The Multiphase Flowing Material Balance Integral

Abstract The primary objective of this paper is to introduce the Flowing Material Balance (FMB) integral, building upon the work of Thompson & Ruddick (2022). The MFMB integral enhances the existing MFMB method by providing a smoother representation of multiphase production data, especially in noisy datasets. The MFMB integral is designed to improve the accuracy of the MFMB method by applying an integral smoothing technique to multiphase production data. This approach calculates the integral of the material balance equation, ensuring that noise is reduced without compromising the essential signal. The method uses production data, bottomhole pressures, and PVT data, while bypassing the need for relative permeability assumptions. By focusing on mass material balance and leveraging initial reservoir conditions, the MFMB integral provides a reliable and fast estimate of contacted pore volume. The introduction of the MFMB integral allows for more robust analysis of multiphase production data, particularly in the presence of noisy or incomplete datasets. By integrating over time, the MFMB integral offers a smoothed diagnostic plot that preserves critical data trends while minimizing noise interference. This integral-based approach enhances the estimation of lower bounds for OOIP, OGIP, and contacted pore volume. This paper presents the novel application of the MFMB integral, which refines the standard MFMB method by addressing data noise and improving the accuracy of pore volume estimations. The introduction of the integral calculation contributes to the state of knowledge in reservoir engineering, offering a faster, more accurate tool for analyzing complex multiphase flow scenarios without reliance on permeability models.