Abstract:
The present invention generally relates to a flow-actuated valve for use in a wellbore. The invention includes a body having a closing member and a seat. The closing member and seat are separable to open and close the valve, thereby allowing the flow of fluid through the valve. The invention further includes a retainer to initially retain the valve in the open position absent a predetermined fluid flow rate in a first direction for a predetermined time period. A biasing member thereafter urges the valve to the closed position, absent another fluid flow rate in the first direction.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a flow actuated valve for use in a wellbore. More particularly, the invention relates to a flow-actuated valve that is initially retained in an open position and is closeable with the application of fluid flow. More particularly still, the invention relates to a flow-actuated valve for use in float equipment to facilitate the injection of zonal isolation fluids into an annular area between a string of casing and a surrounding formation.  
           [0003]    2. Description of the Related Art  
           [0004]    Hydrocarbon wells are conventionally formed one section at a time. Typically, a first section of wellbore is drilled in the earth to a predetermined depth. Thereafter, that section is lined with a tubular string, or casing, to prevent cave-in. After the first section of the well is completed, another section of well is drilled and subsequently lined with its own string of tubulars, comprised of casing or liners. Each time a section of wellbore is completed and a section of tubulars is installed in the wellbore, the tubular is typically anchored into the wellbore through the use of wellbore zonal isolation fluids, i.e. cementing. Wellbore zonal isolation fluids includes, but not limited to, the injection of cement into an annular area formed between the exterior of the tubular string and the borehole in the earth therearound. Zonal isolation protects the integrity of the wellbore and is especially useful to prevent migration of hydrocarbons towards the surface of the well via the annulus.  
           [0005]    Zonal Isolation of strings of tubulars in a wellbore is well-known in the art. Typically, the zonal isolation fluid is initially inserted in the tubular, and then forced to the bottom of the well and up the annular area toward the surface. With the use of other fluids, a column of zonal isolation fluids can be forced down the tubular string and into the annulus, resulting in a completely isolated annulus and leaving only a small amount of zonal isolation fluid at the bottom of the borehole. The cured fluid is drillable and is easily destroyed by subsequent drilling to form the next section of wellbore.  
           [0006]    Float shoes and float collars facilitate zonal isolation procedures. In this specification, a float shoe is a valve-containing apparatus disposed at or near the lower end of the tubular string that is run into in a wellbore. A float collar is a valve-containing apparatus which is installed at some predetermined location, typically above a shoe within the tubular string. In certain cases, float collars are required rather than float shoes. However, in this specification, the term float shoe and float collar will be used interchangeably.  
           [0007]    The main purpose of a float shoe is to facilitate the passage of zonal isolation fluids from the tubular to the annulus of the well while preventing the zonal isolation fluids from returning or “u-tubing” back into the tubular due to gravity and fluid density of the liquid zonal isolation fluids. In its most basic form, the float shoe includes a one way valve permitting fluid to flow in one direction through the valve, but preventing fluid from flowing back into the tubular from the opposite direction. The float shoes usually include a cone-shaped body to prevent binding of the tubular string during run-in.  
           [0008]    As mentioned, wellbores are typically full of fluid to protect the drilled formation of the borehole and aid in carrying out cuttings created by a drill bit. When a new string of tubulars is inserted into the wellbore the tubulars must necessarily be filled with fluid to avoid buoyancy and equalize pressures between the inside and the outside of the tubular. For these reasons, a float shoe can be capable to temporarily permit fluid to flow inwards from the well bore as the tubular string is run into the wellbore and fills the tubular string with fluid. In one simple example, a spring loaded, normally closed, one-way valve in a float shoe is temporarily propped in an open position during run-in of the tubular by a wooden object which is thereafter destroyed and no longer affects the operation of the valve.  
           [0009]    Other, more sophisticated solutions have been used that temporarily hold the valve in an open position and subsequently permit it to close and operate as a normally closed, one way valve. In a prior art arrangement, a valve is temporarily held in an open position during run-in and, thereafter, a weighted ball is dropped from the surface. The ball sinks to a seated position within the valve of a float collar and then, with pressure applied from the surface of the well, the valve is then enabled to shift to its normally closed position. In another prior art solution, a spring-loaded plunger is moved from an open position to a closed position utilizing hydrostatic pressure. The design utilizes an atmospheric chamber and shears screws. The number of shear screws determines the trip point of the device. As the tubular string is run deeper into a wellbore, hydrostatic pressure builds until it generates sufficient force on the shear screws to cause them to fail. The shearing action releases the plunger converting the valve to a normally closed, one-way valve.  
           [0010]    More recently, spring loaded plunger valves in float shoes have been moved from a retained open position with the flow of fluid. The existing designs use energy from wellbore fluid that is circulated with pumps through the valve to depress the plunger and subsequently trip the device. These devices are typically comprised of some form of stop which temporarily retains the valve in an open position. Typically, wedges, tabs, balls, or knobs are mechanically lodged between the plunger and its retainer. These hold the plunger open against the spring force. When sufficient flow is established, the plunger moves downward, compressing the spring further and releasing the wedged stops.  
           [0011]    There are problems associated with the prior art devices. Particularly, these devices are susceptible to premature release of the mechanism retaining the valve in an open position. For example, devices requiring a burst of fluid flow for deactivation can sometimes operate prematurely due to naturally occurring flow increases. Devices using an atmospheric chamber sometimes fail to operate as designed due to either design flaws or changes in well bore fluid density. If the valve releases premature, it is no longer possible to fill the tubular string with fluid from below. Because the tubular string must necessarily be filled with fluid to prevent pressure collapse and buoyancy, fluid must then be introduced from the surface of the well, thereby increasing the already high cost of completing drilled sections of wells.  
         SUMMARY OF THE INVENTION  
         [0012]    The present invention generally relates to a flow-actuated valve for use in a wellbore. The invention includes a body having a closing member and a seat. The closing member and seat are separable to open and close the valve, thereby allowing the flow of fluid through the valve. The invention further includes a retainer to initially retain the valve in the open position absent a predetermined fluid flow rate in one direction for a predetermined time period. A biasing member thereafter urges the valve to the closed position, absent another fluid flow rate in one direction. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    So that the manner in which the above recited features of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.  
         [0014]    [0014]FIG. 1 is a perspective view of a valve of the present invention.  
         [0015]    [0015]FIG. 2 is an exploded view of the valve of FIG. 1.  
         [0016]    [0016]FIG. 3 is a section view of the valve of FIG. 1, with a retention assembly retaining the valve in an open position.  
         [0017]    [0017]FIG. 4 is a section view of a wellbore with a valve of the present invention disposed in a tubular.  
         [0018]    [0018]FIG. 5 is a section view of the valve of FIG. 4 as the retention assembly is being deactivated.  
         [0019]    [0019]FIG. 6 is a section view of the valve operable as a one way, normally closed valve.  
         [0020]    [0020]FIG. 7 is a section view of the valve operating to permit fluid to flow from its upper end to and through its lower end.  
         [0021]    [0021]FIG. 8 is a section view showing an alternative embodiment of the valve with a retention assembly activated.  
         [0022]    [0022]FIG. 9 is a section view of the valve of FIG. 8 with the retention assembly deactivated. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]    [0023]FIG. 1 is a perspective view of a valve  100  of the present invention. Visible in FIG. 1 is an upper housing  105  and a lower  110  housing. Also visible is an impeller  120  partially extending from the lower housing  110 . In use, the valve  100  is disposed in the interior of a tubular string (not shown) in a manner whereby all fluid passing through the tubular in either direction must flow through the valve  100 . In one example, the valve  100  is disposed at a lower end of a tubular string. In another example, the valve  100  is disposed at some location within the tubular apparatus, such as in a collar within a string of casing.  
         [0024]    [0024]FIG. 2 is an exploded view of the valve  100  of FIG. 1. Visible in FIG. 2 are the upper  105  and lower  110  housings. The upper housing  105  includes an aperture  107  formed therethrough with a seat (not visible) formed in an interior surface thereof. Additional components of the valve  100  are substantially housed between the upper  105  and lower  110  housings. A plunger  125  with a head portion  127  and a sealing member  130  therearound creates a sealing relationship between the plunger  125  and the valve body  105  when the valve  100  is closed. The sealing member, therefore blocks the inward flow of fluid of valve  100  as fluids attempt to enter the tubular string. The plunger  125  includes a shaft  135 . A biasing member, in this case a spring  140 , is locatable between the head  127  of the plunger  125  and a surface  142  formed in a support member  145 . The spring  140  is constructed and arranged to become compressed as the head  127  of the plunger moves away from the upper housing  105 . In this manner, valve  100  is biased in a closed position. The support member  145  also includes a fluid path therethrough with radially disposed spokes  147  extending between an inner and an outer portion. Below the support member  145  is an annular diverter  150  for diverting the flow of fluid through the valve as is illustrated in FIGS.  3 - 7 .  
         [0025]    The valve of the present invention also includes a retention assembly  200 . The retention assembly  200  serves to temporarily hold the valve  100  in an open position. The open position is especially useful to permit a tubular string to fill with fluid during run-in into a wellbore. The retention assembly  200  operates by holding the plunger head  127  away from the seat in the upper housing  105  until a sustained fluid flow rate is applied through the valve  100  in a forward direction. Typically, the forward direction is a downward direction. A partially threaded bolt  205  having a head  206  at an upper end is insertable into a hollow portion of the shaft  135  of the plunger  125 . A sleeve  210  is attachable to the bolt  205  and is extendable through a body of an impeller  120 , where it is retained at a bottom end thereof with a fastener  222 . The impeller  120 , as will be described, include blades  122  formed on a body thereof to urge the impeller  120  to rotate as the blades are acted upon by a fluid flow. The bolt  205  and the upper portion of sleeve  210  are held within the plunger shaft by a bushing  215  having threads on an inner and outer diameter. The release assembly  200  is designed whereby the bolt and sleeve will rotate with the impeller  120  while the bushing  215  and the plunger  125  will remain rotationally fixed. In this manner, axial movement of the impeller and bolt is transmitted by the interaction of the threads of the bolt  205  and the bushing  215 .  
         [0026]    [0026]FIG. 3 is a section view of the valve  100  with the retention assembly  200  retaining the valve in an open position. Visible in the figure is an aperture  107  in an upper end of upper housing  105 . In the interior of the housing  105  is seat  109  providing a sealing surface for the sealing member  130  of the plunger  125 . In the retained position, the spring  140  is compressed between an annular surface  217  formed on the underside of the plunger head  127  and annular surface  142  of support member  145 . The retention assembly  200  operates to hold plunger  125  in the position of FIG. 3 through a mechanical connection between bushing  215  and bolt  205 . As illustrated, the bushing  215  is held in the lower end of the shaft  135  of plunger  125  while the bolt  205  is held within the sleeve  210 . The threaded connection between the bushing  215  and the bolt  205  determines the relative position of the plunger head  127  with respect to the seat  109 .  
         [0027]    Impeller  120  with blades  122  is retained between an underside  220  of support member  145  and fastener  222  threaded to a lower end of the sleeve  210 . The purpose of the impeller  120  is to rotate in one of two directions depending upon the flow force of fluid past its blades  122 . Because the bolt  205  moves with the impeller  120 , rotation of the impeller  120  in either direction will cause relative axial movement between the bolt  205  and the bushing  215 .  
         [0028]    [0028]FIG. 4 is a section view of the valve  100  illustrating the flow of fluid through the valve  100  in direction  225 . As previously described, the valve  100  is typically disposed in the bottom end of the tubular string  101  which is then run into a wellbore  102  having drilling fluid therein. One purpose of the valve  100  is to initially permit fluid to pass from a lower to an upper portion of the valve  100  as the tubular string  101  is being lowered into the wellbore  102 . Arrow  224  illustrates the movement of the tubular string  101  in relation to the wellbore  102 . Thereafter, the retention assembly  200  of the valve  100  is deactivated, and the valve  100  operates as a normally closed, one-way valve permitting fluid to pass from an upper to a lower portion.  
         [0029]    In FIG. 4, the valve  100  is illustrated in a run-in position with the retention assembly  200  activated. As illustrated, the head  127  of plunger  125  is separated from seat  109  formed in the upper housing  105  of the valve  100 . As illustrated with arrows  225 , fluid flows from a lower end of the valve  100  through an annular area formed in the valve  100  between the plunger  125  and the upper  105  and lower  110  housing portions. Also illustrated by separate arrow  226  is a rotational force applied to the impeller  120  by fluid moving past blades  122  of impeller  120 . In the illustration of FIG. 4, the fluid flow in direction  225  acts on the impeller blades  122  urging the impeller  120  to rotate in a clockwise direction. However, due to high frictional forces, rotation is prohibited.  
         [0030]    [0030]FIG. 5 is a section view of the valve  100 . In FIG. 5, the retention assembly  200  is being deactivated and the flow of fluid through the valve  100  is illustrated by arrows  230 . The arrows  230  illustrate fluid being pumped from an upper end of the valve  100  through an annular area defined between the outer surface of the plunger  125  and the inner surface of the upper  105  and lower  110  housings. In FIG. 5, the flow of fluid acting on the upper surface of plunger head  127  has depressed the plunger  125  and compressed the spring  140  further than it was originally compressed during run-in. The additional compression of the spring  140  and downward movement of plunger  125  has caused a corresponding downward axial movement of the impeller  120 . An under side  220  of support member  145  is shown separated from the upper surface of the impeller  120 . The result of this separation is greater freedom of the impeller  120  to rotate as the fluid moves across its blades  122 . Of course, the scope of the present invention permits a design of the valve  100  which does require the separation of the support member  145  from the impeller  120  before rotation of the impeller  120 .  
         [0031]    In order to initiate the release of the retention assembly  200  of FIG. 5, two conditions are created simultaneously. First, the plunger  125  is depressed past its originally retained position in order to separate the impeller  120  from the lower surface  220  of support member  145 , making it easier for the impeller to rotate. Second, the impeller  120  must be rotated by fluid passing across the from an upper to a lower portion of the valve  100 . The rotation of the impeller  120  with the bolt  205 , in direction  227 , will cause the threaded portion of the bolt  205  to move downward in relation to the bushing  215 . As the impeller  120  continues to rotate, that portion of the bolt  205  which is threaded will pass through the bushing, allowing the bolt  205  to then slide freely within the bushing  215  after its threads are disengaged therefrom.  
         [0032]    [0032]FIG. 6 is a section view of the valve  100  disposed in a tubular string  101  which is itself disposed in a wellbore  102 . FIG. 6 illustrates the valve  100  with the retention assembly  200  deactivated. As illustrated, bushing  215  is adjacent a portion of the bolt  205  having no threads on its outer diameter. Bolt  205  has slipped through the bushing to a location whereby head  206  of the bolt is retained on an upper surface of the bushing  215 . The axial movement of the bolt  205  with respect to bushing  215  has permitted the plunger  125  with its sealing member  130  to contact seat  109  formed in the underside of upper housing  105 . In this manner, the valve  100  is sealed to the flow of fluid from below, and will only permit fluid entry from above if the fluid flow is adequate to overcome the bias of spring  140 . The retention assembly  200  has thus been permanently disengaged and the valve  100  can now operate as a typical float shoe valve permitting zonal isolation fluids to flow through the valve  100  from the surface downhole, but preventing a back flow of the zonal isolation fluids into the tubular string  101 .  
         [0033]    [0033]FIG. 7 is a section view of wellbore  102  with valve  100  in tubular string  101 . FIG. 7 illustrates the valve  100  in use with zonal isolation fluids such as cement being pumped from an upper end of the tubular, through the valve  100 , to the lower end of the wellbore  102 . The movement of the plunger  125  downward is shown with arrow  229 . The flow of fluid is illustrated with arrows  228 . As illustrated by the arrows  228 , zonal isolation fluids enters the valve  100  from an upper end and acts upon plunger head  127  to depress the plunger head  127  and to unseat sealing member  130  from seat  109  of upper housing  105 . Spring  140  is shown in a somewhat compressed position. The fluid flows through the valve and the annular area created by the inside of the upper and lower housings  105 ,  110  and the outside of plunger  125 . Thereafter, the fluid is guided around diverter  150  and exits through the lower end of the valve  100 . Any effect the passing fluid may have on the blades  122  of the impeller  120  is unimportant as the impeller is free to rotate without creating any change in the valve  100 . This is because the threads of the bolt  205  have now been released from the bushing  215 . From the bottom of the tubular, the zonal isolation fluids flow upward to fill an annular area  103  formed between tubular  101  and wellbore  102 . At some predetermined point, when the annulus  103  is filled with zonal isolation fluids, the flow of zonal isolation fluids is stopped and the fluids are allowed to cure. Thereafter, the cement shoe, including the valve  100  can be drilled up and destroyed by subsequent drilling of another section of wellbore.  
         [0034]    In use, the valve  100  of the present invention is utilized as follows:  
         [0035]    The valve  100  is disposed either at the end or near the end of a tubular  101 , such as a casing or liner string. The tubular string  101  with the valve  100  disposed therein is run into a wellbore  102  with the retention assembly  200  of the valve holding it in an open position. In this manner, as the tubular string  101  is inserted into the wellbore  102 , wellbore fluid is free to pass from a lower to an upper end of the valve  100 , thereby permitting the tubular  101  to fill with fluid.  
         [0036]    After the tubular string reaches a predetermined point in the well, wellbore fluid or some other fluid is pumped through the valve  100  at a predetermined flow rate  140 . The injection of fluid under pressure further depresses the plunger head  127  and further compresses the biasing spring  140 . In this manner, the impeller  120  disposed at the bottom of the valve  100  is separated from its contact with the surface of the support member  145  and is free to rotate. Simultaneously, the fluid utilized to depress the plunger urges the impeller  120  to rotate. The rotation of the impeller in direction  227  causes the threads of the bolt  205  and the bushing  215  to transmit motion of the bolt  205  in a downward direction with respect to the bushing  215 . As that portion of the bolt  205  having threads pass through the bushing  215 , a non-threaded portion of the bolt  205  permits the bolt  205  to drop to a lower position with respect to the bushing  215  and to be retained in the bushing  215  by bolt head  206 . In this position, the retention assembly  200  is deactivated and the valve  100  operates as a normally closed, spring loaded, one-way valve for cementing operations in a wellbore.  
         [0037]    [0037]FIG. 8 is a section view illustrating an alternative embodiment of the invention. The valve  300  of FIG. 8, like the earlier embodiments includes a spring-loaded plunger  325  and an impeller  320  attached to the plunger by a threaded member. In the embodiment of FIG. 8, a bushing  315  is disposed in the interior of the impeller  320  and an interior of the plunger shaft  335  is threaded. A partially threaded bolt  305  is threaded into the plunger shaft at an upper end and is also threaded through the bushing  315 . FIG. 8 illustrates the valve  300  in an initial position in which a head  327  of the plunger  325  is biased against spring member  340  thereby opening the valve to flow therethrough. The bolt  305  also includes a lower end having additional threads  306  formed thereupon and a nut  307  retained on the threads.  
         [0038]    In operation, the valve  300  of FIG. 8 operates as follows: During run-in of a string of tubulars into the wellbore the valve permits the tubular string to fill with fluid. Thereafter, the retention assembly  400  made up of the impeller  320  and bolt  305  is caused to deactivate by the flow of fluid on the plunger head  327  at a specific rate and for a predetermined amount of time. As with the earlier embodiment, the flow of fluid causes the plunger head  327  to move downwards against the spring  340  and permits the impeller  320  to move out of engagement with a support member  145 . With the impeller out of engagement, blades  322  formed on the impeller cause it to rotate in a counterclockwise direction and the bushing  315  and impeller  320  rotate and move axially away from the plunger shaft  335 . As the rotating threads of the bushing  315  reach a portion of the bolt which is unthreaded, the bushing and impeller drop to a second position in relation to the bolt  305 . As the impeller continues to rotate in a counterclockwise direction it becomes threadedly attached to the threads  306  at the lower portion of the bolt  305  and is prevented from additional rotation. The threaded portion at the lower end of the threaded member is designed to prevent the impeller from rotating after the retention assembly  400  is deactivated in order to prevent any damage that might come about due to the freely rotating impeller.  
         [0039]    [0039]FIG. 9 is a section view of the valve  300  illustrating the components of the valve  300  after the retention assembly  400  has been deactivated. The plunger  325  is in its normally closed, spring biased position and the impeller  320  is threaded at a lower end of the bolt  305 , thereby preventing additional rotation of the impeller  320 .  
         [0040]    While the valve of the present invention has been described with the use of an impeller which is rotated by the flow of fluid, it will be understood that the invention could use any type of rotatable member to deactivate the retention assembly and the invention is not limited to the use of an impeller having blades to be acted upon by a passing fluid flow. For instance, the rotatable member could be rotated by a downhole motor, a spring or anything else to translate the rotatable member along the threads of another member to deactivate a retention assembly. These variations are fully within the scope of the invention.  
         [0041]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. For example, the retention assembly  200  could be used with various valve devices including flapper valves and the invention is not limited to use with plunger-type valves.