Enzymatic Breaker System for Nondamaging Removal of Cellulose-Based Blocking Gels

Abstract

An external breaker system, consisting of a combination of enzymes, has been used to remove polymer damage at low to moderate temperatures. This enzyme mixture produces a stepwise· breakdown of cellulose polymers at temperatures ranging from 60°F to 140°F. The polymer is initially reduced to O-glucose and cellobiose. The complete hydrolysis of the cellobiose is subsequently afforded by the enzyme combination.The entire hydrolysis of the polymer occurs rapidly; therefore, the enzyme complex can be applied as an external breaker after the workover operations have been completed. Post workover injection of the enzyme complex allows blocking gels to retain maximum strength during operations. The enzyme combination is compatible with the brines used to prevent damage from swelling clays. The result is a blocking gel that is reduced to a clean non-viscous fluid that is easily recoverable.References and illustrations at end of paper.

Rheological Behaviors of Bio-degradable Drilling Fluids in Horizontal Drilling of Unconsolidated Coal Seams

“…Such applications have been coupled with a follow-up treatment involving an acid wash to remove acid-soluble bridging agents [2,7,[10][11][12][13][14][15][16][17].…”