CN114151026A

CN114151026A - Titanium alloy drill rod

Info

Publication number: CN114151026A
Application number: CN202111579196.0A
Authority: CN
Inventors: 鲁喜宁; 谢孝文; 欧阳志英; 舒志强
Original assignee: Shanghai Hilong Dirll Pipes Co ltd; SHANGHAI HILONG PETROLEUM TUBULAR GOODS RESEARCH INSTITUTE
Current assignee: Shanghai Hilong Dirll Pipes Co ltd; SHANGHAI HILONG PETROLEUM TUBULAR GOODS RESEARCH INSTITUTE
Priority date: 2021-12-22
Filing date: 2021-12-22
Publication date: 2022-03-08

Abstract

The invention discloses a titanium alloy drill rod which comprises a titanium alloy drill rod pipe body, and an internal thread joint and an external thread joint at two ends of the titanium alloy drill rod pipe body. The inner thread joints and the outer thread joints at two ends of the titanium alloy drill pipe body are special buckle threads, and the inner thread joints and the outer thread joints of the special buckle are tapered thick-tooth wedge-shaped dovetail threads; the invention provides a high fatigue life connection which is simple in screwing operation, excellent in anti-thread gluing performance, low in repair rate, and free of the influence of composite load on connection safety and sealing performance. The problems that the existing titanium alloy drill rod connecting thread is poor in tensile, compressive and bending resistance, is easy to glue and buckle particularly at high dog-leg degrees, and is high in repair rate, poor in fatigue resistance and the like are solved.

Description

Titanium alloy drill rod

Technical Field

The invention relates to the technical field of oil drill pipe joints for threaded connection of oil well pipes, in particular to a titanium alloy drill pipe.

Background

One petroleum drill pipe is connected by a joint to form a drill string of several kilometers in length. The working condition of the drill string is quite severe, the stress condition is quite complex, and the joint is the weakest link. Existing titanium alloy drill pipe is designed and delivered with reference to API 5DP and Spec 7-2.

In the conventional tool joint shown in fig. 1, the internal thread 7 is composed of an external shoulder surface 70 and an internal thread portion 71, and the external thread 8 is composed of an external shoulder surface 80 and an external thread portion 81.

As shown in the attached drawing 2, the conventional drill rod joint thread has an internal thread portion 71 composed of a thread guide surface RS, a bearing surface RL, a crest RT, a circular arc root RR and a profile angle RA, and an external thread portion 81 composed of a thread guide surface RS, a bearing surface RL, a crest RT, a circular arc root RR and a profile angle RA. The drill rod joint with the structure is screwed according to the recommended upper buckling torque, interference is generated between the main shoulder surfaces, and the sealing effect is achieved. After the threads are meshed, only the tooth sides are contacted with each other, an annular gap is reserved between the tooth top and the tooth bottom, and the thread teeth are easy to generate small displacement under the load action.

Compared with the conventional steel drill rod, the titanium alloy drill rod has the advantages of high flexibility, light weight, fatigue resistance and corrosion resistance, and is often applied to special process oil and gas wells with large dogleg degrees, such as deep wells, ultra-deep wells, high corrosion wells, ultra-short radius sidetrack wells and the like. For example, the dogleg degree is 45-55 degrees/30 meters, and after the standard titanium alloy drill rod joint continuously rotates for five ten thousand times, a large number of thread sticking buckles appear, the thread sticking resistance performance is poor, and the repair rate is high. In addition, due to the existence of the main shoulder, the external thread connection section after thread engagement generates pretension load, which is usually 60% of the material yield strength, and in addition, the local stress of the thread root of the first three threads engaged by the big end of the male thread can even exceed the material yield strength, so that the alternating mean stress level of the dangerous section is higher, and the fatigue performance of the drill rod joint is low.

Disclosure of Invention

The invention aims to provide a titanium alloy drill rod connection mode, which mainly solves the technical problems of poor thread gluing resistance, high repair rate, low joint fatigue performance and the like of a drill rod joint when bearing a large composite load.

In order to achieve the purpose, the invention adopts the technical scheme that: a titanium alloy drill rod comprises a drill alloy drill rod pipe body, and an internal thread joint and an external thread joint which are arranged at two ends of the titanium alloy drill rod pipe body, wherein the internal thread joint is composed of a welding diameter area, an elevator area, a tong area and an internal thread area, and the internal thread area comprises an internal thread outer end face, a tapered internal thread section and an internal thread inner end face; the external thread joint consists of a welding diameter area, an elevator area, a tong area and an external thread area, wherein the external thread area comprises an external thread outer end face, an external thread section with taper and an external thread inner end face; the internal thread region is processed with tapered thick tooth wedge forked tail internal thread, the external screw thread region is processed with tapered thick tooth wedge forked tail external screw thread.

Further, the outer end face of the internal thread region of the internal thread joint is a right angle, the inner end face is a negative angle, the angle is 5-10 degrees, the outer end face of the external thread region of the external thread joint is a right angle, the inner end face is a negative angle, the angle is 5-10 degrees, the inner end face and the inner end face are in a mutual matching relationship, and when the inner end face and the inner end face are matched with each other, the negative angles are equal.

Furthermore, the tapered thick-tooth wedge-shaped dovetail internal thread comprises an internal thread guide surface, a bearing surface, a guide surface flank angle, a bearing surface flank angle, a tooth top, a tooth bottom, a tooth top contour line, a tooth bottom contour line, a guide surface height, a bearing surface height, a guide surface thread pitch and a bearing surface thread pitch.

Further, the tapered thick-tooth wedge-shaped dovetail external thread comprises an external thread guide surface, a bearing surface, a guide surface flank angle, a bearing surface flank angle, a tooth top, a tooth bottom, a tooth top contour line, a tooth bottom contour line, a guide surface height, a bearing surface height, a guide surface thread pitch and a bearing surface thread pitch.

Further, the taper range of the internal thread of the tapered thick-tooth wedge-shaped dovetail is 1: 8-1: 36, the taper range of the external thread of the tapered coarse thread wedge dovetail is 1: 8-1: 36, the tapered internal thread of the coarse-tooth wedge-shaped dovetail and the tapered internal thread of the coarse-tooth wedge-shaped dovetail are in an internal and external thread relationship with each other, and the taper is generally the same when the internal thread and the external thread are mutually matched and connected.

Furthermore, the angle of the flank angle of the tapered coarse-tooth wedge-shaped dovetail internal thread guide surface is-10 degrees to 5 degrees, and the angle of the flank angle of the bearing surface is-3 degrees to-10 degrees; the angle of the flank angle of the guide surface of the tapered coarse thread wedge dovetail external thread is-10 degrees to 5 degrees, and the angle of the flank angle of the bearing surface is-3 degrees to-10 degrees.

Furthermore, the included angle between the tooth top of the internal thread of the tapered coarse-tooth wedge dovetail and the axis of the thread is 0-3.58 degrees, the included angle between the tooth bottom and the axis of the thread is 0-3.58 degrees, and the tooth top is parallel to the tooth bottom; the included angle between the tooth top contour line and the thread axis is 0-3.58 degrees, the included angle between the tooth bottom contour line and the thread axis is 0-3.58 degrees, and the tooth top contour line is parallel to the tooth bottom contour line.

Furthermore, the included angle between the tooth top of the external thread with the tapered thick-tooth wedge dovetail and the axis of the thread is 0-3.58 degrees, the included angle between the tooth bottom and the axis of the thread is 0-3.58 degrees, and the tooth top is parallel to the tooth bottom; the included angle between the tooth top contour line and the thread axis is 0-3.58 degrees, the included angle between the tooth bottom contour line and the thread axis is 0-3.58 degrees, and the tooth top contour line is parallel to the tooth bottom contour line.

Furthermore, the height of the guide surface of the tapered coarse-tooth wedge-shaped dovetail internal thread is 2.2-3.5 mm, the height of the bearing surface is 2.2-3.5 mm, and the height of the guide surface is greater than the Height (HL) of the bearing surface. The Pitch (PS) of the guide surface is 8.5-16 mm, the Pitch (PL) of the bearing surface is 8.55-16.5 mm, and the pitch of the guide surface is 0.05-0.5 mm smaller than that of the bearing surface.

Furthermore, the height of the guide surface of the tapered coarse-tooth wedge-shaped dovetail external thread is 2.2-3.5 mm, the height of the bearing surface is 2.2-3.5 mm, and the height of the guide surface is greater than that of the bearing surface. The pitch of the guide surface is 8.5-16 mm, the pitch of the bearing surface is 8.55-16.5 mm, and the Pitch (PS) of the guide surface is 0.05-0.5 mm smaller than that of the bearing surface.

Further, the length of the internal thread is 0.12-1.2mm smaller than that of the external thread.

Compared with the prior art, the invention has the following beneficial effects:

1. the titanium alloy drill rod is connected by adopting the thick-tooth dovetail wedge-shaped threads with the cone, the mutual sliding contact path is small in the screwing process, the screwing process can be completed quickly, and the abrasion among the threads is small. At least three surfaces of the thread guide side, the bearing side, the tooth top and the tooth bottom of the connection mode are in mutual contact, so that the contact area between the engaged thread teeth can be increased, the relative displacement of the threads when bearing loads is reduced, the anti-thread gluing performance of the threads is improved, and the thread repair rate is reduced; the side surfaces of the inner dovetail-shaped thread and the outer dovetail-shaped thread are negative angles, the teeth are mutually clenched, and when the inner dovetail-shaped thread and the outer dovetail-shaped thread bear tensile load, compressive load, bending load and composite load, the pretightening force cannot disappear, so that the inner dovetail-shaped thread and the outer dovetail-shaped thread have good air-tight performance, and the connection safety and the sealing performance are not influenced by the load.

2. After the titanium alloy drill rod is buckled, the threads and the inner shoulder are in meshing contact to generate micro interference, and the sealing effect of the original main shoulder surface can be replaced. The external shoulders are not contacted, the stress at the dangerous section of the male thread is reduced by about 496Mpa (taking the yield strength of a drill rod joint material as an example of 827 Mpa), the average stress at the dangerous section of the joint thread is reduced by about 496Mpa, and the fatigue life of the joint thread can be greatly prolonged due to the reduction of the average stress, so that the connection mode has high fatigue performance.

3. The titanium alloy drill rod is suitable for high-pressure natural gas wells, deep wells, ultra-deep wells, large-displacement horizontal wells, large-inclination wells, ultra-short radius side drilling and other special oil and gas wells with large dog-leg degrees.

4. The titanium alloy drill rod can adopt single-step or double-step or multi-step threaded connection according to the design requirements of the geometric dimension and the mechanical property of the material.

Drawings

FIG. 1 is a cross-sectional view of a conventional drill pipe connection in the prior art.

FIG. 2 is a cross-sectional view of a drill pipe coupling thread engagement of the type commonly used in the prior art.

FIG. 3 is a cross-sectional view of a drill pipe joint thread profile as is commonly used in the prior art.

Description of the drawings: in fig. 1 to 3, 1: titanium alloy drilling rod body, 2: female adapter, 3: pin joint, 7: internal thread, 8: external thread, 71: internal thread external shoulder, 72: internal thread segment, 81: external thread external shoulder, 82: an external thread segment. RS is a thread guide surface, RL is a thread bearing surface, RR is a circular arc thread root, RT is a thread crest, and RA is a thread profile angle.

Fig. 4 is a sectional view of a titanium alloy drill rod connection mode in embodiment 1 of the present invention.

FIG. 5 is a cross-sectional view of a titanium alloy drill pipe joint according to example 1 of the present invention.

FIG. 6 is a cross-sectional view of a titanium alloy drill pipe joint thread profile according to example 1 of the present invention.

Description of the drawings: in fig. 4-6: 1: titanium alloy drilling rod body, 2: female adapter, 3: pin joint, 21: female thread guide surface in the internal thread weld diameter region, 22: female threaded elevator area, 23: female pliers area, 24: internal thread region, 31: external thread weld diameter area box thread guide surface, 32: male threaded elevator area, 33: male pliers region, 34: external thread region, 241: female thread outer end face, 242: tapered internal thread section, 243: internal thread end face, 341: external thread outer end face, 342: tapered external thread section, 343: the inner end surface of the external thread, B is a tapered coarse thread wedge dovetail internal thread, P is a tapered coarse thread wedge dovetail external thread, A1: internal thread inner end face angle, B1: the angle of the inner end surface of the external thread, FS (thread guide surface), FL (thread bearing surface), T (thread crest), R (thread root), LC (thread axis), LT (crest outline), LR (root outline), HS (guide surface height), HL (bearing surface height), PS (guide surface pitch), PL (bearing surface pitch), AS (guide surface flank angle), AL (bearing surface flank angle), LB (internal thread length) and LP (external thread length).

Detailed Description

The invention is further described with reference to specific embodiments. It should be understood that these examples are only for illustrating the present invention and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications to the present patent may be made by those skilled in the art after reading the teachings of the present patent, and such equivalents are also within the scope of the present patent as defined in the appended claims.

Example 1

As shown in fig. 4-6, a titanium alloy drill pipe comprises a drill alloy drill pipe body 1, an internal thread joint 2 and an external thread joint 3 at two ends of the titanium alloy drill pipe body, wherein the internal thread joint 2 is composed of a welding diameter area 21, an elevator area 22, a tong area 23 and an internal thread area 24, and the internal thread area 24 comprises an internal thread outer end surface 241, a tapered internal thread section 242 and an internal thread inner end surface 243; the external thread joint 3 consists of a welding diameter area 31, an elevator area 32, a tong area 33 and an external thread area 34, wherein the external thread area 34 comprises an external thread outer end surface 341, a tapered external thread section 342 and an external thread inner end surface 343; the internal thread region 24 is processed with a tapered thick-tooth wedge-shaped dovetail internal thread B, and the external thread region 34 is processed with a tapered thick-tooth wedge-shaped dovetail external thread P.

In the invention, the outer end surface 241 of the internal thread is a right angle, the inner end surface 243 of the internal thread is a negative angle A1, and the angle of the negative angle A1 is 5-10 degrees; the outer end surface 341 and the inner end surface 343 of the external thread are negative angles B1, and the negative angle B1 is 5-10 degrees; the inner end face 243 of the internal thread and the inner end face 343 of the external thread are in a fitting relationship, and the negative angles are equal.

In the invention, a tapered coarse-tooth wedge-shaped dovetail internal thread B sequentially comprises an internal thread guide surface FS, a bearing surface FL, a guide surface flank angle AS, a bearing surface flank angle AL, a tooth top T, a tooth bottom R, a tooth top contour line LT, a tooth bottom contour line LR, a guide surface height HS, a bearing surface height HL, a guide surface thread pitch PS and a bearing surface thread pitch PL.

In the invention, the tapered coarse thread wedge dovetail external thread P sequentially comprises an external thread guide surface FS, a bearing surface FL, a guide surface flank angle AS, a bearing surface flank angle AL, a tooth top T, a tooth bottom R, a tooth top contour line LT, a tooth bottom contour line LR, a guide surface height HS, a bearing surface height HL, a guide surface thread pitch PS and a bearing surface thread pitch PL.

Through multiple tests, the inner thread outer end face 241 is a right angle, the inner thread inner end face 243 is a 5-degree angle, the outer thread outer end face 341 is a right angle, and the outer thread inner end face 343 is a 5-degree angle.

The taper range of the internal thread B of the tapered coarse-tooth wedge-shaped dovetail is 1: 12, the taper range of the external thread P of the tapered coarse thread wedge dovetail is 1: 12.

the angle of the guide surface flank angle AS of the tapered coarse-tooth wedge-shaped dovetail internal thread is 5 degrees, and the angle of the bearing surface flank angle AL is-10 degrees. The angle of the guide surface flank angle AS of the tapered coarse thread wedge dovetail external thread is 5 degrees, and the angle of the bearing surface flank angle AL is 10 degrees.

The included angle between the tooth top T of the internal thread B of the tapered coarse-tooth wedge dovetail and the thread axis LC is 0-3.58 degrees, the included angle between the tooth bottom R and the thread axis LC is 0-3.58 degrees, and the tooth top T is parallel to the tooth bottom R. The included angle between the tooth crest outline LT and the thread axis LC is 0-3.58 degrees, the included angle between the tooth bottom outline LR and the thread axis LC is 0-3.58 degrees, and the tooth crest outline LT is parallel to the tooth bottom outline LR.

The included angle between the tooth top T of the tapered coarse-tooth wedge-shaped dovetail external thread P and the thread axis LC is 0 degree, the included angle between the tooth bottom R and the thread axis LC is 0 degree, the tooth top T is parallel to the tooth bottom R, the included angle between the tooth top contour line LT and the thread axis LC is 2.48 degrees, the included angle between the tooth bottom contour line LR and the thread axis LC is 2.48 degrees, and the tooth top contour line LT is parallel to the tooth bottom contour line LR.

The height HS of the guide surface of the tapered internal thread of the coarse-tooth wedge dovetail is 2.83mm, and the height HL of the bearing surface is 2.40 mm. The pitch PS of the guide surface is 10.5mm, and the pitch PL of the bearing surface is 10.9 mm.

The height HS of the guide surface of the tapered external thread of the coarse thread wedge dovetail is 2.83mm, and the height HL of the bearing surface is 2.40 mm. The pitch PS of the guide surface is 10.5, and the pitch PL of the bearing surface is 10.9 mm.

The length LB of the internal thread is 0.25mm less than the length LP of the external thread.

In the technical scheme of the invention, the internal thread joint and the external thread joint adopt a double-step structure, which is beneficial to improving the deformation resistance and the thread gluing resistance of the drill rod joint.

The double-step and tapered thick-tooth dovetail wedge-shaped threads are adopted for connection, so that the relative displacement of the threads when bearing load is reduced, the anti-thread gluing performance of the threads is improved, and the thread repair rate is reduced; the side surfaces of the inner dovetail-shaped thread and the outer dovetail-shaped thread are negative angles, and claws are arranged among the teeth, so that the air-tight sealing structure has good air-tight performance when bearing tensile load, compressive load, bending load and composite load, and the connection safety and the air-tight performance are not influenced by the load; the connecting structure reduces the level of the average stress of circulation and greatly improves the fatigue performance of the joint thread. The titanium alloy drill rod connecting mode is suitable for special oil and gas wells with large dog-leg degrees, such as high-pressure natural gas wells, deep wells, ultra-deep wells, large-displacement horizontal wells, large-inclination wells, ultra-short radius side drilling and the like.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and drawings, or applied directly or indirectly to other related technical fields, are included in the scope of the present invention.

Claims

1. A titanium alloy drill rod comprises a drill alloy drill rod pipe body (1), and an internal thread joint (2) and an external thread joint (3) which are arranged at two ends of the titanium alloy drill rod pipe body, wherein the internal thread joint (2) consists of a welding diameter area (21), an elevator area (22), a tong area (23) and an internal thread area (24), and the internal thread area (24) comprises an internal thread outer end surface (241), an internal thread section (242) with a taper and an internal thread inner end surface (243); the external thread joint (3) is composed of a welding diameter area (31), an elevator area (32), a tong area (33) and an external thread area (34), wherein the external thread area (34) comprises an external thread outer end face (341), a tapered external thread section (342) and an external thread inner end face (343), and is characterized in that the internal thread area (24) is processed with a tapered thick-tooth wedge-shaped dovetail inner thread (B), and the external thread area (34) is processed with a tapered thick-tooth wedge-shaped dovetail outer thread (P).

2. A titanium alloy drill rod according to claim 1, characterized in that the female thread outer end surface (241) is a right angle and the female thread inner end surface (243) is a negative angle (a1), the negative angle (a1) being 5-10 °; the outer end face (341) of the external thread and the inner end face (343) of the external thread are negative angles (B1), and the angle of the negative angle (B1) is 5-10 degrees; wherein the inner end surface (243) of the internal thread is matched with the inner end surface (343) of the external thread, and the negative angles are equal.

3. The titanium alloy drill rod AS claimed in claim 1, wherein the tapered coarse-tooth wedge-shaped dovetail internal thread (B) comprises an internal thread guide surface (FS), a bearing surface (FL), a guide surface flank Angle (AS), a bearing surface flank Angle (AL), a tooth crest (T), a tooth bottom (R), a tooth top contour Line (LT), a tooth bottom contour Line (LR), a guide surface Height (HS), a bearing surface Height (HL), a guide surface thread Pitch (PS), and a bearing surface thread Pitch (PL) in this order.

4. The titanium alloy drill rod AS claimed in claim 1, characterized in that the tapered coarse-tooth wedge-shaped dovetail external thread (P) comprises an external thread guide surface (FS), a bearing surface (FL), a guide surface flank Angle (AS), a bearing surface flank Angle (AL), a tooth crest (T), a tooth bottom (R), a tooth top contour Line (LT), a tooth bottom contour Line (LR), a guide surface Height (HS), a bearing surface Height (HL), a guide surface thread Pitch (PS), and a bearing surface thread Pitch (PL) in this order.

5. A titanium alloy drill rod according to any one of claims 3 or 4, characterized in that the taper range of the tapered coarse-pitch wedge-dovetail internal thread (B) is 1: 8-1: 36; the taper range of the external thread (P) with the tapered coarse thread wedge dovetail is 1: 8-1: 36; the tapered coarse-tooth wedge-shaped dovetail internal thread (B) and the tapered coarse-tooth wedge-shaped dovetail internal thread (P) are in an internal and external thread relationship of mutual connection, and the taper of the internal and external thread relationship is the same when the internal and external thread relationship and the tapered coarse-tooth wedge-shaped dovetail internal threads are mutually matched and connected.

6. The titanium alloy drill rod AS claimed in any one of claims 3 or 4, wherein the angle of the flank Angle (AS) of the guiding surface of the tapered coarse-pitch wedge-shaped dovetail internal thread (B) is-10 ° to 5 °, and the angle of the flank Angle (AL) of the bearing surface is-3 ° to-10 °; the angle of a guide surface flank Angle (AS) of the tapered coarse thread wedge dovetail external thread (P) is-10-5 degrees, and the angle of a bearing surface flank Angle (AL) is-3-10 degrees.

7. The titanium alloy drill rod as claimed in any one of claims 3 or 4, wherein the included angle between the tooth crest (T) of the tapered coarse-tooth wedge-shaped dovetail internal thread (B) and the thread axis (LC) is 0-3.58 degrees, the included angle between the tooth bottom (R) and the thread axis (LC) is 0-3.58 degrees, and the tooth crest (T) and the tooth bottom (R) are parallel; the included angle between the tooth top contour Line (LT) and the thread axis (LC) is 0-3.58 degrees, the included angle between the tooth bottom contour Line (LR) and the thread axis (LC) is 0-3.58 degrees, and the tooth top contour Line (LT) is parallel to the tooth bottom contour Line (LR).

8. The titanium alloy drill rod as claimed in claim 4, wherein the included angle between the tooth crest (T) of the tapered coarse-tooth wedge-shaped dovetail external thread (P) and the thread axis (LC) is 0-3.58 °, the included angle between the tooth bottom (R) and the thread axis (LC) is 0-3.58 °, and the tooth crest (T) and the tooth bottom (R) are parallel. The included angle between the tooth top contour Line (LT) and the thread axis (LC) is 0-3.58 degrees, the included angle between the tooth bottom contour Line (LR) and the thread axis (LC) is 0-3.58 degrees, and the tooth top contour Line (LT) is parallel to the tooth bottom contour Line (LR).

9. The titanium alloy drill pipe as claimed in claim 7, wherein the tapered coarse dovetail internal thread (B) has a guide surface Height (HS) of 2.2mm to 3.5mm, a bearing surface Height (HL) of 2.2mm to 3.5mm, the guide surface Height (HS) is greater than the bearing surface Height (HL), a guide surface Pitch (PS) of 8.5 mm to 16mm, a bearing surface Pitch (PL) of 8.55 mm to 16.5mm, and the guide surface Pitch (PS) is 0.05 mm to 0.5mm smaller than the bearing surface Pitch (PL).

10. The titanium alloy drill pipe as recited in claim 8, wherein the tapered coarse-tooth wedge-shaped dovetail external thread (P) has a guide surface Height (HS) of 2.2mm to 3.5mm, a bearing surface Height (HL) of 2.2mm to 3.5mm, the guide surface Height (HS) being greater than the bearing surface Height (HL); the Pitch (PS) of the guide surface is 8.5-16 mm, the Pitch (PL) of the bearing surface is 8.55-16.5 mm, and the Pitch (PS) of the guide surface is 0.05-0.5 mm smaller than the Pitch (PL) of the bearing surface.

11. A titanium alloy drill rod according to claim 1, characterized in that the Length (LB) of the internal thread is 0.12-1.2mm smaller than the Length (LP) of the external thread.