Page 52: of Offshore Engineer Magazine (Jul/Aug 2014)

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Pipelines

Global perspective on ? ow assurance

FPSO, deepwater riser and subsea

Flow assurance is set to play many different types of system. The architecture. Photos from Flowsure .

analytical insight provided can be used a fundamental role in solving to develop technologies which enhance major future industry challenges. the ef? cient transport of multiphase associated with slugging can be signi? - ? ow, making it possible to develop ? elds cantly magni? ed.

Martin Brown discusses some of which would otherwise be uneconomic. Both the slugging characteristics and the challenges.

Flowsure has noticed that global ? ow the conditions under which slugging is assurance efforts are increasingly becom- initiated must be analyzed and de? ned so nsuring successful ? uid ? ow has ing focused on a number of key develop- that effective mitigation measures can be always been at the heart of the oil ment types. developed. The interface of ? ow assur-

E and gas industry. However, it is ance with the topside facilities is there-

Deepwater only in the last 20 years that ? ow assur- fore critical and facilities for handling

Deepwater currently accounts for about slugs during normal operation, start-up ance has become a classi? cation in its 7% of total conventional production but, and system depressurization need to be own right. The origins of the term are not year-on-year, the proportion of global provided and sized correctly. Where this known, however, in the early 1990s, the discoveries that are classed as deepwater is not possible, the use of innovative term garantia do escoamento, meaning is on the increase. solutions including intelligent chokes guarantee of ? ow, was coined by Petrobras.

Since then, ? ow assurance has become The key regions for deepwater dis- need to be considered.

a key term associated with new and exist- coveries are North America (e.g. Gulf of

Heavy Oil ing developments, and is now generally Mexico), Latin America (e.g. Brazil) and considered to address all issues critical Africa (e.g. Angola). Worldwide heavy oil resources (both to ensuring the multiphase transport of Deepwater ? ow assurance is focused onshore and offshore) have been esti- ? uids, from reservoir to processing host. on managing the low ambient-tempera- mated as in excess of 7.4MMbbl (2009).

The simultaneous transport of oil, tures and high-pressures on the sea? oor. Heavy oil production is well estab- gas, and water through pipelines is now In deepwater remediation costs are very lished in onshore and shallow water standard practice for new developments. high and any shutdown resulting from ? elds. However, the production costs are

Ensuring the successful transit of multi- a ? ow assurance incident can be both higher than more conventional resources, phase ? uids over signi? cant distances is lengthy and costly. and when situated remotely and in deep- crucial to ensuring development pro? t- Managing hydrates during a system water this effect is heightened.

ability. The ? nancial implications of a shutdown is a crucial operation, which Heavy oils are characterized by high production interruption, as a result of a requires complex analysis. Using chemi- viscosity and a low API gravity. Heavy oil loss of ? ow, can be catastrophic. Flow cal inhibition is not always the most is typically de? ned as an oil exhibiting an assurance is, therefore, not only a major economical option and complex “pres- API gravity < 22°. These factors mean pro- technical challenge but a serious eco- ervation” sequences involving partial duction and transportation of heavy oils nomic concern. depressurization and system ? ushing can be a major ? ow assurance challenge.

Flow assurance techniques include the usually need to be developed. As deep- Heavy oils can be complex and ? uid application of analytical multiphase soft- water risers are signi? cantly longer than properties dif? cult to predict using ware, to help understand and evaluate conventional risers, the ? ow instabilities conventional software. Care needs to be

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