A Novel Hybrid Method to Design Horizontal Gas-Liquid Separators

Abstract

Separators are a vital part of almost every oil and gas production facility. Because of their importance, optimal separator design is critical. Semi-empirical design method is a conventional and more primitive way of determining the optimal dimensions for separators. However, because of the simplifying assumptions used to derive semi-empirical correlations, this method can only be used to obtain a rough estimate for separator dimensions. In this study, a novel hybrid method to design multiphase separators is presented using experimentation, dimensional analysis, and CFD simulation. This method contains performing experiments on a pilot two-phase separation unit; CFD simulating of the laboratory-scale separator and validating the simulation using the experimental data; determining a range for the slenderness ratio of practical surface separators using dimensional analysis; CFD simulating the separators with slenderness ratios within the specified range using the procedure, and determining the optimum slenderness ratio. The pilot two-phase separation unit consists of a laboratory-scale horizontal two-phase separator, pumps, compressors and a static mixer to create a two-phase flow, and a liquid filter to extract liquid droplets from the separator gas outflow. The diameter of the trapped liquid droplets and their weight are, then, determined by imaging and weighing processes. The CFD model is validated with the experimental data (with less than 8% relative error). Using these steps, the dimensions of a surface separator for one of the production wells located in phase 9 of South Pars gas field are determined. One of the most important achievements of this research is to provide the necessary basis for the optimal design of surface separators.