鄂尔多斯盆地延长组长7段沉积速率及其对烃源岩有机质丰度的影响  

Deposition Rate of the Seventh Member of Yangchang Formation,Ordos Basin and Its Impact on Organic Matter Abundance of Hydrocarbon Source Rock

作　　者：袁伟[1,2] 柳广弟[1,2] 罗文斌[1,2] 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)地球科学学院,北京102249

出　　处：《西安石油大学学报（自然科学版）》2016年第5期20-26,共7页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：国家重点基础研究发展计划(973计划)(编号:2014CB239003)

摘　　要：以鄂尔多斯盆地延长组长7段富有机质页岩为对象,基于米兰科维奇旋回理论,计算了该段3个小层的沉积速率,发现长7段的沉积速率整体较小(平均1.31 cm·a^(-1)),并且具有从长73到长71逐渐增大的特征。另外,利用△logR法对已经计算了沉积速率的井进行TOC含量测井预测,并结合沉积速率和TOC含量的数据建立了两者的相关关系。研究表明:当沉积速率小于1.35 cm·a^(-1)时,TOC含量与沉积速率没有明显的相关关系,沉积物中的有机质丰度主要受其他因素的控制,如古生产力条件和保存条件;当沉积速率大于1.35 cm·a^(-1)时,TOC含量具有随沉积速率变大而逐渐减小的趋势,说明沉积速率越大,沉积物中的有机质被稀释或破坏越严重,有机质丰度就越小。The deposition rate of organic-rich shale in three sub-members of the seventh member of Yanchang Formation（ Chang 7） in Ordos Basin was calculated using the method based on Milankovitch cycles. It is found that the deposition rate of the Chang 7 reservoir is very low,the average deposition rate is 1. 31 cm / ka,and the deposition rate of from Chang 73 to Chang 71 gradually increases. The TOC content of the reservoir was predicted using △log R method,and the relationship between the deposition rate and TOC content was established based on the calculation result of the deposition rate and the prediction result of TOC content of some oil wells. It is shown that when the deposition rate is less than 1. 35 cm / ka,there is no obvious correlation between TOC content and deposition rate,and the abundance of organic matter in sediments is mainly controlled by other factors such as the paleoproductivity and preservation conditions;when the deposition rate is more than 1. 35 cm / ka,the TOC content gradually decreases with the increase of the deposition rate,which indicates that the greater the deposition rate,the less the abundance of organic matter because the organic matter is diluted and destroyed seriously.

关 键 词：沉积速率 有机质丰度 烃源岩 米兰科维奇旋回 延长组 鄂尔多斯盆地 

分 类 号：TE121.3[石油与天然气工程—油气勘探]