基于全岩心CT的遗迹化石定量表征新方法:以加拿大麦凯Ⅲ油砂区块为例  

Quantitative characterization of ichnology based on CT scan:A case study of Mackay-Ⅲoil sands,Canada

作　　者：陈浩[1,2] 黄继新 聂志泉[3] 周久宁 史晓星 Chen Hao;Huang Jixin;Nie Zhiquan;Zhou Jiuning;Shi Xiaoxing(Research Institute of Petroleum Exploitation and Development,Beijing 100083,China;China National Oil and Gas Exploration and Development Company,Beijing 100034,China;PetroChina Canada,Calgary AB T2P 1V8)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油国际勘探开发有限公司,北京100034 [3]中国石油加拿大公司,卡尔加里AB T2P 1V8

出　　处：《地质科技通报》2021年第4期252-259,共8页Bulletin of Geological Science and Technology

基　　金：美洲地区超重油与油砂高效开发关键技术(2016ZX05031);国家自然科学基金项目(41472119)。

摘　　要：根据高分辨率岩心照片、全岩心CT扫描和测井资料,以加拿大麦凯Ⅲ油砂区块下白垩统McMurray组为研究对象,开展了遗迹化石属种识别、定量表征及其空间分布特征研究。在划分目的层岩相类型的基础上,综合生物扰动指数(BI)、遗迹尺寸多样性指数(SDI)和围岩平均粒径,提出了生物扰动综合指数(BCI),并采用序贯高斯随机模拟建立了目的层BCI三维地质模型。结果表明:目的层发育9种碎屑岩岩相和9属遗迹化石。岩相以富含油块状中粒砂岩相、富生物扰动细粒砂岩相和富生物扰动泥质粉砂岩相为主,遗迹化石以Skoliths、Palaeophycus和Planolites为主。根据BCI模型,可将全区划分为Ⅰ类弱生物扰动(BCI<1.5),Ⅱ类中等生物扰动(1.5<BCI<3)和Ⅲ类强生物扰动(BCI>3)区域。本研究为定量表征遗迹化石的发育特征和空间分布提供了新的思路与方法。Based on high-resolution core photos,CT scan pictures,and well logging,the classification,features and spatial distributions of trace fossils in McMurray Formation,Lower Cretaceous,Mackay-III oil sands,Canada,were characterized quantitatively.Based on lithofacies,a new parameter,bioturbation comprehensive index(BCI),was proposed by combining bioturbation index(BI),size diversity index(SDI),and the mean grain size of hostrock.A three-dimension BCI model was built by sequential Gaussian stochastic simulation.Results show that there are nine lithofacies and nine genera trace fossils in McMurray Formation.Lithofacies were dominated by oil saturated medium-grained sandstone,high bioturbation fine-grained sandstone,and high bioturbation muddy siltstone.Trace fossils were dominated by Skoliths,Palaeophycus,and Planolites.According to BCI model,the study area was subdivided into TypeⅠweak Bioturbation(BCI<1.5),TypeⅡmoderate bioturbation(1.5<BCI<3)and TypeⅢstrong bioturbation(BCI>3).This paper provides a novel method and process to characterize the features and spatial distributions of trace fossils quantitatively.

关 键 词：加拿大油砂 CT扫描 岩相划分 遗迹化石 定量表征 

分 类 号：Q913.2[天文地球—古生物学与地层学]