Expandable float shoe and associated methods

#The present invention relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides an expandable float shoe and associated methods.

#In a well in which intersecting wellbores are utilized, it is known to convey a wellbore junction into the well and position it at the desired wellbore intersection. In one method, the wellbore junction is conveyed into the well in a compressed shape, so that the wellbore junction may be displaced through casing above the wellbore intersection. The wellbore junction is then expanded at the wellbore intersection. This expansion provides enhanced access and flow through the junction.

#Expansion of the wellbore junction may be accomplished by applying pressure internally to the junction, thereby inflating the junction. For example, one leg of the junction may be compressed and placed against the remainder of the junction, and then pressure applied internally to the leg causes it to move and expand outward. Unfortunately, such wellbore junction designs have met with limited success in satisfactorily expanding the junction leg.

#FIG. 1 is a partially cross-sectional view of a method embodying principles of the present invention;

#FIG. 2 is a partially cross-sectional view of the method of FIG. 1, wherein a wellbore junction has been expanded in a well;

#FIG. 3 is a cross-sectional view of a float shoe which may be used in the method of FIG. 1, the float shoe embodying principles of the invention;

#Representatively illustrated in FIG. 1 is a method 10 which embodies principles of the present invention. In the following description of the method 10 and other apparatus and methods described herein, directional terms, such as “above”, “below”, “upper”, “lower”, etc., are used only for convenience in referring to the accompanying drawings. Additionally, it is to be understood that the various embodiments of the present invention described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the present invention.

#In the method 10, an expandable wellbore junction 12 is conveyed into a wellbore 22 through a casing or liner string 14. To permit the junction 12 to pass through the casing 14, the junction is formed into a compressed shape prior to conveying it into the well. As depicted in FIG. 1, a main tubular housing 18 of the junction 12 is folded somewhat along its length, and a tubular leg assembly 16 of the junction is also folded and positioned against the housing. It should be understood, however, that many different particular expanding apparatus configurations, methods of compressing the apparatus, etc. may be utilized without departing from the principles of the invention.

#The compressed wellbore junction 12 is positioned within a radially enlarged cavity 20 formed in the well. The cavity 20 is formed at a location where it is desired to drill another wellbore (not shown) extending outwardly therefrom. To drill the intersecting wellbore, the wellbore junction 12 is expanded so that cutting tools, such as mills and drills, may pass therethrough. In particular, the leg assembly 16 is expanded in the method 10 so that the cutting tools are permitted to pass therethrough to drill the intersecting wellbore.