ABSTRACT: Application of Seal Properties to Exploration and Development Part II: Examples from the Permian and Canning Basins

WEEDEN, ROBERT, Western Mining Corporation, Limited, Houston, TX

Seals from the Canning Basin, Western Australia and the Permian Basin, Texas, were injected with mercury under high pressure to give capillary pressure curves. Five categories of seal lithology types, rated A to E (excellent to poor), were defined to determine sealing capacity. Where capillary pressure curves are not available, seal quality is determined by visual comparison with known seal types.

In parts of the Permian Basin, oil columns of only 10 m or less occur in individual reservoirs capped by "A" class seals. A decrease in seal quality off structure and changes in structural dip explain the observed oil columns.

In the Canning Basin core data near the structurally high relief "X" Prospect show "D-E" class seals capping the main Tangalgoo Sandstone reservoir. A substantial oil column is required to make the structure economic to drill.

The "Y" Prospect, a carbonate play, with 85 m of structural relief, is capped by an "A" class seal. Potential existed for an additional 200 m of vertical sealing capacity and stratigraphic entrapment outside of structure.

The Ordovician Nita Formation is typically capped by red beds, "D-E" class seals, of the Carribuddy Group. Salt, an "A" class seal in the Carribuddy, occurs approximately 200 m above the top Nita. This suggests high structural relief traps might hold sufficient hydrocarbons to justify drilling. However, reconnaissance seismic indicates only low relief structures.

AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)