Testing and Qualification of a New Multiphase Flow Simulator
Authors: Danielson Thomas John , Bansal Krishan M. , Djoric Biljana , Duret Emmanuel-Denis , Johansen Stein Tore , Hellan Oyvind 
Published: May 2011

This paper presents test cases, methodologies, and test results from the extensive testing and qualification program that have been conducted with LedaFlow®. This new transient multiphase flowline simulator has been built with focus on multiphase flow challenges in the oil and gas industry, and the resulting software includes both transient 1D and quasi 3D multiphase models. Development has been based both on existing and new large-scale experimental data from the SINTEF multiphase laboratory, taken over a nearly ten-year period. The focus of this paper is the transient 1D model.

The transient three-phase 1D simulator offers new modeling capabilities as it is based on a model concept conserving mass for 9 fields (bubbles, droplets, and continuous fluids), using three momentum equations, and solving for the enthalpy and temperature of the three individual fluid zones. Improved closure relations have been built from a combination of new large-scale multiphase flow experiments and sub-models which represents the distribution of droplets over the pipe cross section.

Before introduction of this new tool to the industry, it was taken through an extensive testing and qualification program. The testing included comparison with experimental data (over 10,000 experimental points) and field data (over a dozen pipelines and wells, from wet-gas to oil), as well as comparisons to other commercially available software. Another part of the testing was focused on typical flow assurance user cases; transient simulations such as turn-down, shut-down, start-up and depressurization were run for a number of realistic field geometries.

The new multiphase flow simulator reproduces experimental data and field data within defined acceptance criteria. This new multiphase flow software can be used as an alternative to other commercially available software and as a valuable new tool for flow assurance work for field development, operational studies and decision support.

Introduction

The development of the new transient multiphase flow simulator, with both one- and multi-dimensional capabilities has been ongoing for almost a decade. The goal of the development has been to meet industry needs for improved and alternative 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 and network solver.

Figure 1 illustrates the three main phases of the development project and focus areas in each phase. The first phase of the project was primarily focused on extensive testing at the SINTEF Multiphase Flow Laboratory. The extensive test campaign was conducted in a 12-inch loop for 2-phase flow, and an 8-inch loop for 3-phase flow (Danielson et al, 2005). New 1D data was acquired for hold-up, pressure gradient, and flow regime. These data are exclusive available for development of the new multiphase simulator and filled data gaps in the existing SINTEF Tilda database, which now in total includes more than 10,000 data points.