Sensitivity analysis on steam and gas push to reduce heat loss in to the top water-bearing area overlaying oil sands

초록

SAGD (Steam Assisted Gravity Drainage) has been a primary production method with its successive performance for recovering viscous oil sands. If water- or gas-bearing zone is located nearby the bitumen layer, the significant heat loss occurs into these layers (i.e. thief zone) so that the efficiency of SAGD decreases dramatically. The injected steam in vapor chamber can be condensed faster when it encounter the water layer because of the high heat capacity of water. If the internal pressure in vapor chamber cannot be maintained for the injection constraints, water influx from water-bearing zone causes collapse of vapor chamber. To prevent the invasion phenomenon, we simulate SAGP (Steam And Gas Push) process that co-injects noncondensable gas with the steam of SAGD. 2D synthetic reservoir with top water-bearing zone is assumed. Non-condensable gas is accumulated within a reservoir and maintains the chamber pressure enough to prevent water inflow from top water-bearing thief zone. Sensitivity analysis is carried out changing operating conditions to obtain optimal operation strategy. Copyright © 2013 by the International Society of Offshore and Polar Engineers (ISOPE).

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