Downhole fluid recirculation valve

Abstract

A downhole valve for insertion in a production tubing string permits recirculation of fluid pumped into the casing annulus. The valve includes a cylindrical housing defining an opening, an internal mandrel disposed within the housing, defining a central bore and defining an opening, a valve between the housing and the mandrel, wherein said valve opens to allow fluid communication from the mandrel central bore to the annulus space in response to a pressure differential between the mandrel central bore and the annular space, and biasing means for biasing the valve in a closed position. The valve may be set within a completion string by wireline techniques

1 . A method of setting a downhole fluid recirculation valve within a completion string, comprising the steps of placing a completion string comprising a tubing sliding sleeve within a wellbore, setting an upper packoff and a lower packoff to define a valve zone, running the valve within the completion string to a position within the valve zone by a wireline. 
     
     
         2 . The method of  claim 1  wherein the valve comprises:
 (a) a cylindrical housing defining an opening; 
 (b) an internal mandrel disposed within the housing, defining a central bore and defining an opening; 
 (c) a valve disposed between the housing and the mandrel, wherein said valve is moveable between an open position which allows fluid communication from the mandrel central bore through the housing opening and the mandrel opening, wherein said valve is responsive to a pressure differential between the mandrel central bore and the valve environment; and 
 (d) a spring for biasing the valve in a closed position, wherein the spring comprises a coil spring concentrically disposed within the housing, and around the mandrel. 
 
     
     
         3 . The method of  claim 2  wherein the valve comprises a sliding member having a sealing portion at its distal end, wherein said sealing portion covers the mandrel opening when the valve is in its closed position. 
     
     
         4 . The method of  claim 3  wherein the sliding member is a cylindrical member concentrically disposed within the housing and around the mandrel. 
     
     
         5 . The method of  claim 4  wherein the spring comprises a coil spring concentrically disposed within the housing, and around the mandrel. 
     
     
         6 . The method of  claim 2  wherein the valve further comprises a pressure equalization chamber formed between the housing and the mandrel, a first portion of which is in fluid communication with the mandrel inner bore, and a second portion of which is in fluid communication with the annulus, and further comprising a valve extension piston which engages the upper end of the valve which comprises an upper end which reciprocates in the pressure equalization chamber between the first and second portions.