Tubular airlock assembly

#Not Applicable

#1. Field of the Invention

#The present invention generally relates to an apparatus and method for facilitating deployment of a tubular string (i.e., tubing) in a casing string or wellbore. More specifically, the present invention provides a rupture assembly for use at the bottom of a tubing string that in conjunction with a sealing assembly higher up in the tubing string, creates an airlock or buoyancy chamber in the tubing to allow a float environment during deployment of the tubing where in the rupture and sealing assemblies are designed to rupture from applied hydraulic pressure in a way to make for easy removal of the pieces once the tubing is set at the desired depth in the casing string or wellbore.

#A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing figures wherein:

#FIG. 1 is a cross-sectional view of a wellbore incorporating the sealing and the rupture assemblies according to an exemplary embodiment of the present invention;

#FIG. 2 is a cross-sectional view of a rupture assembly of the tubular airlock assembly according to an exemplary embodiment of the present invention;

#In one particular exemplary embodiment of the invention, a In the following description, directional terms such as “above”, “below”, “upper”, “lower”, “uphole”, “downhole”, etc. are used for convenience in referring to the accompanying drawings. One of ordinary skill in the art will recognize that such directional language refers to locations in downhole tubing either closer or farther from the wellhead and that various embodiments of the present invention may be utilized in various orientations, such as inclined, deviated, horizontal, vertical, and the like.

#Referring to FIGS. 1-6, the present invention relates to a tubular airlock assembly and method for facilitating deployment of a tubing string 10 into a wellbore 12. The tubular airlock assembly of the present invention preferably includes a rupture assembly 100 disposed in the tubing 10, that along with a sealing assembly 22, maintains an airlock or buoyancy chamber 20 in the tubing 10 to assist in positioning the tubing 10 in the wellbore 12, particularly in a horizontal section 14 of the wellbore 12. Once the tubing 10 is fully deployed to its desired vertical depth and/or horizontal position in the wellbore 12, the sealing assembly 22 is designed to easily rupture into very small fragments through application of hydraulic pressure allowing the buoyance chamber 20 to be filled with fluid from above. Once fluid fills the buoyancy chamber 20, the rupture assembly 100 is designed to easily rupture into very small fragments through the application of hydraulic pressure so that the fragments of the sealing assembly 22 and rupture assembly 100 may be circulated out of the well. The sealing assembly 22 and rupture assembly 100 in a preferred embodiment, once ruptured, do not reduce the inner diameter ID1 (FIG. 2) of the tubing 10.

#As seen in FIG. 1, the rupture assembly 100 of the present invention is preferably disposed at the toe or bottom of the tubing 10 to form a temporary isolation barrier to seal off the fluid from the wellbore 12 as the tubing 10 is being run therein, thereby maintaining and protecting the integrity of a buoyant chamber 20 in the tubing 10. The buoyant chamber 20 may be filled with air, or any fluid that provide buoyancy, to provide float to the tubing 10. The buoyant chamber 20 is formed between the rupture assembly 100, which is the lower boundary of the chamber, and a sealing assembly 22 located at or near the heel or upper part of the tubing 10, which is the upper boundary of the chamber. Air in the buoyant chamber 20 is trapped between the rupture assembly 100 of the present invention and the sealing assembly 22. The buoyant chamber 20 in the tubing 10 may be created as a result of sealing of the lower or toe end 24 of the tubing 10 with the rupture assembly 100 of the present invention and sealing of the upper or heel end 26 of tubing 10 with the sealing assembly 22. The distance between the rupture assembly 100 and sealing assembly 22 is selected to control the force tending to run the tubing into the hole and to maximize the vertical weight of the tubing.