Abstract: Early Paleogene-Neogene of the Dafeng-Xinghua region has been affected by extensional strike-slip, presenting a structural framework of òearly fault depression and late sagó. Research shows that hydrocarbon accumulation in the region has the laws as follows: the reservoir distribution is controlled by the hydrocarbon-generating center, the scale of reservoirs is determined by the size of sags, to discover good sand bodies is very important because the oil bearing series is single and the individual reservoir is thin and changes fast horizontally, the large fault leading to deep sags is critical to oil and gas migration and now oil reservoirs are located in the vicinity of the large fault. In addition, the activity of most reservoirs with the characteristics of lateral sealing has ceased before source rocks get mature. Structural traps are favorable oil and gas accumulation zones, so structural reservoirs and structural-lithologic reservoirs generated from small complex faults are the main types. Taken together, the main idea of "to discover oil in traps in oilrich sand bodies based on faults" is put forward.

Key words: fault, trap, source rocks, structural reservoir, structural-lithologic reservoir, Dafeng-Xinghua region