Abstract:
Apparatuses and methods to communicate with a zone below a subsurface safety valve ( 104, 204 ) independent of the position of a closure member ( 106 ) of the safety valve are disclosed. The apparatuses and methods include deploying a subsurface safety valve ( 104, 204 ) to a profile located within a string of production tubing. The subsurface safety valve ( 104, 204 ) is in communication with a surface station through an injection conduit ( 150,152; 250,252 ) and includes a bypass pathway ( 144, 244 ) to inject various fluids to a zone below.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of provisional application U.S. Ser. No. 60/593,217 filed Dec. 22, 2004. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to subsurface apparatuses used in the petroleum production industry. More particularly, the present invention relates to an apparatus and method to conduct fluid through subsurface apparatuses, such as a subsurface safety valve, to a downhole location. More particularly still, the present invention relates to apparatuses and methods to install a subsurface safety valve incorporating a bypass conduit allowing communications between a surface station and a lower zone regardless of the operation of the safety valve. 
     Various obstructions exist within strings of production tubing in subterranean wellbores. Valves, whipstocks, packers, plugs, sliding side doors, flow control devices, expansion joints, on/off attachments, landing nipples, dual completion components, and other tubing retrievable completion equipment can obstruct the deployment of capillary tubing strings to subterranean production zones. One or more of these types of obstructions or tools are shown in the following United States Patents which are incorporated herein by reference: Young U.S. Pat. No. 3,814,181; Pringle U.S. Pat. No. 4,520,870; Carmody et al. U.S. Pat. No. 4,415,036; Pringle U.S. Pat. No. 4,460,046; Mott U.S. Pat. No. 3,763,933; Morris U.S. Pat. No. 4,605,070; and Jackson et al. U.S. Pat. No. 4,144,937. Particularly, in circumstances where stimulation operations are to be performed on non-producing hydrocarbon wells, the obstructions stand in the way of operations that are capable of obtaining continued production out of a well long considered depleted. Most depleted wells are not lacking in hydrocarbon reserves, rather the natural pressure of the hydrocarbon producing zone is so low that it fails to overcome the hydrostatic pressure or head of the production column. Often, secondary recovery and artificial lift operations will be performed to retrieve the remaining resources, but such operations are often too complex and costly to be performed on all wells. Fortunately, many new systems enable continued hydrocarbon production without costly secondary recovery and artificial lift mechanisms. Many of these systems utilize the periodic injection of various chemical substances into the production zone to stimulate the production zone thereby increasing the production of marketable quantities of oil and gas. However, obstructions in the producing wells often stand in the way of deploying an injection conduit to the production zone so that the stimulation chemicals can be injected. While many of these obstructions are removable, they are typically components required to maintain production of the well so permanent removal is not feasible. Therefore, a mechanism to work around them would be highly desirable. 
     The most common of these obstructions found in production tubing strings are subsurface safety valves. Subsurface safety valves are typically installed in strings of tubing deployed to subterranean wellbores to prevent the escape of fluids from the wellbore to the surface. Absent safety valves, sudden increases in downhole pressure can lead to disastrous blowouts of fluids into the atmosphere. Therefore, numerous drilling and production regulations throughout the world require safety valves be in place within strings of production tubing before certain operations are allowed to proceed. 
     Safety valves allow communication between the isolated zones and the surface under regular conditions but are designed to shut when undesirable conditions exist. One popular type of safety valve is commonly referred to as a surface controlled subsurface safety valve (SCSSV). SCSSVs typically include a closure member generally in the form of a circular or curved disc, a rotatable ball, or a poppet, that engages a corresponding valve seat to isolate zones located above and below the closure member in the subsurface well. The closure member is preferably constructed such that the flow through the valve seat is as unrestricted as possible. Usually, the SCSSVs are located within the production tubing and isolate production zones from upper portions of the production tubing. Optimally, SCSSVs function as high-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. 
     SCSSVs normally have a control line extending from the valve, said control line disposed in an annulus formed by the well casing and the production tubing and extending from the surface. Pressure in the control line opens the valve allowing production or tool entry through the valve. Any loss of pressure in the control line closes the valve, prohibiting flow from the subterranean formation to the surface. 
     Closure members are often energized with a biasing member (spring, hydraulic cylinder, gas charge and the like, as well known in the industry) such that in a condition with no pressure, the valve remains closed. In this closed position, any build-up of pressure from the production zone below will thrust the closure member against the valve seat and act to strengthen any seal therebetween. During use, closure members are opened to allow the free flow and travel of production fluids and tools therethrough. 
     Formerly, to install a chemical injection conduit around a production tubing obstruction, the entire string of production tubing had to be retrieved from the well and the injection conduit incorporated into the string prior to replacement often costing millions of dollars. This process is not only expensive but also time consuming, thus it can only be performed on wells having enough production capability to justify the expense. A simpler and less costly solution would be well received within the petroleum production industry and enable wells that have been abandoned for economic reasons to continue to operate. 
     SUMMARY OF THE INVENTION 
     The deficiencies of the prior art are addressed by an assembly to inject fluid around a well tool located within a string of production tubing. 
     In one embodiment, an assembly to inject fluid from a surface station around a well tool located within a string of production tubing, the assembly comprises a lower anchor socket located in the string of production tubing below the well tool, an upper anchor socket located in the string of production tubing above the well tool, a lower injection anchor seal assembly engaged within the lower anchor socket, an upper injection anchor seal assembly engaged within the upper anchor socket, a first injection conduit extending from the surface station to the upper injection anchor seal assembly, the first injection conduit in communication with a first hydraulic port of the upper anchor socket, a second injection conduit extending from the lower injection anchor seal assembly to a location below the well tool, the second injection conduit in communication with a second hydraulic port of the lower anchor socket, and a fluid pathway to bypass the well tool and allow hydraulic communication between the first hydraulic port and the second hydraulic port. The well tool can be a subsurface safety valve. The well tool can be selected from the group consisting of whipstocks, packers, bore plugs, and dual completion components. 
     In another embodiment, the lower anchor socket, the well tool, and the upper anchor socket can be a single tubular sub in the string of production tubing. 
     In yet another embodiment, the lower anchor socket, the well tool, and the upper anchor socket can each be a separate tubular sub in the string of production tubing, the lower anchor socket tubular sub threadably engaged to the well tool tubular sub and the well tool tubular sub threadably engaged to the upper anchor socket tubular sub. 
     In another embodiment, an assembly to inject fluid from a surface station around a well tool located within a string of production tubing comprises an operating conduit extending from the subsurface safety valve to the surface station through an annulus formed between the string of production tubing and a wellbore. The assembly can further comprise an alternative injection conduit extending from the surface station to the second hydraulic port. The assembly can further comprise an alternative injection conduit extending from the surface station to the first hydraulic port. The first or second injection conduit can include a check valve. The fluid pathway can be internal to the assembly. The fluid pathway can be a tubular conduit external to the assembly. 
     The assembly to inject fluid around a well tool located within a string of production tubing can further comprise at least one shear plug to block the first hydraulic port and the second hydraulic port from communication with a bore of the string of production tubing when the injection anchor seal assemblies are not engaged therein. 
     In yet another embodiment, an assembly to inject fluid around a well tool located within a string of production tubing comprises a lower anchor socket located in the string of production tubing below the well tool and an upper anchor socket located in the string of production tubing above the well tool, a lower injection anchor seal assembly engaged within the lower anchor socket and an upper injection anchor seal assembly engaged within the upper anchor socket, a lower injection conduit extending from the lower injection anchor seal assembly to a location below the well tool, the lower injection conduit in hydraulic communication with a hydraulic port of the lower anchor socket, an upper injection conduit extending from a surface station to the upper injection anchor seal assembly, the upper injection conduit in hydraulic communication with a hydraulic port of the upper anchor socket, and a fluid pathway extending between the upper and lower anchor sockets through an annulus between the string of production tubing and a wellbore, the fluid pathway in hydraulic communication with the upper and lower hydraulic ports. The well tool can be a subsurface safety valve. The well tool can be selected from the group consisting of whipstocks, packers, bore plugs, and dual completion components. The assembly can further comprise a check valve in at least one of the upper and lower injection conduits. 
     In another embodiment, an assembly to inject fluid around a well tool located within a string of production tubing comprises an anchor socket located in the string of production tubing below the well tool, an injection anchor seal assembly engaged within the anchor socket, an injection conduit extending from the injection anchor seal assembly to a location below the well tool, the injection conduit in hydraulic communication with a hydraulic port of the anchor socket, and a fluid pathway extending from a surface station through an annulus between the string of production tubing and a wellbore, the fluid pathway in hydraulic communication with the hydraulic port. 
     In yet another embodiment, an assembly to inject fluid around a well tool located within a string of production tubing further comprises an upper anchor socket located in the string of production tubing above the well tool, an upper injection anchor seal assembly engaged within the upper anchor socket, an upper injection conduit extending from the surface station to the upper injection anchor seal, the upper injection conduit in hydraulic communication with an upper hydraulic port of the upper anchor socket, and a second fluid pathway hydraulically connecting the upper hydraulic port with the hydraulic port of the anchor socket below the well tool. 
     In another embodiment, a method to inject fluid around a well tool located within a string of production tubing comprises installing the string of production tubing into a wellbore, the string of production tubing including a lower anchor socket below the well tool and an upper anchor socket above the well tool, installing a lower anchor seal assembly to the lower anchor socket, the lower anchor seal assembly including a lower injection conduit extending therebelow, installing an upper anchor seal assembly to the upper anchor socket, the upper anchor seal assembly disposed upon a distal end of an upper injection conduit extending from a surface station, and communicating between the upper injection conduit and the lower injection conduit through a fluid pathway around the well tool. The well tool can be a subsurface safety valve. 
     In yet another embodiment, a method to inject fluid around a well tool located within a string of production tubing further comprises installing an alternative injection conduit extending from the surface station to the lower anchor seal assembly. 
     In another embodiment, a method to inject fluid around a well tool located within a string of production tubing further comprises installing an alternative injection conduit extending from the surface station to the upper anchor seal assembly. 
     In another embodiment, a method to inject fluid around a well tool located within a string of production tubing further comprises restricting reverse fluid flow in the lower injection conduit with a check valve. 
     In yet another embodiment, a method to inject fluid around a well tool located within a string of production tubing comprises installing the string of production tubing into a wellbore, the string of production tubing including the well tool, an anchor socket above the well tool, and a lower string of injection conduit extending below the well tool, installing an anchor seal assembly to the anchor socket, the anchor seal assembly deposed upon a distal end of an upper string of injection conduit extending from a surface station, and communicating between the upper string of injection conduit and the lower string of injection conduit through a fluid pathway extending from the anchor seal assembly to the lower string of injection conduit around the well tool. The well tool can be selected from the group consisting of subsurface safety valves, whipstocks, packers, bore plugs, and dual completion components. 
     In another embodiment, a method to inject fluid around a well tool located within a string of production tubing comprises installing the string of production tubing into a wellbore, the string of production tubing including the well tool and an anchor socket below the well tool, installing an anchor seal assembly to the anchor socket, the anchor seal assembly including a lower injection conduit extending therebelow, deploying a fluid pathway from a surface location to the anchor socket through an annulus formed between the string of production tubing and the wellbore, and providing hydraulic communication between the surface location and the lower injection conduit through the fluid pathway. 
     In yet another embodiment, a method to inject fluid around a well tool located within a string of production tubing comprises providing an upper anchor socket in the string of production tubing above the well tool, installing an upper anchor seal assembly to the upper anchor socket, the upper anchor seal assembly disposed upon a distal end of an upper injection conduit extending from the surface location, and communicating between the upper injection conduit and the lower injection conduit through a second fluid pathway extending between the upper anchor seal assembly and the anchor seal assembly located in the anchor socket below the well tool. 
     In another embodiment, a method to inject fluid around a well tool located within a string of production tubing comprises installing the string of production tubing into a wellbore, the string of production tubing including a lower anchor socket below the well tool providing an inner chamber circumferentially spaced about a longitudinal axis of the lower anchor socket, an upper anchor socket above the well tool providing an inner chamber circumferentially spaced about a longitudinal axis of the upper anchor socket, and a fluid pathway on an exterior of the well tool hydraulically connecting the inner chambers of the upper and lower anchor sockets, establishing a fluid communication pathway between an inner surface of the upper and lower anchor sockets and the respective circumferentially spaced inner chambers, installing a lower anchor seal assembly to the lower anchor socket, the lower anchor seal assembly including a lower injection conduit extending therebelow, installing an upper anchor seal assembly in the upper anchor socket, the upper anchor seal assembly disposed upon a distal end of an upper injection conduit extending from a surface station, and communicating between the upper and lower injection conduits through the fluid communication pathway of the upper anchor socket, the fluid pathway, and the fluid communication pathway of the lower anchor socket. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic section-view drawing of a fluid bypass assembly in accordance with an embodiment of the present invention wherein the fluid bypass pathway may be used with any industry standard SCSSV. 
         FIG. 2  is a schematic section-view drawing of a fluid bypass assembly in accordance with an alternative embodiment of the present invention wherein the fluid bypass pathway is integral to the SCSSV assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring initially to  FIG. 1 , a fluid bypass assembly  100  according to an embodiment of the present invention is shown. Fluid bypass assembly  100  is preferably run within a string of production tubing  102  and allows fluid to bypass a well tool  104 . In  FIG. 1 , well tool  104  is shown as a subsurface safety valve but it should be understood by one skilled in the art that any well tool deployable upon a string of tubing can be similarly bypassed using the apparatuses and methods of the present invention. Nonetheless, well tool  104  of  FIG. 1  is a subsurface safety valve run in-line with production tubing  102 , and includes a flapper disc  106 , an operating mandrel  108 , and a hydraulic control line  110 . Flapper disc  106  is preferably biased such that as operating mandrel  108  is retrieved from the bore of a valve seat  112 , disc  106  closes and prevents fluids below safety valve  104  from communicating uphole. Hydraulic control line  110  operates operating mandrel  108  into and out of engagement with flapper disc  106 , thereby allowing a user at the surface to manipulate the status of flapper disc  106 . 
     Furthermore, fluid bypass assembly  100  includes a lower anchor socket  120  and an upper anchor socket  122 , each configured to receive an anchor seal assembly  124 ,  126 . Upper  126  and lower  124  anchor seal assemblies are configured to be engaged within anchor sockets  120 ,  122  and transmit injected fluids across well tool  104  with minimal obstruction of production fluids flowing through bore  114 . Anchor seal assemblies  124 ,  126  include engagement members  128 ,  130  and packer seals  132 ,  134 . Engagement members  128 ,  130  are configured to engage with and be retained by anchor sockets  120 ,  122 , which may include an engagement profile. While one embodiment for engagement members  128 ,  130  and corresponding anchor sockets  120 ,  122  is shown schematically, it should be understood that numerous systems for engaging anchor seal assemblies  124 ,  126  into anchor sockets  120 ,  122  are possible without departing from the present invention. 
     Packer seals  132 ,  134  are located on either side of injection port zones  136 ,  138  of anchor seal assemblies  124 ,  126  and serve to isolate injection port zones  136 ,  138  from production fluids  160  traveling through bore  114  of well tool  104  and/or the bore of the string of production tubing  102 . Furthermore, injection port zones  136 ,  138  are in communication with hydraulic ports  140 ,  142  in the circumferential wall of fluid bypass assembly  100  and hydraulic ports  140 ,  142  are in communication with each other through a hydraulic bypass pathway  144 . Hydraulic ports  140 ,  142  can include a fluid communication pathway  141 ,  143  between an inner surface of the upper and lower anchor socket  120 ,  122  and a respective circumferentially spaced inner chamber in each anchor socket. Hydraulic ports  140 ,  142  may include a plurality of fluid communication pathways  141 ,  143 . A hydraulic port  140 ,  142  may also communicate directly with the hydraulic bypass pathway  144  without the shown circumferentially spaced inner chamber. 
     Hydraulic bypass pathway  144  is shown schematically on  FIG. 1  as an exterior line connecting hydraulic ports  140  and  142 , but it should be understood that hydraulic bypass pathway  144  can be either a pathway inside (not shown) the body of bypass assembly  100  or an external conduit. Regardless of internal or external construction, hydraulic bypass pathway  144 , hydraulic ports  140 ,  142 , and packer seals  132 ,  134  enable injection port zone  138  to hydraulically communicate with injection port zone  136  without contamination from production fluids  160  flowing through bore  114  of well tool  104  and/or the bore of the string of production tubing  102 . Additionally, it should be understood by one of ordinary skill in the art that it may be desired to use the production tubing  102  and well tool  104  of assembly  100  before anchor seal assemblies  124 ,  126  are installed into sockets  120 ,  122 . As such, any premature hydraulic communication around well tool  104  between hydraulic ports  140  and  142  through hydraulic bypass pathway  144  could compromise the functionality of well tool  104  and such communication would need to be prevented. Therefore, shear plugs (not shown) can be located in hydraulic ports  140 ,  142  prior to deployment of well tool  104  upon production tubing  102  to prevent hydraulic bypass pathway  144  from allowing communication before it is desired. The shear plugs could be constructed to shear away and expose hydraulic ports  140  and  142  when anchor seal assemblies  124 ,  126 , or another device, are engaged thereby. 
     A lower string of injection conduit  150  is suspended from lower anchor seal assembly  124  and upper anchor seal assembly  126  is connected to an upper string of injection conduit  152 . Because lower injection conduit  150  is in communication with injection port zone  136  of lower anchor seal assembly  124  and upper injection conduit  152  is in communication with injection port zone  138  of upper anchor seal assembly  126 , fluids flow from upper injection conduit  152 , through hydraulic bypass pathway  144  to lower injection conduit  150 . This communication may occur through an internal bypass pathway, shown as a dotted conduit in  FIG. 1 , in either or both of the upper or lower anchor seal assemblies  126 ,  124 . As such, by using fluid bypass assembly  100 , an operator can inject fluids below a well tool  104  regardless of the state or condition of well tool  104 . Using fluid bypass assembly  100 , fluids can be injected (or retrieved) past well tools  104  that would otherwise prohibit such communication. For example, where well tool  104  is a subsurface safety valve, the injection can occur when the flapper disc  106  is closed. 
     To install bypass assembly  100  of  FIG. 1 , the well tool  104 , lower anchor socket  120  and upper anchor socket  122  are deployed downhole in-line with the string of production tubing  102 . Once installed, well tool  104  can function as designed until injection below well tool  104  is desired. Once desired, lower anchor seal assembly  124  is lowered down production tubing  102  bore until it reaches well tool  104 . Preferably, lower anchor seal assembly  124  is constructed such that it is able to pass through upper anchor socket  122  and bore  114  of well tool  104  without obstruction en route to lower anchor socket  120 . Once lower anchor seal assembly  124  reaches lower anchor socket  120 , it is engaged therein such that packer seals  132  properly isolate injection port zone  136  in contact with hydraulic port  140 . 
     With lower anchor seal assembly  124  installed, upper anchor seal assembly  126  is lowered down production tubing  102  upon a distal end of upper injection conduit  152 . Because upper anchor seal assembly  126  does not need to pass through bore  114  of well tool  104 , it can be of larger geometry and configuration than lower anchor seal assembly  124 . With upper anchor seal assembly  126  engaged within upper anchor socket  122 , packer seals  134  isolate injection port zone  138  in contact with hydraulic port  142 . Once installed, communication can occur between upper injection conduit  152  and lower injection conduit  150  through hydraulic ports  142 ,  140 , injection port zones  138 ,  136 , and hydraulic bypass pathway  144 . Optionally, a check valve  154  can be located in lower injection conduit  150  to prevent production fluids  160  from flowing up to the surface through upper injection conduit  152 . A check valve may be located in any section of the upper  152  or lower  150  injection conduits as well as the hydraulic bypass pathway  144 . A check valve can be integrated into the upper or lower anchor seal assemblies  126 , 124 . 
     Ports  156 ,  158  in lower and upper anchor seal assemblies  124 ,  126  allow the flow of production fluids  160  to pass through with minimal obstruction. Furthermore, in circumstances where well tool  104  is to be a device that would not allow lower anchor seal assembly  124  to pass through a bore  114  of a well tool  104 , the lower anchor seal assembly  124  can be installed before the production tubing  102  is installed into the well, leaving only upper anchor seal assembly  126  to be installed after production tubing  102  is disposed in the well. 
     Referring briefly now to  FIG. 2 , an alternative embodiment for a fluid bypass assembly  200  is shown. Fluid bypass assembly  200  differs from fluid bypass assembly  100  of  FIG. 1  in that assembly  200  is constructed from several threaded components rather than the unitary arrangement detailed in  FIG. 1 . Particularly, a string of production tubing  202  is connected to a well tool  204  through anchor socket subs  222 ,  220 . Well tool  204  is itself constructed as a sub with threaded connections  270 ,  272  on either end. Threaded connections  270 ,  272  allow for varied configurations of well tool  204  and anchor socket subs  220 ,  222  to be made. For instance, several well tools  204  can be strung together to form a combination of tools. Additionally, threaded connections  270 ,  272  allow more versatility and easier inventory management for remote locations, whereby an appropriate combination of anchor socket subs  220 ,  222  and well tools  204  can be made up for each particular well. Regardless of configuration of fluid bypass assembly  200 , hydraulic bypass pathway  244  connects injection conduits  250  and  252  through hydraulic ports  240  and  242 . Because of the modular arrangement of fluid bypass assembly  200 , a hydraulic bypass pathway  244  is more likely to be an external conduit extending between anchor socket subs  220 ,  222 , but with increased complexity, can still be constructed as an internal pathway, if so desired. The primary advantage derived from having hydraulic bypass pathway  244  as a pathway internal to fluid bypass assembly  200  is the reduced likelihood of damage from contact with the wellbore, well fluids, or other obstructions during installation. An internal hydraulic bypass pathway (not shown) would be shielded from such hazards by the bodies of anchor socket subs  220 ,  222  and well tool  204 . 
       FIG. 2  further displays an alternative upper injection conduit  252 A that may be deployed in the annulus between production tubing string  202  and the wellbore. Alternative upper injection conduit  252 A would be installed in place of upper injection conduit  252  and would allow the injection of fluids into a zone below well tool  204  without the need for upper anchor seal assembly  226 . Alternative upper injection conduit  252 A would extend to hydraulic port  242  from the surface and communicate directly with hydraulic bypass pathway  244 . Alternatively still, alternative upper injection conduit  252 A could be installed in addition to upper injection conduit  252  to serve as a backup pathway to lower injection conduit  250  in the event of failure of upper injection conduit  252 , hydraulic port  242 , or upper anchor seal assembly  226 . Furthermore, alternative upper injection conduit  252 A can communicate directly with lower anchor seal assembly  224  through hydraulic port  240  if desired. A check valve may be located in any section of the upper  252  or lower  250  injection conduits as well as the hydraulic bypass pathway  244 . A check valve can be integrated into the upper or lower anchor socket subs  222 ,  220 . 
     Numerous embodiments and alternatives thereof have been disclosed. While the above disclosure includes the best mode belief in carrying out the invention as contemplated by the inventors, not all possible alternatives have been disclosed. For that reason, the scope and limitation of the present invention is not to be restricted to the above disclosure, but is instead to be defined and construed by the appended claims.