Introduction
Variable-rate time (I.e. Material Balance Time) creates an equivalent constant rate PSS response, and generally provides a zero-order deconvolution response. It is entirely rigorous for PSS time, and an approximation for transient flow periods.
The figure below illustrates the practical concept of material balance time. It is heavily used in diagnostic plots to identify flow regimes.
References:
-
Juan Manuel Lacayo Ortiz, Pressure Normalization of Production Rates Improves Forecasting Results, M.Sc . Texas A&M University 2013.
-
RTA in whitson+, Mathias Carlsen, Mohamad Dahouk, Curtis Whitson, 26 June 2023