Enzymatic decomposition of drilling mud

Claim 3

The method of claim 1 further comprising the step of after allowing said enzyme to degrade said polymeric organic viscosifier and said well treatment fluid to disperse said used drilling mud, recovering said well treatment fluid and used drilling mud from said well.

Claim 4

The method of claim 1 wherein said well treatment fluid further comprises a pH modifying agent for modifying the pH of said well treatment fluid to a value in the pH-active range of said enzyme.

Claim 5

The method of claim 1 wherein said enzyme is present in said well treatment fluid in an amount in the range of from about 0.01% to about 2% by weight based on the weight of said polymeric organic viscosifier.

Claim 6

The method of claim 1 wherein said polymeric organic viscosifier is selected from the group of carboxymethylcellulose and derivatives of carboxymethylcellulose, and said enzyme is selected from the group of hemicellulase, cellulase, amyloglucosidase, α-amylase, β-amylase, glucan 1,4-α-glucosidase, glucan 1,6-β-glucosidase, and cellulose 1,4-β-cellobiosidase.

Claim 7

The method of claim 1 wherein said polymeric organic viscosifier is hydroxyethylcellulose, and said enzyme is selected from the group of hemicellulase, cellulase, amyloglucosidase, and cellulose 1,4-β-cellobiosidase.

Claim 8

The method of claim 1 wherein said polymeric organic viscosifier is guar flour, and said enzyme is selected from the group of hemicellulase, cellulase, amyloglucosidase, and cellulose 1,4-β-cellobiosidase.

Claim 9

The method of claim 1 wherein said polymeric organic viscosifier is xanthan, and said enzyme is selected from the group consisting of glucosidase, glucan 1,4-α-glucosidase, glucan 1,6-α-glucosidase and α-glucosidase.

Claim 10

The method of claim 1 wherein said polymeric organic viscosifier is a glucan, and said enzyme is selected from the group of glucan 1,4-α-maltotetraohydrolase, glucan 1,4-α-glucosidase and cellulase.

Claim 11

In a method of drilling a well wherein a drill bit is advanced into the earth to form a bore therein, the drill bit is withdrawn from the bore, annular well casing having an outside diameter less than the diameter of the bore is placed in the bore and cement is placed between the wall of the bore and the casing, the improvement comprising: prior to placing the cement between the wall of the bore and the casing, injecting a well treatment fluid into said well to remove used drilling mud of the type comprising solid materials including at least one polymeric organic viscosifier therefrom, said well treatment fluid comprising an enzyme capable of rapidly enzymatically degrading said polymeric organic viscosifier; and allowing said enzyme to degrade said polymeric organic viscosifier and said well treatment fluid to disperse said used drilling mud.

Claim 12

In a method of drilling a well wherein a drill bit is advanced into the earth to form a bore therein, the drill bit is withdrawn from the bore, annular well casing having an outside diameter less than the diameter of the bore is placed in the bore and cement is placed between the wall of the bore and the casing, the improvement comprising: prior to placing the cement between the wall of the bore and the casing, injecting a well treatment fluid into said well to remove used drilling mud of the type comprising solid materials including at least one polymeric organic viscosifier therefrom, said well treatment fluid comprising an enzyme capable of rapidly enzymatically degrading said polymeric organic viscosifier; and allowing said enzyme to degrade said polymeric organic viscosifier and said well treatment fluid to disperse said used drilling mud.

Claim 13

The method of claim 10 further comprising the step of after allowing said enzyme to degrade said polymeric organic viscosifier and said well treatment fluid to disperse said used drilling mud, recovering said well treatment fluid and used drilling mud from said well.

Claim 14

The method of claim 10 wherein said well treatment fluid further comprises a pH modifying agent for modifying the pH of said well treatment fluid to a value in the pH-active range of said enzyme.

Claim 15

The method of claim 10 wherein said enzyme is present in said well treatment fluid in an amount in the range of from about 0.01% to about 2% by weight based on the weight of said polymeric organic viscosifier.

Claim 16

The method of claim 10 wherein said polymeric organic viscosifier is selected from the group of carboxymethylcellulose and derivatives of carboxymethylcellulose, and said enzyme is selected from the group of hemicellulase, cellulase, amyloglucosidase, α-amylase, β-amylase glucan 1,4-α-glucosidase, glucan 1,6-α-glucosidase, and cellulose 1,4-β-cellobiosidase.

Claim 17

The method of claim 10 wherein said polymeric organic viscosifier is hydroxyethylcellulose, and said enzyme is selected from the group of hemicellulase, cellulase, amyloglucosidase, and cellulose 1,4-β-cellobiosidase.

Claim 18

The method of claim 10 wherein said polymeric organic viscosifier is guar flour, and said enzyme is selected from the group of hemicellulase, cellulase, amyloglucosidase, and cellulose 1,4-β-cellobiosidase.

Claim 19

The method of claim 10 wherein said polymeric organic viscosifier is xanthan, and said enzyme is selected from the group consisting of glucosidase, glucan 1,4-α-glycosidase, glucan 1,6-α-glucosidase and α-glucosidase.

Claim 20

The method of claim 10 wherein said polymeric organic viscosifier is a glucan, and said enzyme is selected from the group of glucan 1,4-α-maltotetraohydrolase, glucan 1,4-α-glucosidase and cellulase.