An Interpretation of M-Site Hydraulic Fracture Diagnostic Results

Abstract

Abstract Experiments at the GRI/DOE M-Site have shown that hydraulic fractures have a considerable degree of complexity that is difficult to account for using current understanding. Several of the key features are reviewed and an attempt is made to examine them relative to fracture mechanics, elasticity, and fluid-flow mechanisms. Key features include unexpected fracture containment, multiple fracture strands, secondary and T-shaped fracturing, large pressure drops down the fracture, significant differences in microseismically imaged geometry as a result of fluid-system changes, unexpectedly large residual width/deformation measurements after unpropped fracturing, large discrepancies in fracture area (and, thus, volume) between imaging and modeling results, evidence of complexities in proppant transport, and measurement of a clearly defined fracture closure pressure using a pressure independent technique.