Multidimensional Simulations of Multiphase Flow for Improved Design and Management of Production and Processing Operation

摘要

Over the past five years, ConocoPhillips, TOTAL, and SINTEF have developed a novel transient multiphase flow simulator, called LedaFlow, with both one- and multi-dimensional capabilities. The aim of the development is to meet industry needs for improved simulation of fluids management and related flow assurance issues in oil/gas production and processing operations. LedaFlow is composed of a suite of models, including a complete one-dimensional transient model with compositional tracking, a complex network solver, and algorithms to couple models of different dimensions. The transient multi-dimensional model offers detailed flow distributions that are impossible to obtain with one-dimensional models. It was demonstrated recently that flow regime transitions, observed pressure gradients and liquid holdup can be accurately reproduced (Laux et al., 2007). In the present paper, we analyze 2-phase flows in vertical risers and demonstrate the capabilities of multi-dimensional modeling. The prediction of vertical flows are very good except for low flow rates. We demonstrate that complex flow regimes (such as churn flow) are predicted with the LedaFlow quasi three dimensional (Q3D) model, without resorting to assumptions about flow regimes and structures. Q3D simulations show that small deviations from perfectly vertical flow may have a large effect on liquid hold-up and pressure drop. The Q3D model is furthermore applied to simulate an operational situation where fluids are displaced to prevent hydrate formation during shut-down.