Abstract
Buildup data from multiply-fractured horizontal wells (MFHW) in tight (micro to nano-Darcy permeability) unconventional reservoirs often display a derivative signature which appears like radial flow and is frequently misinterpreted as such without due consideration of the expected flow regimes from these systems. Studies based on both numerical and analytical modeling suggest that radial flow regimes will not be observed, due to the large number of hydraulically induced fractures, and the geometry of a typical MFHW completion. Analysis of production data continues to show no evidence of radial flow, but instead, reveals that linear flow regimes dominate for the majority of a well's lifetime. This is more consistent with the expected flow behavior, and leads to confusion on how to interpret buildup data that often appear like radial flow. This paper provides explanations for the different pressure behavior exhibited during a buildup. In doing so, the value of conducting a buildup test to assess the reservoir characteristics and completion effectiveness, is demonstrated. Two examples of actual buildup data obtained from MFHWs completed in unconventional reservoirs are presented to support the findings of this paper.
