Active control of hydrodynamic slug flow

Show simple item record

dc.contributor.advisor Cao, Yi Inyiama, Fidelis Chidozie 2013-07-23T11:01:49Z 2013-07-23T11:01:49Z 2013-04
dc.description.abstract Multiphase flow is associated with concurrent flow of more than one phase (gas-liquid, liquid-solid, or gas-liquid-solid) in a conduit. The simultaneous flow of these phases in a flow line, may initiate a slug flow in the pipeline. Hydrodynamic slug flow is an alternate or irregular flow with surges of liquid slug and gas pocket. This occurs when the velocity difference between the gas flow rate and liquid flow rate is high enough resulting in an unstable hydrodynamic behaviour usually caused by the Kelvin-Helmholtz instability. Active feedback control technology, though found effective for the control of severe slugs, has not been studied for hydrodynamic slug mitigation in the literature. This work extends active feedback control application for mitigating hydrodynamic slug problem to enhance oil production and recovery. Active feedback Proportional-Integral (PI) control strategy based on measurement of pressure at the riser base as controlled variable with topside choking as manipulated variable was investigated through Olga simulation in this project. A control system that uses the topside choke valve to keep the pressure at the riser base at or below the average pressure in the riser slug cycle has been implemented. This has been found to prevent liquid accumulation or blockage of the flow line. OLGA (olga is a commercial software widely tested and used in oil and gas industries) has been used to assess the capability of active feedback control strategy for hydrodynamic slug control and has been found to give useful results and most interestingly the increase in oil production and recovery. The riser slugging was suppressed and the choke valve opening was improved from 5% to 12.65% using riser base pressure as controlled variable and topside choke valve as the manipulated variable for the manual choking when compared to the automatic choking in a stabilised operation, representing an improvement of 7.65% in the valve opening. Secondly, implementing active control at open-loop condition reduced the riser base pressure from 15.3881bara to 13.4016bara. en_UK
dc.language.iso en en_UK
dc.publisher Cranfield University en_UK
dc.rights © Cranfield University 2013. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright owner. en_UK
dc.subject Choking en_UK
dc.subject multiphase en_UK
dc.subject flow regime en_UK
dc.subject feedback control en_UK
dc.subject close-loop en_UK
dc.subject open-loop en_UK
dc.subject bifurcation map en_UK
dc.subject OLGA en_UK
dc.title Active control of hydrodynamic slug flow en_UK
dc.type Thesis or dissertation en_UK
dc.type.qualificationlevel Masters en_UK
dc.type.qualificationname MSc by Research en_UK

Files in this item

This item appears in the following Collection(s)

Show simple item record

Search CERES


My Account