age indicated as early late Ordovician.
Corals, stromatoporoids, solenoporaceans and calcimicrobes as reef builders.
Largest oil field in China. oil in reef-flat and grainstones.
Reef facies in well Tazhong-30: Reef mounds are coral framestones coral bafflestones in 10-20 m thick horizons. Mud mounds are up to 30 m thick.