Internal Blowout Preventer Apparatus

Abstract

An internal blowout preventer assembly having a central through-bore and flapper valve. The flapper valve permits fluid flow in a downward direction, but not the opposite (upward) direction. A retrievable tubular lockout sleeve can be conveyed via wireline, coiled tubing or other similar means and installed within the through-bore of the internal blowout preventer assembly. Once installed, the lockout sleeve prevents the flapper valve from closing, thereby permitting wireline or other concentric operations to be performed (as well as upward fluid flow) though the internal blowout preventer.

1 . An internal blow out preventer comprising:
 a) a body member having a top, a bottom, a longitudinal axis and a through-bore extending from said top to said bottom along said longitudinal axis;   b) a flapper pivotally connected to said body member, wherein said flapper permits fluid flow in one axial direction through said through bore but not the opposite axial direction; and   c) a tubular sleeve member adapted to be received within said through bore of said body member, wherein said tubular sleeve prevents said flapper from closing when said tubular sleeve member is installed in said through bore of said body member.   
     
     
         2 . The internal blowout preventer of  claim 1 , further comprising:
 a) a pin having a first end and second end, movably received within a transverse bore extending through said body member, wherein said transverse bore is oriented substantially perpendicular to said longitudinal axis of said body member, and said first end of said pin extends into said through bore;   b) a spring biasing said pin toward said through bore; and   c) a recess on the outer surface of said tubular sleeve for receiving said first end of said pin.   
     
     
         3 . The internal blowout preventer of  claim 2 , wherein said recess on the outer surface of said tubular sleeve comprises a groove extending substantially around the circumference of said tubular sleeve. 
     
     
         4 . A method of conducting wireline operations in a well having a drill string equipped with an internal blow out preventer, comprising:
 a) installing an internal blowout preventer in a drill string, said internal blowout preventer comprising:
 i) a body member having a top, a bottom, a longitudinal axis and a through-bore extending from said top to said bottom along said longitudinal axis; 
 ii) a flapper pivotally connected to said body member, wherein said flapper permits fluid flow in one axial direction through said through bore but not the opposite axial direction; 
   b) installing a tubular sleeve member within said through bore of said body member of said internal blowout preventer, wherein said tubular sleeve prevents said flapper from closing; and   c) conducting wireline operations through said tubular sleeve member.   
     
     
         5 . The method of  claim 4 , wherein said internal blowout preventer further comprises:
 a. a pin having a first end and second end, movably received within a transverse bore extending through said body member, wherein said transverse bore is oriented substantially perpendicular to said longitudinal axis of said body member, and said first end of said pin extends into said through bore;   b. a spring biasing said pin toward said through bore; and   c. a recess on the outer surface of said tubular sleeve for receiving said first end of said pin.   
     
     
         6 . The method of  claim 5 , wherein said recess on the outer surface of said tubular sleeve comprises a groove extending substantially around the circumference of said tubular sleeve.