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利用裂变径迹分析方法测量了取自花海拗陷的钻井磷灰石样品的裂变径迹年龄和长度。结果表明,随井深增加年龄减小,平均径迹长度亦变短。取自白垩纪地层的磷灰石样品的裂变径迹年龄都比地层年龄年轻得多,表明沉积后曾长时间处于磷灰石裂变径迹退火带中,沉积前的径迹记录已部分消失,古地温高于今地温。利用蒙特卡罗随机取样的热史模拟方法对裂变径迹数据进行了分析,结果表明白垩纪地层沉积后曾经历过超过110 ℃的加热,达到最高古地温的地质时代是早白垩世晚期—晚白垩世末,为主要生烃期。新生代以来盆地变冷,生油岩的成熟度主要受古地温控制。在此基础上对该盆地的油气勘探方向进行了评价。
Fission track analysis was used to measure the fission track age and length of the apatite samples taken from the Huahai depression. The results show that as the well depth increases, the average track length also decreases. Apatite samples taken from the Cretaceous stratum have fission track age much younger than the stratigraphic age, indicating that they were in the apatite fission track annealing zone for a long time after deposition, and the track records before deposition have partially disappeared, Ancient geothermal temperature is higher than today. The fission track data were analyzed by Monte Carlo random thermal history simulation. The results show that the Cretaceous strata experienced more than 110 ℃ of heating after deposition, and reached the highest paleolage temperature in the late Early Cretaceous - late Late Cretaceous, as the main period of hydrocarbon generation. Since the Cenozoic, the basin cooled, and the maturity of the source rock is mainly controlled by paleo-geothermal temperature. On this basis, the direction of oil and gas exploration in this basin was evaluated.