Chapter 13 - Hydraulics

Abstract

This chapter explains the composition and phase behavior of hydrocarbons. It discusses the hydraulic analyses for single-phase flow and multiphase flow, which include pressure drop versus production flow rate and pipeline sizing. The petroleum fluids from reservoirs normally are multiphase and multicomponent mixtures, primarily consisting of hydrocarbons, which can be classified into the following three groups: paraffins; naphthenes; and aromatics. In addition to hydrocarbons, water (H2O), nitrogen (N2), carbon dioxide (CO2), hydrogen sulfide (H2S), salts, and solids are often found in petroleum mixtures. A multicomponent mixture exhibits an envelope for liquid/vapor phase change in the pressure/temperature diagram, which contains a bubble-point line and a dew-point line, compared with only a phase change line for a pure component. Various reservoir types of oil and gas systems based on the phase behavior of hydrocarbons in the reservoir is distinguished into five types: black oils; volatile oils; condensate; wet gases; and dry gases. Further the fluid flow in pipelines is divided into three categories based on the fluid phase condition: single-phase condition: black oil or dry gas transport pipeline, export pipeline, gas or water injection pipeline, and chemical inhibitors service pipelines such as methanol and glycol lines; two-phase condition: oil + released gas flowline, gas + produced oil flowline; three-phase condition: water + oil + gas.