Method for recovering viscous asphaltic or bituminous petroleum
First Claim
1. A method of recovering viscous, asphaltic or bituminous petroleum from a permeable, subterranean, viscous asphaltic or bituminous petroleum-containing formation including a tar sand deposit, penetrated by at least one well in fluid communication with the formation comprising:
- a. forming a zone of increased permeability in at least a portion of the formation,b. introducing chlorine gas into said zone of increased permeability to oxidize labile groups on the bituminous petroleum, to form surface active agents in the formation,c. introducing an alkalinity agent into said zone of increased permeability to neutralize oxidized groups generated by action of the chlorine gas,d. introducing into the formation a recovery fluid selected from the group consisting of steam, a mixture of steam and an oxygen containing gas including air, a mixture of steam and ammonia, or a mixture of steam, ammonia and an oxygen containing gas, ande. recovering formation petroleum from the formation.
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Abstract
Disclosed is a process for recovering petroleum from subterranean, viscous asphaltic or bituminous petroleum-containing formations, including subterranean tar sand deposits. A zone of gas permeability is established in the formation first, such as by fracturing or gas sweeping a section of the formation. Oxidizing gas such as oxygen, air, oxygen enriched air, ozone, or chlorine, or a mixture of steam and an oxidizing gas is introduced into the zone of increased gas permeability to expand the zone and further to cause a reaction to occur between the oxidizing gas and the oxygen-susceptible groups or labile groups associated witn the bituminous or asphaltic petroleum molecules forming acidic or aldehyde groups. Next, a gaseous or liquid alkalinity agent such as ammonia is introduced into the formation to react with the oxidatively pre-treated groups in the bituminous or asphaltic petroleum to form surface active agents or surfactants in situ. Finally, steam or a mixture of steam and an alkalinity agent such as ammonia or steam and air or a mixture of steam, oxidative gas and an excess of ammonia is introduced into the treated zone to recover petroleum. This process may be applied as a push-pull process or it may be applied in a multi well, throughput process. In a preferred embodiment, gaseous ammonia serves as an alkaline agent to neutralize the surface active agents formed in the formation, and also functions as a non-condensable gas to prevent loss of gas permeability as the viscous petroleum is heated in the final stages of the process.
44 Citations
11 Claims
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1. A method of recovering viscous, asphaltic or bituminous petroleum from a permeable, subterranean, viscous asphaltic or bituminous petroleum-containing formation including a tar sand deposit, penetrated by at least one well in fluid communication with the formation comprising:
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a. forming a zone of increased permeability in at least a portion of the formation, b. introducing chlorine gas into said zone of increased permeability to oxidize labile groups on the bituminous petroleum, to form surface active agents in the formation, c. introducing an alkalinity agent into said zone of increased permeability to neutralize oxidized groups generated by action of the chlorine gas, d. introducing into the formation a recovery fluid selected from the group consisting of steam, a mixture of steam and an oxygen containing gas including air, a mixture of steam and ammonia, or a mixture of steam, ammonia and an oxygen containing gas, and e. recovering formation petroleum from the formation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification