ABSTRACT
In-well fiber optics Distributed Acoustic Sensing (DAS) data are widely used to estimate cluster fluid contribution and monitor cross-stage fluid communication. One common way of visualizing fluid distribution is through waterfall plots of energy attribute derived from the DAS data. The energy attribute in combination with the treatment data is used to quantitatively calculate fluid contribution, which is usually visualized as histogram or dynamic flow-rate plots. Using the relationship between the energy attribute and the flow rate, we compute cumulative slurry per cluster and plot them with time (cumsum-time curves) on top of treatment curves. The slope of the cumulative slurry curves can be used to estimate the average flow rate through each perf cluster, where higher slopes represent higher flow rates and vice versa. The curves can also be used to visualize how the flow rate is changing with stimulation. We showed these curves for DAS data acquired in a treatment well in the Marcellus Shale. We observed a varying slope (infers varying flow rate) of cumulative slurry for inter and intra-stage perf clusters reacting to changes in proppant concentration. The cumsum-time curves provide new insights into flow-rate dynamics of individual clusters in relation to the treatment data.
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