The discovery of oil storage blocks through exploration refers to the use of special equipment and technology to drill cylindrical holes with a certain diameter down or on one side at the pre selected surface position and reach the underground oil and gas reservoir. The drill pipe is the core tool in the process of oil drilling. At present, double wall drill pipe is used in oil drilling, The existing double wall drill pipe for oil still has the following shortcomings:

1. Although its mechanical properties can meet the needs, the inner diameter of drill pipe with the same mechanical property grade is small, resulting in great flow resistance, which is not conducive to oil drilling construction;

2. When using the drill pipe, the two drill pipes are usually connected by screw thread. After using one end of the drill pipe for a long time, the drill pipe will become loose and the sealing is not good, resulting in the failure of drilling work and the trouble of assembling the drill pipe.

Technical realization elements:



In view of the shortcomings of the prior art, the utility model provides an oil drilling double wall drill pipe, which solves the problem that the oil drilling double wall drill pipe has large flow resistance and can not assemble the drill pipe quickly and stably.



In order to achieve the above purpose, the utility model is realized through the following technical scheme: a double wall drill pipe for oil drilling, which comprises an upper joint of the outer pipe, an outer pipe body, a lower joint of the outer pipe, an inner sleeve, an upper joint of the inner pipe, an inner pipe body and a lower joint of the inner pipe. The bottom of the upper joint of the outer pipe is fixedly connected with the top of the outer pipe body by friction welding, The bottom end of the outer pipe body is fixedly connected with the top of the lower joint of the outer pipe by friction welding, the outer surface of the inner sleeve is connected with the top of the inner wall of the upper joint of the inner pipe by thread, the bottom of the inner wall of the upper joint of the inner pipe is connected with the top of the surface of the inner pipe body by thread, and the bottom of the surface of the inner pipe body is connected with the top of the inner wall of the lower joint of the inner pipe by thread.



Preferably, both sides of the upper joint surface of the outer pipe are fixedly connected with a sleeve through a connecting block, and both sides of the bottom of the surface of the outer pipe body are fixedly connected with a sleeve rod matched with the sleeve.



Preferably, both sides of the top of the surface of the outer pipe body and directly below the sleeve are fixedly connected with a support block, one side of the top of the support block is fixedly connected with a first threaded sleeve, the internal thread of the first threaded sleeve is connected with a rotating screw, and the other side of the top of the support block is fixedly connected with a second threaded sleeve used in conjunction with the rotating screw.



Preferably, the bottom of the surface of the sleeve rod is provided with a positioning hole matched with the rotating screw.



Preferably, the surface of the inner sleeve is fixedly connected with a first sealing ring used in conjunction with the lower joint of the inner pipe.



Preferably, the inner wall of the upper joint of the outer pipe is fixedly connected with a second sealing ring used in conjunction with the lower joint of the outer pipe.



Beneficial effect



The utility model provides a double wall drill pipe for oil drilling. It has the following beneficial effects: