Metal deforming – Process – Tube making or reshaping
Patent
1999-04-15
2000-09-05
Larson, Lowell A.
Metal deforming
Process
Tube making or reshaping
72203, B21D 2828
Patent
active
061125709
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method for making slots in metal pipe and, in particular, slots less than 15 thousandths of an inch in width.
BACKGROUND OF THE INVENTION
The oil industry uses slotted metal pipe as a screening mechanism when drilling for heavy oil. Heavy oil is commonly found in oil bearing sand formations. Oil wells are drilled that have horizontal sections, which can be 1000 meters or more in length. These horizontal sections have a tendency to collapse and become filled with sand. In order to prevent this from occurring, slotted metal pipe is placed in the horizontal sections. The sand is supported by the metal pipe, while the heavy oil seeps through the slots into the pipe where it can be pumped to surface.
It is not unusual for the slots to have a width of between 25 and 15 thousandths of an inch. Even with slots of that width, some sand enters the pipe. In order to further restrict the entry of sand into the pipe, the industry is demanding slots of less than 15 thousandths of an inch. It has yet to be determined how small the slots can be without unduly restricting the rate of flow into the pipe. It has been speculated that between 5 and 7 thousandths of an inch will be optimum. Unfortunately, most slot cutting equipment is unable to cut slots with a width of less than 15 thousandths of an inch. German Offenlegungsschrift DE 32 13 46 A1 discloses slot cutting equipment capable of cutting multiple slots around a circumference of a pipe. The reference discloses a support for supporting a pipe in a horizontal orientation and a plurality of cutting heads positioned along the axial length of the pipe.
SUMMARY OF THE INVENTION
What is required is a method for making slots in metal pipe that is better suited for making slots less than 15 thousandths of an inch in width.
According to the present invention there is provided a method for making slots in metal pipe. Firstly, providing a metal pipe having an exterior surface and an interior surface which defines an axially extending interior bore. Secondly, cutting an axially extending elongate slot having a width that is larger than desired in the pipe with a cutting tool. The slot extends through the pipe providing fluid communication from the exterior surface to the interior surface. The slot has longitudinal peripheral edges. Thirdly, applying pressure to the exterior surface of the pipe along at least one of the longitudinal peripheral edges of the slot until the metal pipe is deformed sufficiently to close the slot to a desired width.
With the method, as described above, short comings in cutting equipment are overcome by applying pressure until the material surrounding the slot yields to narrow the slot to a desired width. There are a variety of ways that this can be done. A preferred manner of applying pressure is by means of a roller.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings, wherein:
FIG. 1 is a side elevation view, in cut away section, of a pipe which is in the process of being slotted in accordance with the teachings of the present method.
FIG. 2 is a side elevation view, in cut away section, of a slot in the pipe illustrated in FIG. 1, being treated by a pressure roller.
FIG. 3 is a side elevation view, in cut away section, of a pipe that has been slotted in accordance with the teachings of the present method.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred method for making slots less than 15 thousandths of an inch in width in metal pipe will now be described with reference to FIGS. 1 through 3.
Referring to FIG. 1, firstly, provide a metal pipe 10 having an exterior surface 12 and an interior surface 14 which defines an axially extending interior bore 16. Secondly, cut an axially extending elongate slot 18 having a width that is larger than desired in metal pipe 10 with a cutting tool (not shown). The cutting tool can take various forms f
REFERENCES:
patent: 1207808 (1916-12-01), Steps
patent: 2306945 (1942-12-01), Hebron
Hruschak Lawrence Alexander
Larson Lowell A.
Mclean Terry James
Venning Laurie Alfred
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