AU2021101349A4 - An expandable casing connection with improved liquid pressure seal performance - Google Patents
An expandable casing connection with improved liquid pressure seal performance Download PDFInfo
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- AU2021101349A4 AU2021101349A4 AU2021101349A AU2021101349A AU2021101349A4 AU 2021101349 A4 AU2021101349 A4 AU 2021101349A4 AU 2021101349 A AU2021101349 A AU 2021101349A AU 2021101349 A AU2021101349 A AU 2021101349A AU 2021101349 A4 AU2021101349 A4 AU 2021101349A4
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- AU
- Australia
- Prior art keywords
- thread
- seal
- pin
- inverted hook
- improved
- Prior art date
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- 239000007788 liquid Substances 0.000 title claims abstract description 14
- 238000007789 sealing Methods 0.000 claims abstract description 20
- 239000002184 metal Substances 0.000 claims description 17
- 239000000565 sealant Substances 0.000 claims description 6
- 238000012545 processing Methods 0.000 abstract description 6
- 230000006872 improvement Effects 0.000 description 10
- 238000005516 engineering process Methods 0.000 description 8
- 238000000034 method Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 238000010276 construction Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000005553 drilling Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000000641 cold extrusion Methods 0.000 description 1
- 230000009918 complex formation Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/02—Couplings; joints
- E21B17/08—Casing joints
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Non-Disconnectible Joints And Screw-Threaded Joints (AREA)
- Gasket Seals (AREA)
Abstract
The invention discloses an expandable casing connection with
improved liquid pressure seal performance, which includes a pin and a box.
The pin is arranged from the end to the inside in turn with the first negative
angle torque shoulder, the first improved API round thread and the first
inverted hook thread. And the box has the second negative angle torque
shoulder, the second improved API round thread and the second inverted
hook thread at the corresponding position with the pin. There is a seal
structure between the first improved API round thread and the first
inverted hook thread. The combination of the inverted hook thread with
strong connection and the improved API round thread with good sealing is
adopted to provide a suitable connection for the expandable casing, which
has high strength, good seal performance and easy processing.
A6
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2 16 7 17
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Fig. 2
Fig. 3
Description
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2 16 7 17
Fig. 1
Fig. 2
Fig. 3
FIELD OF THE INVENTION The invention belongs to the field of oil and gas exploration and development, and in particular relates to an expandable casing connection with improved liquid pressure seal performance.
BACKGROUND OF THE INVENTION In the process of oil and gas exploration and development, there are a large number of deep wells, ultra-deep wells and special wells with complex formations, and the level of casing running increases with the increase of well depth, resulting in the continuous reduction of borehole diameter and insufficient space for follow-up operations . And ultimately unable to achieve the expected target level economically. In order to overcome this problem, expandable casing technology appeared. Expandable casing technology is a technology that uses an expansion cone to expand its diameter to meet the engineering requirements by cold-extrusion downhole, with the ultimate goal of achieving a single well diameter. This technology can increase the depth of the drilling, effectively reduce the loss of the well diameter, and can shorten the well construction time and reduce the drilling cost. One of the core and difficult points of expandable casing technology is the connection, which requires that the pipe threaded connection still has a certain connection strength and liquid pressure seal ability after being expanded and deformed with the casing body. Ordinary standard pipe threads and current premium thread connections cannot meet this requirement.
The currently known expandable casing connections mainly rely on rubber rings to achieve sealing. The schematic diagram of the structure is shown in Figure 1. The connection is composed of a pin and a box with inverted hook threads, and the pin is also provided with a seal groove and a torque shoulder. The connection performance of this connection is realized by inverted hook threads, the seal performance is mainly realized by the sealing rubber ring, and the control of lifting buckle torque is realized by the torque shoulder. In the expansion process, this kind of expandable casing connection with elastic sealing ring has the following disadvantages: (1) The rubber ring is easily squeezed out of the seal groove by the end of the pin during the buckling process; (2) The diameter of the casing becomes larger after expansion, causing the rubber ring to break easily. These factors make the reliability of the elastic rubber ring seal method low, and the seal performance of the expandable casing connection cannot be ensured during the site construction process. With these sealing problems, the expected liquid pressure in the expandable casing string cannot be reached, which can easily lead to the casing expansion failed.
Therefore, it is necessary to develop an expandable casing connection with good seal performance, high connection strength and easy processing.
In order to solve the problem of poor seal performance in the existing technology, this invention provides an expandable casing connection with improved liquid pressure seal performance. The combination of the inverted hook thread with strong connection and the improved API round thread with good sealability is adopted to provide a suitable connection for the expandable casing , which has high strength, good seal performance and easy processing.
To achieve the above purposes, the invention adopts the following technical schemes :
An expandable casing connection with improved liquid pressure seal performance is composed of a pin and a box.
The pin is arranged in turn from the end to the inside with the first negative angle torque shoulder, the first improved API round thread and the first inverted hook thread, matching with the second negative angle torque shoulder, the second API round thread and the second inverted hook thread of the box. The elastic seal structure is provided between the first improved API round thread and the first inverted hook thread. There is interference fit between the first improved API round thread and the second API round thread.
As a further improvement of the invention, the wall thickness of the pin is greater than that of the box. As a further improvement of this invention, the round thread structure comprises a tooth tip, tooth bottom and tooth flanks connected sequentially. The first tooth tip of the pin and the second tooth bottom of the box form the interference fit of metal-to-metal seal structure, and produce close contact on the tooth flanks.
As a further improvement of the invention, the elastic seal structure includes a seal groove, a seal surface and a seal body. The seal groove is filled with the seal body and squeezed outward, and then the seal body squeezes the seal surface to form a seal.
As a further improvement of the invention, the seal groove is set on the pin, and the seal surface is set on the box.
As a further improvement of the invention, the seal body can be an elastic sealing ring, soft metal or thread sealant.
As a further improvement of the invention, the inverted hook thread is a single hook thread with negative angle, including an inverted hook thread hook surface, an inverted hook thread hook tip and an inverted hook thread guide surface connected in sequence.
As a further improvement of the invention, the bearing surface angle of the inverted hook thread is - 150 - 20, the thread taper is 1: ( 20 ),the hook tip of the inverted hook thread is an arc surface, and the guide surface angle of the inverted hook thread is 10° ~25°.
The optimized bearing surface angle of the inverted hook thread is 18, and the optimized guide surface angle of the inverted hook thread is 200.
As a further improvement of the invention, the first negative angle torque shoulder of the pin is in interference contact with the second negative angle torque shoulder of the box ; The angle of the first negative angle torque shoulder is - 200 ~ - 25°.
Compared with existing technologies, the invention has the following advantages:
The connection of this invention has a triple seal structure in total, in which the improved API round thread is the main metal seal, the negative angle torque shoulder is the auxiliary metal seal, and the seal in the seal groove is the elastic seal. The combination of the inverted hook thread with strong connection and the improved API round thread with good seal performance is used to provide a suitable connection for expanding casing. The expandable casing connection has high strength, good seal performance and easy processing. The improved API round thread in the joint is an improvement based on the API standard round thread, which retains the advantages of mature API standard round thread technology, simple processing and measurement, high processing efficiency, low cost and convenient maintenance. At the same time, it avoids the defect that the diameter of API thread connection coupling becomes larger.
Further, the improved API round thread is improved in the geometric structure of the API standard round thread. There is a gap between the first tooth tip and the second tooth bottom after the API standard round thread is buckled, which becomes the leakage channel of the fluid.
Further, this improved API round thread filled the leakage channel of API standard round thread. After expanding, the tooth tip and tooth bottom of the improved API round thread form a metal-to-metal seal structure, which has the advantages of metal-to-metal seal structure and improves the seal performance of the connection.
Further, the negative angle hook-shaped pin and box threads of the connection are tightly engaged, which can eliminate stress concentration, and have strong connection strength and high anti-slip ability.
Further, the negative angle torque shoulder in the connection can not only enhance the anti-torsion ability of the connection, but also play an auxiliary sealing role. In the process of expansion, the inner wall is not uneven due to the springback deformation of the end of the pin, maintaining the structure reliable.
FIG. 1 is a schematic diagram of a common expandable casing connection structure.
FIG. 2 is a schematic diagram of unilateral transverse section suitable for expandable casing connection structure.
FIG. 3 is a schematic diagram of the transverse section of the pin suitable for the connection structure of the expandable casing.
FIG. 4 is a local enlarged section of A in Figure 3 of the invention.
FIG. 5 is the B local zoom section in Figure 4 of the invention.
FIG. 6 is the C local zoom section in Figure 4 of the invention.
FIG. 7 is API standard round thread diagram.
List of reference numerals:
1. Pin, 2. Box, 3. Seal structure, 4. Inverted hook thread, 5. improved API round thread, 6. Negative angle torque shoulder, 7. Seal groove, 8. Seal surface , 9. Seal body, 10. Inverted hook thread hook surface, 11. inverted hook thread hook tip, 12. Inverted hook thread guide surface, 13. API round thread tooth tip, 14. API round thread tooth bottom, 15 . API round thread tooth flanks, 16. Seal ring, 17. Torque shoulder.
The above technical characteristics are explained by the pin as the main body. In order to distinguish the specific description, 'first' represents the characteristics of the pin, and 'second' represents the characteristics of the box.
In order to make the technical scheme in the invention better understood by the personnel in the technical field, the technical scheme in the embodiment of the invention will be clearly and completely described below in combination with the appendix to the embodiment of the invention, and it is obvious that the embodiment described is only part of the embodiment of the invention, not all of the embodiment. Based on the embodiment of the invention, all other embodiments obtained by ordinary technicians in this field without creative labor shall fall within the scope of the protection of the invention.
As shown in Fig. 2 and Fig. 3, the invention relates to an expandable casing connection with improved liquid pressure seal performance, which is suitable for the expandable casing and adopts a straight connected thread structure consisting of a pin 1 and a box 2. The wall thickness of the pin 1 is slightly larger than that of the box 2. The pin 1 is arranged from the end to the inside with negative angle torque shoulder 6, improved API round thread 5, seal groove 7 and inverted hook thread 4. The box 2 has negative angle torque shoulder, improved API round thread, seal surface 8 and inverted hook thread at the corresponding position with the pin. The joint has a triple seal structure, in which the improved API round thread is the main metal seal, the negative angle torque shoulder is the auxiliary metal seal, and the seal in the seal groove is the elastic seal.
The wall thickness of the pin 1 is slightly larger than that of the female thread 2.
As an optimized implementation example, the inverted hook thread of the connection is a single hook thread with a negative angle. The bearing surface angle is - 15° ~ - 200, the thread taper is 1 : 20 ~ 1 : 25, the hook tip of the inverted hook thread is an arc surface, and the deviation angle of the thread guide surface is 100 ~25°. The pin and box hook threads with negative angle are tightly engaged, which can eliminate stress concentration and mainly play a connecting role.
As an optimization example, the improved API round thread is improved in the geometric structure. The API standard round thread has a gap between the tooth tip and the tooth bottom after the upper buckle, which becomes the leakage channel of the fluid and cannot be effectively sealed.
(1) The improved API round thread increases the tooth height of the pin and box thread, and the increase range is about 0.076 mm ~ 0.13 mm. After the tooth height increases, the interference contact between the tooth tip and the tooth bottom of the pin and box thread is made, which fills the gap between the tooth tip and the tooth bottom of the improved API round thread and eliminates the leakage channel of the API standard round thread.
(2) According to the improved API round thread structure of the invention, during expanding, the male thread squeezes the female thread from the inside to the outside. At the same time, because the wall thickness of the box is smaller than that of the pin, and the axial shrinkage of the female thread is larger than that of the male thread, the thread surface of the pin and box thread is more closely contacted, and the contact stress is further increased, thus further sealing effect is achieved.
There are three solutions for the seal body between the seal groove of the pin and the metal seal surface of the box: elastic sealing ring, soft metal or thread sealant.
The elastic sealing ring / soft metal is fixed in the seal groove of the pin, and the rectangular section is adopted. The height is flat with the top of the thread teeth on both sides, which does not affect the installation. During expansion, the pin is extruded first, and the elastic sealing ring / soft metal is extruded outward, so that it continues to squeeze the seal surface of the box outward, which plays the role of auxiliary sealing. The thread sealant is filled in the gap between the two different tooth threads of the connection. During expansion, the pin is extruded first, and the thread sealant is extruded outward to fill the gap of the third sealing part, which plays an auxiliary sealing role.
During expansion, the negative angle torque shoulder at the end of the pin interferes with the negative angle torque shoulder at the inner end of the box, forming a metal seal, which plays an auxiliary sealing role, and its angle is - 20° ~- 25°.
Taking a connection suitable for expandable casing as an example, the invention is further explained in detail.
Referring to Fig.2, the connection structure suitable for expandable casing is composed of a pin 1 and a box 2.
Referring to Fig. 3, the pin 1 is arranged in turn from the end to the inside with the first negative angle torque shoulder 6, the first improved API round thread 5, the seal groove 7 and the first inverted hook thread 4.
Referring to Fig. 2, the negative angle torque shoulder 6 of the pin 1 and the negative angle torque shoulder 6' of the inner end of the box 2 are matched, and the interference contact is caused during expansion, which plays the first auxiliary sealing role.
Referring to Fig. 2 and Fig. 6, the improved API round thread 5 of the pin 1 is matched with the improved API round thread 5' of the box 2. During expansion, the tooth tip 13 and tooth bottom 14 of the male and box form a metal-to-metal interference fit of the seal structure, and produce close contact on the tooth flanks15. The entire section of the improved API round thread 5 and 5' serves as the second sealing function and is also the primary seal.
Referring to Fig. 4, the seal structure 3 is composed of the seal groove 7, the seal surface 8 and the seal body 9. There are three options for the seal body 9: elastic sealing ring, soft metal or thread sealant. During expanding, the seal groove 7 extrudes the seal body 9 outward, and the seal body 9 extrudes the seal surface 8 to form a seal and play a third sealing function.
Referring to Fig. 5, the deflection angle of the inverted hook thread hook surface 10 of the inverted hook thread 4 is -18, the inverted hook thread hook tip 11 adopts an arc surface, and the deflection angle of the inverted hook thread guide surface 12 is 20°.
Referring to Fig. 6, Fig. 7 and Fig. 1, the tooth angle of improved API round thread 5 is 60 0, which is the same as that of API standard round thread. The improved API round thread fills the leakage channel of API standard round thread.
The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the range described in this specification. The above embodiments only express several embodiments of the invention, which are more specific and detailed, but cannot be understood as restrictions on the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, some deformations and improvements can be made without breaking away from the concept of the invention, which are all within the scope of the protection of the invention. Therefore, the scope of protection of the invention patent shall be subject to the attached claims. It should be understood that the above description is for illustration rather than restriction. By reading the above description, many implementations and applications beyond the embodiments provided will be obvious to technicians in this field. The scope of this instruction should therefore not be determined in the light of the above description, but rather in the light of the foregoing claims and the full scope of the equivalents they possess. For comprehensive purposes, all articles and references, including disclosure of patent applications and announcements, are incorporated in this article through reference. The omission of any aspect of the subject matter disclosed here in the aforementioned claim is not intended to give up the subject matter, nor should it be considered that the applicant did not consider the subject matter as part of the subject matter of the invention disclosed.
EDITORIAL NOTE 2021101349
There are 2 pages of claims only.
Claims (5)
1. An expandable casing connection with improved liquid pressure seal performance, characterized in that it comprises a pin and a box. The first negative angle torque shoulder, the first improved API round thread, and the first inverted hook thread are arranged in sequence from the end to the inside of the pin. The box is arranged from the inside to the end with the second negative angle torque shoulder, the second improved API round thread and the second inverted hook thread matching the pin. The elastic seal structure is provided between the first improved API round thread and the first inverted hook thread. There is interference fit between the first improved API round thread and the second improved API round thread.
2. The expandable casing connection with improved liquid pressure seal performance according to claim 1, the wall thickness of the pin is greater than the wall thickness of the box. The first negative angle torque shoulder of the pin is interference fit with the second negative angle torque shoulder of the box. The angle of the first negative angle torque shoulder is -20°~ -25°.
3. The expandable casing connection with improved liquid pressure seal performance according to claim 1, wherein the improved API round thread structure comprises a tooth tip, a tooth bottom and tooth flanks. The first tooth tip of the pin and the second tooth bottom of the box form the interference fit of metal-to-metal seal structure, and produce close contact on the tooth flanks.
4. The expandable casing connection with improved liquid pressure seal performance according to claim 1, the elastic seal structure comprises a seal groove, a seal surface and a seal body. The seal groove is filled with the seal body and squeezed outward, and the seal body squeezes the seal surface to form a seal. The seal groove is arranged on the pin, and the seal surface is arranged on the box. The seal body can be an elastic sealing ring, soft metal or thread sealant.
5. The expandable casing connection with improved liquid pressure seal performance according to claim 1, wherein the inverted hook thread is a single hook thread with negative angle, including an inverted hook thread hook surface, an inverted hook thread hook tip and an inverted hook thread guide surface connected in sequence. The bearing surface angle of the inverted hook thread is - 150 ~- 200, the thread taper is 1 : ( 20 ~ 25 ), the hook tip of the inverted hook thread is an arc surface, and the guide surface angle of the inverted hook thread is 100 ~25°. The bearing surface angle of the inverted hook thread is - 180, and the guide surface angle of the inverted hook thread is 200.
1 /2 16 Mar 2021 2021101349
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2 /2 16 Mar 2021 2021101349
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Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010345215.2 | 2020-04-27 | ||
| CN202010345215.2A CN111379528A (en) | 2020-04-27 | 2020-04-27 | Expansion sleeve joint for improving liquid sealing performance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2021101349A4 true AU2021101349A4 (en) | 2021-05-13 |
Family
ID=71222093
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2021101349A Ceased AU2021101349A4 (en) | 2020-04-27 | 2021-03-16 | An expandable casing connection with improved liquid pressure seal performance |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN111379528A (en) |
| AU (1) | AU2021101349A4 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117722141B (en) * | 2024-02-07 | 2024-04-26 | 大庆市瑞斯德石油机械制造有限公司 | Airtight casing nipple with special threads |
-
2020
- 2020-04-27 CN CN202010345215.2A patent/CN111379528A/en active Pending
-
2021
- 2021-03-16 AU AU2021101349A patent/AU2021101349A4/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| CN111379528A (en) | 2020-07-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FGI | Letters patent sealed or granted (innovation patent) | ||
| MK22 | Patent ceased section 143a(d), or expired - non payment of renewal fee or expiry |