Extendable spool

An extendable spool is disclosed. The length of the extendable spool is able to continuously varied. The extendable spool accounts for length variances in flow lines by extending the flow line rather than redirecting the flow. Because the flow direction does not make any turns, erosion is minimized on both the extendable spool and downstream parts. The extendable spool is readily scalable from small diameters to large diameters. Because of this, it requires fewer lines and therefore less setup time to account for length differences between large diameter lines.

TECHNICAL FIELD

The present disclosure relates generally to oil or gas wellbore equipment, and, more particularly, to an extendable spool connector.

BACKGROUND

Accounting for length variances on non-permanent, pressurized, fluid-flow lines is normally accomplished by redirecting the flow through one or more turns until the desired length is achieved. Examples of the traditional length make-up methods are seen with hoses (via their flexible nature) and swiveling elbows (e.g., Chiksans). However, flow redirection through elbows or hoses accelerates erosion, especially when there are particulates in the fluid and/or when the fluid is flowing at a high rate, as seen during hydraulic fracturing operations. Erosion is accelerated not only on the parts redirecting the flow, but also on parts downstream.

Another drawback of using flow redirection for length make-up is that the method is not easily scalable to larger diameters—the required wall thicknesses quickly make installation difficult at best, to impractical at worst; therefore, traditional flow redirection lines used to make up for length variances are, relatively speaking, smaller diameters. One drawback of only being able to redirect flow with small diameter lines is that multiple redirected-flow lines must be used to account for length differences between large diameter lines. Therefore, what is needed is an apparatus, system, or method that addresses one or more of the foregoing issues, among one or more other issues.

SUMMARY OF THE INVENTION

The extendable spool accounts for length variances by extending the flow line rather than redirecting the flow. Because the flow direction does not make any turns, erosion is minimized on both the extendable spool and downstream parts. The extendable spool is readily scalable from small diameters to large diameters. Because of this, it requires fewer lines and therefore less setup time to account for length differences between large diameter lines.

DETAILED DESCRIPTION

In an exemplary embodiment,FIGS. 1 and 2schematically illustrate an extendable spool100. The extendable spool100is a flow spool with a variable length.FIG. 1illustrates the extendable spool100in fully contracted or compressed configuration, andFIG. 2illustrates it in its fully extended configuration. The length is able to be varied continuously, rather than discretely, between the fully contracted and fully extended configurations.FIGS. 3 and 4show isometric cutaway views of an embodiment of an extendable spool in fully contracted and fully extended positions.

The structure for two tubular sections of the extendable spool100through which fluid flows are described first. These sections are the threaded tube101and the inner tube102. Each tubular section is designed to withstand pressurized fluids that may be used in hydraulic fracturing or other high-pressure downhole operations. The threaded tube101may have an inner diameter, referenced inFIG. 1as ‘A,’ that is equivalent to the inner diameter of other tubular equipment to which the extendable spool may be connected. The threaded tube101may comprise an inner beveled shoulder120at which point the inner diameter of the threaded tube101increases from ‘A’ to a larger diameter ‘B.’ This increased diameter ‘B’ of the threaded tube101allows it to accommodate the outer diameter of inner tube102. The inner surface of the threaded tube101and the outer surface of inner tube102are both smooth, such that the inner tube102is able to freely move axially within the increased inner diameter of the threaded tube101. If inner tube102has an inner diameter of ‘A,’ then increased inner diameter ‘B’ of the threaded tube101will be substantially similar to diameter ‘A’ plus twice the wall thickness of inner tube102.

The inner beveled shoulder120of the threaded tube101may act as a physical stop to the inward axial movement of inner tube102when inner tube102is axially moved relative to threaded tube101. The inner tube102comprises an outer shoulder130which similarly may act a physical stop to the inward axial movement of inner tube102relative to threaded tube101. The inner end portion of inner tube102may include a beveled end cap called a wash cone107which may be threadably engaged with inner tube102. In an embodiment, the wash cone107may be integral to inner tube102. The wash cone107has an outer diameter that is equal to the outer diameter of the inner tube102, and the inner diameter of the wash cone107varies radially along the bevel from the inner diameter of the inner tube102to the increased inner diameter of the threaded tube101.

In the embodiment above, both the inner beveled shoulder120of the threaded tube101and the beveled surface of wash cone107are configured to gradually change their inner diameter from ‘A’ to ‘B.’ Accordingly, there are no abrupt interior edges along the flow path through the threaded tube101and the inner tube102, even when the threaded tube101and inner tube102are configured to different axial lengths of the extendable spool100.

The ends of the threaded tube101and the inner tube102may each threadably engage with a spool flange103, which enables both ends of the extendable spool100to be connected to other tubular equipment. In an embodiment, the spool flanges may be integral to the threaded tube101and the inner tube102.

Sealing between the threaded tube101and the inner tube102is accomplished via seals113, such as o-rings, that sit in grooves on the outer surface of the inner tube102. Similarly, the wash cone107may accommodate one or more seals113in grooves on its outer surface. The seals113mate with a corrosion resistant sealing surface on the inner surface of the threaded tube101. Bronze pieces109,110, and111may be used to facilitate sliding between the different steel parts.

The structure for setting and fixing the length of the extendable spool100is now described. As noted above, the threaded tube101and the inner tube102are movable relative to each other. They may be fixed relative to each other using other components, including tensile tube104, inner wing105, and outer wing106. Referring still toFIGS. 1 and 2, the threaded tube101includes a threaded outer surface with which the inner wing105is threadably engaged. The axial location of the inner wing105along the threaded outer surface of the threaded tube101serves to define the length of extendable spool100and the position of the tensile tube104, as will be described further below.

Still referring toFIGS. 1 and 2, the tensile tube104may be threadably engaged with inner tube102at or around the outer shoulder130of inner tube102. Aside from the inner threaded connection that tensile tube104uses to connect to the outer shoulder130of inner tube102, the inner surface of tensile tube104is smooth and not threaded. This allows the inner tube102and the tensile tube104together to freely move axially with respect to threaded tube101even though the outer surface of threaded tube101is threaded. The inner tube102and the tensile tube104are axially positioned such that the tensile tube104abuts the inner wing105. As shown inFIGS. 1and2, the inner wing105and the tensile tube104abut at beveled ends, which allows the inner wing105to have a longer thread on its outer surface. In another embodiment, the inner wing105and the tensile tube104abut at straight ends.

Tensile tube104is fixed in place by outer wing106, which threadably engages with the threaded outer surface of inner wing105, and which locks the position of tensile tube104by engaging with a mating shoulder140of tensile tube104.

To change the length of the extendable spool100, the inner wing105and outer wing106are unscrewed from each other, which allows outer wing106and tensile tube104to axially move relative to each other, and also allows tensile tube104and inner tube102to move relative to threaded tube101. To extend the length of the spool100, hydraulic cylinders (shown as element150inFIG. 5) can be used to stroke the extendable spool100to a desired length by longitudinally moving the tensile tube104and the inner tube102relative to threaded tube101. Once the desired length is reached, the inner wing105is screwed to the desired position, or until inner wing105abuts tensile tube104. In order to minimize the number of turns required to move inner wing105into the desired position, the outer surface of threaded tube101may be configured with multiple-start threads. Once inner wing105is in the desired position, outer wing106is screwed back on to inner wing105to lock the position of tensile tube104.

If the operator desires to bring the ends of the spool closer together, the outer wing106is unscrewed from the inner wing105, and the inner wing105must be backed away from the tensile tube104until inner wing105reaches the desired position. Then, hydraulic cylinders can retract the two ends together until the tensile tube104makes contact with the inner wing105again. The inner and outer wings105and106are then screwed back together to lock the spool100at the desired length.

It should be noted that, although tensile tube104and inner tube102are shown as threadably engaged, they may also be connected using pins, bolts, or any other known method of connecting tubular members. The only requirement of the tensile tube is that it remain connected to inner tube102in order to transfer longitudinal force from one end of the spool to the other and to facilitate adjustment of the length of the extendable spool as described above. As a result, tensile tube104and inner tube102could be formed as a single piece without departing from the scope of the present disclosure.

The threads on the outer surface of threaded tube101may be left-hand, or reverse, threads, such that relative counter-clockwise rotation will cause engagement of threaded tube101and the inner threads of inner wing105. The threads that connect the wings (the outer threads of the inner wing105and the inner threads of outer wing106) may be right-hand threads, such that relative clockwise rotation will cause engagement of the outer threads of inner wing105and inner threads of outer wing106. The combination of right-hand threads at the inner-to-outer wing connection and left-hand threads at the inner-wing-to-threaded tube connection ensures that tightening the wings tightens both ends of the spool together. To accomplish this optional objective, the particular orientation of the two threaded portions of the inner wing is not important; in other words, it is irrelevant which set of threads is right-handed and which set of threads is left-handed. What matters is that the orientation of the threads that connect the inner wing to the outer wing is the opposite of the orientation of the threads that connect the inner wing to the threaded tube. The inner wing105and outer wing106may have radially outwardly extending protrusions, or lugs, which facilitate screwing and unscrewing.

FIG. 6illustrates an alternate embodiment of an extendable spool200. In this embodiment, the threaded tube201maintains a constant inner diameter ‘A.’ Inner tube202has an outer diameter that is substantially equal to ‘A’ and an inner diameter ‘C’ that is smaller. Other components and aspects of the extendable spool200are similar to those described above.

It is understood that variations may be made in the foregoing without departing from the scope of the present disclosure. In several exemplary embodiments, the elements and teachings of the various illustrative exemplary embodiments may be combined in whole or in part in some or all of the illustrative exemplary embodiments. In addition, one or more of the elements and teachings of the various illustrative exemplary embodiments may be omitted, at least in part, and/or combined, at least in part, with one or more of the other elements and teachings of the various illustrative embodiments.

Although several exemplary embodiments have been described in detail above, the embodiments described are exemplary only and are not limiting, and those skilled in the art will readily appreciate that many other modifications, changes and/or substitutions are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of the present disclosure. Accordingly, all such modifications, changes, and/or substitutions are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, any means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Moreover, it is the express intention of the applicant not to invoke 35 U.S.C. § 112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the word “means” together with an associated function.