鄂尔多斯盆地西部延长组烃源岩地化特征  

Geochemical characteristics of Yanchang Formation source rocks in the western Ordos Basin

作　　者：谭世豪 王瑞飞[1] TAN Shihao;WANG Ruifei(Collegeof Petroleum Engineering,Xi'an Shiyou University,Xi'an 710065,China)

机构地区：[1]西安石油大学石油工程学院,陕西西安710000

出　　处：《精细石油化工进展》2022年第6期48-52,共5页Advances in Fine Petrochemicals

摘　　要：鄂尔多斯盆地延长组长7段湖盆发育最为成熟,是三叠系油藏主力烃源岩层,页岩油层具有低渗致密、含油性较好、开发潜力大及源岩品质高等特点。以鄂尔多斯盆地西缘姬塬油田为例,通过有机质丰度、有机质类型及有机质成熟度3个方面评价该区烃源岩地化特征。结果表明:姬塬地区总有机碳(TOC)平均含量为6.11%,氯仿沥青“A”平均含量为0.86%,氯仿沥青“A”中总烃(HC)平均值为585.5μg/g,生烃潜量(S_(1)+S_(2))平均值为20.39 mg/g。根据烃源岩有机质丰度评价标准,姬塬地区长7层烃源岩属于好-最好级别;干酪根类型主要为Ⅱ_(1)~Ⅱ_(2)型,富含大量腐泥型和腐殖-腐泥型有机质;镜质体反射率(Ro)平均为0.697%,最大热解峰温T_(max)平均为447.37℃,热演化处于较成熟阶段,开始进入生油高峰阶段;烃源岩生烃强度平均为2.903×10^(6)t/km^(2),排烃强度平均为2.032×10^(6)t/km^(2),具有较强的生排烃能力,为页岩油的形成奠定了物质基础。The Chang 7-layer lacustrine basin of the Yanchang Formation in the Ordos Basin is the most developed area,and it is the main source rock of the triassic reservoir.In this paper,the Jiyuan oilfield in the western margin of the Ordos Basin is taken as an example,and the geochemical characteristics of the source rocks in this area were evaluated from three aspects:the abundance of organic matter,the type of organic matter and the maturity of organic matter.The experimental results showed that the average content of total organic carbon(TOC)in Jiyuan area was 6.11%,the average content of chloroform asphalt“A”was 0.86%,and the average content of saturated hydrocarbons and aromatic hydrocarbons(total hydrocarbons HC)in chloroform asphalt“A”was 585.5μg/g,and the average value of hydrocarbon generation potential(free hydrocarbon S_(1)+pyrolysis hydrocarbon S_(2))was 20.39 mg/g.According to the evaluation standard of organic matter abundance of source rocks,the Chang 7 source rocks in the Jiyuan area belonged to the good-best source rocks.The kerogen types were mainlyⅡ_(1)-Ⅱ_(2) types,rich in a large amount of sapropelic and humic-Sapropel organic matter.The average vitrinite reflectance Rovalue was 0.697%,the maximum pyrolysis peak temperature Tmaxwas 447.37℃on average,the thermal evolution was in a relatively mature stage,and began to enter the peak oil generation stage.The average hydrocarbon generation intensity of source rocks was 290.3×10^(4)t/km^(2),the average hydrocarbon expulsion intensity was 203.2×10^(4)t/km^(2),and it had strong hydrocarbon generation and expulsion ability,which laid a material foundation for the formation of shale oil.

关 键 词：鄂尔多斯盆地 烃源岩地化特征 有机质丰度 生烃潜量 页岩油 

分 类 号：P618.13[天文地球—矿床学]