Transitional Flow Regimes in Multi-Fractured Horizontal Wells

摘要

The diverse types of transitions that prevail in a multi-fractured horizontal well (MFHW) are described by new flow regimes. This enhanced description of flow history is validated using field data and simulation results. Shale wells exhibit very long transient periods (months or years) owing to the low formation permeability. This fact also prolongs the transitions between the flow regimes, long enough to describe them as flow regimes themselves. This paper identifies different types of transitions that occur in MFHW and categorizes them based on the factors that lead to the distinct nature of the transitions. It also presents a semi-analytical real space solution of elliptical flow for early intermediate and late intermediate times, which we define as sustained elliptical flow and boundary influenced elliptical flow, respectively. Using the understanding of these transition types and the constituent flow regimes, we propose methods to determine permeability of the matrix, fracture half length, fracture spacing as well as boundaries beyond the stimulated reservoir volume (SRV). Our novel method of describing transitions as combinations of derived flow regimes helps us not only in estimating accurate properties but also aids us in future rate predictions and improved EUR determinations and quantifies the impact of the unstimulated matrix.