在线PY-GC分析技术在气源岩评价中的应用  

Application of on line pyrolysis-gas chromatography technique to evaluationof gas source rock

作　　者：贾蓉芬[1] 邵敏[1] 刘德汉[1] 

机构地区：[1]中国科学院广州地球化学研究所,广东广州510640

出　　处：《地球化学》2001年第6期592-598,共7页Geochimica

基　　金：国家油气攻关项目(99-110-01-01-02)

摘　　要：为了研究高演化地区气源岩的生气特征与生气潜力,分别采用热解温度为560℃不加内标、CDS2000热解系统,700℃加内标(聚苯乙烯)、由实验室自制热解系统的在线热解气相色谱分析技术,对不同气源岩(代表性的煤、固体沥青及四川地区以下古生界碎屑岩为主的全岩)进行5s的快速热解分折。在对实验系统加内标定量的可行性进行了认真研究后,提出了产烃定量公式。560℃的热解谱图可清楚地将烃源岩分为生油、生气和生凝析油三种类型,并可根据谱图计算出油气比(GOGI)。根据700℃加内标的热解测试结果,计算了气源岩的热解烃总量和C1-5-C5-15-C15+组分的相对含量。热解烃总量随热演变程度增高而递减,其中以碎屑岩的热解烃量减低最快。相同样品的热解烃量与TOC和Rock-Eval测定结果具有很好的可比性。对比不同演化阶段热解产物的相对组成,显示低演化阶段的烃源岩热解产物以C1-5组分为主。由此表明,在高演化阶段,好的油源岩就是好的气源岩。较高演化阶段(测试前Ro为2.5%～4.2%)烃源岩的热解烃中C5-15含量呈增加趋势,这一结果与前人资料吻合,它除了表明C5-15组分的含量可能与烃存在的载体,如无机矿物或固体有机质对早期轻烃的包裹与吸附有关外,可能还揭示了有机质在石墨化过程中高演化阶段有着与低演化阶段不同的特性。固体?To understand the characteristics of gas source rocks and potentiality of gas produced in the area of high evolution of organic matter, two methods(without and with internal standard) are adopted in different PY GC systems. In the first method, 560 ℃PY GC is in CDS2000 PY system, which is linked toGC PE9000 with column of HP 5 (30 m×0.32 mm×0.25 μm); in the second method, internal standard, polystyrene, is added, and 700 ℃PY system is also linked to GC PE9000 with column of ultra2 (25 m×0.32 mm×0.52 μm) and have 2 m prepared column. Both of the data are processed on a 586 computer with GC work center CDMC 21 software, which needs the response values in the range of 0～1 000. Feasibility of quantitative determination in the analysis system is based on the fact that linear relations between the response values and the different concentration of internal standard at the same temperature, and between the response values and different temperatures in the same concentration of internal standard. Internal standard polystyrene has 3 group peaks at 700 ℃in PY GC chromatogram, and the third peak (P3) is the biggest main peak. The ratio of the area of P3 and the sum area of the 7 peaks is 74.13%based on 5 times measured at the same condition. The formula for determining the amount of hydrocarbon (HC) pyrolyzed is presented:{[Ps(sample)-Ps(standard)]/M(sample)}×[M(standard)/Ps(standard)]×K,Where M(sample) is mass of the sample (in g), and M(standard) is mass of the internal standard (in mg), K=0.74. Gas source rocks analyzed include typical coal, solid bitumen and clastic rock collected from different places and mainly from Lower Paleozoic strata in Sichuan Province. Based on the chromatogram of PY GC at 560 ℃, the source rock could be divided clearly into 3 types (oil generated, condensate oil generated and gas generated), and the ratio of gas/oil(GOGI) could be calculated. Based on the results of PY GC at 700 ℃, the total HC amount, and the relative content of C1-5, C5-15, and C15+of each sourc

关 键 词：热解-气相色谱技术 气源岩 内标法 高演化地区 固体沥青 

分 类 号：P618.110.8[天文地球—矿床学]