Abstract

Rate Transient Analysis (RTA) is a classic characterization method for unconventional wells. In this paper, we propose to leverage RTA rate-pressure transforms by analyzing the data at play scale, using pattern and anomaly classification algorithms, to derive new quantitative and qualitative indicators for more than 600 wells operated by Chesapeake Energy on Utica gas shale play.

This paper will present:

  • a workflow of automated classification and extraction of RTA characteristics, including the collection of weak signals associated to well-to-well interferences.

  • the major large-scale observation of this study: Stimulated Rock Volume (SRV) characteristics change over time

The comprehensive review of the context of occurrence of these evolutions in SRV characteristics introduces a new field of discussion on hydraulic fracture geomechanical behavior under depletion.

In particular, these evolutions of SRV characteristics occur in a fairly structured way (in term of timing and geographic distribution), and the late RTA slopes (in transient flow regime) show a strong trend of convergence toward an apparent geomechanical stable state.

These evolutions in SRV characteristics have multiple implications for the reservoir engineer as well as for the understanding/benchmarking of the performance of fracturing techniques. A new stimulation indicator is proposed, 1_m2_clusters.

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