Multibranch injector/producer wells in thick heavy-crude reservoirs

With modem drilling techniques, it is now possible to drill wells with mult iple branches emanating from the same vertical or even horizontal trunk. Se veral heavy-crude reservoirs are very thick, and low vertical permeability would make them unattractive for single horizontal wells. Further the much higher viscosity of the reservoir fluid results in highly unfavorable mobil ity. Thus, drilling stacked horizontal branches would create effectively th inner drainage areas in which the vertical mobility is far more forgiving. However, the clear benefit derived from thermal recovery favors steam injec tion and invites investigation of ways to improve on the Steam Assisted Gra vity Drive (SAGD) application. As an extension of the SAGD concept, this paper uses thermal reservoir simu lation to investigate the effects of increasing the spacing between the inj ector and producer, or adding producers above or below the SAGD configurati on, to mine more of the heat transferred to the reservoir by the injected s team. Simulations are performed with the Eclipse 500 thermal simulator usin g reservoir and fluid properties typical of the Bachaquero field in Venezue la. Economics confirm the merits of the approach.