James T. Smith, Texas Tech University & William M. Cobb, Cornell Oil Company
Since the inception in 1947 of hydraulic fracturing as a method of stimulating oil and gas wells, fractured wells have become a commonplace throughout the world. This is particularly true in regions noted for low permeability and accompanying low productivity. Transient pressure test conducted in fractured reservoirs are subject to unconventional behavior which requires special interpretational skills and procedures. The purpose of this paper is to discuss those methods of pressure analysis which have been most successfully applied to wells that intersect single-plane vertical fractures. Procedures for evaluating reservoir permeability, formation damage, and fracture length are presented for both conventional and type-curve methods of analysis. Practical tests and rules-of-thumb which will help an engineer avoid common pitfalls in fractured well analysis are presented. Both infinite- and finite-conductivity fractures are discussed.