Patent ID: 7204327

Claim:
A method of drilling a directional or horizontal wellbore in a hydrocarbon formation, comprising: providing a concentric drill string comprising an inner pipe having an inside wall and an outside wall and an outer pipe having an inside wall and an outside wall, said outside wall of said inner pipe and said inside wall of said outer pipe defining an annulus between the pipes; connecting a bottomhole assembly, said bottomhole assembly comprising a directional drilling means for forming a borehole, to the concentric drill string; delivering drilling medium through one of said annulus or inner pipe to the directional drilling means and removing exhaust drilling medium by extracting said exhaust drilling medium through the other of said annulus or inner pipe to the surface of the wellbore; and providing a downhole flow control means positioned at or near the directional drilling means, said downhole flow control means having an open position and a closed position, whereby said downhole flow control means is in the open position during active drilling to allow the flow of drilling medium or exhaust drilling medium through the inner pipe and the annulus and in the closed position when well control is necessary to prevent the flow of hydrocarbons through the inner pipe and the annulus to the surface of the wellbore.