Abstract: Tengge 'er formation in Erlian basin is of higher geothermal gradient on the whole, but at shallow and deep strata of the basin, it is rel-atively low. In plane, such a lower paleogeothermal gradient occurs in the center of the sag or source area, while higher one in the uplift or slope area. Also, the paleotemperature is higher than the present temperature; in different sags, there exist different characteristics of geothermal field-dependent geothermal anomalies; the depth of oil threshold is becoming shallower gradually from the sag center toward the sag edges. The for-mation pressure coefficients are measured to be less than 1.0, showing its abnormally low pressure system. In different sags, somewhat different abnormally low pressure occurs in different depths, for instance, the shallowest is in Anan sag, the deepest in W uliyastai sag. Vertically, individ-ual geotherm-geopressure system appears for different sags; laterally, normal temperature and normal pressure distribute broadly. According to the fluid dynamic characteristics in this area, the petroleum migration direction and accumulation locat ion could be determined,showing that the reservoirs will mainly be found in fault terrace belt and structural belt with relatively low energy.

Key words: Erlian basin, formation temperature, abnormally low pressure, geothermal anomaly, geotherm-geopressure system