Fracture quality from integrating time-lapse VSP and microseismic data

Abstract

Tight gas reservoirs are problematic to produce, often requiring multiple stages of hydraulic fracturing in order to create connected pathways through which hydrocarbons may flow. In this paper, we propose a new methodology to characterize the quality of hydraulic fractures. Using synthetic VSP and microseismic data, we test the concept that the rock volume containing open, gas-filled fractures will scatter seismic energy more profusely than a volume containing closed, nonproductive fractures. By measuring the amount of scattered energy in a time-lapse 3D VSP study taken before and after the hydraulic fracturing episode, we hope to compare the productive flow quality of different regions of the hydraulically fractured rock. The microseismic recordings allow us to locate areas which have been hydraulically fractured and create imaging operators to extract the scattered signals from the time-lapse VSP data.