四川盆地东北地区古地温梯度一直缺乏研究.以普光气田已有的实测反射率数据为依据,应用EasyR.模拟计算方法,研究了该区主要生烃期的古地温梯度.结果表明,对川东北地区主要埋藏与生烃期(三叠纪-早白垩世)进行的成熟度模拟计算,应用古地温梯度为3.0℃/100m的古地温模式计算所得的结果与实测结果非常吻合.进一步提出了该区的简化古地温模式为[3.0℃/100m(>96Ma)-2.8℃/100m(65Ma)-2.2℃/100m(0Ma)].

Few researches of paleogeothermal gradients in the northeastern area of Sichuan Basin has been reported. The paleogeothermal gradients during the key period of hydrocarbon maturation were investigated by EasyRo modeling in the light of the available measured reflectance data of well samples from Puguang Gas Field in this area. The result shows that among four modeled REasy values, the one that modeled with 3.0℃/100m of paleogeothermal gradient during the Triassic-Early Cretaceous period may match well with its measured Ro and Rb values. Therefore, a simplified model of paleogeothermal gradient, i. e. 3.0℃/100m (＞96Ma)-2.8℃/100m (65Ma)-2.2℃/100 m (0Ma), was suggested for the northeastern part of Sichuan Basin. It was believed that this model can give a good explanation for the geochemical characteristics of natural gas in this area.