Drill pipe

Abstract

A drill pipe ( 10 ) having an elongate tubular body ( 12 ) with an interior surface enclosing a main bore ( 14 ) which extends generally parallel to a longitudinal axis (A) of the tubular body ( 12 ) from a first end to a second end of the tubular body ( 12 ), a side port ( 16 ) provided in an exterior surface of the tubular body ( 12 ), a side bore ( 18 ) extending through the body ( 12 ) from the main bore ( 14 ) to the side port ( 16 ), and a valve assembly ( 20, 22 ) which is operable to substantially prevent flow of fluid along the main bore ( 14 ) and to substantially prevent flow of fluid along the side bore ( 18 ), wherein the valve assembly ( 20, 22 ), side port ( 16 ) and side bore ( 18 ) are provided in a first connection portion ( 10 a ) of the drill pipe ( 10 ) at the first end thereof, the first connection portion ( 10 a ) comprising a thickened portion of the tubular body ( 12 ) in which the separation of the interior surface and the exterior surface is substantially greater than the adjacent portion of the tubular body ( 12 ), the length of the connection portion ( 10 a ) parallel to the longitudinal axis (A) of the tubular body ( 12 ) being less than 64 cm.

1 . A drill pipe having an elongate tubular body with an interior surface enclosing a main bore which extends generally parallel to a longitudinal axis of the tubular body from a first end to a second end of the tubular body, a side port provided in an exterior surface of the tubular body, a side bore extending through the body from the main bore to the side port, and a valve assembly which is operable to substantially prevent flow of fluid along the main bore and to substantially prevent flow of fluid along the side bore, wherein the valve assembly, side port and side bore are provided in a first connection portion of the drill pipe at the first end thereof, the first connection portion comprising a thickened portion of the tubular body in which the separation of the interior surface and the exterior surface is substantially greater than the adjacent portion of the tubular body, the length of the connection portion parallel to the longitudinal axis of the tubular body being less than 64 cm. 
     
     
         2 . A drill pipe according to  claim 1  wherein the valve assembly includes a first valve member which is movable between an open position, in which flow of fluid along the main bore is permitted, and a closed position, in which flow of fluid along the main bore is substantially prevented, and a second, separate, valve member which is movable between an open position, in which flow of fluid along the side bore is permitted, and a closed position, in which flow of fluid along the side bore is substantially prevented. 
     
     
         3 . A drill pipe according to  claim 2  wherein the first valve member comprises a ball which is rotatable between the open position and the closed position. 
     
     
         4 . A drill pipe according to  claim 2  wherein the second valve member is mounted at least predominantly within the side bore, and is slidable in the side bore between the open position and the closed position. 
     
     
         5 . A drill pipe according to  claim 1  wherein the first connection portion is provided with a first threaded portion. 
     
     
         6 . A drill pipe according to  claim 5  wherein the first threaded portion is provided in the interior surface of the drill pipe, and the second threaded portion is provided in the exterior surface of the drill pipe. 
     
     
         7 . A drill pipe according to  claim 1  wherein there is a second connection portion at the second end of the tubular body, the second connection portion also comprising a thickened portion of the tubular body in which the separation of the interior surface and the exterior surface is substantially greater than the adjacent portion of the tubular body. 
     
     
         8 . A drill pipe according to  claim 7  wherein the second connection portion is provided with a second threaded portion which is a mate for the first threaded portion.