Modular saddle flapper valve

Abstract

A flapper valve assembly is provided, 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. An insert assembly is used in the modular saddle flapper valve assembly which has a flapper seat, flapper valve and sleeve. The insert assembly is 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 being easily accomplished without disassembly of the insert assembly.

1 . 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.   
   
   
       2 . The flapper valve assembly of  claim 1 , wherein the flapper seat further comprises side portions, the side portions having top, inwardly directed bevels; and further wherein 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 substantially preventing lateral movement of the flapper during flapper deformation. 
   
   
       3 . The flapper valve assembly of  claim 1 , wherein the flapper further has opposing side edges and a front edge, the flapper seat further having an elevation about 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 substantially preventing lateral movement of the flapper during flapper deformation. 
   
   
       4 . The apparatus of  claim 1 , further comprising a plurality of pins, and further wherein 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. 
   
   
       5 . The apparatus of  claim 4 , further comprising 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. 
   
   
       6 . The apparatus of  claim 5 , wherein 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. 
   
   
       7 . The flapper valve assembly of  claim 1 , wherein 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. 
   
   
       8 . The flapper valve assembly of  claim 6 , wherein 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. 
   
   
       9 . The flapper valve assembly of  claim 1 , wherein:
 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.   
   
   
       10 . The flapper valve assembly of  claim 1 , wherein:
 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.   
   
   
       11 . The flapper valve assembly of  claim 1 , wherein:
 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.   
   
   
       12 . The flapper valve assembly of  claim 1 , wherein the tubular housing, the tubular housing top member and the tubular housing bottom member have substantially equal outside diameters. 
   
   
       13 . The flapper valve assembly of  claim 1 , wherein the insert assembly is attached to the bottom member top. 
   
   
       14 . The flapper valve assembly of  claim 1 , wherein the bottom member top forms an upwardly facing interior shoulder, the shoulder supporting the inserted insert assembly. 
   
   
       15 . The flapper valve assembly of  claim 14 , wherein:
 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.   
   
   
       16 . 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.   
   
   
       17 . The apparatus of  claim 16 , further comprising 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.