Sampling a Stimulated Rock Volume: An Eagle Ford Example

TLDR

The study describes the design, execution, and results of a pilot drilling program to sample reservoir stimulation in the Eagle Ford Formation. Between 2014 and 2016, ConocoPhillips drilled five deviated wells adjacent to a multistage, stimulated horizontal producer in the Eagle Ford Formation to sample the physical characteristics of hydraulic‑fracture stimulation. The pilot demonstrates that the area has few natural fractures, that hydraulic fracturing creates a complex array of fractures more closely spaced near the producer, that some fractures extend over 1,000 ft, and that proppant transport is limited to within 75 ft of the producer, suggesting the stimulated rock volume exceeds the effectively drained volume.

Abstract

Summary 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.