PESA WA: November Technical Evening Presentation: Andres Gongora

The Jurassic Cattamarra Coal Measures of the central Perth Basin near Gingin have long looked like an ugly duckling. In the Beermullah segment the Jurassic succession differs from the northern Perth Basin area as it is thicker and has markedly distinct reservoir sequences interbedded with claystone dominated sequences. The reservoirs are relatively thin, low-connectivity fluvial channel belts that prograde towards marine conditions at the top of the Cadda Formation. The base of the Lower Cattamarra, the J20, is claystone-dominated. The Beermullah area has also undergone episodes of compression, which have compartmentalised the structures. Together, these factors have made hydrocarbon shows localised and hard to predict.

This talk presents ongoing work to change that picture. Interpretation of 2D and 3D seismic, petrophysics and subsurface geology are being combined with HyLogger mineralogy and elemental characterisation to classify and correlate channel sequences. The J30D interval now appears to be the most significant channel-belt feature. Hydrocarbon shows in the Lower Cattamarra (J20) add further exploration potential. Historical gas and condensate production shows a petroleum system that works.