【摘要】 鄂尔多斯盆地上三叠统延长组长7段富有机质页岩是这一区域页岩油、致密油的主要烃源岩,其生排烃特征是石油勘探开发的关键问题。采取鄂尔多斯盆地西南缘三叠系延长组长7段低熟(R_o=0.55%)页岩岩心样品(TOC=3.59%),设置不同模拟温度(300～570℃),开展原岩岩心柱状样品的半封闭体系生排烃模拟实验,获得了不同成熟度梯度的页岩模拟样品残余及排出烃类。利用低熟煤样标定各模拟温度点的成熟度(0.60%<R_o<3.95%),模拟前后的页岩样品均进行质量称重、总有机碳(TOC)分析、岩石热解(Rock-Eval)分析、溶剂抽提及排烃定量分析。结果表明:随模拟实验温度增加,页岩的质量损失率及排水率逐渐增加。页岩生油过程主要发生在400℃以前,残留烃(二氯甲烷–甲醇混合溶剂抽提物)、残留可动烃(正已烷抽提物)及排出液态组分(液态烃和沥青质)高峰均出现在340～360℃(0.78<R_o<0.92%)之间,并且在420℃以前达到排出液态组分的极值,最高可达255.58 mg/g(每克TOC中的生成量)。在半封闭体系下,页岩可排出液态组分总量最高可占到原始样品生烃潜量的44%。更多还原

【Abstract】 Triassic Chang 7 Member(Chang 7) shale is the predominant source rock of shale oil and tight oil in the Ordos Basin, and evaluation of the hydrocarbon generation and expulsion capacity of the source rocks have great significance. Plugs of low maturated Chang 7 shale in the southwest margin of the Ordos Basin were adopted for semi-closed heat simulation experiments between 300 and 570 ℃. A series of post-simulation residues at different temperatures were acquired for weighing, geochemical analysis, and solvent extraction. Furthermore, the expelled hydrocarbons were collected for quantitative analysis. The results showed that weight loss and water expulsion ratios increased with increasing temperature. Oil generation and expulsion were completed before 400 ℃, and the quantity of residue, mobile, and expelled hydrocarbons reached their maximum values at 340 to 360 ℃(0.78%<R_o<0.92%). The total weight of expelled hydrocarbon and asphaltene reached its maximum value of 255.58 mg/g before 420 ℃. These results indicated that approximately 44% of the initial oil potential might be expelled out of the shale as liquid hydrocarbon and bitumens.更多还原