ADJUSTABLE BENT HOUSING
An adjustable bent housing (10) includes a first tubular body (12) and a second tubular body (14). The second tubular body (14) telescopically extends into the first tubular body (12) and is maintained in relative axial position by a threaded engagement (30 & 22). A locking sleeve (44) is provided to maintain the relative rotational position of the first tubular body (12) and the second tubular body (14). The locking sleeve (44) is non-rotatably coupled with and slidably movable the second tubular body (14) between a locking position and an adjusting position. A locking nut (48) is movable on the external surface (24) of the second tubular body (14) selectively clamps the locking sleeve (44) in the locking position. This adjustable bent housing (10) accommodates larger diameter drive shafts, while allowing adjustment to take place without changing the overall length of the housing.
The present invention relates to an adjustable bent housing used for deviating a drilling string when directional drilling.
BACKGROUND OF THE INVENTIONAn adjustable bent housing is used to accommodate a drive shaft that connects a power section and a bit section of a down hole drilling motor. Canadian Patent 2,022,452 (Wenzel et al from 1990) illustrates a form of adjustable bent housing that has been in use for the past decade. The Wenzel et al reference allows adjustment to take place without changing the overall length of the housing. This is of importance, as it permits more rapid adjustment by the rig crew. If the length had to be increased in order for an adjustment to be made, the rotor of the power section would have to slide axially in the stator of the power section in order for an adjustment to be made.
A moineau-style power unit having a rotor and stator is generally used for the power section. In recent years there has been a trend to lengthen the power section by using longer rotors and stators. This has resulted in increased torque output, which has required that larger drive shafts be used. There is a limit as to the size of drive shaft that can be accommodated by the Wenzel et al adjustable bent housing.
SUMMARY OF THE INVENTIONWhat is required is an adjustable bent housing which can accommodate larger diameter drive shafts, while allowing adjustment to take place without changing the overall length of the housing.
According to the present invention there is provided an adjustable bent housing which includes a first tubular body and a second tubular body. The first tubular body has an internal surface defining a first portion of an interior bore and internal threads in the internal surface at one end. The second tubular body has an external surface, an internal surface defining a second portion of the interior bore, first external threads on the external surface at one end and second external threads on the external surface spaced from the first external threads. The one end of the second tubular body is adapted to telescopically extend into the one end of the first tubular body with the first external threads engaging the internal threads. Means is provided to create a first axial deviation in the first tubular body and means being provided to create a second axial deviation in the second tubular body, such that by relative rotation of the first tubular body and the second tubular body the first axial deviation and the second axial deviation can be either offset, made cumulative or set at an angular range between the offset and cumulative rotational positions. A locking sleeve is non-rotatably coupled with and slidably movable along the exterior surface of the second tubular body between a locking position and an adjusting position. The locking sleeve has an engagement face. In the locking position, the engagement face of the locking sleeve engages the one end of the first tubular body thereby preventing relative rotation of the first tubular body and the second tubular body. In the adjusting position, the locking sleeve is spaced from the one end of the first tubular body, thereby permitting relative rotation of the first tubular body and the second tubular body to occur. A locking nut is movable along the second external threads on the external surface of the second tubular body to selectively clamp the locking sleeve in the locking position.
The adjustable bent housing, as described above, provides a larger interior bore and a stronger body, while still allowing adjustment to take place with minimal change to the overall length of the housing.
The preferred embodiment, hereinafter described, has a number of further features which provide additional benefits. In the past, the incursion of drilling fluids have damaged engagement threads. In the preferred embodiment, all of the threads are sealed to prevent the incursion of drilling fluids. In the past, problems have been encountered in getting the locking sleeve to release. In the preferred embodiment, the locking nut and the locking sleeve have been coupled, so that the locking nut draws the locking sleeve from the locking position to the adjusting position. In the past, metal stress problems have been experienced. In the preferred embodiment, stress relief has been incorporated into the design. In the past, a spline engagement has been provided between the locking sleeve and the second tubular body. In the preferred embodiment, the same function is performed by a single locking key. This makes the adjustable bent housing easier and cheaper to manufacture, more robust, and easier to use in the field.
BRIEF DESCRIPTION OF THE DRAWINGSThese 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:
The preferred embodiment, an adjustable bent housing generally identified by reference numeral 10, will now be described with reference to
Structure and Relationship of Parts:
Referring to
As is known to persons skilled in the art, means must be provided to create a first axial deviation 34 (shown in dotted lines) in first tubular body. Similarly, means must be provided to create a second axial deviation 36 (shown in dotted lines) in second tubular body 38. Upon relative rotation of first tubular body 12 and second tubular body 14, first axial deviation 34 and second axial deviation 36 can be either offset, made cumulative or set at an angular range between the offset and cumulative rotational positions. Referring to
Referring now to
Operation:
The use of adjustable bent housing 10 will now be discussed with reference to
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. An adjustable bent housing (10), comprising:
- a first tubular body (12) having an internal surface (16) defining a first portion (18) of an interior bore (20) and internal threads (22) in the internal surface (16) at one end;
- a second tubular body (14) having an external surface (24), an internal surface (26) defining a second portion (28) of the interior bore (20) and first external threads (30) on the external surface (24) at one end and second external threads (32) on the external surface (24) spaced from the first external threads (30), the one end of the second tubular body (14) being adapted to telescopically extend into the one end of the first tubular body (12) with the first external threads (30) engaging the internal threads (22);
- means being provided to create a first axial deviation (34) in the first tubular body (12) and means being provided to create a second axial deviation (36) in the second tubular body (14), such that by relative rotation of the first tubular body (12) and the second tubular body (14) the first axial deviation (34) and the second axial deviation (36) can be either offset, made cumulative or set at an angular range between the offset and cumulative rotational positions;
- a locking sleeve (44) non-rotatably coupled with and slidably movable along the exterior surface (24) of the second tubular body (14) between a locking position and an adjusting position, the locking sleeve (44) having an engagement face (46), in the locking position the engagement face (46) of the locking sleeve (44) engages the one end of the first tubular body (12) thereby preventing relative rotation of the first tubular body (12) and the second tubular body (14), in the adjusting position the locking sleeve (44) is spaced from the one end of the first tubular body (12), thereby permitting relative rotation of the first tubular body (12) and the second tubular body (14) to occur; and
- a locking nut (48) being movable along the second external threads (32) on the external surface (24) of the second tubular body (14) to selectively clamp the locking sleeve (44) in the locking position, an engagement (50) being provided between the locking nut (48) and the locking sleeve (44), so that the locking nut (48) is used to pull the locking sleeve (44) from the locking position to the adjusting position.
2. The adjustable bent housing as defined in claim 1, wherein the locking sleeve (44) is non-rotatably secured to the external surface (24) of the second tubular body (14) by at least one key (54).
3. The adjustable bent housing as defined in claim 1, wherein the locking sleeve (44) is non-rotatably secured to the external surface (24) of the second tubular body by a splined arrangement (55).
4. The adjustable bent housing as defined in claim 1, wherein the engagement is a retaining ring (50).
5. The adjustable bent housing as defined in claim 1, wherein the engagement is a plurality of flexible fingers (51).
6. The adjustable bent housing as defined in claim 1, wherein a seal (52) is positioned at the one end of the second tubular body (14) between the internal surface (16) of the first tubular body (12) and the external surface (24) of the second tubular body (14) to prevent drilling fluids passing along the interior bore (20) from getting into the first external threads (30).
7. The adjustable bent housing as defined in claim 1, wherein an interlocking engagement (56) is provided between the engagement face (46) of the locking sleeve (44) and the one end of the first tubular body (12).
8. The adjustable bent housing as defined in claim 1, wherein the engagement is a plurality of balls (53) contained within corresponding grooves (55/57) in the locking sleeve (44) and the locking nut (48).
9. The adjustable bent housing as defined in claim 7, wherein the interlocking engagement (56) is in the form of teeth (58).
10. The adjustable bent housing as defined in claim 7, wherein the interlocking engagement (56) is in the form of pins (59).
11. The adjustable bent housing as defined in claim 1, wherein a seal (60) is positioned between an internal face (62) at a remote end of the locking nut (48) and the second tubular body (14) to prevent drilling fluids passing along the second tubular body (14) from getting into the second external threads (32).
12. The adjustable bent housing as defined in claim 1, wherein changes in external diameter are curved to accommodate limited flexing and provide stress relief.
13. The adjustable bent housing as defined in claim 1, wherein changes in internal diameter are curved to accommodate limited flexing and provide stress relief.
14. The adjustable bent housing as defined in claim 1, wherein the means provided to create the first axial deviation (34) includes at least one of: machining the first tubular body (12) to create an inherent deviation or machining the internal threads (22) with an inherent deviation or machining the one end of the first tubular body (12) with an inherent deviation.
15. The adjustable bent housing as defined in claim 1, wherein the means provided to create the second axial deviation (36) includes at least one of: machining the second tubular body (14) to create an inherent deviation or machining the first external threads (30) with an inherent deviation or machining the engagement face (46) on the locking sleeve (44) with an inherent deviation.
Type: Application
Filed: Dec 6, 2006
Publication Date: May 3, 2007
Inventors: Orren Johnson (Edmonton), William Wenzel (Edmonton)
Application Number: 11/567,656
International Classification: E21B 7/08 (20060101);