Abstract:

The fracture-vug type carbonate reservoir bed is strongly heterogeneous. Hydrocarbon accumulation and enrichment in such reservoirs is extremely complicated, so it is very important for further exploration and effective development of carbonate reservoir to fully understand its formation conditions and distribution characteristics. Through statistical analysis of eastern well-block, oil-gas properties of the target bed are closely related to the Tazhong No.1 fault zone and strike-slip faults. Oil and gas of Yingshan Formation in the eastern part of northern slope, Tazhong Low Rise are characterized by “gas in the east, oil in the west, gas in the exterior, oil in the interior” on the plane, and accumulate within 200 m under unconformity in “quasi layer” distribution along weathering crust in the vertical direction. In this paper hydrocarbon accumulation controlling factors were studied from the angle of play elements, such as source, storage, cover, transport and so on, and the results showed that two sets of source rocks which experienced multi-filling and provided supply for oil and gas accumulation developed in the study area. Later structural uplift and fault activities which promoted karstification, improved reservoir bed quality and provided favorable places for hydrocarbon enrichment. Widely distributed, thick compact limestone of Lianglitage third to fifth members effectively sealed oil and gas and provided good preservation conditions for oil and gas accumulation. The faults and unconformity surface of the eastern part of northern slope, Tazhong Low Rise is the key to oil and gas accumulation, source rocks and reservoirs communication.

Key words: oil-gas distribution, play element,  , fracture-vug type carbonate reservoir bed, Yingshan Formation, the eastern of northern slope, Tazhong Low Rise