METHOD FOR UPGRADING IN SITU HEAVY OIL

摘要

A method is provided for producing upgraded heavy oil from a subterranean reservoir by producing a steam chamber within the reservoir by the action of steam and flowing a liquid phase additive into a near wellbore region of the steam chamber to control asphaltenes mobility within the near wellbore region. Build-up of asphaltenes, which derive from the heavy oil, in the near wellbore region has the potential of affecting heavy oil production rates from the reservoir. The additive is formulated to mobilize the asphaltenes within this region.

主权项

1. A method for enhancing oil recovery, comprising:
providing a subterranean reservoir containing heavy oil; providing a production wellbore containing a production tubing and an injection wellbore spaced-apart from the production wellbore a predetermined elevation and containing an injection tubing; injecting steam into the subterranean reservoir and generating a steam chamber in the reservoir, such that the injection tubing is in fluid communication with the production tubing within the steam chamber and producing a heavy oil; and injecting steam into the steam chamber at a predetermined steam injection temperature and at a predetermined steam injection pressure and injecting a liquid phase additive to the steam chamber for mobilizing asphaltenes in the steam chamber; wherein the steam injection at a predetermined steam injection temperature and at a predetermined steam injection pressure and the injection of the liquid phase additive occur concurrently or sequentially; and wherein the liquid phase additive has an initial boiling point that is higher than the predetermined steam injection temperature at the predetermined steam injection pressure; and wherein at least 90 wt. % of the additive remains in the liquid phase in the steam chamber at the predetermined steam injection pressure and the predetermined steam injection temperature.