长岭断陷火石岭组烃源岩特征及勘探远景分析

Source rock features and exploration potential of Huoshiling Formation,Changling Fault Depression

长岭断陷层油源对比研究表明,登娄库组、火石岭组地层中发现多套来自火石岭组烃源岩的油层。地化指标显示,火石岭组烃源岩有机质丰度较好,干酪根类型以Ⅱ型为主,成熟度演化处于生气的高—过成熟阶段,综合评价属中等烃源岩;平面上主要分布在前七号、北正镇和流水镇等局部地区,且厚度较大。其在沙河子组沉积时期(约140Ma)进入生烃门限,开始持续生烃,并在登娄库组沉积末期达到生烃高峰,至嫩江组沉积早期(约80Ma)全面进入成熟门限,之后生烃能力逐渐下降。盆地模拟计算火石岭组累积生烃量为224.46×108t,其资源贡献占整个长岭断陷层资源量的31.96%,资源贡献值仅次于沙河子组而大于营城组,具有良好的资源前景和勘探潜力。

The correlation of oil and source in the Changling Fault Depression has indicated that several oil reservoirs originated from Huoshiling Formation are preserved in Denglouku and Huoshiling Formations.Geochemical parameters have proved that the source rocks in Huoshiling Formation are relatively rich in organic matter.Kerogen is type II.Maturity evolution is during the high and over-mature stages,generating gas.The source rocks in Huoshiling Formation are evaluated as moderate ones,and mainly locate in Qianqihao,Beizheng and Liushui regions with big thickness.During Shahezi period（about 140 Ma）,the source rocks in Huoshiling Formation began to generate hydrocarbon and reached the peak at the end of Denglouku period.They completely entered into mature threshold at the early Nenjiang period（about 80 Ma） and then decreased.Based on basin simulation,the accumulated hydrocarbon yield from Huoshiling Formation is 224.46×108 t,accounting for 31.96% of resource amount in the Changling Fault Depression.The contribution of Huoshiling Formation is less than Shahezi Formation and more than Yingcheng Formation,indicating good potential for exploration.