Foam drilling and workover in high temperature wells

Claim 2

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.

Claim 3

The method defined in claim 1 wherein said aqueous solution of a foaming agent contains about 0.03 to 3.5 percent by weight of unneutralized ammonia.

Claim 4

The method defined in claim 2 wherein said unneutralized ammonia is added as ammonia or ammonium hydroxide.

Claim 5

The method defined in claim 2 wherein the amount of unneutralized ammonia used is sufficient to maintain the aqueous solution of the foaming agent during its use at a pH of 9.5 to 11.

Claim 6

The method defined in claim 1 wherein the gas is selected from the group consisting of nitrogen, natural gas, methane, carbon dioxide and air.

Claim 7

The method defined in claim 5 wherein the gas is air.

Claim 8

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 0.08 to 1.0 percent by weight of a first foaming agent comprising coco dimethyl ammonium carboxylic acid betaine, and about 0.02 to 0.4 percent by weight of a second foaming agent comprising a salt of sodium olefin sulfonate having from 10-18 carbon atoms.

Claim 9

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 0.08 to 1.0 percent by weight of a first foaming agent comprising coco dimethyl ammonium carboxylic acid betaine, and about 0.02 to 0.4 percent by weight of a second foaming agent comprising a salt of sodium olefin sulfonate having from 10-18 carbon atoms.

Claim 10

The method defined in claim 7 wherein said sodium olefin sulfonate has 14 carbon atoms per molecule.

Claim 11

The method defined in claim 1 wherein said aqueous solution of a foaming agent contains about 0.03 to 3.5 percent by weight of unneutralized ammonia.

Claim 12

The method defined in claim 9 wherein said unneutralized ammonia is added as ammonia or ammonium hydroxide.

Claim 13

The method defined in claim 9 wherein the amount of unneutralized ammonia used is sufficient to maintain the aqueous solution of the foaming agent during its use at a pH of 9.5 to 11.

Claim 14

The method defined in claim 1 wherein the gas is selected from the group consisting of nitrogen, natural gas, methane, carbon dioxide and air.

Claim 15

The method defined in claim 12 wherein the gas is air.

Claim 16

In the method for conducting foam drilling and workover operations in a bore hole penetrating a subterranean geothermal formation 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 said 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 sodium olefin sulfonate having 14 carbon atoms per molecule.

Claim 17

In the method for conducting foam drilling and workover operations in a bore hole penetrating a subterranean geothermal formation 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 said 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 sodium olefin sulfonate having 14 carbon atoms per molecule.

Claim 18

The method defined in claim 14 where said aqueous solution of a foaming agent contains about 0.03 to 3.5 percent by weight unneutralized ammonia.

Claim 19

The method defined in claim 15 wherein said unneutralized ammonia is added as ammonia or ammonium hydroxide.

Claim 20

The method defined in claim 15 wherein the amount of unneutralized ammonia used is sufficient to maintain the aqueous solution of the foaming agent during its use at a pH of 9.5 to 11.

Claim 21

The method defined in claim 14 wherein the gas is selected from the group consisting of nitrogen, natural gas, methane, carbon dioxide and air.

Claim 22

The method defined in claim 18 wherein the gas is air.