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在西宁盆地下侏罗统发现了一套湖沼相烃源岩。为了研究该套烃源岩的生烃潜力和赋存页岩油气的可能性,在大茶石浪下侏罗统剖面系统地采集了有机地球化学样品,完成了湖相暗色泥岩和高位沼泽炭质泥岩有机质丰度、类型和成熟度的测试和研究。结果表明,西宁盆地下侏罗统暗色泥岩有机质丰度较高,属于中等偏好的烃源岩,炭质泥岩有机质丰度属于中等偏差的烃源岩;湖相暗色泥岩和高位沼泽相炭质泥岩有机质类型均以Ⅲ1型为主,生油能力较差,生气能力较好;其镜质组反射率分布在0.7%~0.94%之间,已进入大量生烃的成熟阶段。其地球化学特征和世界上许多页岩油气田的烃源岩有相似之处,据此推测,西宁盆地下侏罗统具有形成常规油气和页岩油气的潜力。
A set of lacustrine facies source rocks have been found in the Lower Jurassic in the Xining basin. In order to study the hydrocarbon generation potential of this set of source rocks and the possibility of occurrence of shale gas, organic geochemical samples were systematically collected from the Lower Jurassic section of the Daqu Dashilang Formation, completing the lacustrine dark mudstone and upper marsh carbon Testing and research on organic matter abundance, type and maturity of mudstone. The results show that the lower Jurassic dark mudstone of Xining Basin is rich in organic matter and belongs to middle-preferred source rock. The organic matter abundance of carbonaceous mudstone belongs to medium-deviation source rock, and the lacustrine dark mudstone and high-marsh facies carbonaceous mudstone The main types of organic matter are Type III1, which have poor oil generation ability and good gas generating ability. The vitrinite reflectance is between 0.7% and 0.94% and has entered into mature stage of large amount of hydrocarbon generation. Its geochemical characteristics are similar to those of many shale oil and gas fields in the world. Based on this, it is presumed that the Lower Jurassic of Xining Basin has the potential to form conventional oil and gas and shale oil and gas.