_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 230265, “Maximizing SAGD Performance at Blowdown Phase Through Autonomous Inflow Control Valves, ” by Maria A. Roa, SPE, Ismarullizam M. Ismail, SPE, and Einar Gisholt, SPE, InflowControl AS, et al. The paper has not been peer-reviewed. _ During late-life phases of steam-assisted gravity drainage (SAGD) projects, noncondensable gas (NCG) and water breakthrough from thief zones of aquifer connectivity can leave pockets of bitumen untouched. This study integrates laboratory testing with reservoir simulation to evaluate the effectiveness of autonomous inflow control valves (AICVs) in managing late-life SAGD production challenges. The results highlight the potential of AICVs to mitigate production issues, optimize fluid regulation, and extend the productive life of SAGD wells. Working Principles of the AICV In 2012, the AICV was introduced, featuring a self-adjusting flow area that responds to both viscosity and density. The AICV shuts off automatically in the presence of 100% water or gas, enabling efficient reservoir drainage. This technology enhances productivity index (PI) in oil-rich zones while minimizing flow in high-water-cut areas, thereby improving overall reservoir management. The AICV operates based on the principles of Hagen–Poiseuille and Bernoulli and features two flow paths: the main path (97%) and the pilot path (3%). The Hagen–Poiseuille law, which describes laminar flow through a cylindrical pipe, helps predict pressure drops caused by viscous resistance in the laminar flow element (LFE). Meanwhile, the Bernoulli principle, which relates pressure to fluid velocity in a streamlined flow, governs the behavior of the turbulent flow element (TFE), where velocity-induced pressure changes are critical. These two restrictive elements in the pilot path control the pressure in the piston chamber (P2) (Fig. 1). The pressure drop across each of these elements is determined by the viscosity and density of the fluids. The pressure in the chamber below the piston (P2) is controlled by the configuration of the LFE and TFE. The pressure drop in the LFE is determined by the fluid’s viscosity and velocity (higher viscosity results in greater pressure drop, and vice versa). The pressure drop in the TFE is proportional to the fluid’s density and the square of its velocity (higher density results in greater pressure drop, and vice versa). In the presence of single-phase oil, the configuration generates a high pressure drop across the LFE, keeping the AICV open with minimal pressure drop in the main flow path. However, if single-phase water or gas is present, the valve will automatically close, allowing production only through the pilot path. In the case of multiphase flow, the AICV progressively chokes as water cut or gas volume fraction increases, resulting in lower PI in zones with higher presence of undesired phases. Laboratory Testing Experimental single-phase flow performance tests for the AICV were performed to verify single-phase flow behavior. The tests have been performed for gas, water, and six different oil viscosities to resemble the potential emulsion viscosities in SAGD at the blowdown phase. The tests range between 3. 1 and 192 cp.
Chris Carpenter (Wed,) studied this question.