Patent ID: 8434568

Claim:
A system comprising: a substantially vertical well bore extending from a surface to a subterranean zone; an articulated well bore extending from the surface to the subterranean zone and intersecting the substantially vertical well bore at a junction proximate the subterranean zone; a drainage bore extending from the junction into the subterranean zone; a drill string disposed within the articulated well bore, the drill string extending into the drainage bore; a drilling fluid provided through the drill string and exiting the drill string proximate a drill bit of the drill string; a tubing disposed within the substantially vertical well bore, the tubing having an open end at the junction; a second fluid provided down the substantially vertical well bore, the second fluid exiting the tubing at the junction; and a fluid mixture returning up the substantially vertical well bore outside of the tubing, the fluid mixture comprising the drilling fluid after the drilling fluid exits the drill string.