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A method for conducting foam drilling and workover operations in a bore hole penetrating a subterranean reservoir, particularly a high-temperature reservoir such as a geothermal reservoir, employing an aqueous foaming solution of about 0.08 to 1.0 percent by weight of an amphoteric betaine, about 0.

A method for conducting foam drilling and workover operations in a bore hole penetrating a subterranean reservoir, particularly a high-temperature reservoir such as a geothermal reservoir, employing an aqueous foaming solution of about 0.08 to 1.0 percent by weight of an amphoteric betaine, about 0.02 to 0.4 percent by weight of a salt of a linear aliphatic or alkyl aryl hydrocarbon sulfonate, and, optionally, from 0.03 to 3.5 percent by weight unneutralized ammonia.

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In the method for conducting foam drilling and workover operations in a bore hole penetrating a subterranean reservoir having a temperature of about 400°to 700°F., wherein foam is generated by contacting an aqueous solution of a foaming agent with a gas, and said foam is caused to flow upwardly thro

In the method for conducting foam drilling and workover operations in a bore hole penetrating a subterranean reservoir having a temperature of about 400°to 700°F., wherein foam is generated by contacting an aqueous solution of a foaming agent with a gas, and said foam is caused to flow upwardly through the bore hole to carry solid and liquid materials out of the bore hole, the improvement which comprises using as the foaming agent a mixture comprising: about 0.15 to 0.6 percent by weight of a first foaming agent comprising a high alkyl amphoteric betaine selected from the group consisting of coco-dimethyl carboxymethyl betaine, lauryl dimethyl carboxymethyl betaine, lauryl dimethyl alpha-carboxyethyl betaine, cetyl dimethyl carboxymethyl betaine, lauryl bis-(2 hydroxy-ethyl) carboxymethyl betaine, oleyl dimethyl gamma-carboxypropyl betaine, lauryl bis-(2 hydroxypropyl) alpha-carboxyethyl betaine, and the ammonium salts of the foregoing; and about 0.06 to 0.25 percent by weight of a second foaming agent comprising a sodium olefin sulfonate having from 10-18 carbon atoms.