245 m thick bioherm (atoll structure).
best reservoir quality in organic facies of reef margin.

Massive stromatoporoids, tabulate corals, rugose corals, Stachyodes, Amphipora, brachiopods, crinoids.

Reef: Massiv stromatoporoids
Reef flat: Skeletal rudstone
Interior: Amphipora beds

7 % avg. porosity.