MOBILIZING COMPOSITION FOR USE IN GRAVITY DRAINAGE PROCESS FOR RECOVERING VISCOUS OIL AND START-UP COMPOSITION FOR USE IN A START-UP PHASE OF A PROCESS FOR RECOVERING VISCOUS OIL FROM AN UNDERGROUND RESERVOIR

摘要

Generally, described herein is a mobilizing composition for use in a gravitydrainage processfor recovering viscous oil from an underground reservoir. The mobilizingcomposition maycomprise (i) 75-98 vol. % diluting agent; (ii) 2-25 vol. % steam having asteam quality of atleast 5%; and (iii) 0-5 vol. % accelerating agent for accelerating penetrationof the dilutingagent into the viscous oil.Also generally described herein is a start-up composition for use in a start-up phase of aprocess for recovering viscous oil from an underground reservoir. The start-upcompositioncomprises (i) 74.9-97.9 vol. % diluting agent; (ii) 2-25 vol. % steam having asteam quality ofat least 5%; and (iii) 0.1-5 vol. % accelerating agent for acceleratingpenetration of thediluting agent into the viscous oil.