Analysis Of Three - Dimensional Structure Of Kenli Block

Kenli block was located in the Laizhou Bay depression of the south of the Bohai Sea. As the Cenozoic depression, the Laizhou Bay depression was developed on the Mesozoic basement with the Tanlu strike slip fault extending from the east to west. In recent years, hundred million tons of oil was discovered in the area. Previous study shows that these oil are shallowly buried with high abundance and big capacity. However, due to the complexity hydrocarbon accumulation characteristics, the area is still a low exploration one.In this paper, based on previous studies and offshore oil exploration characteristics, we make the seismic profiles interpretation, geological section balancing,3D structural modeling and restoration, of the Kenli Block by using the modern tectonics theory and the structural geometric analysis method. Then, potential fractures are forecasted on the basis of the three-dimensional structural restoration.Combined with the former geological research on the Laizhou Bay depression, we think the fractures system of the Kenli block was controlled and influenced by the Tanlu strike slip fault. Furthermore, the Laibei fault of the Kenli block was an extensional based fault system, which was derived from the Tanlu strike-slip faults, with small strike-slip component.The balance restoration of6regional seismic interpretation profiles in the Kenli block shows that faulting of the Kenli block began from the Kongdian formation deposition, but the intense faulting initiated during the third paragraph of Shahejie formation deposition and induced secondary inherited fault system with reverse direction in the entire work area.The Kenli block deformation was mainly affected by the Laibei fault (level one fracture). We think that the level one fractures can derive a number of reverse secondary faults (level two fracture), the level two fracture also can derive a number of reverse secondary faults (level three fracture), and so on. And all of these derived fractures make up a good conjugate fault system with structural inherited relationship.The three-dimensional structure restoration shows the level one and the level two potential fractures were mainly distributed in the northern and western of fault block near the secondary fractures. The level one potential fractures has a NE trend, so do the level two potential fractures. Furthermore, we find out that the level three and the level four potential fractures were mainly distributed around the level one and the level two potential fractures with mostly oblique or parallel direction. We consider that the potential fractures distributed near the level one and the level two potential fractures are concentrated and intense, and they are the favorable exploration area.