ALTERNATING SAGD INJECTIONS

摘要

Methods produce heavy oil with steam assisted gravity drainage. Such methods alternate a traditional steam injection with an injection of a steam-plus-non-condensable gas (such as CO2 or CO2-plus-diluent) mixture. The CO2/diluent mixture is soluble in bitumen, leading to a reduction in viscosity of the heavy oil. Additionally, the steam-only injection reduces the accumulation of vapor NCG along the edge of the steam chamber, leading to improved thermal efficiency.

主权项

1. A method of enhancing recovery of hydrocarbons from a heavy oil reservoir, comprising:
a) providing an injection well that intersects the heavy oil reservoir; b) providing a production well that intersects the heavy oil reservoir, wherein the injection well is in fluid communication with the production well; c) co-injecting steam and a non-hydrocarbon non-condensable gas (NCG) into the injection well for a first time; d) injecting steam without the NCG into the injection well for a second time subsequent to the first time; e) producing hydrocarbons from the production well; and f) repeating steps c and d.