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当阳复向斜上组合存在志留系、二叠系及下三叠统三套烃源层,以碳酸盐岩及泥质岩为主。以志留系底部厚约50m的黑色页岩生油条件最好,在王家湾剖面有机碳含量平均达3.77%;次为二叠系碳酸盐岩,全区有机碳平均含量为0.36%。干酪根碳同位素特征和扫描电镜特征均显示该区烃源岩母质类型主要为I型和Ⅱ型。有机质热演化程度普遍较高,应以天然气勘探为主。利用“二维源岩评价系统”软件进行了盆地模拟,三套烃源层的累积生烃强度为56.89×10~8m~3/km~2。总体分析,当阳复向斜烃源岩厚度大,生烃量大,具备寻找大、中型气藏的气源条件。推测上组合有两个含油气系统:早期成藏含油气系统,关键时刻为早燕山末期,气源充足,但保存条件相对较差;晚期成藏含油气系统,关键时刻为喜马拉雅末期,保存条件好,但气源不足。研究重点应以早期成藏含油气系统为主。
There are three hydrocarbon source rocks of Silurian, Permian and Lower Triassic in the combination of Dangyang synclinorium, mainly composed of carbonate rocks and argillaceous rocks. The black shale with the thickness of about 50m at the bottom of Silurian was the best oil producing condition. The average organic carbon content in Wangjiawan section was 3.77%. The second was Permian carbonate rock. The average organic carbon content in the whole area was 0.36%. The carbon isotopic characteristics of kerogen and the features of scanning electron microscopy indicate that the parent rock types are mainly Type I and Type II. The degree of organic matter thermal evolution is generally high, and should be mainly natural gas exploration. The basin simulation was carried out by using the software of “2D source rock evaluation system”. The cumulative hydrocarbon generation intensity of three sets of hydrocarbon source layers was 56.89 × 10 ~ 8m ~ 3 / km ~ 2. The overall analysis shows that when the Yangyang synclinorium source rock has a large thickness and a large amount of hydrocarbon generation, it is necessary to find gas source conditions for large and medium-sized gas reservoirs. It is speculated that there are two hydrocarbon-bearing systems in the upper combination: the early hydrocarbon accumulation in the reservoir, the key time is the end of Early Yanshanian, the source of gas is sufficient, but the storage conditions are relatively poor; late accumulation of hydrocarbon-bearing systems, the key moment is Himalayan end, Good, but not enough air. Research should focus on early hydrocarbon accumulation in the reservoir system.