US 10,472,942 B2 · Blowdown pressure maintenance with foam

Abstract

A method and system in which foams are used (instead of, or in addition to, NCG) to maintain pressure in a mature chamber during blowdown operations of a SAGD process or other enhanced oil recovery process. The foam occupies the depleted void space within the mature chamber after injection ceases, maintaining pressure, and improving blowdown performance. This use of the foam in the method and system also improves the performance of less mature chambers that are being operated at higher pressure adjacent to the mature chamber in blowdown. Foaming agents, such as metal carbonates, bicarbonates, and hydroxides, surfactants or any other colloidal foams, aerosols, hydrosols, emulsions or dispersions can be utilized. The method and system can be utilized in conjunction with other known art, such as heat scavenging in the chamber, or enhanced oil recovery utilizing foams, to displace oil in the chamber.

Claims30

Dependent claims

A method for recovering petroleum from a formation containing heavy hydrocarbons, wherein an injection well and a production well are in fluid communication with the formation, and wherein the method comprises:

a) injecting a first fluid into the formation through the injection well in an enhanced oil recovery process to form a chamber in the formation, wherein the first fluid comprises one or more of solvents, steam, and combinations thereof;
b) recovering a second fluid comprising heavy hydrocarbons from the production well with said enhanced oil recovery process and forming a mature chamber, wherein economic recovery can no longer be achieved with said enhanced oil recovery process;
c) engaging in blowdown operations after the formation of the mature chamber, wherein the blowdown operations comprise (i) ceasing said injecting the first fluid into the injection well and said enhanced oil recovery process;
and (ii) providing a foam in the mature chamber to maintain pressure in the mature chamber with said foam instead of the first fluid;
and
d) recovering the second fluid comprising heavy hydrocarbons during the blowdown operations.

3 more elements

(a) injecting steam into the formation through the injection well in an enhanced oil recovery process to form a steam chamber in the formation;
(b) recovering a fluid comprising heavy hydrocarbons from the production well with said enhanced oil recovery process;
(c) forming a mature chamber from the steam chamber with said enhanced oil recovery process, whereby economic production is no longer achievable with said enhanced oil recovery process;
(d) engaging in a blowdown operation after the formation of the mature chamber, wherein:
the blowdown operation comprises ceasing said injecting steam and said enhanced oil recovery process and instead providing a foam in the mature chamber, so that the foam in the mature chamber maintains pressure of the mature chamber;
and
(e) recovering the fluid comprising heavy hydrocarbons during the blowdown operation.

4 more elements

Dependencies are inferred from the claim text.

Blowdown pressure maintenance with foam

Life of this patent

Blowdown pressure maintenance with foam

Life of this patent

Abstract

Claims30