Polyurethane quasi prepolymer for proppant consolidation

摘要

A method of preparing a consolidating agent in the form of a polyurethane prepolymer for consolidating a proppant in a subterranean formation about a well employing the improvement characterized by a quasi prepolymer formed by reacting a diol with a stoichiometric excess of isomeric methylene diphenylene diisocyanate and a diluent; and allowing the reactants to stand for a period in excess of two hours at 25 degrees C., whereby to form oligmers of polyurethane chains. The method enables consolidating a proppant in fractures by a slow polymerization process, whereby the curing agent can be added at the same time the proppant is placed. Also disclosed are specific examples of diluents and curing agents.