications. When the contact length of the sealing surface is too long, the risk of bonding of the joint sealing contact point is increased; when the contact length of the sealing surface is too short, the risk of sealing failure due to transportation or misoperation is increased. Similarly, if the contact depth of the sealing surface is too large, the risk of bonding the joint of the joint seal will increase; if the contact depth of the sealing surface is too small, the risk of failure of the joint seal will increase. At the same time, excessive contact depth of the sealing surface may cause excessive interference, and the first sealing surface and the second sealing surface may be plastically deformed, thereby affecting the multiple air sealing effect.

Further, in the hermetic sleeve joint of the present invention, the first retaining shoulder and the second retaining shoulder are fed from the top to the bottom with respect to the radial direction of the hermetic sleeve joint away from the external thread. The direction is tilted.

Further, the angle Θ between the first stop shoulder and the second stop shoulder and the radial direction of the hermetic sleeve joint is in the range of 8 to 20°.

The hermetic sleeve joint of the invention is arranged through the sealing surface + the anti-retracting shoulder, so that the joint has good anti-compression and anti-torque capability, and excellent gas sealing performance to avoid the discharge of harmful or high-pressure gas. , can carry out drilling work in the three super gas fields (ultra-deep, ultra-high temperature, ultra-high corrosion gas wells). In addition, the hermetic sleeve joint of the present invention is provided with a gap between the inner and outer threads, which reduces the risk of the sleeve joint being stuck and improves the anti-adhesive performance of the joint. DRAWINGS

Figure 1 is a schematic view showing the structure of a hermetic sleeve joint according to an embodiment of the present invention. Figure 2 is a schematic view showing the structure of an external thread in a hermetic sleeve joint according to an embodiment of the present invention.

Fig. 3 is a structural schematic view of the external thread and the internal thread shown in Fig. 2 after assembly of the hermetic sleeve joint.

Figure 4 is a schematic view showing the structure of the first sealing surface and the second sealing surface in the hermetic sleeve joint of the present invention in an embodiment.

Figure 5 is a partial enlarged view of the first sealing surface and the second sealing surface shown in Figure 4 at A.

Fig. 6 is another partial enlarged view of the first sealing surface and the second sealing surface shown in Fig. 4.

Figure 7 is a schematic view showing the structure of the first retaining shoulder in the hermetic sleeve joint of the present invention in an embodiment. detailed description

The hermetic sleeve joint of the present invention will be further explained and explained in conjunction with the drawings and specific embodiments of the present invention. However, the explanation and description are not intended to unduly limit the technical solutions of the present invention.

Figure 1 shows the construction of a hermetic sleeve joint of the present invention in one embodiment. As shown in FIG. 1, the hermetic sleeve joint 10 in this embodiment comprises a sleeve male end 1 and a sleeve female end 2, and an external thread 3 is provided along the axial direction of the sleeve male end, along the sleeve. The axial direction of the female end is provided with an internal thread 4, and the external thread of the male end of the sleeve is in mesh with the internal thread of the female end of the sleeve, and the external thread 3 and the internal thread 4 are all trapezoidal; the thread along the external thread 3 In the direction P, the rear side of the male thread 3 on the male end of the sleeve is provided with a first sealing surface 5 and a first stop shoulder 7 engaging with the first sealing surface, the first stop shoulder 7 is located at the male end of the sleeve 1 End of the sleeve; the sleeve female end 2 has a second sealing surface 6 and a second retaining shoulder 8, the second sealing surface 6 is interference fit with the first sealing surface 5, and the second retaining shoulder 8 is the first stop The retractable shoulders 7 are matched, and the second sealing surface 6 is also engaged with the second anti-retracting shoulder 8; wherein the inner and outer threads are not completely in contact, and a gap 11 is provided between the inner and outer threads.

Figure 2 shows the structure of the external thread in the hermetic sleeve joint of the present invention in one embodiment, and Figure 3 shows the external thread and the internal thread shown in Figure 2 in the hermetic sleeve joint assembly. After the structure. As shown in FIGS. 2 and 3, the gap between the internal thread and the external thread includes a first gap 12 in the tooth height direction and a second gap 13 in the tooth width direction, the external thread having a lower tooth height than the internal thread The tooth height is such that the tooth top of the external thread and the tooth bottom of the internal thread cannot be in full contact, wherein the tooth height h of the external thread ranges from 1.0 to 2.5 mm, and the range of the first gap 12, g卩Hh The range of 0.1 to 0.8 mm, the second gap 13, and §M is -0.04 to 0.08 mm.

It should be noted that, as shown in FIG. 3, in order to better improve the gas sealing performance of the joint, a thread grease 9 may be filled between the first gap and the second gap to further improve the gas sealing performance of the joint.

Continuing to refer to Figure 2, the angle α is the bearing angle of the internal thread and the external thread. The size of tan a can be determined by the ratio of X/Z. The X represents the feed value of the external thread 3 along the tooth height direction, and Z represents the outside. The feed value of the thread 3 along the pitch direction.

Figure 4 shows the structure of the first sealing surface and the second sealing surface in the hermetic sleeve joint of the present invention in one embodiment, and Figures 5 and 6 are the first seal shown in Figure 4, respectively. A partial enlarged view of the face and the second sealing face.

As shown in Figures 4 and 6, the first sealing surface 5 of the sleeve male end 1 and the second sealing surface 6 of the sleeve female end 2 are each provided with an inclined sealing surface, the inclined direction of the inclined sealing surface being along The feed direction P of the external thread is disposed obliquely downward, and the inclination angle of the first sealing surface 5 is the same as the inclination angle of the second sealing surface 6, wherein the inclination angle β satisfies: 0.1 tan e 1.8.

As shown in FIG. 5, the length L1 of the first sealing surface 5 and the second sealing surface 6 in the thread feeding direction ranges from 0.5 to 8.0 mm, and the first sealing surface 5 and the second sealing surface 6 are interspersed. The depth HI of the mating direction in the tooth height direction ranges from 0.1 to 1.8 mm.

Figure 7 shows the construction of a first stop shoulder in a hermetic sleeve joint of the present invention in one embodiment.

As shown in Fig. 7, if necessary, referring to Fig. 1, the first retaining shoulder 7 and the second retaining shoulder are oriented from the top to the bottom in the radial direction of the hermetic sleeve joint away from the external thread feeding direction. The P is inclined, and the angle Θ between the first stop shoulder 7 and the second stop shoulder and the radial direction of the hermetic sleeve joint ranges from 8 to 20°.

Table 1 shows the relevant design parameters of the hermetic casing joints of the present technical solution corresponding to different specifications of the casing, wherein the definitions of the parameters are as follows:

Dl is the inner bore diameter (mm) of the male end of the sleeve;

D2 is the inner bore diameter (mm) of the female end of the sleeve; D3 casing coupling dangerous section inner diameter (mm):

d is the outer diameter (mm) of the casing coupling;

Z is the efficiency coefficient, Z=(d ² -d3 ² ) /[D ² -(D-2t) ² ], Z is in the range of (0.8, 1.3 ); H is the internal thread height of the female end of the sleeve ( Mm);

h is the external thread height (mm) of the male end of the sleeve, the spacing of the first gap is H-h (mm); M is the spacing of the second gap (mm);

HI is the depth (mm) in the tooth height direction of the interference fit of the first sealing surface and the second sealing surface; L1 is the length (mm) of the first sealing surface and the second sealing surface in the thread feeding direction;

Tan a , where a is the bearing angle of the internal thread and the external thread;

Ααη β , where β is the inclination angle of the first sealing surface and the second sealing surface;

Θ is the angle between the first stop shoulder and the second stop shoulder and the radial direction of the hermetic sleeve joint

Table 1

Table 2 shows the relevant mechanical performance parameters of the hermetic casing joint described in the technical solution, Table 2.

It can be seen from Table 2 that the hermetic sleeve joint of the present invention has good tensile strength, compression resistance and torque resistance, and has excellent gas sealing performance and good anti-sticking performance.

In addition, the hermetic sleeve joint of the present invention passes the ISO 13679 CAL IV international certification standard which is the most stringent for the oil well pipe joint. Under the condition of composite loading, the structural and performance integrity can satisfy the three super gas fields ( Drilling development of ultra-deep, ultra-high temperature, ultra-high corrosion gas wells. The hermetic sleeve joint of the present invention has an outer diameter of between Φ 127 and 339.7 mm. It is to be noted that the above is only specific embodiments of the present invention, and it is obvious that the present invention is not limited to the above embodiments, and there are many similar variations. Any modifications directly derived or associated by those skilled in the art from the disclosure of the present invention should fall within the scope of the present invention.

Claims

Claim

A hermetic sleeve joint comprising a sleeve male end and a sleeve female end, the sleeve male end having an external thread, the sleeve female end having an internal thread, the male thread of the sleeve male end and the sleeve female The internal thread of the end is engaged, and the external and internal threads are all trapezoidal; the feature is:

In a feeding direction of the external thread, a rear side of the male thread on the male end of the sleeve is provided with a first sealing surface and a first stopping shoulder engaged with the first sealing surface, wherein the first stopping shoulder is located in the sleeve The end of the male end of the tube;

The sleeve female end has a second sealing surface that is in an interference fit with the first sealing surface, and a second retaining shoulder that mates with the first retaining shoulder, the second sealing surface is also The second stop shoulder is connected;

There is a gap between the internal thread and the external thread.

2. The hermetic sleeve joint of claim 1 wherein the gap between the internal thread and the external thread comprises a first gap in the direction of the tooth height, the tooth height of the external thread being lower than The tooth height of the thread.

3. The hermetic sleeve joint of claim 2 wherein said first gap has a range of 0.

4. The hermetic sleeve joint of claim 2 wherein the gap between the internal thread and the external thread further comprises a second gap in the direction of the tooth width.

5. The hermetic sleeve joint of claim 4 wherein said second gap ranges from -0.04 to 0.08 mm.

6. The hermetic sleeve joint of claim 1 wherein said external thread has a tooth height in the range of 1.0 to 2.5 mm.

7. The hermetic sleeve joint of claim 1 wherein 1.0 t _a ti ci li), wherein a is a bearing angle of said internal and external threads.

8. The hermetic sleeve joint according to claim 1, wherein the first sealing surface and the second sealing surface are both inclined sealing surfaces, and the inclined sealing surface is inclined along the outer direction. The feeding direction of the thread is inclined downward, and the inclination angle of the first sealing surface is the same as the inclination angle of the second sealing surface.

9. The hermetic sleeve joint of claim 8, wherein: oi t _an e i.8, wherein β is the inclined food of the first sealing surface and the second sealing surface. The hermetic sleeve joint according to claim 1, wherein the first sealing surface and the second sealing surface have a length in the thread feeding direction of 0.5 to 8.0 mm.

A hermetic seal joint according to claim 1 wherein the first sealing surface and the second sealing surface have an interference fit in the tooth height direction of 0.1 to 1.8 mm.

A hermetic sleeve joint according to claim 1 wherein said first and second retaining shoulders are facing away from the radial direction of the hermetic sleeve joint from top to bottom The direction of thread feed is inclined.

A hermetic sleeve joint according to claim 12, wherein a range of angles Θ between said first and second retaining shoulders and a radial direction of the hermetic sleeve joint For 8~20°.

The hermetic sleeve joint of claim 1 wherein said gap is filled with a thread.