The study of the oil and gas controlled by faults in Yong 8 Area.

Block Yong 8 is an area with high exploring risk. Although the exploring has succeeded in this area since 1998, the oil and gas distribution law is not very clear. By using the theory of fault sealing property the author has studied the fault sealing properties of two group fault systems which intersect vertically each other in this area from the two respects of fault mechanics and the relationship of lithology juxtaposition. Although the two fault systems' fault sealing mechanisms are different, they have the good fault sealing properties identically. So the difference of oil and gas distribution in Block Yong 106 and the main Block Yong 8 lies on ability of the southern east-west striking fault in migrating oil. The oil migrating layer in Yong 106 fault-block's direction of downdip is offset by the fault, so the oil is poor in this fault-block. And the Yong 8 main fault-block has a smooth migrating layer in the direction of downdip so the oil is very rich is this fault-block.