A small-size, large-water-hole friction-welded titanium alloy drill pipe

Abstract

The present invention provides a small-size large-water-hole friction-welded titanium alloy drill pipe, wherein the body is connected to the first cylindrical section via a first conical surface, the first cylindrical section is connected to the second conical surface, the second conical surface is connected to the second cylindrical section, and the second cylindrical section is friction-welded to one end of a drill pipe joint. The advantages are as follows: the present invention thickens the drill pipe body at two levels, so that the pipe body size at the pipe end friction welding position is the same as the drill pipe joint size, effectively reducing the wall thickness of the first cylindrical section, increasing the water-hole diameter of the pipe body, and reducing the outer diameter of the second cylindrical section at the same time, so that the outer diameter of the drill pipe joint friction-welded therewith is reduced, increasing the water-hole diameter of the drill pipe, reducing the hydraulic loss of the drilling fluid, reducing the outer diameter of the joint, reducing the cost of the titanium alloy drill pipe, and improving the applicability of the drill pipe under small-hole drilling conditions.

Description

Technical Field

[0001] The invention relates to the field of drill rods, in particular to a small-size large-water-hole friction-welded titanium alloy drill rod. Background Art

[0002] The titanium alloy drill pipe used in the exploration and development of oil and gas has the characteristics of corrosion resistance, low density, high strength and good elasticity. It is used in drilling operations of highly acidic oil and gas reservoirs, ultra-deep wells and ultra-short horizontal wells. At present, there are two structures of titanium alloy drill pipes. One is to connect the titanium alloy pipe body with a steel joint, and the other is to use a titanium alloy joint and a titanium alloy pipe body through friction welding. When the titanium alloy joint is used for friction welding with the titanium alloy pipe body, the end of the titanium alloy pipe body needs to be upset. Since the material properties at the weld are lower than those of the titanium alloy joint / body material, the end of the titanium alloy pipe body needs to be thickened a lot. Since the outer diameter of the pipe body weld is restricted by the elevator tool, the method of reducing the inner diameter is often used. The reduction of the inner diameter of the pipe body will inevitably lead to high pump pressure, low displacement and high pump consumption of the drilling fluid during the drilling process. When a small-sized drill pipe body is used, this phenomenon is more serious, which affects the large displacement and low pump pressure requirements of the drilling fluid during the drilling process, reduces the drilling efficiency, and restricts the application and promotion of titanium alloy drill pipes. Summary of the invention

[0003] The purpose of the present invention is to solve the problems existing in the prior art that the outer diameter of the pipe body weld is restricted by the hanging tool, and the method of reducing the inner diameter is often adopted. The reduction of the inner diameter of the pipe body leads to high pump pressure, low displacement and high pump consumption of the drilling fluid in the drilling process, which affects the large displacement and low pump pressure requirements of the drilling fluid in the drilling process, reduces the drilling efficiency, and restricts the application and promotion of titanium alloy drill pipes. A small-sized and large-water-hole friction-welded titanium alloy drill pipe is provided.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A small-sized, large-water-hole friction-welded titanium alloy drill pipe comprises a drill pipe body and a drill pipe joint. The drill pipe body comprises a body, a first conical surface, a second conical surface, a third conical surface, a first cylindrical section and a second cylindrical section. The body is connected to one end of the first cylindrical section via the first conical surface, the other end of the first cylindrical section is connected to one end of the second conical surface, the other end of the second conical surface is connected to one end of the second cylindrical section, and the other end of the second cylindrical section is friction-welded to one end of the drill pipe joint.

[0006] Preferably, the outer diameter of the body is less than or equal to 88.9 mm.

[0007] Preferably, the outer diameter of the first cylindrical section is larger than the outer diameter of the main body, and the inner diameter of the first cylindrical section is smaller than or equal to the inner diameter of the main body.

[0008] Preferably, the ratio of the outer diameter of the first cylindrical section to the outer diameter of the main body is 1.08-1.14, and the cross-sectional area ratio is 1.3-1.8.

[0009] Preferably, a first conical surface transition of 4 to 8 degrees is adopted between the outer diameter of the first cylindrical section and the outer diameter of the main body.

[0010] Preferably, the outer diameter of the second cylindrical section is greater than that of the first cylindrical section, and is equivalent to the outer diameter of the drill pipe joint, and the inner diameter of the second cylindrical section is greater than that of the first cylindrical section, and is equivalent to the inner diameter of the drill pipe joint.

[0011] Preferably, the ratio of the outer diameter of the second cylindrical section to the outer diameter of the main body is 1.30-1.48, the cross-sectional area ratio is 2.36-3.58, and the ratio of the inner diameter of the second cylindrical section to the inner diameter of the main body is 0.85-1.00.

[0012] Preferably, a second conical surface transition of 18° is adopted between the outer diameter of the first cylindrical section and the outer diameter of the second cylindrical section.

[0013] Preferably, a third conical surface is used for transition between the inner diameter of the first cylindrical section and the inner diameter of the second cylindrical section, and the cone angle of the third conical surface is less than or equal to 6°.

[0014] The beneficial effects of the present invention are as follows: the present invention thickens the drill pipe body at two levels, so that the size of the pipe body at the friction welding position of the pipe end is the same as the size of the drill pipe joint, effectively reducing the wall thickness of the first cylindrical section, increasing the water hole diameter of the pipe body, and reducing the outer diameter of the second cylindrical section at the same time, so that the outer diameter of the drill pipe joint friction-welded therewith is reduced, the water hole diameter of the drill pipe is increased, the hydraulic loss of the drilling fluid is reduced, the outer diameter of the joint is reduced, the cost of the titanium alloy drill pipe is reduced, and the applicability of the drill pipe in small wellbore drilling conditions is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the present invention.

[0016] Wherein: 1. body, 2. first conical surface, 3. first cylindrical section, 4. second conical surface, 5. third conical surface, 6. second cylindrical section, 7. drill pipe joint. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0018] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0019] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0020] A small-sized, large-water-hole friction-welded titanium alloy drill pipe comprises a drill pipe body and a drill pipe joint 7. The drill pipe body comprises a body 1, a first conical surface 2, a second conical surface 4, a third conical surface 5, a first cylindrical section 3 and a second cylindrical section 6. The body 1 is connected to one end of the first cylindrical section 3 through the first conical surface 2, the other end of the first cylindrical section 3 is connected to one end of the second conical surface 4, the other end of the second conical surface 4 is connected to one end of the second cylindrical section 6, and the other end of the second cylindrical section 6 is friction-welded to one end of the drill pipe joint 7.

[0021] Preferably, the outer diameter of the body 1 is less than or equal to 88.9 mm.

[0022] Preferably, the outer diameter of the first cylindrical section 3 is greater than the outer diameter of the body 1 , and the inner diameter of the first cylindrical section 3 is less than or equal to the inner diameter of the body 1 .

[0023] Preferably, the ratio of the outer diameter of the first cylindrical section 3 to the outer diameter of the body 1 is 1.08-1.14, and the cross-sectional area ratio is 1.3-1.8.

[0024] Preferably, a first conical surface 2 with a transition angle of 4 to 8 degrees is used between the outer diameter of the first cylindrical section 3 and the outer diameter of the body 1 .

[0025] Preferably, the outer diameter of the second cylindrical section 6 is greater than the outer diameter of the first cylindrical section 3, and the outer diameter of the second cylindrical section 6 is equivalent to the outer diameter of the drill rod joint 7, and the inner diameter of the second cylindrical section 6 is greater than the inner diameter of the first cylindrical section 3, and the inner diameter of the second cylindrical section 6 is equivalent to the inner diameter of the drill rod joint 7.

[0026] Preferably, the ratio of the outer diameter of the second cylindrical section 6 to the outer diameter of the body 1 is 1.30-1.48, the cross-sectional area ratio is 2.36-3.58, and the ratio of the inner diameter of the second cylindrical section 6 to the inner diameter of the body 1 is 0.85-1.00.

[0027] Preferably, a second conical surface 4 with an angle of 18° is used to transition between the outer diameter of the first cylindrical section 3 and the outer diameter of the second cylindrical section 6 .

[0028] Preferably, a third conical surface 5 is used to transition between the inner diameter of the first cylindrical section 3 and the inner diameter of the second cylindrical section 6, and the cone angle of the third conical surface 5 is less than or equal to 6°.

[0029] Example:

[0030] The outer diameter of the body 1 is 73.02 mm, the inner diameter is 54.64 mm, and the cross-sectional area is 1843 mm 2 The outer diameter of the first cylindrical section 3 is 81 mm, the inner diameter is 54.64 mm, and the cross-sectional area is 2808 mm 2 , which is 1.52 times the cross-sectional area of ​​the body 1; the outer diameter of the second cylindrical section 6 is 98 mm, the inner diameter is 54 mm, and the cross-sectional area is 5252 mm 2 , which is 2.85 times the cross-sectional area of ​​the body 1; the outer diameter of the drill pipe joint 7 is 98 mm, the inner diameter is 54 mm, and the cross-sectional area is 5252 mm 2 The water hole diameter of the drill pipe is 50.8mm. Compared with the conventional structure, the water hole diameter is increased by 33.3%, the outer diameter of the drill pipe joint 7 is reduced by 11.8%, and the weight of a single drill pipe is reduced by 6.3 kg, which can save 2,266 yuan (market price is about 360 yuan / kg). For every 1,000m long drill string, the cost can be saved by 236,000 yuan.

[0031] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A small-size, large-hole friction-welded titanium alloy drill pipe, comprising a drill pipe body and a drill pipe joint, wherein the drill pipe body comprises a body, a first conical surface, a second conical surface, a third conical surface, a first cylindrical section and a second cylindrical section, characterized in that: The body is connected to one end of the first cylindrical section through a first conical surface, the other end of the first cylindrical section is connected to one end of the second conical surface, the other end of the second conical surface is connected to one end of the second cylindrical section, and the other end of the second cylindrical section is friction welded to one end of the drill pipe joint; The outer diameter of the body is less than or equal to 88.9 mm; the outer diameter of the first cylindrical section is greater than the outer diameter of the body, and the inner diameter of the first cylindrical section is less than or equal to the inner diameter of the body; the ratio of the outer diameter of the first cylindrical section to the outer diameter of the body is 1.08-1.14, and the cross-sectional area ratio is 1.3-1.8; a first conical surface transition of 4~8° is adopted between the outer diameter of the first cylindrical section and the outer diameter of the body.

2. The small-size large-water-hole friction-welded titanium alloy drill pipe according to claim 1, characterized in that: The outer diameter of the second cylindrical section is greater than that of the first cylindrical section, and is equivalent to the outer diameter of the drill pipe joint. The inner diameter of the second cylindrical section is greater than that of the first cylindrical section, and is equivalent to the inner diameter of the drill pipe joint.

3. The small-size large-water-hole friction-welded titanium alloy drill pipe according to claim 1, characterized in that: The ratio of the outer diameter of the second cylindrical section to the outer diameter of the main body is 1.30-1.48, the cross-sectional area ratio is 2.36-3.58, and the ratio of the inner diameter of the second cylindrical section to the inner diameter of the main body is 0.85-1.

00.

4. The small-size large-water-hole friction-welded titanium alloy drill pipe according to claim 1, characterized in that: A second conical surface transition of 18° is adopted between the outer diameter of the first cylindrical section and the outer diameter of the second cylindrical section.

5. A small-size large-water-hole friction-welded titanium alloy drill pipe according to claim 1 or 4, characterized in that: A third conical surface is used to transition between the inner diameter of the first cylindrical section and the inner diameter of the second cylindrical section, and the cone angle of the third conical surface is less than or equal to 6°.

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