re: Ann: Senex confirms basin centred gas pla... 101 ... As a rule you want shale formed in marine environments. They tend to produce more oil and liquids, as a rule. The Cooper Basin shales are mostly from non marine (lake) environments, so more plant matter. Most of the best US shales are marine, as is the Canning. The Cooper, being non-marine, tends to produce relatively dry gas often with relatively high CO2 (eg. Beach/Napamerri Trough).