Finding New Oil In Old Ground

The technology, called FAMM (Fluorescence alteration of multiple macerals), is refining the art of oil exploration by determining if minute quantities of plant material have been ‘cooked’ just right by the earth.

Developed by scientists at CSIRO Petroleum, the novel technique is now being used widely by national and international exploration companies and research institutes, says FAMM project manager, Dr Neil Sherwood.

Petroleum is generated when preserved organic material (called macerals) is buried and thermally ‘matured’ by the earth’s internal heat over millions of years.

“The level of heating or thermal maturity is fundamental and critical in assessing an area’s potential for petroleum,” says Dr Sherwood.

Inaccuracies in other techniques used to assess thermal maturity have led to the underestimation of the petroleum potential of many areas.

“The use of FAMM means that areas previously downgraded or ignored because of poor thermal maturity information can now be re-evaluated,” he says.

FAMM was initially developed to identify the maturity of material in sediments of Australia’s North-west Shelf, some of which was considered to have low prospective value. In many cases FAMM found otherwise.

FAMM has now given improved assessments of the petroleum potential of all Australia’s major oil and gas producing areas. These include the Timor Sea region, Victoria’s Gippsland Basin and the Eromanga/Cooper Basin of Central Australia.

“We expect this technology eventually to be used world-wide, as one of the standard techniques used in petroleum exploration. This will place FAMM equipment in many eminent international research labs,” says Dr Sherwood.

The FAMM instrumentation measures fluorescence, following exposure to a laser light. Microscopic samples of organic plant material that have been wedged in between grains of sedimentary rock are exposed to a laser microprobe.

The fluorescence emitted over time from the samples is measured and then used to tell how much the plant matter has been heated by the earth. This then indicates the potential of the material to have produced petroleum.

Different parts of a plant and different plant types give different information when analysed for their thermal maturity.

Unlike other techniques, FAMM is able to measure the fluorescence from specific parts of individual plant types. This eliminates the effects of extraneous plant material that distorts the measurements from many other methods.

A new model is now being developed that will increase the range of sedimentary rocks that can be sampled and allow measurement of thermal maturity over a greater range of temperatures.

More information: Jason.Major@nap.csiro.au