Multi-Size Piping Approach to Increase Gas Pipeline Productivity by Selective Reduction of Holdup

Abstract

Hydraulic performance and thermal characterization are the main parameters dictating proper consideration of flow assurance in pipelines. Hydraulic performance considers the evaluation of multiphase systems, specifically the equilibrium of phases and consequent flow patterns and their impact on pressure loss, holdup and sustainable and safe flow transport characteristics. Secure supply of hydrocarbons via pipelines plays crucial importance to maximize their production. In this study, a multiphase flow simulation of gas-condensate is developed using PIPESIM™ software. The data and main physical parameters correspond to a projected off-shore natural gas pipeline located in the north sea of Venezuela. The flow of hydrocarbons is analyzed and potential improvements are presented using both a traditional single-size and an ¨out-of-the-box¨ multi-sizing technique with the objective to reduce predicted overall holdups and pressure drops along the pipeline. The simulation permitted to assess different flow characteristics as liquid holdup, flow rate and pressure drop through different sections and accessories of the pipeline. Fixed pipeline insulation was maintained along all the study to keep a practical number of independent variables. The outcome of the analysis demonstrates that with a reasonable adjustment of pipe diameter, it is possible to increase the gas production without extra energy to compress the line, favoring the project economy and reducing its carbon footprint.