Creation of a hydrate barrier during in situ hydrocarbon recovery

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.