On-site interactive hydraulic fracturing procedures for determining the minimum in situ stress from fracture closure and reopening pressures

Abstract

This paper proposes modifications to hydraulic fracture stress test procedures currently in use, and presents techniques for design and analysis of such tests. Limitations of the conventional approach are identified and illustrated by an example. Three tests used to determine the minimum in situ stress from fracture closure and reopening pressures are discussed. Fracture reopening pressure is defined in the low-rate injection test (fracture reopening test). Fracture closure pressure is defined from flowback and/or extended falloff tests. The test performance and data analysis are on-site interactive processes that quantify the in situ conditions and optimize accordingly the controlling test parameters, such as the reopening and flowback rates and the pumped volume. The theory for the design and the interpretation of hydraulic fracture tests is outlined.