Enzymatically degradable fluid loss additive

摘要

In treating oil well down hole bores, a method of treating subterranean formations by fracturing by utilization of a fluid loss additive (FLA) comprising starch or a mixture of natural and modified starches plus an enzyme which degrades the alpha linkage of starch and does not the degrade the beta linkage of guar and modified guar where used as a viscosity modifier. Natural/modified starches are utilized in a preferred ratio of 3:7 to 7:3 or 1:9 to 9:1 with optimum at 1:1, and the mix is used in the dry form for application from the surface down the bore hole.