Study of Phase Wetting in Three-Phase Oil-Water-Gas Horizontal Pipe Flow - Recommendations for Corrosion Risk Assessment

摘要

Accurate prediction of the phase wetting regime of internal pipe walls of oil production lines is of paramount importance when performing internal corrosion assessments. Therefore, corrosion control costs can be reduced as mitigation efforts can be directly aimed at the most critical pipeline areas where water is most likely to segregate and wet the pipe wall. Surface wetting regime (e.g., oil wet or water wet) depends on several factors, such as flow rates and physicochemical properties of the transported fluids, pipe diameter and inclination, and also pipe surface wettability. This work studies phase wetting regimes in three-phase oil-water-gas horizontal flow in a 0.1 m diameter carbon steel pipe in a flow loop, for flow conditions where liquid-gas slug flow pattern is predominant. Phase wetting and water layer thickness (when water wet) were measured using high frequency impedance probes flush-mounted at the internal pipe wall. Different mechanisms of water wetting are inferred from the obtained data for the bottom and top pipe walls. Maps of phase wetting regime and water layer thickness versus operating conditions are shown for different water cuts. Experimental data is discussed and compared with predictions from a proposed three-phase hydrodynamic model. Consequently, recommendations are provided for direct internal corrosion assessment.