FR2658439A1 - DRILLING TUBE. - Google Patents

Abstract

A method of manufacturing a borehole tube (10) for drilling operations, in which several lengths of tubes (11) are cast by centrifugation and the lengths of tubes are welded together to form welds (12) after which welds are welded. Threaded end fittings (13,15) to form welds (14,16) at opposite ends of the drill pipe. The threaded end fittings can also be partially formed during centrifugal casting of the tube lengths to form the ends of the drill tube and supplemented with appropriate machining and threading operations. Application to drill pipes.

Description

DRILLING TUBE

  The present invention relates to the manufacture

  drilling tubes of the type adapted to be progressively joined at their ends to produce a drill string that is rotatably drivable to drill oil wells, boreholes and boreholes;

similar drilling applications.

  The drill pipes for these applications are conventionally formed by a piercing method resulting in a seamless tube and can also be formed by rolling a flat steel sheet to turn it into a tube and weld together the longitudinal edges abutting the tube. against each other to form a welded tube In both cases, the internally and externally threaded components required at the opposite ends of the tube, which are used for the purpose of assembling the tubes in a tower of drilling, are then

  inserted into the ends of the tube and are welded to it.

  The main drawbacks of these tube-forming techniques are their high cost, mainly because of the complex manufacturing techniques and associated equipment and the relatively small number of suppliers. The object of the invention is therefore to provide a method for manufacturing a tube of drilling operations that are less costly than the drilling and fabrication techniques mentioned above, and also uses the manufacturing facilities that are most

  readily available The problem posed by

  anterior process involving a piercing process is likely to increase in size and as the general prices of steel increase, particularly since the drilling technique requires

  starting product a round bar of forged steel.

  According to the invention, there is provided a method of manufacturing a drill pipe for drilling operations in which several lengths of pipe are centrifugally cast and said lengths of tubes are joined end to end to form a tube.

drilling the desired length.

  Centrifugal pouring of a tube is generally less costly than the drilling and fabrication techniques discussed above, while the availability of manufacturing facilities is greater. In addition, since the invention can utilize In addition, since the invention involves a casting technique, there is a possibility of changing the composition of the alloy of the steel, making it possible to have a degree of lower wear and thus a longer service life In particular, pierced tubes have limitations on the variations in the alloy composition because the piercing process requires a limitation of the alloy composition that can be used. currently used tubes are operational for about 3 months, after which time they must be removed from the borehole and sent to a workshop where their diameter is corrected for To replace the spent material by a continuous welding process, which incurs additional costs The use of the correct alloys with high wear resistance, made possible by the invention, leads to an increase in the service life. If the costs can be reduced enough, it may be possible to throw a worn tube rather than rebuild

circumferential diameter.

  The threaded end fittings for the tube may be later joined to the respective ends of the drill pipe manufactured at the same time as it is manufactured, or may be joined therein more

  late by the end user of the drill pipe.

  The production of end fittings could also be incorporated as part of the centrifugal casting operation and supplemented with appropriate machining and training techniques.

a thread.

  The invention also contemplates a tube

  drilling made according to the method described above.

  An embodiment of the invention will now be described by way of example with reference to the accompanying drawing. The drawing shows a longitudinal view, in partial section, of a complete drill pipe manufactured according to the method of the invention. invention. In the example of this preferred embodiment, the main length of the drill pipe designated by 10 is formed from several lengths of thick-walled tubes 11. Each length of tube 11 is centrifugally cast from a metal material, using a permanent cylindrical mold which is rotated at high speed while pouring molten metal thereon, and which results in the metal being thrown onto the inner surface of the mold to produce a hollow cylinder or tube The resulting tube lengths have an outer surface of uniformly thin grain, and therefore can be expected to be healthier with a smaller number of inclusions. the lengths of individual tubes 11 to produce welds 12 between their ends, and collectively the lengths of tubes constitute

  the desired length of the drill pipe 10.

  In order to complete the pierced tube for use

  In drilling applications, a conventional external threaded end component 13 and 14 are welded to one end of the drill pipe, and a conventional internal threaded end component 16 is welded at the other end of the drill pipe. drilling tube The end components 13 and 15 can be welded to the drill pipe at the time of its manufacture,

  or to be connected later by the user

  Another possible solution is to partially form the end components in question as parts of a length of

  special centrifugal casting tube 11

  involves the formation of the relevant end of the

  final drill pipe during centrifugal casting

  fugation of this length of tube, the end components receiving their finishing by machining operations and threading operations using

appropriate equipment.

  In the example of the invention as described a typical drill pipe 10 can be formed from

  four lengths of centrifugally cast tubes

  228.6 cm in length, which, when welded end to end, lead to a

drilling 914.4 cm in length.

  Centrifug casting of the lengths of tubes 11 should be adjusted to produce a uniform tube wall thickness for each

  length intended to constitute the drill pipe.

  These wall thicknesses can comply with the

  wall thickness range normally available in conventional machined drilled and welded seamless drill pipes Thicknesses depend on the type and depth of the drilling operation

  to which the drill pipe will be applied.

  It is expected that at full speed the

  drilling tubes according to the method of the invention

  the price (in 1990 dollars) of a conventional length of borehole is barely A $ 8,500.00. This figure can be compared with a length of borehole made by known techniques and price can reach

A $ 13,000.00.

Claims (4)

  A method of manufacturing a drill pipe for drilling operations in which several lengths of pipe are centrifugally cast and said lengths of pipe are welded together end to end to form a tube drilling the desired length.   The method of claim 1, wherein the threaded end fittings for the tube are subsequently joined at the opposite ends. made tube.   The method of claim 1, wherein the threaded end fittings for the tube are partially formed during centrifugal casting of the lengths of tubes that are to form the ends of the drill pipe, and are supplemented by appropriate machining operations. and threading.   4 Drill tube manufactured by the method of   any one of the preceding claims.