Researchers seek safe way to get last drops from ageing oilfields

By ALISTAIR MUNRO
Published on 23/06/2012 00:34

The lifespan of oilfields nearing the end of their existence could be extended, thanks to a major research project being led in Orkney.

The study is aimed at mini-mising the impact on the environment as oil companies recover more oil using enhanced techniques.

A specialist team is heading the £430,000 project which involves six leading giants: Opus, BP, Shell, Statoil, Total and Wintershall.

It is being carried out at test facilities in Orkney, operated by Opus, and will examine the effects that enhanced oil recovery (EOR) techniques used in the sector have on fluid separation efficiency.

It will investigate ways of lessening the environmental impact of the water that is produced when the oil is being taken out.

When drilling operations begin on a new well, almost 100 per cent pure oil being is extracted. But, as operations continue and more oil is pumped out, the pressure from the well drives up “produced” water, which needs to be separated and cleaned before being returned to sea.

EOR techniques are being used to increase the amount of trapped crude oil that can be extracted from oilfields – many of which are nearing the end of their lives – and therefore prolong their economic viability.

Operators are increasingly using EOR because it can improve the amount of oil that can be recovered by between 10 and 20 per cent, earning hundreds of millions of pounds from fuel that was previously unrecoverable.

Many of the techniques can present environmental challenges and, therefore, minimising any impacts will further improve production benefits.

Surrey-based Opus specialises in oil separation and treatments for “produced water” which is a by-product of petroleum production. Large quantities of water are produced along with hydrocarbons in oil and gasfields during extraction, and water production quantities rise as the oil and gasfields reach maturity. The water needs to be managed efficiently in order to reduce potential risk to the marine environment.

The Orkney facility will carry out a bulk separation test and then a produced water test, to investigate the effect each EOR method has on specific produced water treatment technologies.

Phase one of the project, due for completion in October, will focus on a technique called polymer flooding.

Adding polymer to water makes it thicker, which helps to force more oil towards the wellhead, but the resultant produced water is a main cause of separation difficulties.

Opus’s director of strategic operations, Glen McLellan, said: “The partners will enjoy a number of benefits, including access to a shared database of results from the work, which will provide recommended mitigation methods and technologies to treat the polymer flood produced water. We look forward to playing a key role in enhancing the performances of the industry’s producing assets.”

Other EOR techniques include carbon dioxide injection, where the gas can be pumped in to help the displacement of oil.

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