ADVANCE ANALYSIS OF WELL TREATMENT AND MICROSEISMIC EVENTS FOR TWO PARALLEL HORIZANTAL WELLS IN THE UTICA SHALE

Since unconventional reservoirs have become a major oil and gas resource there have been hundreds of studies and methods targeting every aspect of hydraulic fracturing, all attempting to optimize the treatment process and maximize well production of hydrocarbons. This is uniquely important in tight formations such as shales due to their low permeability and large spatial distribution. Hydraulic fracturing stimulation creates additional permeability and increase pore pressure within the formation by injecting fluids directly into the target formation. Microseismic data provide an insight into the effectiveness and efficiency of the hydraulic fracturing operation and show how fractures are progressing during treatment. Collections of injection specific microseismic emissions, or microseismic clouds show the stimulated volume and any possible communication with preexisting fracture systems. However, cloud volume whether it is a stage or the entire well could be exaggerated and misleading if irrelevant events are not excluded from the analyzes, such as dry events and/ or low frequent events, which are distinguished by the Gutenberg–Richter relation. This study utilizes multiple microseismic analytical techniques: triggering fronts and RT plots (S. Shapiro 2015), seismogenic index (Shapiro, et al. 2010) and the variation of b-value/ D-value for each stage.  The triggering front method provides an approximate outermost envelope of the distances between event locations and the injection point as function of the time (Hummel and Shapiro 2012). On top of that it serves as quality control measure to separate between relevant microseismic events or wet events and dry events that occurred on preexisting fractures. This becomes important when there is pattern which can be recognized though multiple stages as this study shows.  Seismogenic index is the level of seismic activity one should expect from injecting fluid into rocks (Shapiro, et al. 2010). The index is not expected to be high due to low seismic activity in the region.