Pressure Transient Analysis of Two-Phase Flow Problems

Abstract

Summary This paper considers the analysis of pressure drawdown and buildup data for two-phase flow problems. Of primary concern is the analysis of data influenced by saturation gradients that exist within the reservoir. Wellbore storage effects are assumed to be negligible. The pressure data considered are obtained from a two-dimensional (2D) numerical coning model for an oil/water system. We consider constant-rate production followed by a buildup period and assume that the top, bottom, and outer boundaries of the reservoir are sealed. First, we consider the case where the producing interval is equal to the total formation thickness. Second, we discuss the effect of partial penetration. In both cases, we show that average pressure can be estimated by the Matthews-Brons-Hazebroek method and consider the computation of the skin factor. We also show that a reservoir limit test can estimate reservoir PV only if the total mobility adjacent to the wellbore does not vary with time.