Patent Publication Number: US-10323478-B2

Title: Modular insert float system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO APPENDIX 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This disclosure relates to float valves used for hydrocarbon wells when conducting cementing operations. More specifically, this disclosure relates to float valves capable of being inserted within a casing. 
     Description of the Related Art 
     In the oil and gas industry, there is a need for equipment to cement casing into a drilled wellbore for hydrocarbon production from a well. Casing is usually inserted into the wellbore with “floating equipment” threaded onto the end of the casing (known as a “float shoe”) and/or threaded between pieces of casing often at the end of the casing string (known as “float collars”). This floating equipment has check valves built into their assemblies that will eventually prevent fluid (often, pumped cement) from entering into the casing by backing up after it has been pumped from the surface, down the internal bore of the casing, and up the annular space between the casing and the drilled hole of the wellbore. The heavier fluids being pumped downhole would tend to flow back up into the casing if the float valves were not in place. The float valves block the flow back into the casing, so that the cement in the annulus is held in place until the cement can set up hard, creating a protective barrier around the casing OD. 
     Most all floating equipment currently in use must have matching threads in order to make up the bodies of the float equipment to the thread profiles on the casing for the wellbore that forms a “string” of joints and connections. While standard threads exist, many operators prefer various proprietary threads that may offer strength, reduced torque to make up the connection, or other features for a given application. The different thread types are many. In addition to the matching threads, the float equipment is generally required to match the type of materials for the casing to ensure strength and performance of the casing string. There are many grades of steel and alloys available. These requirement alone make it an arduous task for users of float equipment to ensure all floating equipment matches the casing specifically. 
     Some efforts have been made to avoid the need of matching casing threads by inserting floating equipment into the bore of the casing. For example, U.S. Pat. No. 5,379,835 teaches in its abstract, “Insert type floating equipment valves for use in the cementing of casing in oil and gas wells and the like which may be retained in the casing therein through the use of slips or set screws or anchors and uses either cup type or compression type sealing members.” Another example is in U.S. Pat. No. 6,497,291 that teaches, “An improved float valve according to the present invention includes a packer  10  for positioning within a joint of the casing C while at the surface of the well, the packer including a float valve receptacle therein for at least partially receiving a float valve. The float valve body includes a valve seat  56  and a valve member  54  is positioned for selective engagement and disengagement with the valve seat. A guide nose  58  may be optionally provided for positioning within the casing joint between the valve body and the pin end of the casing joint. The float valve body may be reliably fixed and sealed to the packer body. After the packer setting operation, the casing joint and the packer and the float valve may then be positioned as an assembly within the well.” In both examples of inserted float equipment, the float valve is spring-loaded in a normally closed position and the fluid must overcome the spring force to open the valve. Further, there has to be a sufficient flow area between the valve and the seat without undue pressure drop, and the interface between the seat and the valve must be clear to reseal after the fluid passes through to avoid back flow. Because these systems are closed during insertion down the casing, wellbore fluid in the casing is pushed out from the inside of the casing and can cause excessive installation pressure on the float equipment and tooling that inserts the float equipment. The excessive pressure can also cause damage to the surrounding formation and hinder hydrocarbon production. Further, the absence of the wellbore fluid inside the casing can cause collapse from the pressure outside the casing. 
     Therefore, there remains a need for a float system that can be inserted into a casing, provide sufficient flow area for the fluid to flow through the valve without undue pressure drop, and reliably seal when the flow is finished to avoid back flow. 
     BRIEF SUMMARY OF THE INVENTION 
     The present disclosure provides a modular insert float system and method that can be inserted into a casing and attached to the casing internal surface by internal slips and sealing components. The system is modular in that three main components: an upper valve assembly, a lower valve assembly, and a pair of casing anchor and seal assemblies along with top and bottom shoes form a kit that can be used for virtually any casing of a given size regardless of the threads, casing material grades, length of joint, or other variations. Further, the system allows for insertion of the casing into the wellbore without damaging the formation from forcing wellbore fluid into the formation and causing the loss of wellbore fluid in the wellbore. 
     The disclosure provides a modular insert float system, comprising: a casing anchor and seal assembly, comprising: a mandrel having two interchangeable ends configured to allow a downhole component to be coupled to either end; a sealing element coupled to mandrel; and a slip coupled to the mandrel on each side of the sealing element. The system can also comprise a lower assembly formed from the casing anchor and seal assembly and a lower valve assembly, the lower valve assembly comprising: a lower valve housing; and a valve coupled to the lower valve housing; the lower assembly being configured to be coupled to an inside bore of a casing independent of being coupled to a casing end. The system can also comprise an upper assembly formed from the casing anchor and seal assembly and an upper valve assembly, the upper valve assembly comprising: an upper valve housing; and a valve coupled to the upper valve housing; the upper assembly being configured to be coupled to an inside bore of a casing independent of being coupled to a casing end. 
     The disclosure also provides a modular insert float system, comprising: a lower assembly, and an upper assembly, the lower assembly and upper assembly configured to be coupled to an inside bore of a casing independent of being coupled to a casing end. The lower assembly comprises: a lower valve assembly, comprising: a lower valve housing, and a valve coupled to the lower valve housing; and a lower casing anchor and seal assembly coupled with the lower valve assembly, comprising: a mandrel having two interchangeable ends configured to allow coupling to either end, and a sealing element coupled to mandrel. The upper assembly comprises: an upper valve assembly, comprising: an upper valve housing, and a valve coupled to the upper valve housing; and an upper casing anchor and seal assembly interchangeable with the lower casing anchor and seal assembly, comprising: a mandrel having two interchangeable ends configured to allow coupling to either end, and a sealing element coupled to mandrel. 
     The disclosure further provides a method of installing a modular insert float system into a bore of a casing, the float system having an assembly having a valve assembly with a valve housing, and a valve coupled with the valve housing; and a casing anchor and seal assembly having a mandrel with two interchangeable ends, and a sealing element coupled to mandrel; the method comprising: installing a downhole component on either interchangeable end of the casing anchor and seal assembly; inserting the casing anchor and seal assembly and downhole component a predetermined distance into the bore of the casing; and setting the casing anchor and seal assembly to engage the bore of the casing independent of being coupled to a casing end. 
     The disclosure also provides a method of installing a modular insert float system into a bore of a casing, the float system having: a lower assembly having a lower valve assembly with a lower valve housing, and a valve coupled with the lower valve housing; an upper assembly having an upper valve assembly with an upper valve housing, a valve coupled with the upper valve housing: and an upper casing anchor and seal assembly interchangeable with a lower casing anchor and seal assembly, each casing anchor and seal assembly, having a mandrel with two interchangeable ends and a sealing element coupled to mandrel; the method comprising: installing a bottom shoe on either end of the lower casing anchor and seal assembly; inserting the lower casing anchor and seal assembly a predetermined distance into the bore of the casing; setting the lower casing anchor and seal assembly to engage the bore of the casing independent of being coupled to a casing end; coupling an end of the lower casing anchor and seal assembly distal from the bottom shoe to the lower valve assembly; installing the upper valve assembly on either end of the upper casing anchor and seal assembly; inserting the upper casing anchor and seal assembly and upper valve assembly a predetermined distance into the bore of the casing; setting the upper casing anchor and seal assembly to engage the bore of the casing independent of being coupled to a casing end; and coupling a top shoe to an end of the upper casing anchor and seal assembly distal from the upper valve assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a schematic cross sectional view of an exemplary modular insert float system within a casing. 
         FIG. 2A  is a schematic perspective view of the lower valve assembly of the float system of  FIG. 1 . 
         FIG. 2B  is a schematic cross sectional view of the lower valve assembly of  FIG. 2A . 
         FIG. 3A  is a schematic perspective view of a housing of the lower valve assembly of  FIG. 2A  with a flapper slot formed in the housing. 
         FIG. 3B  is a schematic top view of the housing of  FIG. 3A . 
         FIG. 3C  is a schematic cross sectional side view of the housing of  FIG. 3A . 
         FIG. 4A  is a schematic perspective view of an exemplary flapper valve. 
         FIG. 4B  is a schematic cross sectional view of the flapper valve of  FIG. 4A . 
         FIG. 5A  is a schematic perspective view of the upper valve assembly of the float system of  FIG. 1 . 
         FIG. 5B  is a schematic cross sectional view of the upper valve assembly of  FIG. 5A . 
         FIG. 6A  is a schematic perspective view of a housing of the upper valve assembly of  FIG. 5A  with a flapper slot formed in the housing. 
         FIG. 6B  is a schematic top view of the housing of  FIG. 6A . 
         FIG. 6C  is a schematic cross sectional side view of the housing of  FIGS. 6A and 6B . 
         FIG. 7A  is a schematic perspective view of a shoe for the upper valve assembly. 
         FIG. 7B  is a schematic cross sectional view of the shoe of  FIG. 7A . 
         FIG. 8A  is a schematic perspective view of a sliding sleeve for the upper valve assembly. 
         FIG. 8B  is a schematic end view of the sliding sleeve of  FIG. 8A  showing locations of exemplary cross sections. 
         FIG. 8C  is a schematic cross sectional view of the sliding sleeve of  FIGS. 8A and 8B . 
         FIG. 8D  is another schematic cross sectional view of the sliding sleeve of  FIGS. 8A and 8B . 
         FIG. 9A  is a schematic perspective view of a ball holder for the upper valve assembly. 
         FIG. 9B  is a schematic cross sectional view of the ball holder of  FIG. 9A . 
         FIG. 10A  is a schematic perspective of a ball restrictor plate for the upper valve assembly. 
         FIG. 10B  is a schematic cross sectional view of the ball restrictor plate of  FIG. 10A . 
         FIG. 10C  is a schematic perspective of another exemplary embodiment of a ball restrictor plate for the upper valve assembly for a given pressure release. 
         FIG. 10D  is a schematic cross sectional view of the ball restrictor plate of  FIG. 10C . 
         FIG. 11A  is a schematic perspective view of the casing anchor and seal assembly (CAASA) of  FIG. 1 . 
         FIG. 11B  is a schematic cross sectional view of the CAASA of  FIG. 11A . 
         FIG. 12A  is a schematic perspective view of a wedge for the CAASA. 
         FIG. 12B  is a schematic cross sectional view of the wedge of  FIG. 12A . 
         FIG. 12C  is a schematic end view of the wedge of  FIGS. 12A and 12B . 
         FIG. 13A  is a schematic perspective view of a slip for the CAASA. 
         FIG. 13B  is a schematic cross sectional view of the slip of  FIG. 13A . 
         FIG. 13C  is a schematic end view of the slip of  FIGS. 13A and 13B . 
         FIG. 14A  is a schematic perspective view of a sealing element for the CAASA. 
         FIG. 14B  is a schematic cross sectional view of the sealing element of  FIG. 14A . 
         FIG. 15A  is a schematic perspective view of a top shoe for the CAASA. 
         FIG. 15B  is a schematic cross sectional view of the top shoe of  FIG. 15A . 
         FIG. 15C  is a schematic end view of the top shoe of  FIG. 15A . 
         FIG. 15D  is a schematic partial cross sectional view of a portion of the top shoe shown in  FIG. 15C  with an opening for gripping elements. 
         FIG. 16A  is a schematic perspective view of a bottom shoe for the CAASA. 
         FIG. 16B  is a schematic cross sectional view of the bottom shoe of  FIG. 16A . 
         FIG. 160  is a schematic end view of the bottom shoe of  FIGS. 16A and 16B . 
         FIG. 17A  is a schematic partial cross sectional view of a lower CAASA and the bottom shoe ready for coupling with the CAASA. 
         FIG. 17B  is a schematic partial cross sectional view of the CAASA coupled with the bottom shoe. 
         FIG. 17C  is a schematic partial cross sectional view of the CAASA and bottom shoe with a setting tool coupled to the CAASA. 
         FIG. 17D  is a schematic partial cross sectional view of the CAASA, bottom shoe, and setting tool inserted into a casing at the pin end. 
         FIG. 17E  is a schematic partial cross sectional view of the CAASA, bottom shoe, and setting tool with a setting sleeve assembly ready for insertion into the casing. 
         FIG. 17F  is a schematic partial cross sectional view of the CAASA, bottom shoe, and setting tool with the setting sleeve assembly inserted into the casing and abutting the end of the casing. 
         FIG. 17G  is a schematic partial cross sectional view of the CAASA, bottom shoe, setting tool, and setting sleeve assembly with a jack coupled to the setting tool tension mandrel. 
         FIG. 17H  is a schematic partial cross sectional view of the CAASA, bottom shoe, setting tool, and setting sleeve assembly with the jack initially tensioned on the setting tool tension mandrel. 
         FIG. 17I  is a schematic partial cross sectional view of the CAASA, bottom shoe, setting tool, and setting sleeve assembly with the jack activated to set the CAASA to the casing bore. 
         FIG. 17J  is a schematic partial cross sectional view of the CAASA and bottom shoe with the setting tool, setting sleeve assembly, and jack removed. 
         FIG. 17K  is a schematic partial cross sectional view of the CAASA and bottom shoe with a lower valve assembly. 
         FIG. 17L  is a schematic partial cross sectional view of the CAASA and bottom shoe with the lower valve assembly coupled to the CAASA. 
         FIG. 17M  is a schematic partial cross sectional view of the CAASA, bottom shoe, and lower valve assembly inserted a further distance into the casing. 
         FIG. 18A  is a schematic partial cross sectional view of an upper CAASA and an upper valve assembly ready for coupling with the CAASA. 
         FIG. 18B  is a schematic partial cross sectional view of the CAASA coupled with the upper valve assembly. 
         FIG. 18C  is a schematic partial cross sectional view of the CAASA and upper valve assembly with a setting tool coupled to the CAASA. 
         FIG. 18D  is a schematic partial cross sectional view of the CAASA, upper valve assembly, and setting tool inserted into a casing at the collar end. 
         FIG. 18E  is a schematic partial cross sectional view of the CAASA, upper valve assembly, and setting tool with a setting sleeve assembly ready for insertion into the casing at the collar end. 
         FIG. 18F  is a schematic partial cross sectional view of the CAASA, upper valve assembly, and setting tool with the setting sleeve assembly inserted into the casing and abutting the collar end. 
         FIG. 18G  is a schematic partial cross sectional view of the CAASA, upper valve assembly, setting tool, and setting sleeve assembly with a jack coupled to the setting tool tension mandrel. 
         FIG. 18H  is a schematic partial cross sectional view of the CAASA, upper valve assembly, setting tool, and setting sleeve assembly with the jack initially tensioned on the setting tool tension mandrel. 
         FIG. 18I  is a schematic partial cross sectional view of the CAASA, upper valve assembly, setting tool, and setting sleeve assembly with the jack activated to set the CAASA to the casing bore. 
         FIG. 18J  is a schematic partial cross sectional view of the CAASA and upper valve assembly with the setting tool, setting sleeve assembly, and jack removed. 
         FIG. 18K  is a schematic partial cross sectional view of the CAASA and upper valve assembly with a top shoe installation fixture coupled to a top shoe ready for coupling with the CAASA distal from the upper valve assembly. 
         FIG. 18L  is a schematic partial cross sectional view of the CAASA and upper valve assembly with the shoe installation fixture coupling the top shoe with the CAASA. 
         FIG. 18M  is a schematic partial cross sectional view of the CAASA, upper valve assembly, and top shoe with the shoe installation fixture removed. 
         FIG. 19A  is a schematic perspective view of an exemplary setting tool mandrel connector. 
         FIG. 19B  is a schematic cross sectional view of the setting tool mandrel connector of  FIG. 19A . 
         FIG. 20A  is a schematic perspective view of an exemplary shoe installation fixture. 
         FIG. 20B  is a schematic cross sectional view of the shoe installation fixture of  FIG. 20A . 
         FIG. 21A  is a schematic cross sectional view of another embodiment of the lower valve assembly in a pre-activated position. 
         FIG. 21B  is a schematic cross sectional view of the embodiment of  FIG. 21A  in an activated position. 
     
    
    
     DETAILED DESCRIPTION 
     The Figures described above with the written description of exemplary structures and functions below are not presented to limit the scope of what the inventor(s) have invented or the scope of the appended claims. Rather, the Figures and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. Those skilled in the art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding. Persons of skill in this art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present disclosure will require numerous implementation-specific decisions to achieve the developer&#39;s ultimate goal for the commercial embodiment. Such implementation-specific decisions may include, and likely are not limited to, compliance with system-related, business-related, government-related and other constraints, which may vary by specific implementation and location from time to time. While a developer&#39;s efforts might be complex and time-consuming in an absolute sense, such efforts would be, nevertheless, a routine undertaking for those of ordinary skill in this art having benefit of this disclosure. It must be understood that the inventions disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. 
     The use of a singular term, such as, but not limited to, “a,” is not intended as limiting of the number of items. Also, the use of relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and like terms are used in the written description for clarity in specific reference to the Figures as would be viewed in a typical orientation of a system installation, and are not intended to limit the scope of the invention or the appended claims. Generally, left to right in the Figures is upper to lower in the casing. For ease of cross reference among the Figures, elements are labeled in various Figures even though the actual textual description of a given element may be detailed in some other Figure. Further, the various methods and embodiments of the system can be included in combination with each other to produce variations of the disclosed methods and embodiments. Discussion of singular elements can include plural elements and vice-versa. References to at least one item may include one or more items. Also, various aspects of the embodiments could be used in conjunction with each other to accomplish the understood goals of the disclosure. Unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising” should be understood to imply the inclusion of at least the stated element or step or group of elements or steps or equivalents thereof, and not the exclusion of a greater numerical quantity or any other element or step or group of elements or steps or equivalents thereof. The device or system may be used in a number of directions and orientations. The terms such as “coupled”, “coupling”, “coupler”, and like are used broadly herein and may include any method or device for securing, binding, bonding, fastening, attaching, joining, inserting therein, forming thereon or therein, communicating, or otherwise associating, for example, mechanically, magnetically, electrically, chemically, operably, directly or indirectly with intermediate elements, one or more pieces of members together and may further include without limitation integrally forming one functional member with another in a unity fashion. The coupling may occur in any direction, including rotationally. The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and/or split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions. 
     The present disclosure provides a modular insert float system and method that can be inserted into a casing and attached to the casing internal surface by internal slips and sealing components. The system is modular in that three main components: an upper valve assembly, a lower valve assembly, and a pair of casing anchor and seal assemblies along with top and bottom shoes form a kit that can be used for virtually any casing of a given size regardless of the threads, casing material grades, length of joint, or other variations. Further, the system allows for insertion of the casing into the wellbore without damaging the formation from forcing wellbore fluid into the formation and causing the loss of wellbore fluid in the wellbore. 
       FIG. 1  is a schematic cross sectional view of an exemplary modular insert float system within a casing. The modular insert float system  2  generally includes two assemblies: a lower assembly  4  and an upper assembly  6 . The lower assembly  4  generally includes a lower casing anchor and seal assembly (CAASA)  100  coupled with a lower valve assembly  200 . The upper assembly  6  generally includes an upper CAASA  100  coupled with an upper valve assembly  300 . The lower and upper CAASAs can be the same or similar for modularity and interchangeability between the lower and upper assemblies. A CAASA bottom shoe  12  can be coupled to the lower CAASA  100  in the lower assembly  4 . Similarly, CAASA top shoe  10  can be coupled to upper CAASA  100  of the upper assembly  6 . The components described above can be coupled using slips and seals to the internal bore of one or more casing joints, herein singularly or collectively “a casing”  8 . The term “casing” is used broadly to include casing, drill pipe, and other tubular goods. The casing  8  has ends and, without limitation, the ends generally have male and female threads for attaching a plurality of casing joints together to form a casing string for insertion down a wellbore with the float system. The female threaded end is termed a “collar end”  8 A and the male threaded end is termed a “pin end”  8 B. Generally, the pin end is inserted into the wellbore with the collar end following, so that the pin end is the lower end in the wellbore. The lower and upper assemblies  4  and  6  do not need attachment to each other and therefore can be flexibly installed within the casing and even within different casings to extend a distance between the assemblies. The float system herein is modular in that three main components: a pair of interchangeable CAASAs  100 , the lower valve assembly  200 , the upper valve assembly  300 , along with top and bottom shoes  10  and  12 , form a kit that can be used for virtually any casing of a given size regardless of the threads, casing material grades, length of joint, or other variations. 
       FIGS. 2A-4B  illustrate an assembly and various components of an exemplary lower valve assembly.  FIG. 2A  is a schematic perspective view of the exemplary lower valve assembly of the float system shown in  FIG. 1 .  FIG. 2B  is a schematic cross sectional view of the lower valve assembly of  FIG. 2A .  FIG. 3A  is a schematic perspective view of a housing of the lower valve assembly of  FIG. 2A  with a flapper slot formed in the housing,  FIG. 3B  is a schematic top view of the housing of  FIG. 3A .  FIG. 3C  is a schematic cross sectional side view of the housing of  FIG. 3A .  FIG. 4A  is a schematic perspective view of an exemplary flapper valve.  FIG. 4B  is a schematic cross sectional view of the flapper valve of  FIG. 4A . The lower valve assembly  200  generally includes a lower valve housing  202  coupled with a case  214  that at least partially encapsulates the components. The case can be coupled to the housing with one or more fastening pins or other restraining elements  240 , including screws, such as set screws, adhesive applied to the relative components, and the like, and can be removable. 
     The lower valve housing  202  is formed with a bore  224  and includes a lower end with a taper  228 . The taper  228  can be formed off-center from a longitudinal centerline  230 . A slot  216  with a recess can be formed in the wall of the housing  202 . A flapper valve  204  having a pair of flapper arms  234  with a pin opening  236  can be rotatably coupled to the housing within the slot with a pin  208  inserted into a pin opening  232  of the slot. The flapper valve can be biased into a closed position that is generally transverse to a bore  224  of the lower valve housing  202  by a bias element  206 . An elastomeric seal  238  can be formed on the body of the flapper valve  204  to assist in sealing the flapper valve in operation. 
     A sliding sleeve  210  can be slidably disposed within the housing bore  224 . The sleeve  210  has an outer periphery  226  that is slightly smaller than the housing bore  224 , so that it can slide within the bore  224  when activated. The sliding sleeve  210  is formed with a first bore  220  and a second bore  222  that is smaller in cross-sectional area than the first bore. The smaller second bore  222  is configured lower than the first bore  220  when the valve assembly is installed in the casing for purposes described herein. The sleeve  210  is held in position temporarily by a restraining element  212  that is inserted through the housing  202 . The restraining element  212  can be sheared or otherwise dislodged between the restrained components when sufficient pressure is exerted on the system as described below. The sleeve  210  is coupled in the housing bore  224  at a longitudinal position that blocks the flapper valve  204  from rotating to the biased closed position, generally transverse to the housing bore  224 . If the flapper valve  204  is held open during installation of the casing into the wellbore (termed “run in”), the fluid in the wellbore can automatically fill the casing and avoid formation damage, casing collapse, and other detrimental effects. This capability, described herein as an “auto-fill” feature, can be activated with the flapper valve held open or can be deactivated so that the flapper valve is closed to block fluid from coming up the casing through the valve assembly during run in. An upper end of the lower valve assembly  200  is formed with a threaded bore  218  for coupling with the CAASA  100  described above. Various seals such as O-rings and other seals can be used to restrict leakage between the components, as would be known to those with ordinary skill in the art. 
       FIGS. 5A-10B  illustrate an assembly and various components of an exemplary upper valve assembly  300 ,  FIG. 5A  is a schematic perspective view of the exemplary upper valve assembly of the float system shown in  FIG. 1 .  FIG. 5B  is a schematic cross sectional view of the upper valve assembly of  FIG. 5A .  FIG. 6A  is a schematic perspective view of a housing of the upper valve assembly of  FIG. 5A  with a flapper slot formed in the housing.  FIG. 6B  is a schematic top view of the housing of  FIG. 6A .  FIG. 6C  is a schematic cross sectional side view of the housing of  FIGS. 6A and 6B .  FIG. 7A  is a schematic perspective view of a shoe for the upper valve assembly.  FIG. 7B  is a schematic cross sectional view of the shoe of  FIG. 7A .  FIG. 8A  is a schematic perspective view of a sliding sleeve for the upper valve assembly.  FIG. 8B  is a schematic end view of the sliding sleeve of  FIG. 8A  showing locations of exemplary cross sections.  FIG. 8C  is a schematic cross sectional view of the sliding sleeve of  FIGS. 8A and 8B .  FIG. 8D  is another schematic cross sectional view of the sliding sleeve of  FIGS. 8A and 8B .  FIG. 9A  is a schematic perspective view of a ball holder for the upper valve assembly,  FIG. 9B  is a schematic cross sectional view of the ball holder of  FIG. 9A ,  FIG. 10A  is a schematic perspective of a ball restrictor plate for the upper valve assembly.  FIG. 10B  is a schematic cross sectional view of the ball restrictor plate of  FIG. 10A . In at least one embodiment, the upper valve assembly  300  can include a housing  302  with associated components and a case  334  as a cover. Further, the upper valve assembly  300  can include an upper valve assembly shoe  320  coupled to the housing  302 . In at least one embodiment, the housing  302  can be coupled to the upper valve assembly shoe  320  and the case  334  with a restraining element  338 , such as pin, set screw, adhesive applied to the components and other restraining elements. 
     More specifically, the housing  302  can include a housing shoe bore  346  formed to receive a shoe extension  348  of the upper valve assembly shoe  320 . The housing  302  can further include a slot  306  formed through a wall of the housing. The slot  306  forms an opening for a flapper valve  304  to be rotatably coupled to the housing and biased toward a sealing position across a housing sleeve bore  376 . The slot  306  and flapper valve  304  can be similar to the slot  216  and the flapper valve  204 , as described above. The flapper valve  304  can be biased to a closed position, so that when the sleeve is removed, the flapper valve can travel to a sealing position transverse to the longitudinal axis of the bore  376 . 
     A sliding sleeve  308  can be inserted into a housing sleeve bore  376  of the housing. The sliding sleeve outer periphery can be slightly less than the bore  376  to allow the sliding sleeve  308  to slide longitudinally when activated. The sliding sleeve can be coupled into a position longitudinally with a restraining element  318  that can restrain the flapper valve  304  from actuating and sealing across the housing sleeve bore  376 . Further, the sliding sleeve can include a taper  310  that can align with a corresponding taper  312  in the housing. The tapers can facilitate a ball  326  or other actuator in alignment in the internal bore  314  of the sliding sleeve for actuation of the valve assemblies as described herein. The sliding sleeve can further include slotted sleeve fingers  350 , shown in more detail in  FIGS. 8A-8D . The slotted sleeve fingers  350  are generally on a lower end of the sliding sleeve, so that the ball  326  can travel down the sleeve bore  314  of the sliding sleeve to engage the slotted fingers until the ball is restrained when it engages a ball catch  316  at the lower end of the slotted fingers  350 . The slotted fingers can be filled and sealed with an elastomeric material  360 , as shown in  FIGS. 8C-8D  to assist in creating a sealing surface against which pressure is applied to on the ball to activate the upper valve assembly. 
     A ball holder  322  is disposed in the upper valve assembly  300  above the upper valve housing  302 . The ball holder can be restrained in position by a restraining element  336  coupled to the case  334 . With the upper valve housing  302  coupled to the case  334  with the restraining element  338  and the ball holder  322  also coupled to the case with the restraining element  336 , then the upper valve housing  302  is coupled with the ball holder  322 . The ball holder  322  includes a threaded bore that can engage the CAASA  100  shown in  FIG. 1 , A seal groove  368  can be formed above the threaded bore  370  to accept a seal, such as an O-ring, and seal against the CAASA when inserted into the bore. One or more other seal grooves  366  on an external surface of the ball holder can be similarly used to seal against other surfaces such as the inner periphery of the case  334 . (Other seal grooves and seals throughout the system and assemblies can be formed for sealing the components and would be known to those with ordinary skill in the art.) A smaller bore  372  is formed below the threaded bore  370  in the ball holder. The bore  372  is sized for a small clearance of the ball  326  when inserted through the bore  372 . A cross opening  374  is formed through the ball holder and can be used with a restraining element  324  to restrict upward movement of the ball after the ball has been inserted into the ball holder. A plate bore  378  is formed toward a lower end of the ball holder. The plate bore  378  can accept the ball restrictor plate  328 , shown in  FIGS. 5B and 10A-10B . The ball restrictor plate  328  can include a taper  380  that allows flow into a plate receiver bore  382  and then to a plate restrictor  332 . The ball restrictor plate  328  can initially hold the ball in position between the cross pin or other restraining element  324  and the plate restrictor  332 , shown in  FIG. 5B . A plurality of plate passages  330  are formed in the ball restrictor plate  328  to allow flow through the plate while the ball is restricted by the plate restrictor  332 , thus generally sealing flow through the plate restrictor  332 . Upon insertion into the casing, wellbore fluid can flow up into the upper valve assembly and pass the ball  326  without dislodging the ball from the upper valve assembly because it is held in position by the restraining element  324  for upward flow. Conversely, if downward flow is desired, such as circulation, then the passages  330  of the ball restrictor plate  328  allow downward flow up to a certain pressure without dislodging the ball  326  through the plate restrictor  332 . 
     For operation, if sufficient fluid pressure is applied to the ball  326  from an upper location such from the surface of the well, the pressure can force the ball through the opening of the plate restrictor  332  to become aligned with the sleeve  308  by passing the tapers  312  and  310  to enter the bore  314  of the sleeve until the ball engages the ball catch  316 . Additional pressure on the ball can activate the upper valve assembly by forcing the ball to exert a sufficient force on the ball catch  316  to shear or otherwise disengage the restraining element  318  and then to push the sleeve  308  toward the upper valve assembly shoe  320 . When the sleeve  308  has cleared the location of the flapper valve  304 , the flapper valve can rotate across the housing bore  376  through the slot  306  in the housing and seal against any backflow in a reverse direction from a lower location to an upper location. A housing release bore  356  is formed in the shoe  320  that is of a sufficient diameter to allow the slotted sleeve fingers  350  to expand radially outward and release the ball from the ball catch  316  to travel further down to the lower assembly  4  shown in  FIG. 1 . A sleeve taper  340  on the sleeve can engage a corresponding shoe taper  342  on the shoe to help the slotted fingers  350  expand radially to release the ball. 
     The upper valve assembly shoe  320  also includes a lead taper  362 , as shown in  FIGS. 7A-7B , that can correspondingly engage a lead taper on the CAASA bottom shoe  12  when drilling out the modular insert float system  2  after the float system has been used to complete cementing operations for the well. A counter taper  364  can be formed on a portion of the lead taper  362  to reduce the edge profile of the lead taper. 
       FIG. 10C  is a schematic perspective of another exemplary embodiment of a ball restrictor plate for the upper valve assembly for a given pressure release.  FIG. 10D  is a schematic cross sectional view of the ball restrictor plate of  FIG. 10C . The embodiment shown in  FIGS. 10C and 10D  has similar structure and function as the embodiment shown in  FIGS. 10A and 10B , but is omnidirectional, that is, the plate can be facing either direction in the flow path. The plate restrictor plate  328  is formed with a plate receiver bore  382  on both sides of the plate restrictor  332 . The ball  326 , described in  FIG. 5B , can locate on the plate restrictor  332  from either side of the plate. Sufficient pressure on the ball can create sufficient force to press the ball through the bore of the plate restrictor  332  by deforming the plate restrictor to allow the ball to pass therethrough. 
     The bore and width of the plate restrictor  332  can be designed to deform at preselected pressures or ranges of pressures. Field conditions and design parameters can allow an operator to select a ball restrictor plate  328  with a certain rated pressure from a kit or assortment of plates, and relatively easily insert the plate on site between the upper valve housing  302  and the ball holder  322  shown in  FIG. 5B . Because the plate can be inserted in either direction, operator errors can be reduced. 
       FIGS. 11A-14B  illustrate an assembly and various components of an exemplary casing anchor and seal assembly (CAASA).  FIG. 11A  is a schematic perspective view of the exemplary CAASA shown in  FIG. 1 ,  FIG. 11B  is a schematic cross sectional view of the CAASA of  FIG. 11A .  FIG. 12A  is a schematic perspective view of a wedge for the CAASA.  FIG. 12B  is a schematic cross sectional view of the wedge of  FIG. 12A .  FIG. 12C  is a schematic end view of the wedge of  FIGS. 12A and 12B .  FIG. 13A  is a schematic perspective view of a slip for the CAASA.  FIG. 13B  is a schematic cross sectional view of the slip of  FIG. 13A .  FIG. 13C  is a schematic end view of the slip of  FIGS. 13A and 13B .  FIG. 14A  is a schematic perspective view of a sealing element for the CAASA.  FIG. 14B  is a schematic cross sectional view of the sealing element of  FIG. 14A . As referenced in  FIG. 1 , a CAASA  100  can be coupled to each of the lower valve assembly  200  and the upper valve assembly  300 . 
     The CAASA  100  includes a mandrel  102  with ends, generally pin ends. Each of the mandrel pin ends can be threaded for coupling with adjacent assemblies and components, and are interchangeable between the ends so that the orientation and actuation can occur from either end. This feature of interchangeable ends is advantageous due to the system having modular components. Additional components for the CAASA described below can be coupled to the outer periphery of the mandrel. Starting in the middle, a sealing element  112  can be used to seal the CAASA against a bore of a casing. By compressing axially, the sealing element expands radially. To compress axially, slidable wedges and slips are used generally for both sides of the sealing element. For example, a wedge  106  can be slid along the outer periphery of the mandrel to contact the sealing element  112 . A wedge seal taper  124  can engage a correspondingly seal taper  126  to assist in guiding the longitudinal compression of the sealing element  112 . Further, a slip  108  having a slip taper  120  can slidably engage the wedge  106  along a wedge slip taper  122 . The slip  108  is formed from a plurality of slip elements (for example and without limitation 2-16 elements) that circumscribe the mandrel  102 , where the slip elements are held together by a slip band  110 . As the slip  108  moves longitudinally, the slip taper  120  travels along the wedge slip taper  122  that forces the slip to move radially outward (and expanding or breaking the band  110 ) toward the bore of the casing surrounding the CAASA. A plurality of gripping elements  116  (known as “buttons”) can be coupled to the outer periphery of the slip elements and are generally angled to provide point or line contact with the bore of the casing upon engagement. Upon radial expansion of the slip  108 , the gripping elements  116  can engage the bore of the casing to restrain further longitudinal movement of the slip and therefore the CAASA. A corresponding wedge and slip is provided on the distal side of the sealing element  112  in like fashion. The assembly of the sealing element, wedges, and slips are held in position by a pair of slip support rings  104 , which can be temporarily held in longitudinal position to the mandrel  102  by one or more restraining elements  114  such as shear pins, screws such as set screws, adhesive applied to the relative components, and the like and can be removable. In at least one embodiment, one of the slip support rings can be restrained with a restraining element and the other slip support ring can be slidably coupled with the mandrel, so that upon activation of the CAASA, the slidable support ring is moved longitudinally to compress the sealing member while the other support ring can remain stationary for at least a period of time. In this example, other components, such as a shoe, can be coupled with the CAASA to support the fixed support ring from moving. 
       FIG. 15A  is a schematic perspective view of a top shoe for the CAASA. 
       FIG. 15B  is a schematic cross sectional view of the top shoe of  FIG. 15A .  FIG. 15C  is a schematic end view of the top shoe of  FIG. 15A .  FIG. 15D  is a schematic partial cross sectional view of a portion of the top shoe shown in  FIG. 15C  with an opening for gripping elements. A top shoe  10  is provided for engagement with the CAASA  100  that is attached to the upper valve assembly  300 , as shown in  FIG. 1  for the assembly. The top shoe  10  includes a threaded bore  14  sized to engage the corresponding threaded pin end on the upper CAASA, A top end  16  of the top shoe can include one or more gripping elements  18  that can be inserted in openings  28 , shown in  FIG. 15D . The openings  28  can be angled to provide a line or point contact of the gripping elements to resist slippage of rotating components that may engage the top end  16  of the top shoe  10 . The gripping elements can assist in providing a nonslip surface for drilling out the float system after completion of cementing operations. One or more key slots  26  are formed in a bore of the top shoe to assist in rotating the top shoe during installation to the CAASA, as described herein. 
       FIG. 16A  is a schematic perspective view of a bottom shoe for the CAASA,  FIG. 16B  is a schematic cross sectional view of the bottom shoe of  FIG. 16A .  FIG. 16C  is a schematic end view of the bottom shoe of  FIGS. 16A and 16B . A bottom shoe  12  is provided for engagement with the CAASA  100  that is attached to the lower valve assembly  200 , as shown in  FIG. 1  for the assembly. The bottom shoe  12  includes a threaded bore  20  sized to engage the corresponding threaded pin end on the lower CAASA. The bottom shoe  12  further includes a lead angle  22  that can correspond to the lead angle  362 , described above for the upper valve assembly shoe  320  in  FIGS. 7A-7B . As the float system is drilled out after completion of cementing operations, the upper valve assembly is drilled out first and has various components below the slips that become loose and travel down the casing until the lower valve assembly is reached. The remaining upper valve system components with the lead taper  362 , shown in  FIGS. 5A-5B , can engage the bottom shoe with the lead taper  22  that resists rotation while such portions are drilled further out. 
       FIGS. 17A-17M  illustrate an exemplary assembly method for the lower assembly  4  described above.  FIG. 17A  is a schematic partial cross sectional view of a lower CAASA and the bottom shoe ready for coupling with the CAASA. For installation, adhesive can be applied to internal threads on the bore of the bottom shoe  12 . 
       FIG. 17B  is a schematic partial cross sectional view of the CAASA coupled with the bottom shoe. The bottom shoe  12  can be threaded onto the CAASA and tightened to a predetermined torque. 
       FIG. 17C  is a schematic partial cross sectional view of the CAASA and bottom shoe with a setting tool coupled to the CAASA. An exemplary setting tool  400  is illustrated in  FIGS. 19A-19B  and described herein. The CAASA  100  can be coupled to the setting tool  400  with a tension mandrel  408  by threading the tool onto the CAASA at a distal end from the bottom shoe  12 . Generally, it is not necessary to torque this connection, although the thread should be made up completely between the setting tool and the CAASA for sufficient gripping during the setting procedure. 
       FIG. 17D  is a schematic partial cross sectional view of the CAASA, bottom shoe, and setting tool inserted into a casing at the pin end. The components can be inserted into the casing  8  with the tension mandrel  408 , generally at the pin end  8 B, at a predetermined distance “B” by measuring length “A” of the tension mandrel extending outside of the casing. The slips  108  and sealing element  112  of the CAASA  100  generally have radial clearance from the bore of the casing  8  to allow insertion therein. 
       FIG. 17E  is a schematic partial cross sectional view of the one or CAASA, bottom shoe, and setting tool with a setting sleeve assembly ready for insertion into the casing. A setting sleeve assembly  500  can be inserted into the casing at the pin end and over the protruding tension mandrel  408 . 
       FIG. 17F  is a schematic partial cross sectional view of the CAASA, bottom shoe, and setting tool with the setting sleeve assembly inserted into the casing and abutting the end of the casing. The setting sleeve assembly  500  can be inserted fully into the casing until an outer hub of the setting sleeve assembly abuts the casing pin end  8 B. 
       FIG. 17G  is a schematic partial cross sectional view of the CAASA, bottom shoe, setting tool, and setting sleeve assembly with a jack coupled to the setting tool tension mandrel. A jack  600 , generally a hydraulic jack, can be installed over the tension mandrel  408 . The jack  600  can include a handle  602  threaded onto the tension mandrel for initial tightening. 
       FIG. 17H  is a schematic partial cross sectional view of the CAASA, bottom shoe, setting tool, and setting sleeve assembly with the jack initially tensioned on the setting tool tension mandrel. The handle  602  can be rotated for initial tightening of the CAASA  100  to the bore of the casing  8  until torque increases noticeably as the slips  108  of the CAASA expand radially outward and make contact with the casing bore. The jack  600  can press against the setting sleeve assembly  500 . 
       FIG. 17I  is a schematic partial cross sectional view of the CAASA, bottom shoe, setting tool, and setting sleeve assembly with the jack activated to set the CAASA to the casing bore. The jack  600  can be activated, such as by hydraulic pressure, to pull the tension mandrel thereby forcing the slips  108  and sealing element  112  radially outward as the components longitudinally contact the setting sleeve assembly  500 . The slips  108  grip onto the bore of the casing  8  and the sealing element  112  forms a seal with the casing bore. When sufficient force has been created by the jack on the slips  108  and sealing element  112 , the jack  600  can be held at a given pressure for a period of time, and then any hydraulic pressure released from the jack, so that the jack is deactivated. 
       FIG. 17J  is a schematic partial cross sectional view of the CAASA and bottom shoe with the setting tool, setting sleeve assembly, and jack removed. Disassembly of the installation components can be in reverse order of assembly, including unthreading the setting tool  400  from the CAASA  100 . 
       FIG. 17K  is a schematic partial cross sectional view of the CAASA and bottom shoe with a lower valve assembly. Adhesive can be applied to the bore of the lower valve assembly  200  and one or more O-rings installed to the lower valve assembly. The lower valve assembly  200  can be partially inserted into the casing and is ready for coupling with the CAASA distal from the bottom shoe. 
       FIG. 17L  is a schematic partial cross sectional view of the CAASA and bottom shoe with the lower valve assembly coupled to the CAASA. The lower valve assembly  200  can be threaded onto the CAASA  100  and torqued to a predetermined value. 
       FIG. 17M  is a schematic partial cross sectional view of the CAASA, bottom shoe, and lower valve assembly inserted a further distance into the casing. The lower end of the lower valve assembly  200  can be tapped to seat against the casing pin end  8 B. The lower assembly  4  is now installed in the casing  8 . 
       FIGS. 18A-18M  illustrate an exemplary assembly method for the upper assembly  6  described above.  FIG. 18A  is a schematic partial cross sectional view of an upper CAASA and an upper valve assembly ready for coupling with the CAASA. Adhesive can be applied to the bore of the upper valve assembly  300  and one or more O-rings installed to the upper valve assembly. 
       FIG. 18B  is a schematic partial cross sectional view of the CAASA coupled with the upper valve assembly. The upper valve assembly  200  can be threaded onto the CAASA  100  and torqued to a predetermined value. 
       FIG. 18C  is a schematic partial cross sectional view of the CAASA and upper valve assembly with a setting tool coupled to the CAASA. The CAASA  100  can be coupled with a setting tool  400  with a tension mandrel  408  by threading the tool onto the CAASA at a distal end from the upper valve assembly  300 . Generally, it is not necessary to torque this connection, although the thread should be made up completely between the setting tool and the CAASA for sufficient gripping during the setting procedure. 
       FIG. 18D  is a schematic partial cross sectional view of the CAASA, upper valve assembly, and setting tool inserted into a casing at the collar end. The components can be inserted into the casing  8  with the tension mandrel  408 , generally at the coupling end  8 A of the casing  8 , at a predetermined distance “Y” by measuring length “X” of the tension mandrel extending outside of the casing. The slips  108  and sealing element  112  of the CAASA  100  generally have clearance from the bore of the casing  8  to allow insertion therein. 
       FIG. 18E  is a schematic partial cross sectional view of the CAASA, upper valve assembly, and setting tool with a setting sleeve assembly ready for insertion into the casing at the collar end. A setting sleeve assembly  500  can be inserted into the casing at the coupling end and over the protruding tension mandrel  408 . 
       FIG. 18F  is a schematic partial cross sectional view of the CAASA, upper valve assembly, and setting tool with the setting sleeve assembly inserted into the casing and abutting the collar end. The setting sleeve assembly  500  can be inserted fully into the casing until the outer hub of the setting sleeve assembly abuts the casing coupling end  8 A. 
       FIG. 18G  is a schematic partial cross sectional view of the CAASA, upper valve assembly, setting tool, and setting sleeve assembly with a jack coupled to the setting tool tension mandrel. A jack  600 , generally a hydraulic jack, can be installed over the tension mandrel  408 . The jack  600  can include a handle  602  threaded onto the tension mandrel for initial tightening. 
       FIG. 18H  is a schematic partial cross sectional view of the CAASA, upper valve assembly, setting tool, and setting sleeve assembly with the jack initially tensioned on the setting tool tension mandrel. The handle  602  can be rotated for initial tightening of the CAASA  100  to the bore of the casing  8  until torque increases noticeably as the slips  108  of the CAASA expand radially outward and make contact with the casing bore. The jack  600  can press against the setting sleeve assembly  500 . 
       FIG. 18I  is a schematic partial cross sectional view of the CAASA, upper valve assembly, setting tool, and setting sleeve assembly with the jack activated to set the CAASA to the casing bore. The jack  600  can be activated, such as by hydraulic pressure, to pull the tension mandrel thereby forcing the slips  108  and sealing element  112  radially outward as the components longitudinally contact the setting sleeve assembly  500 . The slips  108  grip onto the bore of the casing  8  and the sealing element  112  forms a seal with the casing bore. When sufficient force has been created by the jack on the slips  108  and sealing element  112 , the jack  600  can be held at a given pressure for a period of time, and then any hydraulic pressure released from the jack, so that the jack is deactivated. 
       FIG. 18J  is a schematic partial cross sectional view of the CAASA and upper valve assembly with the setting tool, setting sleeve assembly, and jack removed. Disassembly of the installation components can be in reverse order of assembly including unthreading the setting tool  400  from the CAASA  100 . 
       FIG. 18K  is a schematic partial cross sectional view of the CAASA and upper valve assembly with a top shoe installation fixture coupled to a top shoe ready for coupling with the CAASA distal from the upper valve assembly. An exemplary top shoe installation fixture  700  is illustrated in  FIGS. 20A-20B  and described herein. Adhesive can be applied to the bore of the top shoe  10  and one or more O-rings installed to the top shoe. The top shoe  10  can be partially inserted into the casing with the key slots  26  of the top shoe engaged with corresponding keys  706  in the installation fixture, and is ready for coupling with the CAASA distally from the upper valve assembly  300 . 
       FIG. 18L  is a schematic partial cross sectional view of the CAASA and upper valve assembly with the shoe installation fixture coupling the top shoe with the CAASA. The top shoe  10  can be threaded onto the CAASA  100  by rotating the installation fixture that is keyed with the top shoe. The top shoe can be torqued to a predetermined value. 
       FIG. 18M  is a schematic partial cross sectional view of the CAASA, upper valve assembly, and top shoe with the shoe installation fixture removed. The top shoe installation fixture can be removed from the CAASA  100  and the upper assembly  6  is now installed in the casing  8 . 
       FIG. 19A  is a schematic perspective view of an exemplary setting tool. 
       FIG. 19B  is a schematic cross sectional view of a setting tool mandrel connector of the setting tool of  FIG. 19A . The setting tool  400  generally includes a setting tool mandrel connector  402  that can be releasably coupled with a tension mandrel  408 . The tension mandrel  408  may be supplied with a jack described herein, where the tension mandrel  408  can have an industry-standard thread that can fit in a suitable threaded bore  406  of the mandrel connector  402 . The mandrel connector  402  further includes a threaded bore  404  that is sized and threaded to fit onto a threaded end of a CAASA  100 . The setting tool  400  can be used to set the engagement of slips and sealing element of the CAASA  100  in a bore of the casing  8  in conjunction with a jack described herein. 
       FIG. 20A  is a schematic perspective view of an exemplary top shoe installation fixture.  FIG. 20B  is a schematic cross sectional view of the top shoe installation fixture of  FIG. 20A . The top shoe installation fixture  700  generally includes a tubular member having a first cylindrical portion  702  with a greater diameter than a second cylindrical portion  704 . The interface between the first cylindrical portion and the second cylindrical portion forms a shoulder which can abut a top surface of the top shoe  10  to assist in installation. The second cylindrical portion  704  can further include one or more keys  706  that can engage corresponding key slots  26  in the top shoe to allow rotating the top shoe to couple onto the CAASA. The first cylindrical portion  702  further can include an opening  708  to insert a handle therethrough to use in rotating the fixture  700 . 
     After the modular insert float system  2  is installed into a casing (that is, into one or more joints of a casing string) as described herein, the system is ready to be run into a wellbore according to normal casing running procedures. The float system  2  can be installed with the flapper valves in an “auto-fill” position to allow the casing to fill from the bottom as the casing is run into the wellbore. It is expected that most float system installations of the present invention will be run into the wellbore with the auto-fill feature activated. The flow paths described above through the valve assemblies when using the auto-fill feature are designed with sufficient flow area to help reduce significantly surge pressures on the wellbore formations during casing run in. The auto fill feature also can reduce the collapse pressure on the casing as fluid is allowed to enter the casing string and reduce differential pressure changes between fluid inside of the casing and outside of the casing. When the float system is installed and run with the auto-fill feature activated, the wellbore fluid can enter the casing through the bottom of the casing string. The fluid can flow up through both of the float valves in the valve assemblies of the float system with minimal pressure drop. This small pressure drop is possible due to the big bore flow areas through the float system. 
     Alternatively, the flapper valves can be run with the auto-fill feature deactivated. If the auto-fill feature has been deactivated, the customer has an option to provide buoyancy to the casing string while it is being lowered into the wellbore. The buoyancy adjustments may help to offset the load on the float system, casing, and drilling rig equipment caused by pressure from the fluids below the float system that are being pushed down the wellbore as the casing is inserted with the auto-fill feature deactivated. 
     While running casing into the hole, the wellbore fluid can enter through the internal bore of the tool. Often during casing run in operations, the casing crew will need to pump fluid down through the casing bore to condition the circulating fluid (often termed “mud”) and establish a circulation up the annulus between the casing and open hole of the wellbore. The float system can allow this circulation without deactivating the auto-fill feature of the system by controlling the circulation rate that does not exceed shearing pressures for shearing pins or otherwise force restraining elements to disengage the surface, and not exceed pressures on the ball to deform and pass through restrictions in the valve assemblies. In at least one nonlimiting example, circulation rates of up to five barrels per minute are allowed. Circulation rates can be established as many times and for as long as needed. 
     After the casing reaches the desired depth, circulation rates can continue at the rate of up to five barrels/min. Once mud has been conditioned satisfactorily and cementing operations are ready to commence, the float system is then ready for cement pumping. There is no need to drop a ball from the surface to deactivate the auto-fill feature of the system. The self-contained ball described above is located inside the float system to deactivate the auto-fill feature. In at least one nonlimiting example, once circulation rates reach ten barrels/min or higher, the ball can self-release and pass through the valve assemblies, thereby deactivating the auto-fill feature and activating the flapper valves to seal against back flow from below the valves. An operator can continue pumping fluids or cement slurry as required. The float valves will reduce or prevent any flow back through the system as pressure differential increase from below. Additional pumping from above is possible. The operator can continue pumping with a cement plug down the casing until the cement plug bumps onto the top of the float system, specifically the top of the top shoe on the upper assembly. The cement plug will land and seal on the top of the top shoe, creating a “bottom” to pump against. The operator can continue pumping until a required casing pressure test is reached or the maximum bump pressure is reached. 
     The float can will hold the pressure differential of the cement in the annulus. After waiting on cement to set, the float system can be drilled out with conventional drilling techniques for floating equipment. The gripping elements on the top surface of the top shoe can assist in restraining rotation of the cement plug until the cement plug is drilled out. The composite materials can be drilled out and lightweight waste materials can be circulated back to the surface. 
       FIG. 21A  is a schematic cross sectional view of another embodiment of the lower valve assembly in a pre-activated position.  FIG. 21B  is a schematic cross sectional view of the embodiment of  FIG. 21A  in an activated position. The lower valve assembly  202  is similar to the embodiment shown in  FIGS. 2A and 2B  with a primary difference. The sleeve described below does not exit the nose of the lower valve housing, but rather forms a sealing surface to force fluid out of jet openings through the sidewall of the housing. The jet openings assist in increasing turbulent flow of the fluid outside of the housing. 
     More specifically, the lower valve assembly  200  includes a lower valve housing  202  coupled with an external case  214  around a portion of the housing that at least partially encapsulates components in the lower valve assembly. The case  214  can be coupled to the housing with one or more fastening pins or other restraining elements  240 , including screws, such as set screws, adhesive applied to the relative components, and the like, and can be removable. The housing  202  includes a flapper slot  216  formed in the sidewall of the housing. A flapper valve  204 , having a pair of flapper arms with a pin opening, can be rotatably coupled to the housing  202  within the flapper slot  216  with a pin  208  inserted into a pin opening of the slot. The flapper valve  204  can be biased into a closed position that is generally transverse to a bore  224  of the lower valve housing  202 . 
     A sliding sleeve  210  can be slidably disposed within the housing bore  224 . The sleeve  210  has an outer periphery  226  that is slightly smaller than the housing bore  224 , so that it can slide within the bore  224  when activated. The sliding sleeve  210  is formed with a first bore  220  and a second bore  222  that is smaller in cross-sectional area than the first bore to form a sealing surface  242  therebetween. The smaller second bore  222  is configured lower than the first bore  220  when the valve assembly is installed in the casing for purposes described herein. The sleeve  210  is held in position temporarily by a restraining element  212  that is inserted through the housing  202 . The restraining element  212  can be sheared or otherwise dislodged between the restrained components when sufficient pressure is exerted on the system as described below. The sleeve  210  is coupled in the housing bore  224  at a longitudinal position that blocks the flapper valve  204  from rotating to the biased closed position, generally transverse to the housing bore  224 . Downstream of the housing bore  224  is a larger diameter bore  250  that allows the sleeve  210  after actuation to move more easily through lower portions of the lower valve housing  202 . At the lower end of the housing  202 , the bore  250  is restricted by a shoulder  244  that forms a bore  246  that is smaller in diameter than the bore  250 . The outer periphery  226  of the sleeve is sized so that the sleeve will not pass through the bore  246 , and so lodges against the shoulder  244 . A plurality of jet openings  252  can be formed through a sidewall of the housing  202 . In some embodiments, the jet openings can be angled upwardly and in some embodiments, the jet openings can be formed in a spiral pattern around the housing  202 . 
     For activation, the ball  326 , described above, can be dropped downhole so that the ball passes through the various components described above including the upper assembly  6  and into the lower assembly  4 , shown in  FIG. 1 . As the ball  326  travels downhole to encounter the sleeve restrained in the position shown in  FIG. 21A , the ball lodges against the sealing surface  242  of the sleeve  210 . Pressure on the ball provides sufficient force against the sleeve to shear the restraining element  212 . The pressure on the ball pushes the sleeve downward into the bore  250  to lodge against the shoulder  244 . The pressure on the ball helps maintain the ball against the sealing surface  242  of the sleeve, thus blocking flow through the bore  246 . Fluid flow into the housing  202  is forced through the jet openings  252 . The jet openings  252  can be angled upwardly and/or in a spiral so that the flow of the fluid flows upwardly out of the jet openings in a spiral pattern to create more turbulence and more equal distribution of the flow around the outside of the lower valve housing  200 . 
     The invention has been described in the context of preferred and other embodiments and not every embodiment of the invention has been described. Obvious modifications and alterations to the described embodiments are available to those of ordinary skill in the art. The disclosed embodiments are not intended to limit or restrict the scope or applicability of the invention conceived of by the Applicant, but rather, in conformity with the patent laws, Applicant intends to protect fully all such modifications and improvements that come within the scope or range of equivalent of the following claims.