Abstract:

Reef-bank reservoir in Ordovician has been discovered in several areas, Tarim Basin- Crop, core, thin section and test data indicate that the bank face always accompanies with reef face. Platform edge can be divided into four types according to the lithologic characteristic of bank face, including low energy environment, relatively low energy environment, relatively low energy environment and high energy environment. Framework reef, bafflereef and lime mud mound represent the environment energy decreasing. Data shows that original reef-bank reservoirs reveal low porosity and permeability and reservoir space is dominated by cavity-fractured type, followed by cavity-freckle type, cavern type, freckle type and complex type. The development of reef-bank reservoirs is controlled by Palaeogeomorphology and structure while high quality reservoirs determined by karstification and clastation.

Key words: reef-bank reservoir, diagenesis, Ordovician, Tarim Basin