Practical Seismic Petrophysics: The Effective Use of Log Data for Seismic Analysis

Abstract

This study demonstrates empirical relationships derived from microseismic, 3D inversion attributes and 4D seismic to production in unconventional shale in the Horn River Basin. Production variations are explained through the use of the above mentioned tools and a careful investigation of stimulated rock volume. These production variations are shown to occur from a highly stressed zone influenced by a fault which intersects the north portion of a well pad. Estimates of stimulated rock volume are driven by the microsesmic event locations and the 4D response. It is shown that high b-values occurred in brittle rock and in a lower stress regime and low b-value stages occur in ductile rock in a relatively higher stress regime.

This talk will focus on the important role of "seismic petrophysics" in the quest to extract additional information from subtle seismic responses. Topics covered will include various aspects of log editing, petrophysical interpretation (including integration of other data sources—core, fluids, pressures, etc.), and some common pitfalls associated with the "workhorses" of rock physics (invasion corrections, shear velocity estimation, and elements of fluid substitution). It is important to recognize that log data should not simply be recomputed to fit prior expectations as defined by a rock physics model. Instead, rock physics models should be used as templates, which allow the interpreter to better understand the underlying physics of observed log responses and how they are governed by local petrophysical properties. Case studies will be used to reinforce critical concepts.