Abstract:

This paper briefly clarifies the basic geological theories of vitrite refle-ctivity（R^o max）and gives a preliminary discussion with R^omax on the con-ditions of oil and gas origin in Taiyuan formation of Carboniferous Sys-tem in northern Ordos Basin.It is suggested that R^omax ranging from 0.5to 1.3% is confirmed as the main stage of oil formation;<0.5%,as im-mature stage;>1.3%,as overmature stage,that is,gas formation stage.The result shows that the organic matter of Otoc County and its south ernregion have reached overmature stage;in its northern region,the Taiyuan formation is just at the main mature stage,but the conditions of conser-vation on both sides of east and west are rather defective,the availableregion is only restricted in a narrow zone in the southern part of the west.Finally,in combination with the geotectonic evolution,sedimentary cha-racteristics and lithofacies of the basin,the districts of oil and gas pot-ential of Taiyuan formation has been divided.