Sampling a Stimulated Rock Volume: An Eagle Ford Example

Between 2014 and 2016, ConocoPhillips drilled five deviated wells adjacent to a multistage, stimulated horizontal producer to sample the physical characteristics of the reservoir stimulation caused by hydraulic fracturing in the Eagle Ford Formation in DeWitt County, Texas. The design, execution, and results of the pilot are described. This pilot establishes the paucity of pre-existing natural fractures in this locale and enables the determination of the spatial characteristics of the stimulation using information derived from the core, cuttings samples, borehole-image logs, tracer logs, microseismic, distributed temperature sensing (DTS)/distributed acoustic sensing (DAS), and pressure data. Results show that stimulation effectively breaks the reservoir rock and makes a complex array of hydraulic fractures that are more closely spaced near the producer. Some fractures, however, extend interwell distances of more than 1,000 ft. The pilot data indicate that abundant proppant transport appears to be limited to distances less than 75 ft from the producer, which suggests that the stimulated rock volume (SRV) might be greater than the volume of rock that can be effectively drained.