"The techniques add value to the large data sets used to select drill targets by providing information about oil migration and the stepwise filling of reservoirs,” Eadington said.

“Innovative applications of microscopy, geochemistry and spectroscopy have led to a suite of fluid history analysis techniques that reveal the geochemical evolution and flow history of hydrocarbons in sedimentary basins, from generation in deeply buried organic matter to present-day petroleum accumulations.”

The techniques are used to investigate fluid flow, reservoir diagenesis and hydrocarbon entrapment history. This leads to a significantly better understanding of hydrocarbon prospectivity in sedimentary basins, and helps determine detailed time aspects in the fill history of the reservoirs to understand fluid continuity as part of production planning.

They were devised in response to discussions and suggestions from geoscientists and executives in oil exploration companies. The techniques are now being widely used in Australia and the South East Asian region and are being licensed to international oil companies.

The FHA team was awarded a CSIRO medal for research excellence. In an organisation with 19 diverse research divisions spanning a range of scientific disciplines, this is the second consecutive year and third since 2001 that Petroleum Resources has been awarded a medal.

The Fluid History techniques are also used in well evaluation where difficult drill hole conditions or a high oil concentration in drilling operations limit conventional testing, according to Eadington.

“Evidence that oil accumulated in a subject reservoir indicates that nearby reservoirs are likely to also have had oil accumulation,” he says.

“When the reason for lack of preservation of oil is identified and correlated to the large amount of data acquired about prospective reservoirs, then a work program can be instigated to exclude nearby prospects sharing the unfavourable characteristics from future drill targets, reducing the risk of drilling unproductive wells.”

By combining various, novel techniques were devised that use the presence of oil trapped within reservoir grains to locate palaeo-oil zones with reliability and precision that had not been possible before.

“The techniques devised by CSIRO use samples of oil preserved within mineral grains that are retained when the reservoir fluid changes to gas or water and that are not visible at the well site,” Eadington says.

“They are investigated in the laboratory using microscopy, spectroscopy and geochemistry.”

This is important information to constrain petroleum systems, particularly the time aspect, the attributes of the palaeo-oil (eg API gravity), and the age and nature of the source rocks. This information is obtained by extracting from the reservoir grains oil samples that have been preserved for millions of years.

There is now ongoing research to increase the level of detail that can be extracted using Fluid History techniques to investigate features such as reservoir fluid properties and fluid compartments in reservoirs.