松辽盆地松科1井青山口组沉积有机质特征及生烃潜力  

Sedimentary organic matter characteristics and hydrocarbon potential of Qingshankou Formation of SK-1 drilling from Songliao basin

作　　者：钟艳飞[1,2] 郭江涛[1,2] 王丽[1,2] 宋之光[1] 

机构地区：[1]中国科学院广州地球化学研究所有机地球化学国家重点实验室,广东广州510640 [2]中国科学院研究生院,北京100049

出　　处：《地球化学》2009年第5期487-497,共11页Geochimica

基　　金：国家重点基础研究发展计划项目(2006CB701404)

摘　　要：对松辽盆地陆相白垩系科学钻孔松科1井青山口组连续取芯剖面开展了一系列有机地球化学分析,从有机质丰度、烃类组成、萜类生物标志物及岩石热解参数等方面对该层段沉积有机质组成分布特征和生烃潜力进行了系统研究。结果显示,松辽盆地青山口组有机质类型、丰度组成具有明显的阶段性分布;松科1井所在区域的青一段和青二三段底部总厚153.64m的沉积层段有机质丰度高,有机碳含量在2.32%～5.24%之间,有机质类型以腐泥质Ⅰ型为主,IH指数在355～594mg/g之间,生烃潜力指数在11.8～27.0mg/g之间,是具有极高生烃潜力的优质烃源岩;青二三段中上部有机碳含量相对较低,岩石热解参数显示有机质类型以Ⅱ-Ⅲ型为主,其中顶部以Ⅲ型为主,中部以Ⅱ型为主;综合生烃潜力指数表明青二三段中下部仍具有一定的生烃潜力,属于中等至良好烃源岩。TOC与IH相关性显示有机质特征在剖面上的阶段性变化可能主要受原始有机质埋藏保存条件的控制,即在沉积环境条件不利于有机质埋葬保存时,有机质被大量氧化分解,造成有机质丰度降低、有机质类型变差;而当水体沉积环境有利于有机质埋藏保存时,大量有机质的堆积保存导致优质烃源岩的形成。要强调指出的是,松科1井所在区域青二三段底部厚达80m富有机质沉积是与青一段性质、厚度相当的优质富有机质烃源岩,应作为松辽盆地扩大油气资源潜力的重点勘探评价方向予以重视。A continuous profile of core samples from the Qingshankou Formation of Songliao basin, obtained from the Chinese Cretaceous Terrestrial Scientific Drilling, SK-1, has been investigated in terms of the abundance of organic matter, hydrocarbon composition and distribution, the terpane biomarkers and pyrolysis data, aiming to characterize the organic matter in the source rocks and their petroleum hydrocarbon potentials. The results show that the abundance of organic matter displays a periodical variation on the profile which implies a similar variation in palaeoclimate and sedimentary environments. The source rocks of member 1 and the low part of member 2 ＋ 3 of Qingshankou Formation that extended a thickness of 153.64 meters are organic matter rich source rocks with a total organic carbon （TOC） of 2.32% to 5.24%, and the soluble organic matter （SOM） of 0. 76% - 1.7%. The organic matters are dominated by Type I as their hydrogen index （IH） ranged from 355 mg/g to 594 mg/g, and hydrocarbon potential index from 11.8 to 27.0 mg/g. Therefore, the member 1 and the low part of member 2 ＋ 3 are classified as excellent source rocks with very high hydrocarbon potential. The middle and upper parts of member 2 ＋ 3 show much lower content of TOC and the Rock-Eval data suggest that organic matter are dominated by Type Ⅱ and Type Ⅲ, respectively. Multiindex suggest that the low middle part of member 2 ＋ 3 shows a certain level of hydrocarbon potential and could be qualified as medium to fairly good source rocks. The correlation of TOC vs In suggests that the abundance and type of organic matter were likely controlled by the burial and preservation condition of original sedimentary environments, i.e. when the conditions were in favor of organic matter preservation, sediments with a high abundance and type I organic matter were deposited, while when the conditions were against the preservation of organic matter, sediments with lower contents and Type Ⅲ organic matter would be formed. It is worthwhile to em

关 键 词：烃源岩 有机质丰度 烃类组成 热解特征 青山口组 松辽盆地 

分 类 号：P593[天文地球—地球化学]