Abstract: Kongnan area is one of major targets for oil?gas exploration in buried hill reservoir of Huanghua depression in Bohai Bay basin,in which commercial oil flow is found in its Ordovician carbonate rocks and Permian clastic rocks. This paper studies the petroleum geological conditions, hydrocarbon accumulation control factor and enrichment pattern in the Permian clastic reservoir using hydrocarbon accumulation theory and geophysical prospecting technologies, and suggests that there exist two types of fault?block anticline?like and thrus?nappe anticline?like buried hill traps of Permian in this area; the regional compression in Indosinian movement epoch and the tensional and fault?block processes since Yanshan movement laid the foundation of the formation of buried hill reservoirs; the deep and large fault system, inner buried hill highs, fractured sand bodies and stable cap rocks control the oil?gas migration and enrichment in buried hill reservoirs, and forming the favorable reservoir combination. So Kongnan area has favorable conditions for forming large?scale oil and gas field