Gas entrapment in the Elmworth deep basin occurs under a variety of conditions. Typical trap types include (1) stratigraphic, (2) structural-stratigraphic, and (3) deep basin. The deep basin type of gas trap is the most important in terms of its large size and unconventional trapping conditions. The three main physical conditions associated with the deep basin type of gas trap are (1) an updip water/gas contact, (2) a downdip gas/water contact is generally absent, and (3) the original reservoir gas pressures are equal to, or less than, water pressures at the same depth based on extrapolation of water pressure gradients from the updip water saturated region.

The physical principles underlying this kind of gas entrapment, together with the intimate association of mature source rocks, constitute a fundamental relationship which is applicable to gas exploration in other sedimentary basins of the world.

End_of_Article - Last_Page 572------------