Method for controlling corrosion in thermal vapor injection gases

Claim 1

In a method of producing a high pressure thermal vapor stream of water vapor and combustion gases, for injection into a subterranean formation to stimulate the production of viscous minerals, comprising burning a substantially stoichiometric ratio of fuel and air in a combustion zone under pressure to produce combustion gases, and contacting the combustion gases with water in a vapor producing vessel, to form a thermal vapor stream for injecting into the formation, the improvement for preventing corrosion of equipment which comprises: injecting sufficient water into the combustion zone simultaneously with burning the fuel to maintain a temperature within such combustion chamber within the range of from 1100° C. to 1650° C.; and injecting ammonia into the thermal vapor stream exiting the vapor producing vessel whereby such thermal vapor stream is rendered substantially noncorrosive to ferrous metals.

Claim 9

A method of producing a high pressure thermal vapor stream of water vapor and combustion gases, for injection into a subterranean formation to stimulate the production of viscous minerals, comprising, burning in a combustion zone, a substantially stoichiometric ratio of fuel and air in the presence of from about 0.2 to about 4 liters of water per liter of fuel, such water being atomized into the flame zone through a plurality of nozzles, to form combustion gases; conducting the combustion gases from the combustion zone into a vapor producing vessel causing the combustion gases to impinge upon the surface of water being maintained in the vessel at a level below the opening of a combustion gases injection means; and contacting the combustion gases, in countercurrent flow, with an atomized water spray containing from about 1.0 to about 6.0 weight percent ammonia in an amount such that from about 0.001 to about 0.005 kilograms of ammonia per kilogram of steam produced is injected, thereby producing a substantially non-corrosive thermal vapor is roduced.

Claim 10

A method of producing a high pressure thermal vapor stream of water vapor and combustion gases, for injection into a subterranean formation to stimulate the production of viscous minerals, comprising, burning in a combustion zone, a substantially stoichiometric ratio of fuel and air in the presence of from about 0.2 to about 4 liters of water per liter of fuel, such water being atomized into the flame zone through a plurality of nozzles, to form combustion gases; conducting the combustion gases from the combustion zone into a vapor producing vessel causing the combustion gases to impinge upon the surface of water being maintained in the vessel at a level below the opening of a combustion gases injection means; and contacting the combustion gases, in countercurrent flow, with an atomized water spray containing from about 1.0 to about 6.0 weight percent ammonia in an amount such that from about 0.001 to about 0.005 kilograms of ammonia per kilogram of steam produced is injected, thereby producing a substantially non-corrosive thermal vapor is roduced.