DefinePK

Abstract

Unconventional shale reservoirs appear as a solution to the depletion of conventional reserves, however, their ultra low permeability, requires hydraulic fracturing that helps improving the fluid flow towards the well. The design and creation of these fractures is complex. Knowing their properties, and the reservoir's, as well, is of great importance for field management. This study presents a practical methodology for well test interpretation in shale reservoirs using the analytical trilinear flow model, which describes a system consisting of a horizontal well with multiple fractures in extremely low permeability reservoirs. Analytical expressions were developed based upon unique features found on the pressure and pressure derivative curves for the determination of fracture conductivity (kFwF), half-fracture length (xF), matrix permeability (km) and internal reservoir permeability (kI). Finally, synthetic examples for both oil reservoirs and gas formations were developed to successfully verify the accuracy of the developed equations.