Chapter List

A.1 Introduction

Offshore pipelines consist of export pipelines and infield pipelines. Export pipelines transport oil or gas from either platform or FPSO (Floating Production, Storage, and Offloading) to beach for further processing. The flow inside the export pipeline is usually gas-condensate flow or oil flow with a little amount of water. The infield pipelines transport wellstream either from the manifolds or from the wells to the platform or FPSO. The flow in the infield pipeline is usually gas-oil-water multiphase flow for oil fields or gas-condensate-water flow for gas fields. Thus, to properly design offshore pipelines, it is critical to understand the impacts of multiphase flow. All of the flow assurance issues associated with offshore pipeline operations are related to the multiphase flow inside the pipeline.

Pressure drop is one of the most critical parameters for pipeline sizing. For single-phase flow, pressure drop is mainly controlled by the Reynolds number that is a function of the fluid viscosity, fluid density, fluid velocity, and pipeline size. For gas-oil-water three-phase flow, the pressure drop inside the pipeline is governed by the flowing properties of all the fluids:

• Density of oil, water, and gas

• Viscosity of oil, water, and gas

• Velocity of oil, water, and gas

• Volume faction of oil, water, and gas

• Interfacial tension between fluids

• System pressure and temperature

When oil,...