Patent ID: 8555958

Claim:
A system comprising: a string defining an axial flow channel and an annular flow pathway, the annular flow pathway comprising an uphole annular flow pathway and a downhole annular flow pathway, the axial flow channel extending continuously through and between the uphole and downhole annular flow pathways, the string selected from at least one of a steam injection string and a production string of a steam assisted gravity drainage (SAGD) system, the string including an uphole segment and a downhole segment, the uphole segment insertable into the downhole segment, the downhole segment including tubing, and an inside surface of the tubing and an outer surface of the uphole segment defining a portion of the uphole annular flow pathway; a fluid access structure between the axial flow channel and the annular flow pathway; a valve disposed within the annular flow pathway, the valve being selectively closable to selectively inhibit annular flow between the uphole and downhole annular flow channels, the string and valve configured such that a fluid flows in a first direction in the axial flow channel and in a second direction opposite the first direction in the uphole and downhole annular flow pathways when the valve is in an open position, the valve configured to slide along the tubing of the downhole segment to selectively expose an opening in the tubing in an open position and block the opening in the tubing in a closed position.