Field experiences with virtual metering technology

Abstract

This paper presents field experiences with the implementation of virtual well metering technology on the North West Shelf (NWS) of Western Australia. This technology is used to obtain well-by-well flow rate estimates using conventional pressure and temperature instrumentation in a wellbore and Christmas tree without the need for expensive multiphase flow meters. Best practices in project execution—including specifications, acceptance testing and commissioning procedures—are presented for deploying this advanced technology. The paper focusses on two NWS gas-condensate developments operated by Woodside Energy Ltd (WEL) on behalf of the NWS joint venture partners: the Perseus over Goodwyn (PoG) project, which is a four well subsea development of the Perseus and Searipple fields that tie back to the Goodwyn A platform; and a three well subsea development for the Angel field. The PoG virtual metering system (VMS) was commissioned in October 2007 and the Angel VMS more recently in February 2009. The paper compares field data and shows that this technology has provided very reliable and accurate flow rate predictions; historical data suggests that monthly reconciliation factors as low as 3–5% can be achieved. Virtual metering systems are a cost effective and reliable means to obtain well-by-well flow rates. Besides enabling better reservoir management, these well metering systems are easily integrated with real-time pipeline monitoring systems to enable reliable subsea operations. An integrated virtual metering and pipeline management system that includes look-ahead forecasting capabilities and guidance for real-time flow assurance on operational issues, such as hydrate formation and detection of restriction, is being developed for the Pluto field.