Design and control of pig operations through pipelines

To provide an efficient tool to assist in the control and design of pig operations through pipelines, a numerical code has been developed, based on a finite difference scheme. It allows the simulation of two-fluid transient flow, i.e. liquid–liquid, gas–gas or liquid–gas products in the pipeline. Modules to automatically control process variables were included to employ different strategies to reach an efficient operation. Different test cases were investigated to confirm the robustness of the method. The results obtained with the code were compared with a real oil displacement operation of a section of the OSPAR pipeline, with 762 mm diameter and 60 km length, owned by Petrobras; there was good agreement between the two, thereby validating the method.