You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
TECHNICAL FIELD 
     The present invention relates in general to wellbore operations and more specifically to a lubricator valve having pump-through functionality for restoring access to the wellbore during a closed valve failure. 
     BACKGROUND 
     Lubricator valves commonly located in pipe strings above the subsea test tree and below the flowhead are remotely controlled by hydraulic lines in a manner such that the operator can introduce wireline or coiled tubing tools into the well. It is highly desirable to provide a mechanism to pump-through or open the valve upon the failure of the hydraulic system or control system for the valve. 
     Therefore, it is a desire to provide a lubricator valve with pump-through functionality. 
     SUMMARY 
     In view of the foregoing and other considerations, the present invention relates to a lubricator valve with pump-through functionality. 
     Accordingly, a lubricator valve assembly adapted for connection in a pipe string for use in a well includes a tubular valve body having a bore formed longitudinally therethrough; a valve seat connected to the valve body and in communication with the bore; a valve element mounted in the bore and rotatable with respect to the valve seat between positions opening and closing the bore; an operator in connection between the valve element and a hydraulic control system, the operator moving the valve element between the open and close bore positions in response to the hydraulic control system; and a system for opening the valve element upon failure of the hydraulic system. 
     In a well completion having a pipe string extending from a wellhead into a wellbore and a lubricator valve connected in the pipe string for intervening in the wellbore, the lubricator valve includes a body having a longitudinal bore; a valve seat; a ball element mounted in the bore and rotatable with respect to the valve seat between positions opening and closing the bore, the valve seat positioned below the ball element relative to the wellhead; an operator in connection between the ball element and a hydraulic control system, the operator moving the ball element between the open and close bore positions in response to the hydraulic control system, the operator not in fluid communication with the bore; and a means for pumping-through the lubricator valve when the ball element is in the closed position, the pump-through means including a pump-through piston having a first end connected to the operator and a second end in fluid communication with the bore above the ball element and a counter piston having an end connected to the operator and a second end in fluid communication with the bore below the ball element. 
     The foregoing has outlined some of the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features and aspects of the present invention will be best understood with reference to the following detailed description of a specific embodiment of the invention, when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a schematic of an offshore well utilizing a lubricator valve of the present invention; and 
         FIG. 2  is a partial cross-sectional view of a lubricator valve of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views. 
     As used herein, the terms “up” and “down”; “upper” and “lower”; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements of the embodiments of the invention. Commonly, these terms relate to a reference point as the surface from which drilling operations are initiated as being the top point and the total depth of the well being the lowest point. 
       FIG. 1  is a schematic of an offshore well  12  utilizing a lubricator valve  10  of the present invention. Well  12  is being drilled from a vessel  14  such as a platform, rig or ship. A pipe string  16  extends from the vicinity of the rig floor of a derrick  18  to a subsea control valve  20 . A lower pipe string  22  is suspended from the control valve  20  and may have connected thereto a series of well tools such as a tester valve  24   a  and a packer  24   b . A wellhead  26  is connected to the upper end of pipe string  16  at the rig floor of derrick  18 . 
     In accordance with the present invention, lubricator valve  10  is connected in pipe string  16  about 60 to 150 feet (18 to 47 meters) below the rotary inside of the riser  28 . Lubricator valve  10  is hydraulically controlled from a station  30  through two hydraulic lines  32  that are selectively pressurized to cause valve  10  to open and close as desired. Lubricator valve  10  enables the top pipe string portion  34  to be used as a lubricator during intervention operations when running tool strings  36  such as wireline or coil tubing strings. 
     In some embodiments, lubricator valve  10  is a fail-as-is valve with pump-through capability. By “fail-as-is” it is meant that valve  10  remains in its actuated position, open or closed, upon failure of the hydraulic system. The pump-through functionality of valve  10  is the mechanism for restoring access to well  12  when valve  10  fails in the closed position. In embodiments of the present invention the valve may be opened by above ball bore pressure acting on a piston. 
     The pump-through piston alone facilitates pump-through at high ball pressure differentials between the pressure above the ball and below the ball in the range of 600-8,400 psi. It is further identified that pump-through functionality can be achieved for low differential ball pressure, for example 300 to 500 psi, by the addition of a balance piston in addition to the pump-through piston. 
     Refer now to  FIG. 2  wherein a partial cross-sectional view of an embodiment of lubricator valve  10  is provided. Lubricator valve  10  includes a body or housing  38  including upper and lower subs  40   a ,  40   b , a central flow passage or bore  42 , and a valve assembly  44  for controlling fluid flow through bore  42 . Subs  40  are adapted for connecting lubricator valve  10  in pipe string  16 . Upper and lower centralizers may be provided to protect the hydraulic lines  32  that run along side of lubricator  10 . 
     Valve assembly  44  includes a full-opening element such as ball element  46  for controlling fluid flow. Ball element  46  is connected to body  38  and positioned such that bore  42  is divided into an upper bore  42   a  and a lower bore  42   b . As is known in the art, upper bore  42   a  is the portion of the bore between the surface or wellhead  26  and ball element  46  and lower bore  42   b  is on the other side of ball element  46 . 
     Ball valve assembly  44  includes a seal retainer  60  connected within tubular body and positioned below ball element  46 . Thus the ball seat  62  is formed on the lower, or below ball, side of the ball element  46 . Ball element  46  is rotatable in relation to ball seat  62  between positions opening and closing bore  42 . Ball seat  62  is the primary mechanism for preventing fluid communication across ball  46 . In the prior art lubricator valve assemblies, the ball seal is formed on the top side of the ball (e.g., above ball). 
     A valve or ball operator  50  is connected to ball element  46  for moving the ball between an open and closed position. Operator  50  has an upper end  52  facing the above ball end of lubricator  10  and a lower end  54  facing the below ball end of lubricator  10 . Open hydraulic line  32   a  is hydraulically connected to operator upper end  52  through a path  56 . Similarly, close hydraulic line  32   b  is hydraulically connected to lower end  54  of operator  50  through a path  58 . It is noted that operator ends  52 ,  54  are not open to bore  42  and therefore are not affected by the debris in the fluid in bore  42 . Lubricator valve  10  may be operated between the open and closed position via hydraulic pressure transmitted through lines  32  acting on the faces of operator ends  52 ,  54 . 
     In the event of a loss of hydraulic control of ball assembly  44 , due to hydraulic line  32  breakage or the like, it is often necessary to establish a flow path through bore  42  and ball element  46 . To establish the flow path pressure is applied from the surface into above ball portion  42   a . Lubricator valve  10  is of a unique design to provide this pump-through functionality at various differential pressures across ball  46 . 
     In a first example, lubricator valve  10  includes an upper, above ball, or pump-through piston  64  to provide pump-through functionality. Upper piston  64  has an end face  66  that is in fluid and pressure communication with above ball bore portion  42   a  via a passage  68 . Upper piston  64  has an operator end  70  that is connected to the above ball operator end  52  of ball operator  50 . In operation, pressure is provided through pipe string  16  ( FIG. 1 ) into bore portion  42   a  and acts on ball operator  50  via upper piston  64  as shown by the arrow. 
     Implementation and utilization of upper piston  64  alone provides pump-through functionality at high differential pressure across ball element  46 . For example, upper piston  64  alone may provide pump-through functionality for pressure differentials across ball  46  ranging from about 635 psi to 8,308 psi. It is understood and believed that the pump-through functionality is available at higher differential pressures as well. 
     Lubricator valve  10  may further include a lower piston  72 , also referred to as a balance piston herein, to provide an expanded range of pressures for pump-through functionality. This example of lubricator valve  46  is believed to provide pump-through functionality at pressure below ball  46  ranging from zero psi to at least 12,500 psi. Additionally, the pressure differential across the valve will remain relatively low, for example 0 to 500 psi for a common size lubricator valve. 
     Balance piston  72  includes an end face  74  and an operator end  76 . End face  74  is in fluid and pressure communication with the below ball portion of bore  42 , in this example, through passage  78  as shown by the arrow. Operator end  76  is connected to lower end  54  of operator  50 . 
     From the foregoing detailed description of specific embodiments of the invention, it should be apparent that a lubricator valve with pump-through functionality that is novel has been disclosed. Although specific embodiments of the invention have been disclosed herein in some detail, this has been done solely for the purposes of describing various features and aspects of the invention, and is not intended to be limiting with respect to the scope of the invention. It is contemplated that various substitutions, alterations, and/or modifications, including but not limited to those implementation variations which may have been suggested herein, may be made to the disclosed embodiments without departing from the spirit and scope of the invention as defined by the appended claims which follow.

Summary:
A lubricator valve assembly adapted for connection in a pipe string for use in a well includes a tubular valve body having a bore formed longitudinally therethrough; a valve seat connected to the valve body and in communication with the bore; a valve element mounted in the bore and rotatable with respect to the valve seat between positions opening and closing the bore; an operator in connection between the valve element and a hydraulic control system, the operator moving the valve element between the open and close bore positions in response to the hydraulic control system; and a system for opening the valve element upon failure of the hydraulic system.