Abstract:
The application discloses a valve, which may include either a safety valve or a storm surge choke valve or the like, to isolate a zone below a valve from a string of production tubing. Preferably, the valve includes a flow interruption surface assembly, such as a flapper valve or a ball valve, displaced by an operating conduit extending from a surface location to the valve through the inside of the production tubing. The application also discloses a bypass-conduit inside the production tubing to allow communication from a surface location to the production zone when the valve is in either an open or a closed location.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of provisional application U.S. Ser. No. 60/522,498 filed Oct. 7, 2004. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention generally relates to subsurface valves. More particularly, the present invention relates to an apparatus and method to operate a subsurface valve with a capillary tube extending from a surface station. More particularly still, the present invention relates to an apparatus and method to operate a subsurface valve with a capillary tube extending from a surface station from within the tubing string upon which the valve is mounted. The valve may be a safety valve, a storm check valve, or a choke valve. The flow interrupting device or valve may be formed from a flapper, a ball valve, or a gate valve or any other type of flow diverting valve assembly which may be actuated from the surface. 
         [0003]    Subsurface valves are typically installed in strings of tubing deployed to subterranean wellbores to prevent the escape of fluids from one production zone to another, including the surface. The application of the present invention relates to all types of valves, but for the purposes of this disclosure the illustrative application shall be safety valves used to shut in a well in the absence of continued hydraulic pressure from the surface. This limitation on the scope of this disclosure should not be used to limit the scope of the disclosure for non-safety valve applications which may be readily apparent from the disclosure made herein to a person having ordinary skill in this art. 
         [0004]    Absent safety valves, sudden increases in downhole pressure can lead to catastrophic blowouts of production and other fluids into the atmosphere. For this reason, drilling and production regulations throughout the world require safety valves be in place within strings of production tubing before certain operations can be performed. 
         [0005]    One popular type of safety valve is known as a flapper valve. Flapper valves typically include a closure member generally in the form of a circular or curved disc that engages a corresponding valve seat to isolate one or more zones in the subsurface well. The flapper disc is preferably constructed such that the flow through the flapper valve seat is as unrestricted as possible. Usually, flapper-type safety valves are located within the production tubing and isolate one or more production zones from the atmosphere or upper portions of the wellbore or production tubing. Optimally, flapper valves function as large clearance check valves, in that they allow substantially unrestricted flow therethrough when opened and completely seal off flow in one direction when closed. Particularly, production tubing safety valves prevent fluids from production zones from flowing up the production tubing when closed but still allow for the flow of fluids (and movement of tools) into the production zone from above. 
         [0006]    Flapper valve disks are often energized with a biasing member (spring, hydraulic cylinder, etc.) such that in a condition with zero flow and with no actuating force applied, the valve remains closed. In this closed position, any build-up of pressure from the production zone below will thrust the flapper disc against the valve seat and act to strengthen any seal therebetween. During use, flapper valves are opened by various methods to allow the free flow and travel of production fluids and tools therethrough. Flapper valves may be kept open through hydraulic, electrical, or mechanical energy during the production process. 
         [0007]    Examples of subsurface safety valves can be found in U.S. Provisional Patent Application Ser. No. 60/522,360 filed Sep. 20, 2004 by Jeffrey Bolding titled “Downhole Safety Apparatus and Method;” U.S. Provisional Patent Application Ser. No. 60/522,500 filed Oct. 7, 2004 by David R. Smith and Jeffrey Bolding titled “Downhole Safety Valve Apparatus and Method;” U.S. Provisional Patent Application Ser. No. 60/522,499 filed Oct. 7, 2004 by David R. Smith and Jeffrey Bolding titled “Downhole Safety Valve Interface Apparatus and Method;” all hereby incorporated herein by reference. 
         [0008]    This application further incorporates by reference U.S. Non-Provisional application Ser. No. 10/708,338 Filed Feb. 25, 2004, titled “Method and Apparatus to Complete a Well Having Tubing Inserted Through a Valve” and U.S. Provisional Application Ser. No. 60/319,972 Filed Feb. 25, 2003 titled “Method and Apparatus to Complete a Well Having Tubing Inserted Through a Valve”. 
         [0009]    One popular means to counteract the closing force of the biasing member and any production flow therethrough involves the use of a capillary tube to operate the safety valve flapper through hydraulic pressure. Traditionally, production tubing having a subsurface safety valve mounted thereto is disposed down a wellbore to a depth of investigation. In this circumstance, the capillary tubing used to open and shut the subsurface safety valve is deployed in the annulus formed between the outer profile of the production tubing and the inner wall of the borehole or casing. A fitting outside of the subsurface safety valve connects to the capillary tubing and allows pressure in the capillary to operate the flapper of the safety valve. 
         [0010]    Furthermore, because former systems were run with the production tubing, installations after the placement of production tubing in the wellbore are invasive. To accomplish this, the production tubing must be retrieved, the safety valve installed, the capillary tubing attached, and the production tubing, safety valve, and capillary tubing run back into the hole. This process is expensive and time consuming, so it is typically performed on wells having enough long-term production capability to justify the expense. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention is directed to a downhole safety valve apparatus with a bypass-conduit, for example. In one embodiment a valve comprises a flow interruption device operable between an open position and a closed hydraulically sealed position and a bypass-conduit extending from a surface location through the valve to a zone below the valve, the bypass-conduit wholly contained within a bore of a string of tubing carrying the valve. The valve can be a subsurface safety valve or a storm choke valve. The zone below the valve can be a production zone. The flow interruption device can be a flapper. The flapper can be pivotably operable between the open position and the closed hydraulically sealed position. 
         [0012]    In another embodiment, the bypass-conduit is in communication with the surface location and the zone below the valve when the flow interruption device is in the closed hydraulically sealed position. The operating conduit can be in communication with a source of an energy, the operating conduit extending from the surface location to the valve and the energy actuating the flow interruption device from the closed hydraulically sealed position to the open position. The bypass-conduit can be a capillary tube. The capillary tube can be a fluid injection capillary tube in communication with the surface location and the zone below the valve. The fluid can be a liquid or gas. In another embodiment, the fluid is selected from the group comprising surfactant, acid, miscellar solution, corrosion inhibitor, scale inhibitor, hydrate inhibitor, and paraffin inhibitor. 
         [0013]    In another embodiment the bypass-conduit is a logging conduit, a gas lift conduit, an electrical conductor, or an optical fiber. In yet another embodiment, the bypass-conduit is a hydraulic passage. The bypass-conduit can further comprise a check valve attached below the valve or a check valve attached between the valve and a wellhead. 
         [0014]    In another embodiment, the operating conduit is a hydraulic passage. The operating conduit can further comprise a check valve located between the valve and a wellhead. The energy supplied by the operating conduit can actuate a packer element of the valve to an engaged position. The energy supplied by the operating conduit can actuate a packer element of the valve to a disengaged position. The operating conduit can be a continuous tube. The operating conduit can be a capillary tube. 
         [0015]    In yet another embodiment, the operating conduit and the bypass-conduit can be concentric. The operating conduit and the string of tubing can be concentric. The bypass-conduit and the string of tubing can be concentric. The valve can further comprise a second operating conduit extending from the surface location to the valve, the second operating conduit in communication with the source of the energy, the energy actuating the flow interruption device from the open position to the closed hydraulically sealed position. The second operating conduit can extend from the surface location to the valve from outside the string of tubing. 
         [0016]    In yet another embodiment, a method to communicate with a zone below a valve can comprise installing a valve at a downhole location within a string of tubing, connecting an operating conduit inside a bore of the string of tubing between the valve and a surface location, extending a bypass-conduit wholly contained within a bore of a string of tubing carrying the valve from the surface location, through the valve, and to the zone below the valve, selectively opening and closing a flow interruption device with the operating conduit, and communicating with the zone below the valve via the bypass-conduit when the flow interruption device of the valve is in a closed hydraulically sealed position. The valve can be a subsurface safety valve. The flow interruption device can be a flapper. 
         [0017]    In another embodiment, the method can further comprise communicating with the zone below the valve through the bypass-conduit when the flow interruption device of the valve is in an open position. The bypass-conduit can be a continuous tube. The bypass-conduit can be a capillary tube. The method can further comprise constructing the bypass-conduit from a section of jointed pipe deployed from the surface location. The method can further comprise locating a check valve in the bypass-conduit above the valve. The method can further comprise locating a check valve in the bypass-conduit below the valve. The method can further comprise locating a check valve in the operating conduit. 
         [0018]    In yet another embodiment, the method can further comprise injecting a foam to the zone below the valve through the bypass-conduit. The method can further comprise injecting a fluid to the zone below the valve through the bypass-conduit. The fluid can be selected from the group consisting of corrosion inhibitor, scale inhibitor, hydrate inhibitor, paraffin inhibitor, surfactant, acid, and miscellar solution. The bypass conduit can be a logging conduit, a gas lift conduit; an electrical conductor, or an optical fiber. The bore of the logging conduit can be greater than one and a half inches in diameter. 
         [0019]    In another embodiment, the method can further comprise deploying the string of tubing, the bypass-conduit, the operating conduit, and the valve simultaneously. The method can further comprise deploying the valve, the bypass-conduit, and the operating conduit simultaneously into a pre-existing string of tubing. The valve can be installed by actuating a packer element of the valve. The method can further comprise actuating the packer element with the operating conduit. The method can further comprise actuating the packer element with the operating conduit. The method can further comprise actuating the packer element with the bypass-conduit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is schematic representation of a safety valve assembly with a bypass-conduit installed in a string of tubing in accordance with an embodiment of the present invention. 
           [0021]      FIG. 2  is a schematic representation of a tubing injector assembly having installed a safety valve assembly with a bypass-conduit in a pre-existing string of production tubing in accordance with another embodiment of the present invention. 
           [0022]      FIG. 3  is a schematic representation of a safety valve assembly with a bypass-conduit in accordance with another embodiment of the present invention. 
           [0023]      FIG. 4  is a schematic representation of a safety valve assembly with a bypass-conduit in accordance with another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    Referring initially to  FIG. 1 , a safety valve assembly  100  is shown schematically deployed in a string of production tubing  102 . Safety valve assembly  100  can be of any valve type known to one of ordinary skill in the art and may be deployed integrally within tubing string  102  or may be held within a bore  104  of tubing  102  and isolated with a hydraulic seal  106 . Nevertheless, the safety valve assembly  100  functions to selectively isolate a first zone  108  of tubing  102  from a second zone  110  of tubing  102 . Typically, zone  108  is in communication with a surface location (not shown) at the uppermost end of tubing  102  and zone  110  is in communication with one or more production zones  112 . To communicate production fluids from the subsurface formation  114  to the surface, production fluids flow through perforations  116  in a production casing or wellbore  118 , up through lower zone  110  of production tubing  102 , past safety valve  100 , through upper zone  108  of tubing  102  and to the surface. 
         [0025]    Safety valve assembly  100  acts to prevent flow from lower zone  110  to upper zone  108  and typically includes a valve body  120 , a flapper disc  122 , a valve seat  124 , and a flow bore  126 . While a flapper-type design is typical and common for safety valves deployed to subterranean wells, it should be understood that any type of valve assembly known to one skilled in the art may be used. When flapper disc  122  is open, production fluids and other tools and materials are free to flow from zone  108  to zone  110  and vice versa through flow bore  126 . However, when flapper disc  122  is closed and in contact with valve seat  124 , fluids in zone  110  cannot migrate to zone  108  within production tubing  102 . Ideally, flapper disc  122  is biased by a spring (or equivalent) into contact with valve seat  124  so flapper disc  122  will close in the absence of any opening force. 
         [0026]    The operation of flapper disc  122  from closed position in engagement with valve seat  124  to open position allowing flow through bore  126  is accomplished through operating conduit  130 . Operating conduit  130  extends from the surface through bore  104  of tubing string  102  to safety valve assembly  100 . Formerly, operating conduits would extend from the surface to safety valves through an annulus  132  between tubing  102  and wellbore  134 , but operating conduit  130  reaches safety valve  100  through the inner bore of tubing string  102 . Operating conduit  130  can be of any type and style of conduit known to one skilled in the art and can transmit hydraulic, electrical, pneumatic, and mechanical power from the surface to operate flapper disc  122 . Preferably, operating conduit  130  is a hydraulic capillary tube containing fluid at sufficient pressure to operate a cylinder (not shown) in connection with flapper disc  122 . When energized, hydraulic pressure in conduit  130  would overcome any biasing force urging flapper disc  122  closed thereby opening flapper disc  122 . Alternatively, increases in pressure within operating conduit  130  can open flapper disc  122  by displacing a tubing mandrel (not shown) through flow bore  126  to thrust disc  122  open. Alternatively still, operating conduit  130  can include an electrical conductor configured to actuate a downhole motor capable of displacing flapper disc  122  into an open position. 
         [0027]    In addition to an operating conduit  130  located within bore of production tubing  102 , safety valve assembly  100  also preferably includes a bypass-conduit  140 . Bypass-conduit  140  can be of various sizes, shapes, and types and can perform various types of functions, but bypass-conduit  140  is configured to communicate with lower zone  110  regardless of the position (open or closed) of flapper disc  122 . Bypass-conduit  140  can be a straight, curved or otherwise tortuous conduit and is not limited to the shape shown in  FIG. 1 . Functions of bypass-conduit  140  can include, but are not limited to, the performance of chemical injection, gas lift, fiber-optic measurement, pumping, and logging operations. Chemical injection operations can include the injection of a foam, acid, surfactant, miscellar solution, corrosion inhibitor, scale inhibitor, hydrate inhibitor, paraffin inhibitor, or any other chemical injection intended to increase the quality and/or quantity of production fluids flowing to the surface. Depending on the type of operation to be performed by utilizing bypass-conduit  140 , the construction and size of bypass-conduit  140  can vary from a small capillary for chemical injection to a 1.9″ logging conduit, or larger. Although bypass-conduit  140  is shown as larger than operating conduit  140 , the invention is not so limited to any relative sizes as shown in the figures. The term capillary tube is used to describe any small diameter tube and is not limited to a tube that holds liquid by capillary action nor is there any requirement for surface tension to elevate or depress the liquid in the tube. The term hydraulic and hydraulically are used to describe water or any other fluid and are not limited to a liquid or by liquid means, but can be a gas or any mixture thereof. 
         [0028]    Regardless of its function and configuration, bypass-conduit  140  is preferably configured to only allow communication from the bore of bypass-conduit  140  to zone  110  and not from zone  110  to bypass-conduit  140 . In embodiments using bypass-conduit  140  for fluid communication, a check valve device (not shown) is appropriate. For applications where a logging tool is deployed to zone  110  utilizing bypass-conduit  140 , a hydraulic packoff (not shown) is appropriate. Nonetheless, conduit  140  can extend from a surface location, through the bore of tubing  102 , through safety valve assembly  100  and communicate with zone  110  (including production zone  112  below) independent of the position (open, closed, or therebetween) of the flapper disc  122 . 
         [0029]    Referring now to  FIG. 2 , the installation of a safety valve assembly  200  into a pre-existing string of tubing  202  is shown. A wellhead assembly  204  is shown having a valve tree  206 , a Y-spool adapter  208 , a ram-type blowout preventer  210 , and a dual-tubing injection assembly  212 . Y-spool adapter  208  connects injection assembly  212  to valve tree  206  and blowout preventer  210  and enables the engagement of safety valve assembly  200  into the well. Injection assembly  212  includes a dual tubing injector head  214 , a dual tubing hydraulic packoff  216 , and a dual tubing annular blowout preventer  218 . Although dual tubing is shown, a single tube can be used without departing from the spirit of the invention. The conduits can have separate injection means and are not limited to the bypass-conduit  222  being internal to the operating conduit  220 . Safety valve assembly  200  is deployed inside production tubing  202  upon the distal end of two conduits, an operating conduit  220  and a bypass-conduit  222 . Safety valve assembly  200  includes a flow interruption device therein (not shown) and a bypass-conduit  222  therein. 
         [0030]    Operating conduit  220  actuates a flapper valve disc (not shown) or other flow interruption device. Bypass-conduit  222  allows for communication with a zone  224  below safety valve assembly  200  within tubing  202  independent the position (open, closed, or therebetween) of the flow interruption device. As safety valve assembly  200  is lowered to a desired location within tubing string  202 , surface reels (not shown) pay out substantially equal lengths of operating conduit and bypass-conduit,  220  and  222  respectively. Injector head  214  and hydraulic packoff  216  thrust and seal around conduits  220  and  222  to prevent escape of pressurized fluids from tubing string  202 . When safety valve assembly  200  has reached its target depth within the tubing string  202 , a packer element  226  is activated to seal off the portion  224  of tubing  202  below safety valve assembly  200  from the portion above safety valve assembly  200 . Packer element  226  can act to anchor safety valve  200  in place and/or to hydraulically isolate the regions above and below safety valve  200 . The activation of packer element  226  can be through any means known by one of ordinary skill in the art but may be activated through the pressurization of operating conduit  220 . With the safety valve assembly  200  in place and packer element  226  set, operating conduit  220  is capable of opening and closing a flow interruption device (not shown) within valve assembly  200  and furthermore bypass-conduit  222  is capable of communicating with region  224  below safety valve  200  when the flapper disc is closed or open. Operating conduit  220  can be constructed as two strings of hydraulic tubing, whereby one string supplies the energy to open the flow interruption device (not shown) within valve assembly  200  and the second string supplies the energy to close the flow interruption device (not shown) of valve assembly  200 . Although the term flapper disc is used for illustrative purposes, the flow interruption device can be other non-disc shapes. The valve is not limited to flapper devices and can contain any flow interruption device know to those in the art. An operating conduit (or one or more strings of hydraulic tubing comprising operating conduit) could also be extended from the surface to safety valve  200  outside the bore of tubing  202 . Finally, a string of bypass-conduit  222 , operating conduit  220 , or tubing  202  can be any combination of concentric or non-concentric configurations. 
         [0031]    Furthermore, while the installation of safety valve  200  is shown into a pre-existing string of tubing  202  hung within a well, it should be understood by one of ordinary skill in the art that safety valve  200  can be an integral component of tubing  202  and run simultaneously therewith. Such an operation can include the simultaneous injection of tubing  202 , and conduits  220  and  222  into the wellbore, for example through injection assembly  212 . Once in location, tubing  202  can be cut and hung from wellhead assembly  202  using methods and apparatus known to those skilled in the art. 
         [0032]    Referring now to  FIG. 3 , another embodiment of a safety valve assembly  300  is shown schematically deployed in a string of production tubing  302  within a cased wellbore  304 . Safety valve assembly  300  includes a flapper disc  306  operable from a closed position (shown) to an open position (not shown) to regulate the flow of fluids from below safety valve assembly  300 , through operating mandrel  308  and to upper portions of production tubing  302 . Biasing spring  310  biases operating mandrel  308  away from flapper disc  306 , thereby keeping it closed. A hydraulic line  312  extends from a surface station and is used to actuate (not shown) operating mandrel  308  against force of spring  310  and into engagement with flapper element  306 . With operating mandrel  308  engaging the flapper disc  306  open, a clearance bore  314  therethrough is opened and fluids and/or tools are able to flow therethrough. 
         [0033]    Ordinarily, flapper disc  306  (when closed), operating mandrel  308 , and any supporting components would consume the entire bore of production tubing  302 . However, safety valve assembly  300  also includes a bypass-conduit  322  configured to allow communication from a zone above safety valve assembly  300  to a zone below safety valve assembly  300  regardless of the position of flapper disc  306 . Therefore, in safety valve assembly  300  shown in  FIG. 3 , the flapper disc  306  and supporting components consume less than the full inner diameter of production tubing  302 , with a bulkhead  320  occupying the remainder. Bulkhead  320  can be constructed as an integral part of a main body of safety valve assembly  300  or can be a separate component, designed to isolate a small flapper valve disc  306  from a larger string of production tubing  302 . Nonetheless, bulkhead  320  provides a throughway  324  for a bypass-conduit  322 . As mentioned above, bypass-conduit  322  can be of any design or configuration but is shown as a capillary tube for hydraulic injection below safety valve assembly  300 . Bypass-conduit  322  is typically constructed with an upper portion  326  and a lower portion  328 , wherein upper portion  326  communicates with a surface station and lower portion  328  is in communication with a production zone below. Furthermore, as shown in  FIG. 3 , bypass-conduit  322  can be constructed so that upper portion  326  and lower portion  328  are capable of being connected (not shown) and disconnected (shown) while safety valve assembly  300  is located downhole. To prevent fluid from flowing from a zone below the safety valve assembly  300  to the surface through bypass-conduit  322 , check valves (not shown) can be included in the bypass-conduit  322  below safety valve  300 , above safety valve  300 , or both. 
         [0034]    Referring now to  FIG. 4 , another embodiment of a safety valve assembly  400  is shown schematically deployed in a string of production tubing  402  within a cased wellbore  404 . Safety valve assembly  400  includes a flapper disc  406  operable from a closed position (shown) to an open position (not shown) to regulate the flow of production fluids from a production zone  408  below safety valve  400  to the bore  410  of production tubing  402  above safety valve  400 . Production fluids can enter the cased wellbore  404  through perforations  412  in a production zone, flow past flapper disc  406  if open (not shown), through an operating mandrel  414  and into bore  410  of production tubing  402 . Apertures  416  of operating mandrel allow for the free flow of production fluids from inside operating mandrel  414  to bore  410 . As above, a hydraulic operating line  418  can extend from a surface location to operate mandrel  414  in and out of engagement with flapper disc  406  to open or shut safety valve assembly  400 . 
         [0035]    Furthermore, safety valve assembly  400  includes a bulkhead  420  which can provide a throughway  422  to allow a bypass-conduit  424  which can communicate between a production zone  408  and a surface location independent of the position (open or closed) of flapper disk  406  (shown closed). As above, bypass-conduit  424  can be constructed as any type of hydraulic, pneumatic, electrical, mechanical, or fiber-optic communication mechanism, but is shown here as a hydraulic injection conduit. Bypass-conduit  424  is preferably configured to allow the injection of a chemical substance and/or foam into a production zone to improve the production characteristics thereof. Injection conduit  424  of  FIG. 4  includes two check valves, one  430  above bulkhead  420 , and another check valve  432  incorporated into an injection head  434  below safety valve assembly  400 . The invention is not limited to having a check valve or only having two check valves. 
         [0036]    Furthermore, safety valve  400  is configured to be capable of being inserted and retrieved from string of tubing  402  after the tubing  402  is deployed to a depth of interest in the cased wellbore  404 . Tubing string  402  can include a locking nipple  440  in its inner bore  410  at a location where a safety valve assembly  400  would be desired. The outer profile of main body  442  of safety valve assembly  400  would provide locking dogs  444  configured to be received by and retrieved from corresponding locking nipple  440 . The valve can be connected to the tubing using any connective means known in the art. Using the removable configuration, a defective safety valve assembly  400  could be retrieved from the downhole location, repaired (or re-configured), and replaced within a short period of time, making repair operations less costly and more feasible for low production wells. 
         [0037]    While the invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of the invention.