Downhole stabilizer

Abstract

A stabilizer comprised of a tubular body which has an exterior surface with selectively positioned indentations. A sleeve is positioned over the tubular body. The sleeve has an interior surface in contact with the exterior surface and a plurality of radial longitudinally oriented vanes. A plurality of radial apertures extend through the sleeve. The sleeve is secured to the body against rotation or axial movement by set screws. Each of the set screws extend through one of the apertures of the sleeve to engage on to the indentation in the exterior surface of the body.

Description

FIELD OF THE INVENTION

The present invention relates to a stabilizer, that is used to stabilize tubular bodies positioned downhole, such as a down hole drilling motor

BACKGROUND OF THE INVENTION

A downhole drilling motor is in excess of 25 feet in length. When drilling with a downhole drilling motor, some flexing of the downhole drilling motor occurs whenever the drill string becomes differentially stuck down hole, due to uneven fluid pressure acting upon the stator housing. This flexing is undesirable, as it causes excessive wear of the stator. In order to reduce this flexing and protect the drilling motor, stabilizers are placed both above and below the drilling motor. Stabilizers, such as that disclosed in Canadian application number 2,439,331 can be effective, but there are inherent limitations on how small they can be constructed without adversely effecting threaded connections.

SUMMARY OF THE INVENTION

According to the present invention there is provided a stabilizer comprised of a tubular body which has an exterior surface with selectively positioned indentations. A sleeve is positioned over the tubular body. The sleeve has an interior surface in contact with the exterior surface and a plurality of radial longitudinally oriented vanes. A plurality of radial apertures extend through the sleeve. The sleeve is secured to the body against rotation or axial movement by set screws. Each of the set screws extend through one of the apertures of the sleeve to engage on to the indentation in the exterior surface of the body.

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, the drawings are for the purpose of illustration only and are not intended to in any way limit the scope of the invention to the particular embodiment or embodiments shown, wherein:

FIG. 1 is a side elevation view, in section, of a stabilizer constructed in accordance with the teachings of the present invention.

FIG. 2 is a side elevation view, in section, of a tubular body of the stabilizer illustrated in FIG. 1.

FIG. 3 is a side elevation view, in section, of a sleeve of the stabilizer illustrated in FIG. 1.

FIG. 4 is a end elevation view, in section, of the stabilizer illustrated in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment, a stabilizer generally identified by reference numeral 10, will now be described with reference to FIG. 1 through 4.

Structure and Relationship of Parts:

Referring to FIG. 1, there is a stabilizer 10 which includes a tubular body 12 and a sleeve 14.

Referring to FIG. 2, tubular body 12 has an exterior surface 16 with selectively positioned indentations 18. Referring to FIG. 1, sleeve 14 is positioned over tubular body 12. Sleeve 14 has an interior surface 20 in contact with exterior surface 16. Referring to FIG. 4, sleeve 14 has a plurality of radial longitudinally oriented vanes 22. Referring to FIG. 3 and 4, a plurality of radial apertures 24 extend through sleeve 14. Referring to FIG. 3, radial apertures 24are positioned at regular intervals along sleeve 14. Referring to FIG. 1, sleeve 14 is secured to tubular body 12 against rotation or axial movement by set screws 26. Set screws 26 extend through apertures 24 of sleeve 14 to engage on to indentation 18 in exterior surface 16 of tubular body 12. Plurality of radial apertures 24 are positioned on radial longitudinally oriented vanes 22 where the sleeve 14 is thickest.

Operation:

The use and operation of stabilizer 10 will now be described with reference to FIG. 1. Referring to FIG. 1, sleeve 14 is positioned over tubular body 12. Set screws 26 are then threaded through each of apertures 24 of sleeve 14 to engage on to indentation 18 in exterior surface 16 of tubular body 12 such that sleeve 14 is secured to tubular body 12 against rotation or axial movement. As set screws 26 are used to secured sleeve 14 to tubular body 12 rather than threading the parts together, the size of stabilizer is reduced allowing it to operate in smaller spaces. Drilling motors can drill different sizes of bore holes depending upon what bit is used. For example, a 4⅞ inch diameter motor can be used to form a bore hole which may vary in size between 6 inches and 6⅞ inches. Stabilizer 10 can readily be adapted to suit the bore hole, by having several sizes of sleeve 14 on site and selecting an appropriate sized sleeve 14.

Variations:

Stabilizer 10 has been illustrated with one of many possible vane configurations. The vanes illustrated are longitudinally oriented in a linear configuration. It will be appreciated that they vanes could be longitudinally oriented in a helical configuration. The vane configuration is not a critical part of the invention. One skilled in the art will be able to select suitable vane configurations.

In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.

It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiment without departing from the spirit and scope of the invention as hereinafter defined in the Claims.

Claims

1. A stabilizer, comprising:

a tubular body having an exterior surface with selectively positioned indentations; and

a sleeve positioned over the tubular body, the sleeve having an interior surface in contact with the exterior surface, the sleeve having a plurality of radial vanes, a plurality of radial apertures extending through the sleeve, the sleeve being secured to the body against rotation or axial movement by set screws, each of the set screws extending through one of the apertures of the sleeve to engage on to the indentation in the exterior surface of the body.

2. The stabilizer as defined in claim 1, wherein the selectively positioned indentions are positioned at regular intervals.

3. The stabilizer as defined in claim 1, the plurality of radial apertures are positioned on the radial vanes where the sleeve is thickest.