Analyzing SAGD Producer Flow Instability and ESP Deterioration Using Dynamic Flow Simulations: A Field Case Study

Abstract

High-temperature electric submersible pumps (ESPs) are the most commonly used artificial lift method in steam-assisted gravity drainage (SAGD) wells. While conceptually the SAGD process should provide a low-viscosity single-phase flow to the ESP system, changing pressures and temperatures associated with well drawdown create opportunities for introduction of free gas, water vapor, or both, resulting in multiphase flow regimes. This can often lead to wellbore flow instability and ESP performance deterioration. An innovative approach to understanding ESP performance in multiphase flow conditions in SAGD production wells was developed by Shang, S. and Gomez-Bustamante, N. (2017), using well-specific fluid PVT characteristics to create the produced mixture's phase envelope. This analytical approach is able to identify phase boundaries, determine gas-water vapor volume fraction (GWVF), and predict flow regimes as a function of surface and downhole flowing measurements. In this case study, the authors extend the modeling work done by Shang, S. and Gomez-Bustamante, N. (2017) with the objectives of constructing a wellbore model that includes the complex downhole completion, conducting transient analysis of the entire wellbore, analyzing slugging characteristics both upstream and downstream of the ESP, and ultimately providing operational recommendations to maximize well drawdown while maintaining wellbore stability.