Patent Publication Number: US-10767444-B2

Title: Flapper valve tool

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. Patent Application having U.S. Ser. No. 16/212,961, filed Dec. 7, 2018, which is a divisional of U.S. Patent Application having U.S. Ser. No. 15/989,332, filed May 25, 2018, which is a continuation-in-part of U.S. Patent Application having U.S. Ser. No. 15/058,887, filed Mar. 2, 2016, which is a continuation-in-part of U.S. Patent Application having U.S. Ser. No. 14/615,237, filed Feb. 5, 2015, which claims the benefit of U.S. Provisional Application having U.S. Ser. No. 62/038,049, filed Aug. 15, 2014, which claims the benefit under 35 U.S.C. 119(e), the disclosure of which is hereby expressly incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE DISCLOSURE 
     1. Field of the Invention 
     The present disclosure relates to a downhole tool used to control and/or prevent pressurized wellbore fluids from traveling up through the workstring tubing. 
     2. Description of the Related Art 
     Traditionally, flapper valves have been used to prevent pressurized wellbore fluids from entering a workstring from the bottom up. Typical flapper valves can wear out after a period of use. 
     Accordingly, there is a need for a way to be able to reliably maintain a flapper valve in an open position. 
     SUMMARY OF THE DISCLOSURE 
     The disclosure is related to a downhole tool having a flapper valve assembly for controlling the backflow of fluid into a tubing string that includes at least one flapper. The downhole tool also includes a deformable element that maintains the at least one flapper in an open position after the deformable portion is deformed. The disclosure is also related to a method of using this downhole tool. 
     The disclosure is also related to a downhole tool having a flapper valve assembly for controlling the backflow of fluid into a tubing string that includes at least one flapper. The downhole tool also includes a sleeve slidably disposed within at least a portion of the flapper valve assembly and the downhole tool. The downhole tool includes a deformable and dissolvable seat disposed uphole and adjacent to the sleeve and a dissolvable fluid blocking member to engage with the seat to shift the sleeve from first position to a second position within the downhole tool. The disclosure is also related to a method of using this downhole tool. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1C  are cross-sectional views of one embodiment of a downhole tool constructed in accordance with the present invention. 
         FIGS. 2A-2C  are cross-sectional views of another embodiment of the downhole tool constructed in accordance with the present invention. 
         FIG. 3  is a cross-sectional view of yet another embodiment of the downhole tool constructed in accordance with the present disclosure. 
         FIGS. 4A and 4B  are cross-sectional views of the embodiment of the downhole tool shown in  FIG. 3  in a second position and constructed in accordance with the present disclosure. 
         FIGS. 5A and 5B  are cross-sectional views of the embodiment of the downhole tool shown in  FIG. 3  in a third position and constructed in accordance with the present disclosure. 
         FIG. 6A  is a cross-sectional view of another embodiment of the downhole tool shown in  FIGS. 1A-1C  constructed in accordance with the present invention. 
         FIG. 6B  is a cross-sectional view of another embodiment of the downhole tool shown in  FIGS. 2A-2C  constructed in accordance with the present invention. 
         FIGS. 6C-6E  are cross-sectional views of another embodiment of the downhole tool shown in  FIGS. 3-5B  constructed in accordance with the present invention. 
         FIGS. 7A-7C  are cross-sectional views of another embodiment of the downhole tool constructed in accordance with the present invention. 
         FIGS. 8A and 8B  are close-up, cross-sectional views of a portion of the downhole tool shown in  FIGS. 7A-7C  and constructed in accordance with the present invention. 
         FIGS. 9A-9D  are cross-sectional views of another embodiment of the downhole tool constructed in accordance with the present invention. 
         FIGS. 10A-10C  are cross-sectional views of another embodiment of a portion of the downhole tool constructed in accordance with the present invention. 
         FIGS. 11A-11C  are cross-sectional views of another embodiment of a portion of the downhole tool constructed in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     The present disclosure relates to a flapper valve tool  10  that can be designed and implemented into a bottom hole assembly (BHA) that has at least one sleeve disposed therein to either open a flapper  14  or permit the flapper  14  to close. 
     In one embodiment of the present disclosure shown in  FIGS. 1A-1C , the flapper valve tool  10  includes a top sub  16  for connecting to other tools disposed above the flapper valve tool  10  in the BHA, a bottom sub  18  for connecting the flapper valve tool  10  to other tools disposed below the flapper valve tool  10  in the BHA and a housing  20  (or body) connecting the top sub  16  to the bottom sub  18 . In this embodiment, the flapper valve tool  10  includes a closing sleeve  12  slidably disposed in the housing  20  and a flapper assembly  22  disposed in the housing  20 . 
     The flapper assembly  22  includes a flapper  14  for selectively blocking the backflow of fluid through the flapper valve tool  10  and a flapper seat  24  disposed in the housing  20  such that the closing sleeve  12  can slide through the flapper seat  24 . The flapper  14  sits against the flapper seat  24  when the flapper  14  is in the closed position and prevents pressurized fluid from flowing in the uphole direction through the flapper valve tool  10 . The flapper  14  can be hingedly connected to the flapper seat  24  or to the inside of the housing  20 . 
     The closing sleeve  12  shown in  FIGS. 1A-1C  includes a collar  26  disposed around an outside portion of the closing sleeve  12  and the flapper valve tool  10  includes a shoulder  28  disposed therein to engage the collar  26  and prevent further sliding movement of the closing sleeve  12  when the closing sleeve  12  is shifted from a first position in the flapper valve tool  10  to a second position in the flapper valve tool  10 . The shoulder  28  can be disposed on the inside of the bottom sub  18  or the housing  20  of the flapper valve tool  10 . The closing sleeve  12  can be held in the first position in the flapper valve tool  10  via any means known in the art, such as shear pins  30 . The closing sleeve  12  can also include a lip  32  disposed around a portion of the inside of the closing sleeve  12  to create a seat for a fluid blocking member  34  to engage and not be able to pass completely through the closing sleeve  12 . 
       FIG. 1A  shows the closing sleeve  12  in its first position and holding the flapper  14  in an open position.  FIG. 1B  shows the fluid blocking member  34  engaged with the lip  32  of the closing sleeve  12  and the closing sleeve  12  in its second position in the flapper valve tool  10 . When enough pressure is put behind the fluid blocking member  34 , the shear pins  30  fail and permit the closing sleeve  12  to move from its first position to its second position in the flapper valve tool  10 . The closing sleeve  12  will travel a predetermine distance before the collar  26  of the closing sleeve  12  impacts the shoulder  28  disposed on the inside of the flapper valve tool  10 , which prevents further movement of the closing sleeve  12  in the flapper valve tool  10 . After the closing sleeve  12  travels a specific amount, the flapper  14  is no longer prevented from closing and the flapper  14  closes against the flapper seat  24  to prevent fluid from flowing in the uphole direction through the flapper valve tool  10 . If desired, high pressure fluid can be pumped down to force the fluid blocking member  34  past the lip  32  in the closing sleeve  12 , as can be seen in  FIG. 1C . 
     In another embodiment of the present disclosure shown in  FIGS. 2A-2C , the flapper valve tool  10  includes an opening sleeve  36  (as opposed to the closing sleeve  12 ) that has a first position where the flapper  14  is set against the flapper seat  24  (closed). Consequently, the flapper  14  is in the open position when the opening sleeve  36  is in its second position. The opening sleeve  36  has a lip  38  disposed around an inner portion  40  of the opening sleeve  36  and a collar  42  disposed around an outer portion  44  of the opening sleeve  36 . The lip  38  is designed to provide a seat for engaging with the fluid blocking member  34 . The collar  42  is designed to engage with a shoulder  46  disposed within the flapper valve tool  10 . In one embodiment, the collar  42  is disposed on an uphole end  48  of the opening sleeve  36  to engage the shoulder  46 , which can be disposed on an inner portion of the housing  20  or a part of a flapper body  50  of the flapper assembly  22 . Similar to the closing sleeve  12 , the opening sleeve  36  can be held in place via shear pins  30 . 
       FIG. 2A  shows the opening sleeve  36  in its first position wherein the flapper  14  is in the shut position and set against the flapper seat  24  restricting fluid from flowing in the uphole direction through the flapper valve tool  10 .  FIG. 2B  shows the fluid blocking member  34  engaged with the lip  38  of the opening sleeve  36  and the opening sleeve  36  in its second position in the flapper valve tool  10 . When enough pressure is put behind the fluid blocking member  34 , the shear pins  30  fail and permit the opening sleeve  36  to move from its first position to its second position in the flapper valve tool  10 . The opening sleeve  36  will travel a predetermined distance before the collar  42  of the opening sleeve  36  impacts the shoulder  46  disposed on the inside of the flapper valve tool  10 , which prevents further movement of the opening sleeve  36  in the flapper valve tool  10 . 
     After the flapper valve tool  10  travels a specific amount, a downhole end  52  of the opening sleeve  36  contacts the flapper  14  and forces the flapper  14  into the open position as the opening sleeve  36  moves into its second position. This allows fluid to now flow in the uphole direction through the flapper valve tool  10 . If desired, high pressure fluid can be pumped down to force the fluid blocking member  34  past the lip  38  in the opening sleeve  36  as can be seen in  FIG. 2C . 
     The fluid blocking member  34  can be pumped out of the flapper valve tool  10  and into some type of collection area so that fluid is permitted to flow in the uphole direction in the flapper valve tool  10 . In a further embodiment, the downhole end  52  of the opening sleeve  36  can be angled such that opening the flapper  14  is significantly easier. The angle in the downhole end  52  of the opening sleeve  36  is designed such that the longer portion of the opening sleeve  36  contacts the flapper  14  on the opposite side of the flapper  14  from where the flapper  14  is hinged. 
     In yet another embodiment of the present disclosure shown in  FIGS. 3-5B , the flapper valve tool  10  can be designed such that it has a first position where the flapper  14  is in an open position (see  FIG. 3 ), a second position where the flapper  14  is in a closed position (see  FIGS. 4A and 4B ) and a third position where the flapper  14  is back in the open position (see  FIGS. 5A and 5B ). The flapper valve tool  10  includes the top sub  16 , the bottom sub  18  and the housing  20 , as previously described herein. The flapper valve tool  10  also includes the flapper assembly  22 , the closing sleeve  12 , and the opening sleeve  36 , as described herein. The closing sleeve  12  is positioned downhole of the opening sleeve  36  in the flapper valve tool  10 . Furthermore, the flapper assembly  22  can include the flapper  14 , the flapper seat  24  and the flapper body  50 , as previously described herein. 
     In use, the fluid blocking member  34  is pumped into the flapper valve tool  10  to contact the lip  32  in the closing sleeve  12 . Fluid is pressured up behind the fluid blocking member  34  to shear pins  30  holding the closing sleeve  12  in the first position, which holds the flapper  14  in the open position. Once the shear pins  30  are sheared, the closing sleeve  12  is forced in the downhole direction inside the flapper valve tool  10  and into a second position for the closing sleeve  12 , as shown in  FIGS. 4A and 4B . After the closing sleeve  12  travels a predetermined length inside the flapper valve tool  10 , the flapper  14  will spring shut against the flapper seat  24 . Once the closing sleeve  12  is in the second position, fluid in the system can be further pressured up and the fluid blocking member  34  can be forced past the lip  32  disposed in the closing sleeve  12  and out of the flapper valve tool  10 .  FIG. 4B  shows the closing sleeve  12  in the second position after the fluid blocking member  34  is pushed out of the closing sleeve  12  of the flapper valve tool  10  and the opening sleeve  36  in its first position. It should be understood and appreciated that the fluid blocking member  34  is sized such that it can pass by the lip  38  in the opening sleeve  36  and then engage the lip  32  in the closing sleeve  12 . 
     When it is desirous to have the flapper  14  back in the open position, a second fluid blocking member  54  can be pumped down into the flapper valve tool  10 . The second fluid blocking member  54  is pumped down and contacts the lip  38  in the opening sleeve  36 . The fluid in the flapper valve tool  10  is pressured up and shear pins  30  holding the opening sleeve  36  in the opening sleeve&#39;s  36  first position are sheared, allowing the opening sleeve  36  to move in the downhole direction in the flapper valve tool  10 . As the opening sleeve  36  moves in the downhole direction, the opening sleeve  36  contacts the flapper  14  and forces it open. When the opening sleeve  36  reaches its second position in the flapper valve tool  10 , the opening sleeve  36  prevents the flapper  14  from closing and maintains the flapper  14  in the open position, which is shown in  FIG. 5 . 
     Once the opening sleeve  36  is in its second position, fluid in the system can be further pressured up and the second fluid blocking member  54  can be forced past the lip  38  disposed on the opening sleeve  36  and out of the flapper valve tool  10 .  FIG. 5B  shows the closing sleeve  12  in its second position and the opening sleeve  36  in its second position after the second fluid blocking member  54  was pushed out of the flapper valve tool  10 . 
     The present disclosure is also directed toward a method of controlling the flapper valve tool  10  and the backflow of fluid from the BHA into any tubing or tubing string the BHA is attached to. The method can include placing the flapper valve tool  10  into a wellbore, activating the closing sleeve  12  or the opening sleeve  36  to close or open the flapper  14 , respectively. Activation of the closing sleeve  12  or the opening sleeve  36  can be accomplished by pumping the fluid blocking members  34 ,  54  into the flapper valve tool  10  to engage the lips  32 ,  38  of the sleeves  12 ,  36 . 
     In another embodiment of the present disclosure, the flapper valve tool  10  is placed in the wellbore and the closing sleeve  12  is shifted from its first position to its second position, which causes the flapper  14  to transition from an open position to a closed position. The opening sleeve  36  can then be shifted from its first position to its second position, which causes the flapper  14  to transition from the closed position back to the open position. 
     In further embodiments of the present disclosure, the flapper valve tool  10  can include a deformable element that assists in the prevention of movement of the closing sleeve  12  and/or the opening sleeve  36  when they are in their second positions, respectively. The deformable elements can also contribute to maintaining the flappers  14  in the open position. The deformable element can be disposed on the closing sleeve  12  and/or the opening sleeve  36 , the flapper  14  (flapper assembly  22 ) and/or other parts of the flapper valve tool  10 . It should be understood and appreciated that any flapper valve tool described herein can include a deformable element. 
     In one embodiment shown in  FIGS. 6A-6E , the lips  32  and  38  disposed on the closing sleeve  12  and the opening sleeve  36  are deformable.  FIG. 6A  shows the result of the flapper valve tool  10  shown in  FIG. 1B  after the fluid blocking member  34  is forced past the lip  32 . A deformed portion  60  is created in the closing sleeve  12  due to the force and pressure required to force the fluid blocking member  34  past the lip  32  in the closing sleeve  12 . The deformed portion  60  of the closing sleeve  12  extends into a depression area  62  disposed on the inner portion of the housing  20  or bottom sub  18  and prevents the closing sleeve  12  from traveling in the uphole direction in the flapper valve tool  10 . 
       FIG. 6B  shows the result of the flapper valve tool  10  shown in  FIG. 2B  after the fluid blocking member  34  is forced past the lip  38 , a deformed portion  64  is created in the opening sleeve  36  due to the force and pressure required to force the fluid blocking member  34  past the lip  38  in the opening sleeve  36 . The deformed portion  64  of the opening sleeve  36  extends into a depression area  66  disposed on the inner portion of the housing  20  and adjacent to the flapper seat  24 . The deformed portion  64  being wider than the flapper valve seat  24  prevents the opening sleeve  36  from traveling in the uphole direction in the flapper valve tool  10 . 
       FIG. 6C  shows the result of the flapper valve tool  10  shown in  FIG. 4B  after the fluid blocking member  34  is forced past the lip  32 , the deformed portion  60  is created in the closing sleeve  12  due to the force and pressure required to force the fluid blocking member  34  past the lip  32  in the closing sleeve  12 . The deformed portion  60  of the closing sleeve  12  extends into the depression area  62  disposed on the inner portion of the housing  20  or bottom sub  18  and prevents the closing sleeve  12  from traveling in the uphole direction in the flapper valve tool  10 . 
       FIGS. 6D and 6E  show the result of the flapper valve tool  10  shown in  FIGS. 5A and 5B  before and after the fluid blocking member  54  is forced past the lip  38 , the deformed portion  64  is created in the opening sleeve  36  due to the force and pressure required to force the fluid blocking member  54  past the lip  38  in the opening sleeve  36 . The deformed portion  64  of the opening sleeve  36  extends into the depression area  66  disposed on the inner portion of the housing  20  and adjacent to the flapper seat  24 . The deformed portion  64  being wider than the flapper valve seat  24  prevents the opening sleeve  36  from traveling in the uphole direction in the flapper valve tool  10 . 
     Referring now to  FIGS. 7A-10 , shown therein are new embodiments of a flapper valve tool  70 . Shown in more detail in  FIGS. 7A-7C , the flapper valve tool  70  includes a top sub  72  for connection to tools disposed above the flapper valve tool  70 , a bottom sub  74  for attachment of the flapper valve tool  70  to tools disposed below the flapper valve tool  70 , and a housing  76  disposed between the top sub  72  and the bottom sub  74 . The flapper valve tool  70  further includes a flapper assembly  78  and a sleeve  80  slidably disposed within the housing  76 . 
     The flapper assembly  78  includes at least one flapper  82  (multiple flappers  82  can be implemented) for selectively blocking the backflow of fluid through the flapper valve tool  70  and a flapper seat  84  for each flapper  82  disposed in the housing  76  such that the sleeve  80  can slide through the flapper seat(s)  84 . The flapper  82  sits against the flapper seat  84  when the flapper  82  is in the closed position and prevents pressurized fluid from flowing in the uphole direction through the flapper valve tool  70 . The flapper  82  can be hingedly connected to the flapper seat  84  or to the inside of the housing  76 . 
     The sleeve  80  has a first position where the flapper  82  is set against the flapper seat  84  (closed). Consequently, the flapper  82  is in the open position when the sleeve  80  is in its second position. The sleeve  80  has a collar  86  disposed around an outer portion  88  of the sleeve  80 . The collar  86  is designed to engage with a shoulder  90  disposed within the flapper valve tool  70 . In one embodiment, the collar  86  is disposed on an uphole end  92  of the sleeve  80  to engage the shoulder  90 , which can be disposed on an inner portion of the housing  76  or a part of a flapper body  94  of the flapper assembly  78 . The sleeve  80  includes a downhole end  94  that can be angled to more efficiently engage and open the flapper  82 . 
     The flapper valve tool  70  also includes a seat  96  engagable with the uphole end  92  of the sleeve  80 . In one embodiment, the seat  96  is constructed of an extrudable material and be dissolvable in a dissolving solution. The dissolving solution can include an acidic component. The seat  96  can be designed such that a fluid blocking member  98  can be pumped into the flapper valve tool  70  and engage the seat  96  and prevent fluid from flowing through the flapper valve tool  70 . The pressure of the fluid in the flapper valve tool  70  can be increased such that the engagement of the fluid blocking member  98  and the seat  96  causes the sleeve  80  to be shifted in the downhole direction in the flapper valve tool  70 . 
     Shown in more detail in  FIGS. 8A and 8B , the design of the seat  96  and the uphole end  92  of the sleeve  80  permits the fluid blocking member  98  to be passed through the flapper valve tool  70  when the pressure of the fluid is pressured up to a predetermined threshold. The collar  86  of the sleeve  80  includes a recessed portion  100  on an internal part  102  of the collar  86 . Furthermore, the collar  86  includes a shoulder portion  104  that defines the downhole end of the collar  86 . The seat  96  can have a main body  106  positioned adjacent to the uphole end  92  of the sleeve  80  and a sleeve element  108  extending from the main body  106  and into the collar  86  such that the sleeve element  108  is positioned adjacent to the internal part of the collar  86 . Furthermore, the seat  96  includes a lip  110  disposed on an inner surface  112  of the sleeve element  108 . 
     In use, the fluid blocking member  98  is pumped down into the flapper valve tool  70  where it contacts the lip  110  of the seat  96 . Pressure of fluid is increased in the flapper valve tool  70  and the fluid blocking member  98  forces the seat  96  and the sleeve  80  to slide in the downhole direction in the flapper valve tool  70 . The pressure of the fluid in the flapper valve tool  70  can be increased even further wherein the fluid blocking member  98  is forced past the seat  96  and out of the flapper valve tool  70 . In this embodiment, the seat  96  is deformable and the sleeve element  108  can be flexed radially outward into the recessed portion  100  of the collar  86 . A dissolving solution can then be passed through the flapper valve tool  70  to dissolve at least a portion of the seat  96  to widen the passageway through the seat  96  (see  FIG. 8B ). 
     In a further embodiment of the present disclosure, the sleeve  80  includes a recessed area  114  disposed adjacent to the shoulder  104  of the collar  86 . The recessed area  114  engages a snap ring  115  which is statically disposed within the flapper valve tool  70 . When the sleeve  80  is shifted a certain amount in the flapper valve tool  70  in the downhole direction, the snap ring  115  engages the recessed area  114  to prevent the sleeve  80  from shifting back in the uphole direction. In another embodiment, the snap ring  115  can be disposed adjacent to the flapper assembly  78 . 
     In another embodiment of the present disclosure shown in  FIGS. 9A-9D , the flapper valve tool  70  includes a secondary flapper apparatus  116  disposed at least partially within the flapper valve tool  70 . The secondary flapper apparatus  116  can include at least one secondary flapper  118  disposed therein to prevent fluid from flowing in the uphole direction through the flapper valve tool  70  when not desired. The secondary flapper apparatus  116  can have a flapper housing  120  and a sleeve  122  extending therefrom in the uphole direction such that the sleeve  120  maintains the flappers  82  in an open position. The sleeve  122  and the secondary flappers  118  allow fluid to flow through the flapper valve tool  70  in the downhole direction. The secondary flapper apparatus  116  can be held in place in the housing  76  via shear pins  124 . 
     The sleeve  122  can have a propped end  126  that engages with at least one propped ball  128  disposed in an uphole end  130  of the flapper housing  120  to force the propped ball (s)  128  into a depression area  131  disposed on the inside of the housing  76  and a seat  132  disposed in an uphole end  134  of the sleeve  122 . The sleeve  122  can also include a body  136  for engaging with the inside of the housing  76  and stabilizing the secondary flapper apparatus  116  in the housing  76  and a recessed area  138  disposed on the sleeve  122  between the body  136  and the propped end  126 . The secondary flapper apparatus  116  can be configured to have a bottom sub portion so that the flapper valve tool  70  in this embodiment can be attached to other downhole tools downhole of the flapper valve tool  70 . 
     In use, the flapper valve tool  70  can be used in a bottom hole assembly (BHA) and the BHA can be positioned adjacent to a terminal location in a horizontal well. As can be seen in  FIG. 9B , a fluid blocking member  140  can then be pumped down into the flapper valve tool  70 , passed through the sleeve  80  and contacted the seat  132  and prevent fluid from passing through the secondary flapper apparatus  116 . Pressure of the fluid in the flapper valve tool  70  can then be pressured to a specific pressure threshold wherein the shear pins  124  shear and allow the sleeve  122  to slide in the downhole direction in the flapper valve tool  70 . The sliding of the sleeve  122  causes the propped end  126  to slide in the flapper valve tool  70  and cease contact with the propped ball  128  allowing the propped ball  128  to disengage with the sleeve  122  and settle in an area adjacent to the recessed area  138 . 
     The propped end  126  of the sleeve  122  can then be forced to then end of a cavity area  142  disposed in the body  136  of the secondary flapper apparatus  116  wherein the secondary flapper apparatus  116  is then forced out of the flapper valve tool  70 . This permits the flappers  82  to close and prevent fluid from passing in the uphole direction through the flapper valve tool  70 . Once the secondary flapper apparatus  116  is forced out of the flapper valve tool  70 , the flapper valve tool  70  is then positioned at a desired location in the wellbore (e.g. at the heel). The fluid blocking member  98  can then be pumped down into the flapper valve tool  70  to shift the sleeve  80  as previously described herein. 
     In a further embodiment of the present disclosure, the fluid blocking members  34 ,  52 ,  98 ,  140  can be constructed of a material that is dissolvable in specific types of fluid and/or well bore fluids. Thus, after the fluid blocking members  34 ,  52 ,  98 , or  140  are pumped through the sleeves  12 ,  36 ,  80  or  122 , a solution capable of dissolving the fluid blocking members  34 ,  52 ,  98 ,  140  is pumped through the flapper valve tool  70  to dissolve the fluid blocking members  34 ,  52 ,  98 ,  140  so that the fluid blocking members  34 ,  52 ,  98 ,  140  will not hinder production of fluids (oil or gas) from the well. It should be understood that the fluid blocking members  34 ,  52 ,  98 ,  140  can be dissolved in the dissolving solution described above. The dissolving solution can be different for the fluid blocking members  34 ,  52 ,  98 ,  140  or it can be the same. The dissolving solution can include an acidic solution. 
     In an even further embodiment of the present disclosure shown in  FIGS. 10A-10C , the flappers  14 ,  82  can include an opening  144  disposed therein to engage with a deformable pin element  146  extending from the flapper assembly  22 ,  78 . In use, fluid can be passed through the flapper valve tool  10 ,  70  and the opening  144  in the flappers  14 ,  82  do not forcibly engage with the deformable pin element  146  of the flapper assembly  22 ,  78 . In this embodiment, when the last fluid blocking member  34 ,  52 ,  98  is passed through the flapper assembly  22 ,  78  it forces the flapper open further and more forcibly. This more forcible opening causes the deformable pin element  146  to be deformed and forced into the opening  144 . The deformation of the deformable pin element  146  causes the deformable pin element  146  to remain in the opening  144 , which causes the flappers  14 ,  82  to remain open. 
     In an even further embodiment of the present disclosure shown in  FIGS. 11A-11C , the flappers  14 ,  82  can include a deformable pin element  148  disposed thereon to engage with an opening  150  disposed in a portion of the flapper assembly  22 ,  78 . In use, fluid can be passed through the flapper valve tool  10 ,  70  and the deformable pin element  148  on the flappers  14 ,  82  do not forcibly engage with the opening  150  disposed in the flapper assembly  22 ,  78 . In this embodiment, when the last fluid blocking member  34 ,  52 ,  98  is passed through the flapper assembly  22 ,  78  it forces the flapper open further and more forcibly. This more forcible opening causes the deformable pin element  148  to be deformed and forced into the opening  150 . The deformation of the deformable pin element  148  causes the deformable pin element  148  to remain in the opening  150 , which causes the flappers  14 ,  82  to remain open. 
     From the above description, it is clear that the present disclosure is well adapted to carry out the objectives and to attain the advantages mentioned herein as well as those inherent in the disclosure. While presently disclosed embodiments have been described for purposes of this disclosure, it will be understood that numerous changes may be made which will readily suggest themselves to those skilled in the art and which are accomplished within the spirit of the disclosure.