Patent Publication Number: US-11391119-B2

Title: Differential fill valve with collet sleeve

Description:
BACKGROUND 
     In the oil and gas industry, wellbores are drilled into the surface of the earth to access reservoirs for the extraction of hydrocarbons. Wellbores are often lined with casing or a string of casing sections or lengths, and the casing is then secured into place using cement. In one cementing technique, a cement composition is pumped through the interior of the casing and allowed to flow back toward the surface via the annulus defined between the wellbore wall and the casing. Once the cement composition cures within the annulus to form a hardened mass, the casing serves to stabilize the walls of the surrounding subterranean formation to prevent any potential caving into the wellbore. 
     When casing is being run into a wellbore it is sometimes desirable to “float” the casing down to its intended location within the wellbore fluid prior to the time the casing is cemented in the well. It is also desirable to have the casing fill automatically at a predetermined rate. 
     Float valves are one-way valves (i.e., check valves) that can be installed at or near the interior bottom end of a casing string. Once operational, float valves permit fluid (such as mud or cement) to flow down through the inside of the casing, but prevent fluids from flowing in the reverse direction back up the inside of the casing. By doing so float valves prevent cement that is pumped down through the casing and into the annular space from flowing back up through the valves once the cement is in place. 
     Float shoes and float collars permit automatic filling of the casing and incorporate a backpressure valve to prevent cement back flow into the casing after the cementing operation. Certain backpressure valves also permit the option of terminating the filling of the casing at any point in time. During the insertion of casing into the wellbore, a traditional auto-fill, flapper-type float valve is held open by a pin set across a sleeve in the valve assembly bore. When it is desired to actuate the backpressure valve to prevent further filling of the casing a weighted tripping ball is dropped, or carried in with the float valve, which breaks the pin holding the sleeve and thereby freeing the flapper valve to close. After cementing has been completed, the released flapper valve prevents cement flow back into the casing from the wellbore annulus. Due to the close operating pressures of the float valve, premature release of the flapper valve can occur. Additionally, the same operating conditions can cause the flapper valve to not release entirely. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a cross-sectional side view of a casing with the fill valve assembly disclosed therein. 
         FIG. 2  is a cross-sectional view of a fill valve assembly of the current disclosure employed in a casing float collar. 
         FIG. 3  is a cross-sectional view of a fill valve assembly in an open position with a tripping ball engaged with a retaining ring. 
         FIG. 4  is a cross-sectional view of a fill valve assembly with a tripping ball engaging a collet sleeve. 
         FIG. 5  is a cross-sectional view of a fill valve assembly with a first flapper in a closed position and the tripping ball engaging a second collet sleeve. 
         FIG. 6  is a cross-sectional view of a fill valve assembly with first and second flapper valves in a closed position after a tripping ball has passed therethrough. 
     
    
    
     DESCRIPTION OF AN EMBODIMENT 
     Referring now to the figures a wellbore  15  is shown with a casing string  20  lowered therein. Casing string  20  and wellbore  15  define an annulus  25  therebetween. Casing string  20  will be lowered from a wellhead installation at the surface of the earth in a manner known in the art. A casing shoe  36  may be attached at or near the end of casing string  20 . To secure the casing string  20  within wellbore  15  cement  30  is pumped therethrough until it passes out the bottom end  34  of casing string  20 . A casing shoe  36  may be attached to bottom end  34 . Cement will flow out of bottom end  34  through casing shoe  36  and will travel upwardly in annulus  25 . 
     A fill valve assembly  50  may be provided within a float collar  40  of casing string  20 . Float collar  40  may be connected at its upper end  46  to upper casing  42  and at its lower end  48  to lower casing  44 . Fill valve assembly  50  is fixed in float collar  40  with a cementitious body  41 . The fill valve assembly  50  is held firmly in place by the cementitious body  41 . As is apparent from the drawings, fluid, for example cement  30  will be directed through fill valve assembly  50  as there is no path around fill valve assembly  50  through float collar  40 . 
     Fill valve  50  has outer housing  52 , and has upper end  54  and lower end  56  and a central flow passage  57  therethrough. Fill valve  50  comprises a first flapper valve  58  and a second flapper valve  60  connected thereto. A ball cage  64  is connected to the upper end  54  of the housing  52 , which is the upper end of the fill valve assembly  50 . Cage  64  comprises a retaining ring  66  and a crows nest  68 . A tripping ball  70  is initially trapped between retaining ring  66  and crows nest  68 . Retaining ring  66  defines a diameter  74  that is smaller than diameter  72  of tripping ball  70 . Tripping ball  70  may comprise a phenolic tripping ball or other material such that upon the application of pressure tripping ball  70  will deform slightly and pass through the diameter  74  of retainer  66 . Crows nest  68  has a space  78  between the feet  76  thereof that will not allow tripping ball  70  to pass upwardly therethrough. 
     First flapper valve  58  comprises first flapper valve housing  62  which forms a part of outer housing  52 . First flapper valve housing  62  comprises an upper housing portion  82  and a lower housing portion  86 . A flapper  80  is pivotally connected to upper housing portion  82  with a pivot pin  84  or other mechanism. Flapper  80  is biased with a spring or otherwise to move from the open position  102  to the closed position  106  which is shown in  FIG. 6 . 
     A lower housing portion  86  of first flapper valve  58  is connected to upper housing portion  82 . Flapper  80  in the open position extends downwardly into lower housing portion  86  and is restrained in the open position by a first collet sleeve  88 . First collet sleeve  88  is detachably connected in housing  52  and more specifically in lower housing portion  86  of first flapper valve housing  62 . Collet sleeve  88  has upper end  90  and lower end  92 . Collet sleeve  88  has a plurality of collet fingers  94  with radially inward facing collet heads  96  at the lower end  92  of collet sleeve  88 . Collet head  96  defines a breakaway seat  98  which may be referred to as a first breakaway seat  98 . Breakaway seat  98  has a diameter  100  which is smaller than diameter  72  of tripping ball  70 . 
       FIGS. 2-4  show the first position  104  of first collet sleeve  88  in which first collet sleeve  88  restrains flapper  80  in its open position  102 . In the open position  102  two-way flow is permitted through the first flapper valve housing  62 . Thus, fluid will flow through flapper valve  58  as casing  20  is lowered into the wellbore  15  to the desired location. The closed position  106  of flapper  80  is shown in  FIG. 6 . In the closed position  106  one-way flow only is allowed through first flapper valve  58 . Thus, cement can flow downwardly therethrough but upward flow is prevented by flapper valve  58  and specifically by flapper  80  which is biased towards upper housing  82  in which the closed position  106  will engage a seat  83  defined on upper housing portion  82  to prevent upward flow therethrough. Flapper  80  moves to the closed position  106  when first collet sleeve  88  is detached from first flapper valve housing  62  and moves downwardly to its second position  108 . 
     Upper housing portion  82  has a bore  110  with a diameter  111  that is large enough to allow tripping ball  70  to pass therethrough. Housing  52  has a bore  112  and specifically lower housing portion  86  of first flapper valve housing  62  has a bore  112  that extends radially outwardly from bore  110 . Bore  112  has a first portion  114  and a second portion  115  below first portion  114 . Second portion  115  is a generally cylindrical portion. Second portion  115  has at least one groove  116  therein. The at least one groove  116  comprises a first pair of grooves  118 . The pair of first grooves  118  comprises a first upper groove  120  and a first lower groove  122 . 
     At least one lock ring  124  engages collet sleeve  88  and extends into the at least one groove  116  in lower housing portion  86  of first flapper valve housing  62 . The at least one lock ring in the embodiment disclosed comprises a first pair of lock rings which comprises a first upper lock ring  126  and a first lower lock ring  128 . In the first position  104  of collet sleeve  88  first upper lock ring  126  engages collet sleeve  88  and extends radially outwardly into first upper groove  120 . First lower lock ring  128  engages collet sleeve  88  and extends radially outwardly into first lower groove  122 . The first upper and lower lock rings  126  and  128  detachably connect collet sleeve  88  in housing  52  in the first position  104  thereof. 
     Lower housing portion  86  has a radially inwardly extending shoulder  132  below second portion  115 . Shoulder  132  defines an inner diameter  134 . Shoulder  132  will engage first collet sleeve  88  at the lower end thereof in the first position  104  to prevent the collet fingers  94  from moving outwardly prematurely. Thus, lower housing portion  86  will retain collet sleeve  88  in a restrained position. 
     Bore  112  of lower housing  86  extends radially outwardly from shoulder  132  and defines a first annular channel  138  so that when moved to its second position  108  collet sleeve  88  may deform and breakaway seat  98  may spread radially outwardly to allow tripping ball  70  to pass therethrough. 
     In operation once casing  20  has been lowered to a desired location in the well cementing can begin. Fluid may be displaced ahead of the cement  30  and pressure increased so that tripping ball  70  will engage and pass through retaining ring  66 . Tripping ball  70  will be displaced downwardly until it engages breakaway seat  98 . Pressure is applied thereabove until a sufficient force is reached to disengage first collet sleeve  88  from upper and lower lock rings  126  and  128 . Lower lock ring  128  will be received in a groove in first collet sleeve  88  in the second position  108  thereof to prevent further downward movement of collet sleeve  88 . Breakaway seat  98  will be deformed and will spread radially outwardly into annular channel  138  to allow tripping ball  70  to pass therethough. One-way flow in the downward direction through housing  52  and thus through float collar  40  is allowed, but upward flow is prevented. Cementing of casing string  20  can therefore be performed through flapper valve  58 . In one embodiment more than one flapper valve may be utilized. The current disclosure includes a second flapper valve  60 . 
     Flapper valve  60  is generally like flapper valve  58 . Second flapper valve  60  comprises second flapper valve housing  162  which forms a part of outer housing  52 . Second flapper valve housing  162  comprises an upper housing portion  182  and a lower housing portion  186 . A flapper  180  is pivotally connected to upper housing portion  182  with a pivot pin  184  or other mechanism. Flapper  180  is biased with a spring or otherwise to move from the open position  202  to the closed position  206  which is shown in  FIG. 6 . 
     Lower housing portion  186  of second flapper valve  60  is connected to upper housing portion  182 . Flapper  180  in the open position extends downwardly into lower housing portion  186  and is restrained in the open position by a second collet sleeve  188  that is detachably connected in housing  52  and more specifically in lower housing portion  186  of second flapper valve housing  162 . Collet sleeve  188  has upper end  190  and lower end  192 . Collet sleeve  188  has a plurality of collet fingers  194  with radially inward facing collet heads  196  at the lower end  192  of collet sleeve  188 . Collet heads  196  define a breakaway seat  198  which may be referred to as a second breakaway seat  198 . Breakaway seat  198  has a diameter  200  which is smaller than diameter  72  of tripping ball  70 . 
       FIGS. 3-5  show the first position  204  of second collet sleeve  188  in which second collet sleeve  188  restrains flapper  180  in its open position  202 . In the open position  202  two-way flow is permitted through the second flapper valve housing  162 . The closed position  206  of flapper  180  is shown in  FIG. 6 . In the closed position  206  one-way flow only is allowed through second flapper valve  60 . Thus, cement can flow downwardly therethrough but upward flow is prevented by flapper valve  60  and specifically by flapper  180  which is biased towards upper housing  182  in which the closed position  206  will engage a seat  183  defined on upper housing portion  182  to prevent upward flow therethrough. Flapper  180  moves to the closed position  206  when second collet sleeve  188  is detached from second flapper valve housing  162  and moves downwardly to its second position  208 . 
     Upper housing portion  182  of second collet sleeve  188  has a bore  210  with a diameter  211  that is large enough to allow tripping ball  70  to pass therethrough. Housing  52  has a bore  212  and specifically lower housing portion  186  of second flapper valve housing  162  has a bore  212  that extends radially outwardly from bore  210 . Bore  212  has a first portion  214  and a second portion  215  below first portion  214 . Second portion  215  is a generally cylindrical portion. Second portion  215  has at least one groove  216  therein. The at least one groove  216  comprises a second pair of grooves  218 . The second pair of second grooves  218  comprise a second upper groove  220  and a second lower groove  222 . 
     At least one lock ring  224  engages collet sleeve  188  and extends into the at least one groove  216  in lower housing portion  186  of second flapper valve housing  162 . The at least one lock ring  224  in the embodiment disclosed comprises a second pair of lock rings which comprises a second upper lock ring  226  and a second lower lock ring  228 . In the first position  204  of collet sleeve  188  second upper lock ring  226  engages second collet sleeve  188  and extends radially outwardly into second upper groove  220 . Second lower lock ring  228  engages collet sleeve  188  and extends radially outwardly into second lower groove  222 . The second upper and lower lock rings  226  and  228  detachably connect collet sleeve  188  in housing  52  in the first position  204  thereof. 
     Lower housing portion  186  has a radially inwardly extending shoulder  232  below second portion  215 . Shoulder  232  defines an inner diameter  234 . Shoulder  232  will engage second collet sleeve  188  at the lower end  192  of collet sleeve  188  in the first position thereof to prevent the collet fingers  194  from moving outwardly prematurely. Thus, lower housing portion  186  will retain collet sleeve  188  in a restrained position. Bore  212  of lower housing  186  extends radially outwardly from shoulder  232  and defines a second annular channel  238  so that when moved to its second position  208  second collet sleeve  188  may deform and breakaway seat  198  may spread radially outwardly to allow tripping ball  70  to pass therethrough. 
     In operation once casing  20  has been lowered to a desired location in the well cementing can begin. Fluid may be displaced ahead of the cement  30  and pressure increased so that tripping ball  70  will engage and pass through retaining ring  66 . As explained above, tripping ball  70  will be displaced downwardly until it engages breakaway seat  98  and moves collet sleeve  88  to its second position  108 , which allows flapper  80  to move to its closed position  106 . Tripping ball  70  will then engage breakaway seat  198  on second collet sleeve  188 . Pressure is applied thereabove until a sufficient force is reached to disengage upper and lower lock rings  226  and  228  from second collet sleeve  188 . Collet sleeve  188  will move downwardly to its second position  208  and flapper  180  will move to the closed position  106 . Lower lock ring  228  will be received in a groove in second collet sleeve  188  in the second position  208  thereof to prevent further downward movement of collet sleeve  88 . Breakaway seat  198  will be deformed and will spread radially outwardly to allow tripping ball  70  to pass therethough. One-way flow in the downward direction through housing  52  and thus through float collar  40  is allowed, but upward flow is prevented. Cementing of casing string  20  can therefore be performed through flapper valve  60 . 
     Embodiments disclosed herein include: 
     A. A valve assembly comprising a valve housing defining a flow passage therethrough; a first flapper moveable from an open position in the valve housing in which two-way flow is allowed to a closed position in which only one-way flow through the valve housing is permitted; a first collet sleeve moveable from a first position to a second position in the valve housing, the first collet sleeve in the first position retaining the flapper valve in the open position; a breakaway seat at a lower end of the first collet sleeve for receiving a tripping ball; at least one lock ring engaging the first collet sleeve and extending into a groove in the valve housing, the lock ring configured to maintain the first collet sleeve in the first position until a tripping ball is engaged with the breakaway seat and a predetermined first force is applied to move the first collet sleeve from the first to the second position. 
     B. A valve assembly comprising a first flapper in a valve housing; a first collet sleeve in the valve housing, the first collet sleeve having a first position in the valve housing retaining the first flapper in an open position; a second flapper in the valve housing; a second collet sleeve in the valve housing, the second collet sleeve having a first position in the valve housing retaining the second flapper in an open position, wherein two-way flow is allowed through the valve housing when the first and second flappers are in the open position. 
     C. A valve assembly comprising a casing; a valve housing connected in the casing; a first flapper positioned in the valve housing and restrained in an open position by a first collet sleeve detachably connected in the valve housing; a second flapper positioned in the valve housing below the first flapper and restrained in an open position by a second collet sleeve detachably connected in the valve housing. 
     Each of the embodiments A, B and C may have one or more of the following additional elements in combination: 
     At least one lock ring comprising a first upper lock ring and a first lower lock ring, the first upper and lower lock rings engaging the first collet sleeve and extending into first upper and lower grooves in the valve housing in the first position of the collet sleeve. 
     A breakaway seat in a second collet sleeve for receiving the tripping ball after the first collet sleeve has moved to its second position and a breakaway force has been applied to the breakaway seat in the first collet sleeve. 
     A second upper lock ring engaging the second collet sleeve and extending into a second upper groove in the valve housing; and a second lower lock ring engaging the second collet sleeve and extending into a second lower groove in the valve housing. 
     Thus it is seen that the apparatus and methods of the present invention readily achieve the ends and advantages mentioned as well as those inherent therein. While certain preferred embodiments of the invention have been illustrated and described for purposes of the present disclosure, numerous changes in the arrangement and construction of parts and steps may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present invention.