准噶尔盆地准东滴水泉组烃源岩生烃物理模拟研究

Hydrocarbon Generation Simulation of Hydrocarbon Source Rocks in Dishuiquan Formation, East Junggar Basin

准噶尔盆地东部乌伦古坳陷石炭系暗色泥岩的生烃潜力对这一地区开展勘探十分重要。热压模拟生烃实验是评价烃源岩的有效手段,对滴水泉剖面石炭系暗色泥岩进行的生烃模拟表明,模拟温度达到360℃时产油率迅速降低到21.61mg_(烃)/g_(有机碳),其残余生烃能力中等,演化阶段处于生油窗底部;390℃时累计烃类气体产率178.55mL/kg_(岩石),达到较好气源岩标准,气体产物中甲烷体积含量占烃类气体的90％,已进入干气演化阶段;原始生烃能力较大,是准东地区一套有利的烃源岩。模拟气的同位素分析认为属混合偏腐殖型气,对应的有机质类型应该为Ⅱ_2型。

The hydrocarbon potential of the dark mudstones In Wu-lungu Depression is significant for the exploration in East Junggar Basin. In this study one sample from Dishuiquan section is selected for hydrocarbon source rocks evaluation using a series of thermal simulations. As the simulation temperature reached 360 ℃ , the oil generation rate reach 21. 61 mg CH/g rock and shows a sudden decrease. This phenomena indicates that the source rocks locate in the lower part of the oil window with a moderate remnant hydrocarbon potential. As the simulation temperature reached 390℃, the cumulative hydrocarbon gas generation rate amounts to 178.66 ml CH/kg rock, and the total CH4 in the hydrocarbon gas is 90%. These indicate that the source rocks are better for gas generation and reaching the dry gas stage. As the gas products belongs to hu-mic mixing type based on the carbonate isotopes characteristics, we conclude that the source rocks are Ⅱ2, type.