CN201037382Y - Petroleum thick wall sheath capable of reducing connected screw stress centralization - Google Patents
Petroleum thick wall sheath capable of reducing connected screw stress centralization Download PDFInfo
- Publication number
- CN201037382Y CN201037382Y CNU2007200792256U CN200720079225U CN201037382Y CN 201037382 Y CN201037382 Y CN 201037382Y CN U2007200792256 U CNU2007200792256 U CN U2007200792256U CN 200720079225 U CN200720079225 U CN 200720079225U CN 201037382 Y CN201037382 Y CN 201037382Y
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- Prior art keywords
- thick wall
- groove
- screw thread
- petroleum
- connection thread
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Abstract
A petroleum thick wall sleeve capable of reducing connection thread stress concentration is characterized in that a groove with elliptic-curve outline is arranged near a connection thread to reduce the rigidity and relatively increase the flexibility of the connection thread; therefore, the utility model obtains stress distribution improvement of the connection thread, reduction in stress concentration and lower probability of failure of the sleeve and ensures that the thick wall sleeve is convenient for people to go down at a crooked-hole section or a seriously dogleg well section. The utility model is particularly suitable for thick wall sleeve used in salt bed oil and gas well.
Description
Technical field
The utility model relates to the sleeve structure in oil, the natural gas well.
Background technology
In the oil and gas well drilling engineering, the sleeve pipe that adopts for common stratum generally is to choose suitable thin wall casing by API series.Thin wall casing is thinner owing to its wall, and rigidity is little, and flexibility is better relatively, thus fashionable under crooked hole section or the serious well section of dog-leg when sleeve pipe, can allow certain bending, can not damage the connection screw thread.But in the drilling process of salt rock stratum,, cause the well necking down, cause blockage during tripping, and cause that bigger non-homogeneous outer carrying acts on the sleeve outer wall that is lowered to, and causes the very fast inefficacy of sleeve pipe because rock stratum plasticity at high temperature flows.For this reason, people proposed to be lowered to the salt rock stratum with non-API heavy casing, with outer year of opposing salt rock stratum; But existing problems are, since the casing wall thickness increase, the rigidity increase, not yielding, be difficult for being lowered in crooked hole section or the serious well section of dog-leg, cause the stressed complexity of connection screw thread of sleeve pipe simultaneously, stress is concentrated, and causes dropout, fracture or seal failure.Therefore, how improving the force-bearing situation that sleeve pipe connects screw thread, make its unlikely premature failure, is a problem that presses for solution.
Summary of the invention
The purpose of this utility model is, proposes a kind of intensity that neither weakens casing wall, can reduce again to connect the heavy casing structure that screw thread stress is concentrated.
For achieving the above object, the utility model by the following technical solutions:
Heavy casing comprises the connection screw thread 3 at sleeve body 1 and two ends, it is characterized in that, is provided with a groove 2 on the sleeve body 1 at distance screw thread 3 terminal L places.
Because the effect that geometry, position, the degree of depth and the width of set groove 2 and reduction screw thread stress are concentrated is closely related, in order to obtain optimum efficiency, used the FEM mechanics analysis method to study under same formation situation, identical borehole condition, different geometries, different openings position and the opening degree of depth and width are to connecting the influence of screw thread stress level, thereby the outer contour that draws groove 2 is the best to adopt elliptic curve.Elliptic curve cuts mutually with the bus of sleeve body 1, and its scant length a is 0.5～1 meter, and the depth capacity t of the section of cutting is 2～4 millimeters mutually, and the distance L of the starting point of phase secant and screw thread 3 ends should be 0.3～0.5 meter.
The utility model has the advantages that:
1, owing to be provided with groove 2, the rigidity of sleeve pipe 1 reduces, and flexibility improves relatively, is lowered to easily in salt rock stratum crooked hole section or the serious well section of dog eye.
2, owing to the rigidity at groove area reduces relatively, flexibility increases relatively, thereby has improved the stress distribution that connects screw thread effectively, has reduced stress and has concentrated, and has improved the sealing performance of thread connection, and its failure probability is reduced greatly.
3,, can avoid groove area stress to occur and concentrate because the elliptic curve transition is mild; And by mechanical analysis as can be known, tube wall that this groove can not cause this district being set crosses thin and influences its intensity.4, under the existing machinery level of processing, the geometry of this groove can not cause the machining difficulty.
Description of drawings:
Fig. 1 is a structural representation of the present utility model.
Fig. 2 is the enlarged drawing of A among Fig. 1.
The specific embodiment
Heavy casing comprises the connection screw thread 3 at sleeve body 1 and two ends.On the sleeve body 1 at 0.3～0.5 meter of distance screw thread 3 ends, processed a groove 2, the outer contour of groove 2 is an elliptic curve, this elliptic curve cuts mutually with the bus of sleeve body 1, and its scant length a is 0.5～1 meter, and the depth capacity t of the section of cutting is 2～4 millimeters mutually.
Claims (2)
1. one kind can be reduced the oil heavy casing that connection screw thread stress is concentrated, the connection screw thread (3) that comprises sleeve body (1) and two ends, it is characterized in that, on the sleeve body (1) at the terminal L of distance screw thread (3) place, be provided with a groove (2), the outer contour of groove (2) is an elliptic curve, and this elliptic curve cuts mutually with the bus of sleeve body (1).
2. according to claim 1 can the reduction connects the heavy casing that screw thread stress is concentrated, it is characterized in that, the width a of groove (2) is 0.5～1 meter, and the degree of depth t of groove (2) is 2～4 millimeters, and groove (2) distance L terminal with connecting screw thread (3) is 0.3～0.5 meter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200792256U CN201037382Y (en) | 2007-04-18 | 2007-04-18 | Petroleum thick wall sheath capable of reducing connected screw stress centralization |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200792256U CN201037382Y (en) | 2007-04-18 | 2007-04-18 | Petroleum thick wall sheath capable of reducing connected screw stress centralization |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201037382Y true CN201037382Y (en) | 2008-03-19 |
Family
ID=39209898
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2007200792256U Expired - Fee Related CN201037382Y (en) | 2007-04-18 | 2007-04-18 | Petroleum thick wall sheath capable of reducing connected screw stress centralization |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201037382Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10260290B2 (en) | 2016-10-18 | 2019-04-16 | Single Buoy Moorings, Inc. | Connector for steel catenary risers |
-
2007
- 2007-04-18 CN CNU2007200792256U patent/CN201037382Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10260290B2 (en) | 2016-10-18 | 2019-04-16 | Single Buoy Moorings, Inc. | Connector for steel catenary risers |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20080319 Termination date: 20110418 |