Heat scavenging method for thermal recovery process
AssigneeConocoPhillips Company
InventorsDavid A. Brown, Siluni L. Wickramdthilaka, Logan A. Warren, Thomas J. Wheeler, Pradeep A. Govind
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Abstract
Thermal recovery of oils is improved by capturing waste heat from a depleted steam chamber using steam plus foam and an optional gas to carry low quality steam deep into the chamber where the waste heat converts water to steam in situ. Thus, overall steam generation needs and thus costs are reduced.
Claims8
A method of producing heavy oil, comprising:
- providing a horizontal injection well in a reservoir over a horizontal production well in said reservoir and in fluid communication with said injection well;
- injecting a composition into said injection well, said composition comprising a low density foam for heat scavenging (FHS) and for carrying water via buoyancy forces, wherein said FHS comprises methane gas, steam, an alcohol co-solvent, and a foaming agent, wherein the FHS has a density between 0.000598-0.0770 g/cm3 at reservoir conditions;
- producing steam in situ from said FHS to transfer heat from said reservoir to the heavy oil;
- and
- collecting a heavy oil from said production well.
An improved method of steam assisted gravity drainage (SAGD) production of oil, comprising injecting steam into a horizontal injection well and recovering produced hydrocarbons from a lower horizontal production well, the improvement comprising injecting steam into said injection well until a steam to oil ratio (SOR) begins to increase past an economic limit of production, and then injecting a low density, said foam comprising lower quality steam, an alcohol co-solvent, a foaming agent, plus a gas comprising methane, said foam having a density between 0.000598-0.0770 g/cm3 at reservoir conditions, wherein said method reduces an overall cumulative SOR as compared to steam injection alone.
Dependencies are inferred from the claim text.