CN201991453U

CN201991453U - Improved well casing

Info

Publication number: CN201991453U
Application number: CN2011200864547U
Authority: CN
Inventors: 武磊
Original assignee: Tianjin Dehua Petroleum Equipment Manufacturing Co Ltd
Current assignee: Tianjin Dehua Petroleum Equipment Manufacturing Co Ltd
Priority date: 2011-03-29
Filing date: 2011-03-29
Publication date: 2011-09-28
Anticipated expiration: 2021-03-29

Abstract

The utility model discloses an improved well casing, which comprises a pipe body. One end of the pipe body is a male end with external threads, the other end of the pipe body is a female end with internal threads, and an inner wall of the female end is provided with a reversed circular bead. The improved well casing has an excellent sealing property, a good hermetic sealing property under a high pressure environment and an excellent tensile property, can achieve an identical strength of the pipe body, and is provided with the reverse circular bead so as to provide excellent make-up torque, thereby achieving accurate make-up and a smaller coupling stress, being capable of avoiding a reversed angle caused by a wedge-shape effect, accordingly improving intensity of a connecting structure.

Description

A kind of improved well casing

Technical field

The utility model relates to a kind of oil or geological prospecting equipment, relates in particular to a kind of sleeve pipe that is used for drilling well.

Background technology

In the sleeve pipe of prior art, an end of its body is for having externally threaded male end, and the other end is the female end that has internal thread, when a plurality of sleeve pipes interconnect, utilizes male end and female end each other to be threaded.

Along with the continuous development of China's oilfield prospecting developing, deep-well, ultradeep well, high-pressure oil-gas well, thermal production well, directional well, contain CO ₂Or H ₂Corrosive medium wells such as S occur in a large number.Gas tightness, bonding strength and corrosion resistance etc. that these oil gas wells are threaded to well casing are all had higher requirement.The common API round thread and the sleeve pipe of buttress thread form can not satisfy the instructions for use of these hole conditions.

The utility model content

The utility model provides the sleeve pipe of a kind of oil or used for geological prospecting, by the improvement to male end and female end form of structure, has improved bonding strength and sealing.

A kind of improved well casing comprises body, and this body one end is for having externally threaded male end, and the other end is the female end that has internal thread, and the inwall of described female end has reverse shoulder.

Described reverse shoulder is the ring-shaped step that distributes around the body axis, and in the step surface of ring-shaped step (being circular bead surface), the part of close body axis tilts towards the female end opening.

Described step surface has the inclination angle of 15 degree with respect to the vertical plane of body axis.

Under the normal condition, if step surface is parallel with the vertical plane of body axis, be that step surface is perpendicular to the body axis, can become the right angle shoulder so, the step surface of some shoulders is got over away from the female end opening the closer to the body axis, and the utility model step surface the closer to the body axis also just the closer to the female end opening, therefore become reverse shoulder.

In the described female end inwall, the position adjacent with step surface has the trend towards the expansion of female end opening, and tapering is 1: 10.

The tooth depth of the internal thread of described female end is 1.775mm, and the tooth depth of the internal thread of general female end is 1.575mm in the prior art, and the internal thread of the utility model sleeve pipe has increased 0.2mm with tooth depth.

The beneficial effect of the utility model sleeve pipe under hyperbaric environment, has good gas sealing ability for having excellent sealing ability.The tensile property excellence can reach and the body equality strength.Have reverse shoulder, good torque wrench moment is provided, thereby realized accurately going up button and less box cupling stress, the reverse angle that can avoid wedge effect to cause, thus improved syndeton intensity.

Description of drawings

Fig. 1 is the generalized section of the utility model sleeve pipe male end;

Fig. 2 is the generalized section of the utility model sleeve pipe female end;

Fig. 3 is the enlarged drawing at A position among Fig. 1;

Fig. 4 is the enlarged drawing at B position among Fig. 2.

The specific embodiment

Referring to accompanying drawing, a kind of sleeve pipe that improves bonding strength of the utility model, comprise body, body one end is the male end 1 that has external screw thread 3, the other end is the female end 2 that has internal thread 4, can be as required with regard to the external diameter of sleeve pipe, for example diameter (mm) is specifications such as 139.7,177.8,244.5,339.7.

The inwall of female end 2 has reverse shoulder, oppositely shoulder is the ring-shaped step that distributes around the body axis, step surface 6b is 15 degree with respect to the inclination alpha of the vertical plane of body axis, and promptly the angle α of step surface 6b and vertical direction is 15 degree (illustrating with the diagonal angle among the figure) among Fig. 4.

Equally, the shape of the shape of the end face 6a of male end 1 and step surface 6b is corresponding.

In the inwall of female end 2, the position 5b adjacent with step surface 6b has the trend towards the expansion of female end opening, and tapering is 1: 10.

Equally, the shape of the shape of the outer wall 5a at the position, termination of male end 1 and position 5b is corresponding.

The tooth depth of the internal thread 4 of female end 2 is 1.775mm, is generally 1.575mm in the prior art, and the internal thread of the utility model sleeve pipe has increased 0.2mm with tooth depth.

The utility model sleeve pipe has excellent sealing ability, and oppositely shoulder provides good torque wrench moment, thereby has realized accurately going up button and less box cupling stress, has improved syndeton intensity.

Claims

1. an improved well casing comprises body, and this body one end is for having externally threaded male end, and the other end is the female end that has internal thread, it is characterized in that, the inwall of described female end has reverse shoulder.

2. improved well casing as claimed in claim 1 is characterized in that, described reverse shoulder is the ring-shaped step that distributes around the body axis, and in the step surface of ring-shaped step, the part of close body axis tilts towards the female end opening.

3. improved well casing as claimed in claim 2 is characterized in that, described step surface has the inclination angle of 15 degree with respect to the vertical plane of body axis.

4. improved well casing as claimed in claim 3 is characterized in that, in the described female end inwall, the position adjacent with step surface has the trend towards the expansion of female end opening, and tapering is 1: 10.

5. as each described improved well casing of claim 1～4, it is characterized in that the tooth depth of the internal thread of described female end is 1.775mm.