ABSTRACT: Applications of oil fingerprinting on Barrow Island, Carnarvon Basin, Australia
Minifie, Sandra A, Paul A Clark, and Andrew Pitchford , West Australian Petroleum Pty Ltd, Perth, Western Australia, Australia
Barrow Island is the largest oil field in the Carnarvon Basin and has produced to date in excess of 275 million barrels of oil. Hydrocarbons are contained in over thirty separate accumulations, in nine reservoir levels ranging in age from the Jurassic to Late Cretaceous. A suite of peak height ratios from whole oil gas chromatography was chosen to show the maximum difference between the oils. Each of the reservoirs has a unique oil fingerprint, which can be illustrated and compared using star diagrams.
The ability to identify the production reservoir has been instrumental in the discovery of additional Barrow Island oil reserves. Oil fingerprinting highlighted an anomaly between the oil and generic fingerprints for the interval perforated in well B28. The integration of reservoir geochemistry and geological modelling focussed the drilling programme and a new oil discovery was made in the adjoining fault block.
The oil fingerprinting technique was also used to assess the lateral continuity of the Tunney reservoir. These sands are generally beyond the resolution of seismic mapping. Oil fingerprinting determined the sealing properties of the fault between the new discovery well, Z56M, and the main Tunney Field. Statistical differences in the individual oil fingerprints were greater than laboratory error margins and proved the oils analysed were produced from non-communicating reservoirs.
Oil fingerprinting is an economic and reliable tool that can determine from which reservoir oil has been produced and whether individual wells are in communication. It is a valuable tool in the exploration, development and production of Barrow Island oil.
AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia