准噶尔盆地乌伦古坳陷三叠系有机地球化学特征与生烃潜力研究

Organic Geochemistry and Hydrocarbon Generation Potential of the Triassic Source Rocks in the Wulungu Depression of the Northeastern Junggar Basin

准噶尔盆地东北部乌伦古坳陷是该盆地当前油气勘探和研究程度最低的地区之一,为给下步勘探部署提供参考信息,并给国内外其他地区的三叠系烃源岩研究类比参考,针对坳陷内广泛发育的三叠系潜在烃源岩,首次系统报道了其有机地球化学特征,并着重从有机质丰度、类型、成熟度并结合地质背景讨论了生烃潜力。结果表明,三叠系暗色泥岩沉积中心位于凹陷东南部伦参1井一带,有机质丰度较高,总体可达中等质量,有机质类型以II2和III型为主,低成熟-成熟演化,因而具有一定生烃,特别是生气潜力。东南部凹陷区伦参1井一带属于相对优质的烃源岩发育区,值得在下一步勘探中加以重视。

The Wulungu Depression of the northeastern Junggar Basin is one of the areas in the basin with extremely low exploration degree. In order to provide new information for future regional exploration strategy and the study of Triassic source rocks else where, we investigated organic geochemistry and hydrocarbon generation potential of the widely-developed the Triassic source rock, which is one of the potential source rocks in the depression. Basic geo- chemical characteristics of the strata were reported for the first time, including abundance, type and maturity of or ganic matter. They, in combination with geological setting, indicate a discussion on hydrocarbon generation poten- tial. It is revealed that the depositaionl center of the Triassic dark mudstones is located in the southeastern depres- sion, i.e. , the belt around well Luncan 1. The mudstones develop relatively high organic matter abundance, reaching medium quality in general. The organic matter kerogen type is characterized by Ⅱ2 and Ⅲ. Maturity of organic matter is lowly mature to mature. Thus, we concluded that the mudstones have a certain hydrocarbon （gas in parti- cular） generation potential. The southeastern depression surrounding well Luncan 1 develops relatively high-quality source rocks. The area is worthy of paying attention in the next step exploration.