Creation of a hydrate barrier during in situ hydrocarbon recovery
AssigneeExxonMobil Upstream Research Company
InventorsThomas J. Boone, Mori Y. Kwan
Life of this patent
Estimating the term…
Abstract
Certain viscous oil reservoirs are too deep to be commercially mined but lack an adequate top seal to employ in situ recovery methods such as SAGD. Without an adequate top seal, gases from the reservoir can rise into overlying aquifers and potentially to the surface. While ice-like hydrates would not normally form above the oil reservoir during in situ recovery, an additive can be added to promote hydrate formation. In this way, a hydrate barrier can be formed to act as a top seal to contain these gases.
Claims19
A method of forming a hydrate barrier during in situ hydrocarbon production above a reservoir of the hydrocarbons, the method comprising:
- selecting a hydrate promoting additive;
- and
- introducing the hydrate promoting additive into, or above, the reservoir for mixing with generated non-condensable gases, to promote hydrate formation in an area above the reservoir, for forming the hydrate barrier in the area, for limiting passage of non-condensable gases through the area,
- wherein the hydrate barrier comprises hydrates comprising water and non-condensable gases, and
- wherein the hydrate promoting additive is co-injected with steam, the steam being for reducing a viscosity of the hydrocarbons.
A method of forming a hydrate barrier during in situ hydrocarbon production above a reservoir of the hydrocarbons, the method comprising:
- selecting a hydrate promoting additive;
- and
- introducing the hydrate promoting additive into, or above, the reservoir for mixing with generated non-condensable gases, to promote hydrate formation in an area above the reservoir, for forming the hydrate barrier in the area, for limiting passage of non-condensable gases through the area,
- wherein the hydrate barrier comprises hydrates comprising water and non-condensable gases,
- wherein the hydrate promoting additive is co-injected with a viscosity reducing solvent, the viscosity reducing solvent being for reducing the viscosity of the hydrocarbons, and
- wherein the viscosity reducing solvent comprises a C5+gas condensate comprising pentane and hexane.
A method of forming a hydrate barrier during in situ hydrocarbon production above a reservoir of the hydrocarbons, the method comprising:
- selecting a hydrate promoting additive;
- introducing the hydrate promoting additive into, or above, the reservoir for mixing with generated non-condensable gases, to promote hydrate formation in an area above the reservoir, for forming the hydrate barrier in the area, for limiting passage of non-condensable gases through the area, wherein the hydrate barrier comprises hydrates comprising water and non-condensable gases;
- prior to injecting the hydrate promoting additive, estimating relative fractions of the non-condensable gases that will be generated during the in situ hydrocarbon production selected;
- and
- using the estimated relative fractions to select the hydrate promoting additive.
Dependencies are inferred from the claim text.