LAUSR

Waterflood in a viscous oil reservoir is not very efficient because the water fingers through the oil due to adverse viscosity. Typically, thermal methods are used to recover viscous (and heavy) oil. However, thermal methods can be inefficient when the depth of the reservoir is high and pay thickness is low. Nonthermal chemical enhanced-oil-recovery (EOR) methods are being developed as alternatives. Recently, a new low-cost chemical EOR technology called alkali–cosolvent–polymer (ACP) flooding has been developed which does not use any synthetic surfactant. In viscous oil reservoirs, the oil recovery in the first 30 years is more important than the ultimate recovery, which may take many hundreds of years. The purpose of this study is to identify the optimum ACP slug viscosity and the optimum timing for the initiation of the ACP process. ACP formulations that achieve ultralow tension were developed. Since the sweep efficiency is challenging in viscous oil reservoirs, ACP floods were performed in a quarter 5...