I have just finished reading a document from Research News dated Feb 2001. Whilst dated, I feel it is still relevant today. A fair bit of it may go over your heads but it may answer some questions that people have raised and get this forum back on track with informative articles that assist our trading decisions.
Below is an excerpt with the link to the original document down the bottom:
Implications for Exploration This study identified numerous oil families and petroleum systems in Perth Basin. It also positively identified, for the first time, both Permian and Triassic sources for gas in Perth Basin. The Early Triassic Kockatea Shale is the principal source for oil, and it is of the highest quality in the onshore Northern Perth Basin. Carbon isotopic evidence for gas indicates that the Kockatea Shale is also the major source for gas onshore. Gas generation should still have occurred offshore, even though the Kockatea Shale has diminished potential for oil.24 The Permian, and to a lesser extent, Jurassic sediments are also gas sources in Perth Basin. The existence of leaky Permian seals for gas leads to a large scale ‘gas flush’ in the subsurface, compounding the widespread gasstripping of oil in Perth Basin.17 However, this re-mobilisation of hydrocarbons should result in longrange migration and a mechanism for emplacement of petroleum higher in the section. In summary, the identification of Permian and Triassic sources for gas in the onshore Perth Basin, coupled with recognised oil and gas potential in the Mesozoic sediments offshore,25 highlight the potential for multiple petroleum systems active in the region and points to new exploration opportunities.