摘要
Chagan Sag has the most potential of oil and gas exploration in Yingen-Ejinaqi Basin.The geothermal gradient distribution map was drawn by calculating the present geothermal gradients of 9 wells and the terrestrial heat flow value was estimated.The results show that Chagan Sag has the characteristics of middle temperature field in the stable area,with an average thermal gradient value of 3.36 °C/100 m and an average terrestrial heat flow value of 54.04 mW/m2.The geothermal gradient distribution generally shows the highest value in the Maodun Subsag,the middle value in the eastern subsag and the lowest value in the western subsag.The geothermal gradient distribution is not only associated with the basement depth,but also associated with the thermal refraction effects between the huge sedimentary cover in the sags and the uplifts around the sags.In addition,the maturity of source rock is controlled by paleotemperature.This study can provide the geothermal data for evaluating the hydrocarbon generation of source rock in Chagan Sag and other sags in Yingen-Ejinaqi Basin.