In this paper

theoretical calculations of the geothermal data on 55 wellsin the Dongtai depression are made.The results obtained are identicalto those obtained from measurements of the organic geochemical evolution.It has been established that the range of the threshold temperatures for oilgeneration in the area is between 90—166℃(i.e.mature sphere)

and found that the distribution of the oil-gas fields in the area is closely relatedto the anomalous area with geothermal gradients ranging from 3.5-4.0℃per 100M.This shows that the anomalous area is the most favourable areafor oil-gas concentration.The threshold oil-generating depths calculated from the above-mentioned threshold oil-generating temperatures in the area are between 2000 and 4000 M.The prediction and evaluation of the oil-gas prospects in the area showthat there seem to be still considerable potential oil and gas within thethreshold depths in the area that have not been struck by drill holes and that large amounts of condensing oil and gas below the threshold depthremain to be discovered.