Patent Application
20100163241
The field of the invention is subterranean well completions, or, more specifically, valve apparatus for preventing flow through a downhole tubular assembly.
Flapper valves, which prevent downward flow when closed, are known to be useful as part of a casing string cemented into a wellbore. The typical flapper valve will be open as the casing string is run into the well and cemented into place. It is common in such applications, for a flapper valve to be run into a well having a 6.125 in. (15.56 cm) hole diameter, as part of a 3.5 in. (8.89 cm) outside diameter (OD) casing string having a nominal internal diameter (ID) of approximately 3.0 in. (7.62 cm). The 6.125 in. (15.56 cm) hole dictates that the flapper valve outside diameter cannot practically exceed 5.875 in. (14.92 cm).
In the foregoing field situation, it is desirable to use 4.5 in. (11.43 cm) outside diameter casing string, (grade P110, 13.5 pounds per foot (6.12 kg per 30.48 cm) having a nominal internal diameter (ID) of 3.92 in. (9.96 cm), in lieu of the 3.5 in (8.89 cm) OD casing. This ID dictates that a practical flapper valve minimum ID be at least 3.8 in. (9.65 cm) to substantially take advantage of the increased ID of the 4.5 in. (11.43 cm) OD casing. Similarly, anything less causes a restriction in the casing ID that unacceptably prevents the passage of typically associated tools such as bridge plugs, shifting tools, and mechanical packers, some of which have maximum outside diameters of as high as 3.66 in. (9.30 cm). However, no currently available flapper valves, with the required maximum OD of 5.875 in. (14.92 cm), can provide the minimum ID of approximately 3.8 in. (9.65 cm) that would be compatible with the desired 4.5 in. (11.43) OD casing. Operators using currently available flapper valves are limited to the 3.5 in. (8.89 cm) OD casing in a 6.125 in. (15.56 cm) well hole.
Again, with respect to flapper valve assemblies that prevent downward fluid flow when closed, it is not uncommon in current practice for various components in the casing string to require that flapper valves have top and bottom ends with varying thread sizes and types to accommodate the varying pins, collars and boxes to which flapper valves are sometimes attached as the string is assembled. Currently available flapper valves have ends integrated with housing and/or flapper seat structure, or additional structure, generally, which prevent the ready replacement of a flapper valve assembly ends with ends having a different thread size or type.
Additionally, the assembly of flapper valve assemblies is generally complicated when the flapper seat, with flapper attached, has been previously integrated with housing structure and the flapper must be held open by inserting temporary, elongated devices into the housing. As the sleeve is then inserted, it is impossible to see the interaction between the flapper, which is biased to close, and the sleeve which must encounter and move the flapper to its full open position as it is inserted.
The present invention overcomes the shortcomings of the prior art by providing a flapper valve assembly, of the type preventing downward fluid flow when the flapper is closed, which is sized, shaped and configured to provide a smaller maximum outer diameter to minimum internal diameter ratio, thus allowing a larger minimum ID for a given maximum outside diameter, when compared to currently available flapper valve assemblies. Additionally, the present invention provides a modular saddle flapper valve assembly which provides an insert assembly having a flapper seat, flapper valve and sleeve, the insert assembly being secured within a tubular housing and enclosed by standard top and bottom subs, either sub being easily removed and replaced with a sub having a different thread size or type, the removal causing no disturbance to or disassembly of the insert assembly.
In some exemplary embodiments of our invention we have provided, a flapper valve assembly for inclusion in a downhole tubular assembly, the flapper valve assembly comprising: a tubular housing having an interior pocket, the pocket having an inside surface, the tubular housing further having a removable top member forming a tubular housing upper end, and a removable bottom member forming a tubular housing lower end, the bottom member having a top, the upper and lower ends each being attachable within the downhole tubular assembly; and an insert assembly, the insert assembly being insertable into the tubular housing pocket when the top member is removed, and retained within the pocket when the top member is attached, the insert assembly, the insert assembly having: a flapper seat, the flapper seat being substantially sealed against the tubular housing interior pocket inside surface; a flapper having a curved portion, the flapper being movable between a down position and an up position; a bias member biasing the flapper from the up position to the down position; and a sleeve upwardly slidably from a sleeve first position upon the flapper seat, the flapper seat preventing downward movement of the sleeve, to a sleeve second position, such that the flapper is held in the up position when the sleeve is in the first position, the bias member moving the flapper to the down position when the sleeve is in the second position, the sleeve further having a top portion having an outside diameter, and a bottom portion having an outside diameter smaller than the top portion, the sleeve top portion being substantially sealed against the tubular housing interior pocket inside surface, the sleeve bottom portion being saddled by the flapper curved portion when the sleeve is in the first position; wherein flow from the tubular housing pocket through the tubular housing lower end is prevented when the flapper is in the down position and allowed when the flapper is in the up position.
In some exemplary embodiments, the flapper seat further comprises side portions, the side portions having top, inwardly directed bevels; and further the flapper is positioned between the flapper seat side portions when the flapper is in the down position, the flapper being guided by the flapper seat side portion bevels to the down position between the flapper seat side portions, the flapper seat side portions resisting and/or substantially preventing lateral movement of the flapper during flapper deformation.
In some exemplary embodiments, the flapper further has opposing side edges and a front edge, and the flapper seat further has an elevation about at least part of the flapper side and front edges, the elevation having a top, inwardly directed bevel; and further wherein the flapper is positioned within the elevation when the flapper is in the down position, the flapper being guided by the flapper seat elevation bevel to the down position within the elevation, the flapper seat elevation resisting and/or substantially preventing lateral movement of the flapper during flapper deformation.
In some exemplary embodiments, the flapper valve assembly further comprises a plurality of pins, and further the flapper seat has side portions and a curved surface disposed between the side portions, each side portion having at least one pin hole for receiving at least one of the pins, and the flapper seat curved surface having at least one pin hole for receiving at least one of the pins, the flapper curved portion having first and second edges and a forward edge, the flapper curved portion being sized such that when the flapper is in the down position, the flapper curved portion first edge is proximate the at least one pin in the flapper seat first side portion, the flapper curved portion second edge is proximate the at least one pin in the flapper seat second side portion, and the flapper curved portion forward edge is proximate the at least one pin in the flapper seat curved surface. In some exemplary embodiments, the flapper valve assembly further comprises a pair of guide members, each guide member being attachable to one of the flapper seat side portions using the at least one pin received by such side portion, each guide member being shaped and attachably positioned such that one of the flapper curved portion edges is proximate the guide member when the flapper is in the down position. In some exemplary embodiments, the each of the guide members has an inside surface, the inside surface having a top bevel, the bevel being positioned to guide the descending flapper into the flapper's down position between the guide members.
In some exemplary embodiments, the sleeve has a minimum internal diameter and the flapper valve assembly has a maximum outer diameter, the ratio of the maximum outer diameter to the sleeve minimum inside diameter being 1.55 or less. In some exemplary embodiments, the tubular housing has a wall, the wall having a thickness, the wall thickness to flapper valve assembly maximum outer diameter ratio being 0.0625 or greater.
In some exemplary embodiments: the tubular housing bottom member has a bottom end for attachment to a first downhole tubular assembly component, the bottom end having a first attachment configuration; and the flapper valve assembly further comprises a tubular housing substitute bottom member, the substitute bottom member having a bottom end for attachment to a second downhole tubular assembly component, the bottom end having a second attachment configuration, the second attachment configuration being different from the first attachment configuration.
In some exemplary embodiments: the sleeve top portion further comprises at least one channel, the at least one channel being positioned about at least a portion of the sleeve top portion circumference; the tubular housing has at least one hole, the at least one hole being aligned with one of the at least one sleeve top portion channels when the top portion is supported by the flapper seat and the flapper seat is supported by the tubular housing bottom member top; and at least one shear member for insertion into one of the at least one holes and protrusion into one of the at least one sleeve top portion channels; wherein the inserted at least one shear member retains the sleeve within the tubular housing with the tubular housing top member removed.
In some exemplary embodiments: the tubular housing top member has a top end for attachment to a first downhole tubular assembly component, the top end having a first attachment configuration; and the flapper valve assembly further comprises a tubular housing substitute top member, the substitute top member having a top end for attachment to a second downhole tubular assembly component, the top end having a second attachment configuration, the second attachment configuration being different from the first attachment configuration.
In some exemplary embodiments, the tubular housing, the tubular housing top member and the tubular housing bottom member have substantially equal outside diameters. In some exemplary embodiments, the insert assembly is attached to the bottom member top. In some exemplary embodiments, the bottom member top forms an upwardly facing interior shoulder, the shoulder supporting the inserted insert assembly.
In some exemplary embodiments: the flapper seat further comprises at least one channel, the at least one channel being positioned about at least a portion of the flapper seat circumference; the tubular housing has at least one threaded hole, the at least one hole being aligned with one of the at least one flapper seat channels when the flapper seat is supported by the tubular housing bottom member top; and at least one threaded fastener for threaded insertion into one of the at least one threaded holes and protrusion into one of the at least one flapper seat channels; wherein the inserted at least one fastener retains the flapper seat within the tubular housing with the tubular housing bottom member removed.
In some exemplary embodiments of our invention we have provided a flapper valve assembly for inclusion in a downhole tubular assembly, the flapper valve assembly comprising: a tubular housing having an interior pocket, the pocket having an inside surface, the tubular housing further having a removable top member forming a tubular housing upper end, and a removable bottom member forming a tubular housing lower end, the bottom member having a top, the upper and lower ends each being attachable within the downhole tubular assembly; and insert assembly means, the insert assembly means being insertable into the tubular housing pocket when the top member is removed, and retained within the pocket when the top member is attached, the insert assembly means having: flapper seat means, the flapper seat means being substantially sealed against the tubular housing interior pocket inside surface; flapper means having a flapper, the flapper having a curved portion, the flapper being movable between a down position and an up position; bias means for biasing the flapper from the up position to the down position; and sleeve means having a sleeve, the sleeve being upwardly slidably from a sleeve first position upon the flapper seat means, the flapper seat means preventing downward movement of the sleeve, to a sleeve second position, such that the flapper is held in the up position when the sleeve is in the first position, the bias means moving the flapper to the down position when the sleeve is in the second position, the sleeve further having a top portion having an outside diameter, and a bottom portion having an outside diameter smaller than the top portion, the sleeve top portion being substantially sealed against the tubular housing interior pocket inside surface, the sleeve bottom portion being saddled by the flapper curved portion when the sleeve is in the first position; wherein flow from the tubular housing pocket through the tubular housing lower end is prevented when the flapper is in the down position and allowed when the flapper is in the up position.
In some exemplary embodiments of the present invention, the flapper valve assembly further comprises means for substantially preventing lateral movement of the flapper curved portion during deformation of the flapper in response to pressure on the flapper curved portion.
The foregoing features and advantages of our invention will be apparent from the following more particular descriptions of exemplary embodiments of the invention as illustrated, for some embodiments, in the accompanying drawings.
The following discussion describes exemplary embodiments of the invention in detail. This discussion should not be construed, however, as limiting the invention to those particular embodiments. Practitioners skilled in the art will recognize numerous other embodiments as well.
Unless specifically indicated otherwise, terms such as “up,” “upward,” “down,” “downward,” “highest,” “lowest,” “above,” “below,” and other terms suggesting a vertical movement, position or relationship, as used herein, refer to positions along, and/or with respect to, the wellbore axis, with the distal end of the wellbore being considered the lowermost, and the surface end being considered the uppermost. Accordingly, movement “up” is toward the surface within the wellbore, although the true path may actually be horizontal, or even downward, with respect to the surface. Similarly, a point “lower” than another point would be farther from the surface, along the wellbore axis, although the points may actually be on an equal plane with respect to the surface.
The term “running,” as used herein, refers to moving downward into the well with whatever is indicated as being run. The term “pulling,” as used herein, refers to moving upward within a well with whatever is indicated as being pulled.
The term “well,” as used herein, refers to holes drilled vertically, at least in part, and may also refer to holes drilled with deviated, highly deviated, and/or horizontal sections of the wellbore. The term also includes wellhead equipment, surface casing, intermediate casing, and the like, typically associated with oil and gas wells.
The term “target completion interval,” as used herein, refers to a portion of a subterranean formation from which an operator wishes to allow flow of fluids into the well. The term includes both a single formation having one or more such portions (typically the case in a horizontal well) and multiple formations penetrated by the wellbore (typically the case in a vertical well), with each formation being a targeted portion.
The term “frac job,” as used herein, refers to treatment of a hydrocarbon formation, whereby fluids are injected into the formation causing fractures to occur and to enlarge. In some instances, proppants, such as sand, are included in the injection fluid, the proppants being retained within the enlarged fractures, such that the fractures are prevented from fully closing after the injection of the fluid ceases.
As used herein, the term “downhole tubular assembly” means an assembly of components chosen to perform various downhole functions purposes in fluid producing wells, the functions being enabled, at least in part, by the ability of the present invention to be integrated within the assembly and act as a valve with an open and closed position. Such assemblies include, without implied limitation, a production casing string (or a liner) cemented in a drilled hole, which has an exemplary embodiment of the valve of the present invention fastened between two joints of the casing, the casing or liner extending through one or more target completion intervals. In such an example, the “downhole tubular assembly” will often include joints of casing, casing collars, casing centralizers, and the like. For this example, the valve of the present invention will be included within the other components, usually with a casing joint above (pin down) and a casing collar below, and will be open as the components are assembled and run into the well, and during cementing. An example of a flapper valve assembly being included within a downhole tubular assembly is disclosed, generally, in United States Patent Application 2006/0124315, which is incorporated herein by reference.
As used herein, the term “shifting tool” refers to a conventional tool run into a well, which when properly positioned and manipulated, will physically move a sleeve within a downhole tool from a lower position to an upper position. An example of such a tool is the Otis Type B Shifting Tool. A shifting tool will typically have expandable keys (“dogs”) which expand within a larger internal diameter portion of a sleeve and encounter an interior sleeve profile such that the sleeve is pulled as the shifting tool is pulled. This interaction with the sleeve interior is well known in the art.
Turning now to
Turning now to
In the exemplary embodiment of the present invention depicted in
As illustrated in
In such exemplary embodiments, when the shear screws are in place within the sleeve top portion first channel 96, the sleeve 90 is fixed within the tubular housing interior pocket 22. The shear screws prevent the sleeve 90 from moving upwardly within the tubular housing interior pocket 22, while the flapper seat 70 prevents the sleeve 90 from moving downwardly. Accordingly, the insert assembly 60 is secured within the tubular housing interior pocket 22 when the insert assembly 60 bears upon the interior shoulder 44 formed by the bottom sub 40 and the shear screws have extended through shear screw holes 54 in the tubular housing 20 into the sleeve top portion first channel 96. These shear screws are sheared when the sleeve 90 is pulled by a shifting tool. Additional securement is provided by the set screws that protrude into the flapper seat first channel 78. Further, the O-rings in the flapper seat second channel 79 and the sleeve top portion second channel 97 seal the flapper seat 70 and sleeve top portion 92 against the interior pocket inside surface 22.
In the exemplary embodiments of the present invention depicted in
Turning now to
In such exemplary embodiments, it is to be noted that both the top sub 26 and the bottom sub 40 may be removed without disturbing the insert assembly 60. This modular construction allows an operator to readily exchange the bottom sub 40, for example, for another bottom sub having a different thread 48 size or type. The top sub 26 is analogously interchangeable with top subs with different thread 32 sizes and types on the top sub top end.
A notable advantage of the present invention, made possible by the provision of the insert assembly 60, is that manufacturing assembly is greatly simplified by the simultaneous insertion of the flapper seat 70, open flapper 80, and positioned sleeve 90. It is not necessary to hold a pre-integrated flapper in an open position while a sleeve is inserted, as is currently the case.
Turning now to
Exemplary embodiments of the type depicted in
A wall thickness of at least approximately ⅜ in (9.5 mm) will be acceptable for the tubular housing in exemplary embodiments of the present invention, depending on the material used in its construction.
Table 1 below provides information relevant to the foregoing ratio with respect to the prior art and exemplary embodiments of the present invention represented by
From Table 1 it shown that only the present invention can satisfy the 3.8 in. (9.65 cm) minimum internal diameter required.
For some exemplary embodiments of the present invention, construction materials include 4140 steel for the top sub 26 and bottom sub 40, nitride frac hardened steel for the flapper seat 70 and sleeve 90, cast iron for the flapper 80, and 4340 steel for the tubular housing 20.
Prospectively, it is anticipated that the torsion spring 82 will be constructed from 0.0720 in. (1.83 mm) oil tempered steel spring wire (heat number 307096; ASTM-A-229-99 Class 1) in some exemplary embodiments.
Turning now to
As illustrated in
Pins 260 for use in the flapper seat pin holes 210a,b,212a,b, 214 are constructed from conventional drill rod in some exemplary embodiments. In some exemplary embodiments the pins are constructed from plain hardened steel having a double shear strength of approximately 12,800 pounds (5,806 kg), with a Rockwell hardness of C50, as described in the American Society of Mechanical Engineers specification ASME B 18.8.2, effective as of the date of this application. In some exemplary embodiments the pin diameter is approximately ¼ in. (6.35 mm) and overall length approximately ¾ in. (12.7 mm) In some exemplary embodiments the pin diameter is 5/16 in. (7.94 mm) In some exemplary embodiments the flapper 250 is constructed from cast iron bar stock, including heat treated ductile iron having approximately 100,000 psi (689476 kPa) tensile strength, approximately 70,000 psi (482,633 kPa) yield strength, and an approximately 3 percent elongation rating.
In tests, exemplary embodiments have been tested and shown to withstand approximately 7800 psi (53,7779 kPa) of differential pressure on the closed flapper, when the flapper was 0.35″ at its thickest point, and approximately 9800 psi (67,569 kPa) of differential pressure when the flapper was 0.44 in. (11.18 mm) at its thickest point.
Turning now to
As further illustrated for exemplary embodiments of the type illustrated in
Turning now to
The tubular housing 420 also has interior threads 456 for threadable attachment of the top sub 426 using threads 429. The tubular housing also has four (two shown) circumferentially spaced holes 458a,b for positioning four (two shown) shear members, i.e. screws 460a,b for retaining the sleeve 90 in its original position against the flapper seat 300 with the flapper 350 in the open position.
Turning now to
Turning now to
All equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. The descriptions in this specification are for purposes of illustration only and are not to be construed in a limiting sense.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US08/70291 | 7/17/2008 | WO | 00 | 11/21/2009 |
| Number | Date | Country | |
|---|---|---|---|
| 60961331 | Jul 2007 | US | |
| 61024601 | Jan 2008 | US |
