Experimental Study of Three-Phase Slug Flow in Horizontal Pipes Downstream of a Restriction

Summary Gas-oil-water three-phase flow is a common phenomenon in the petroleum industry, especially as the oil fields age and water production becomes inevitable. While extensive research has been conducted on gas-liquid two-phase flow, the understanding of gas-oil-water flow remains limited, particularly considering the intricate mixing dynamics between the water and oil phases due to their low interfacial tension (IFT). It is anticipated that the oil-water flow pattern in gas-oil-water three-phase flow can impact the overall pressure drop. We experimentally investigated this phenomenon in a horizontal pipe equipped with a valve that controlled the phase mixing. Restrictions like chokes are commonly utilized in transportation systems for a variety of reasons, such as regulating pressure or flow rates, to ensure safe transportation and meet facility requirements. However, further understanding of their impacts on three-phase flow behavior is still needed. We systematically investigate this issue in this study. The experiments were carried out in a flow loop featuring a 45-ft-long, 2.067-in. horizontal pipe, with a 2-in. ball valve installed at the inlet of the test section. Flow patterns, phase distributions, and pressure drop were measured 123 pipe diameters downstream of the valve in the test section. A high-speed camera and an electrical capacitance volume tomography (ECVT) system were used in the experimental study. Various tests were conducted to systematically study the impact of oil-water flow patterns on the downstream fluid flow behaviors for gas-oil-water three-phase slug flow at different choke openings, water cuts, and flow rate conditions.