RELATED PRIORITY DATE APPLICATION This application claims the benefit under 35 U.S.C. 119(e) of the U.S. provisional application No. 62/541,866 filed on Aug. 7, 2017.
TECHNICAL FIELD OF THE INVENTION The present invention relates to the field of oil and gas production and, more particularly, to an apparatus for gripping devices on tubular members downhole. Still more particularly, the present invention discloses a stop collar assembly and a method of installing the same.
BACKGROUND OF THE INVENTION The use of stop collar assemblies downhole in oil and gas production operations are well known. Stop collars are used to position the various downhole tools about the casing and wellbore. In the past, stop collar assemblies were ring or hinged ring assemblies with a locking pin that is locked in place by set screws. One disadvantage of the set screws is that they are point loading on the casing whereby corrosive spots maybe caused thereon. Another disadvantage is that the holding force of the set screws are a weak point of the system. Still another disadvantage is that hinged rings are easy to break.
According to the present invention, a stop collar assembly and a method for installing the same are disclosed. The stop collar does not utilize screws, utilizes metal rings and provides a high holding force due to its compression type installation.
These and other advantages of the present invention will become apparent from the following description.
SUMMARY OF THE INVENTION A stop collar assembly and a method of installing it on a tubular member is disclosed. The stop collar assembly includes identical and symmetrically disposed over a tubular member two end rings and an inner sleeve disposed over the tubular member between the end rings. The inner sleeve includes a split section to facilitate the sliding of inner sleeve over the tubular member during installation and to provide a closeable gap when compression is applied on the exterior of the inner sleeve.
In installation, one of the two end rings is slidingly received over the tubular member. Then, the inner sleeve is slidingly received over the tubular member followed by the second of the two end rings.
The stop collar assembly is assembled by pressing on the exterior ends of the end rings to slide them towards each other over inner sleeve until they abut each other in the middle portion of the inner sleeve. In the process, as the end rings advance towards each other, they apply pressure on the exterior surface of the inner sleeve to cause the inner sleeve to form a very tight and strong grip on the tubular member. The pressing on the exterior ends of the end rings to move them towards each other over the inner sleeve is done by a hydraulic tool.
Following the installation of the stop collar assembly on the tubular member, an attachment is slidingly received over the tubular member and the process described above is repeated to install another stop collar assembly on the other side of the attachment so that the attachment is securely attached to the tubular member.
BRIEF DESCRIPTION OF THE DRAWING For a more detailed description of the preferred embodiment of the invention, reference will now be made to the accompanying drawings, wherein:
FIG. 1 is a three dimensional schematic of the stop collar of the present invention showing the stop collar in an unassembled position over a tubular member;
FIG. 2 is a side view of the stop collar in the position depicted in FIG. 1;
FIG. 3 is a three dimensional schematic of the stop collar of FIG. 1 showing the stop collar in a position over a tubular member prior to securely affixing it to the tubular member via compression;
FIG. 4 is a side view of the stop collar in the position depicted in FIG. 3;
FIG. 5 is a three dimensional schematic of the stop collar of FIG. 1 showing the stop collar in a fully compressed position over a tubular member when it is securely affixed to the tubular member via compression;
FIG. 6 is a side view of the stop collar in the position depicted in FIG. 5;
FIG. 7 is a three dimensional schematic of a hydraulic installation tool used to securely affix the stop collar assembly to the tubular member;
FIG. 8 is an exploded schematic view of the stop collar assembly of the present invention in the position depicted in FIG. 1;
FIG. 9 is a schematic side view of the exploded schematic of the stop collar assembly depicted in FIG. 8;
FIG. 10 is a schematic side view of the stop collar assembly of the present invention in the position depicted in FIG. 3;
FIG. 11 is a three dimensional schematic view of the stop collar assembly of the present invention in the fully compressed position depicted in FIG. 5; and
FIG. 12 is a schematic side view of the stop collar assembly depicted in the position depicted in FIG. 11.
DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1, there is shown a three dimensional schematic of a stop collar assembly 10 in an unassembled position disposed over a casing 16 used in oil and gas operations. Stop collar assembly 10 includes identical and symmetrically disposed over casing 16 end rings 12A and 12B and an inner sleeve 14 disposed over casing 16 between end rings 12A and 12B. End rings 12A and 12B are made of strong metal material such as steel and are appropriately sized to slide over the exterior of inner sleeve 14 and to effect the desired compression on inner sleeve 14 as hereinafter described. Inner sleeve 14 is also constructed of metal material such as steel and it is appropriately sized to be intimately received over the exterior of casing 16. Inner sleeve 14 includes a split section 18 to facilitate the sliding of inner sleeve 14 over casing 16 during installation and to provide a closeable gap when compression is applied on inner sleeve 14. The inner surface of inner sleeve is preferably lined with rubber or other material suitable for increasing the gripping force of the stop collar assembly 10 on casing 16 when compression is applied on assembly 10 as hereinafter described.
Referring now to FIG. 2, there is shown a side view of stop collar assembly 10 in the unassembled position depicted in FIG. 1 having end rings 12A and 12 B and inner sleeve 14 with split section 18.
Referring back to FIG. 1, in order to install stop collar assembly 10 over casing 16 one of the two end rings 12 A or 12B is slidingly received over casing 16. Then, inner sleeve 14 is slidingly received over casing 16 followed by the second of the two end rings 12A or 12B. Inner sleeve 14 is positioned in the desired position over casing 16.
Referring now to FIG. 3, following the sliding engagement of end rings 12A and 12B and inner sleeve 14 of stop collar assembly 10 over casing 16 described above, end rings 12A and 12B are secured to both sides of inner sleeve 14 so that they are anchored and perpendicular to the centerline of inner sleeve 14. Split section 18 is shown in the unbiased position prior to the application of the compression force. Referring now to FIG. 4, there is shown the side view of stop collar assembly 10 in the anchored position shown in FIG. 3 comprised of end rings 12A and 12B, and inner sleeve 14 having split section 18.
It should be understood that although the schematics of FIGS. 3 and 4 show end rings 12A and 12B as being over a substantial portion of inner sleeve 14 in the anchoring position, the schematic is an exaggeration to demonstrate the anchoring of the components prior to compression and that, in practice, only the beveled ends 22A and 22B of end rings 12A and 12B, respectively, which are shown and described in FIG. 9 below are over inner sleeve 14.
Referring now to FIG. 5, stop collar assembly 10 is assembled by pressing on the exterior ends of end rings 12A and 12B to slide them towards each other over inner sleeve 14 until they abut each other in the middle portion of inner sleeve 14. In the process, as end rings 12A and 12B advance towards each other, they apply pressure on the exterior surface of inner sleeve 14 to cause inner sleeve 14 to form a very tight and strong grip on casing 16. The pressing on the exterior ends of end rings 12A and 12B to move them towards each other over inner sleeve 14 is effected by a hydraulic tool 30 (not shown in FIG. 5 but shown in FIG. 7).
Referring now to FIG. 6, there is shown the side view of stop collar assembly 10 in the assembled position shown in FIG. 5 comprised of end rings 12A and 12B, and inner sleeve 14.
Referring now to FIG. 7, there is shown a hydraulic tool 30 disposed over casing 16 that is used to apply pressure on the ends of end rings 12A and 12B to move them towards each other over inner sleeve 14 to cause sleeve 14 to form a tight strong grip with casing 16. It s hould be understood that although this embodiment is described in connection with the use of a hydraulic tool to apply pressure on the end rings, any other mechanical devices may be used to apply pressure on the end rings to advance them towards each other as described above to apply pressure on the middle sleeve.
Following the installation of stop collar assembly 10 on casing 16, hydraulic tool 30 is removed. Then, a casing attachment is slidingly received over casing 10 and the process described above is repeated to install another stop collar assembly on the other side of the casing attachment so that the casing attachment is securely attached to casing 16. It should be noted that in the case wherein the casing attachment is a centralizer, sufficient distance between the stop collar assemblies on either side thereof should be provided for the centralizer's expansion when collapsing.
Casing 16 with stop collar assembly 10 and attachments is lowered downhole to conduct well known oil and gas production operations.
Referring now to FIG. 8, there is shown an enlarged exploded schematic stop collar assembly 10 in the unassembled position described in connection with FIG. 1. Stop collar assembly 10 includes identical and symmetrically arranged end rings 12A and 12B and an inner sleeve having split section 18.
Referring to FIG. 9, there is shown a side view of stop collar assembly 10 in the unassembled position depicted in FIG. 8 having end rings 12A and 12 B and inner sleeve 14. End ring 12A has a beveled end 22A and end ring 12B has a beveled end 22B. Beveled ends 22A and 22B are appropriately sized to accommodate the anchoring of end rings 12A and 12B to inner sleeve 14. Referring now to FIG. 10, there is shown a side view of stop collar assembly 10 showing the anchoring connection between end rings 12A and 12B with inner sleeve 14 prior to initiating the pressing on end rings 12A and 12B towards each other by hydraulic tool 30 (not shown) as described above. Beveled ends 22A and 22B of end rings 12A and 12B, respectively, facilitate the initiation of the sliding motion of end rings 12A and 12B over inner sleeve 14 towards each other to cause the compression on the exterior of inner sleeve 14 and to create the tight grip on casing 16.
Referring now to FIGS. 10 and 11, there is shown assembly 10 in its assembled position wherein end rings 12A and 12B have fully advanced towards each over inner sleeve so as to effect a tight grip on casing 16 (not shown).
In an alternative embodiment, in accordance with the present invention, one ring can be used instead of the two end rings to practice the invention. In that embodiment, the stop collar assembly is assembled by sliding the single ring over the sleeve to apply pressure on the exterior surface of the sleeve and to cause it to form a very tight and strong grip on the casing.
While the invention is described with respect to specific embodiments, modifications thereof can be made by one skilled in the art without departing from the spirit of the invention. The details of said embodiments are not to be construed as limitations except to the extent indicated in the following claims.
