鄂尔多斯盆地东部奥陶系马四段生物扰动构造形成的群落古生态及其对储层发育的控制  

Community paleoecology formed by bioturbation and its control over reservoir development in Ma 4 Member of Ordovician Majiagou Formation in eastern Ordos Basin

作　　者：包洪平[1,2] 魏柳斌[1,2] 张立军[3,4] 师平平 王前平 武春英[1,2] BAO Hongping;WEI Liubin;ZHANG Lijun;SHI Pingping;WANG Qianping;WU Chunying(Changqing Oil Field Branch,PetroChina Company Limited,Xi’an 710018,China;National Engineering Laboratory for Exploration and Development of Low Permeability Oil&Gas Fields,Xi’an 710018,China;College of Resources and Environment,Henan University of Technology,Jiaozuo 454003,China;International Joint Laboratory of Biological Relics and Mineralization Processes in Henan Province,Jiaozuo 454003,China)

机构地区：[1]中国石油长庆油田分公司,陕西西安710018 [2]低渗透油气田勘探开发国家工程实验室,陕西西安710018 [3]河南理工大学资源环境学院,河南焦作454003 [4]河南省生物遗迹与成矿过程国际联合实验室,河南焦作454003

出　　处：《西北大学学报（自然科学版）》2024年第6期975-992,共18页Journal of Northwest University（Natural Science Edition）

基　　金：长庆油田基础性研究项目(2024D1JC02);中国石油股份公司科技专项(2023ZZ16YJ01)。

摘　　要：鄂尔多斯盆地奥陶系马家沟组四段马四段形成于最大海侵(海泛)沉积期,属于正常海相沉积环境,海洋生物极其繁盛,在碳酸盐沉积物(尤其是灰泥沉积物)中形成了较为强烈的生物扰动构造。依据近年来盆地内部大量的探井取芯和盆地东缘野外露头地质剖面的综合研究,系统分析了盆地东部马四段的生物扰动构造(遗迹化石)及可能的群落古生态特征,并探讨了生物扰动对于岩石储层发育的控制作用,形成以下主要认识。①马四段生物扰动构造具有普遍性发育的特点,突出表现在大部分层段纵向上连续地发育生物扰动和在横向上广泛分布,表明在其沉积发育的整个过程中底栖生物群落异常活跃,呈现为在较长的地史时期内“生生不息”、不间断地延续着的一种基本相似的生活、生命及生态场景。②本区马四段生物扰动构造类型多样,结合生物扰动构造(遗迹化石)的化石碎片门类鉴定与埋藏学分析认为本区马四段强烈的生物扰动构造主要是由蠕型动物、腹足类、三叶虫及介形类等所为;再结合岩石微相的研究,可将本区马四段划分为5个典型的古生物群落(群落古生态)类型,其演进次序也依次代表了海平面变浅旋回中的古生态环境(沉积环境)演化从早期开阔广海到末期潮上云坪藻席的主要阶段。③本区马四段广泛发育的生物扰动为选择性白云石(岩)化提供了基础条件,也为储层孔隙的形成和有效保持提供了基本保障,进而间接地控制了有效储层的发育。The Ma 4 Member of the Ordovician Majiagou Formation in the Ordos Basin was formed during the period of maximum marine transgression sedimentation,belonging to a normal marine sedimentary environment,and having extremely abundant marine organisms.Strong bioturbation structures have formed in carbonate sediments,especially in lime mud sediments.Based on a comprehensive study of outcrop geological profiles in the eastern margin of the basin,and a large number of core data of exploration well drilled within the basin in recent years,this article analyzed systematically the characteristics of bioturbation structures(trace fossils)and possible paleoecological characteristics of the community in the Ma 4 Member of the eastern basin,and explored the control effect of biological disturbance on the development of rock reservoirs.The main understandings had been formed as follows:①The biological disturbance structure in Ma 4 Member has the characteristic of universal development,which is mainly manifested in the continuous development of biological disturbances in most layers vertically and their widespread distribution horizontally.This indicates that benthic communities had abnormal activity throughout the sedimentary development process,presenting as a basically similar living,life and ecology scene that continues endlessly without interruption throughout a long period of geological history;②There are various types of biological disturbance structures in the Ma 4 Member of this area.Based on the identification of fossil fragment categories and fossil burial analysis,combined with the research on bioturbation structures(trace fossils),it is believed that the strong bioturbation structures in the Ma 4 section of this area are mainly caused by creeping worms,gastropods,trilobites,and ostracods,etc.Through the combination of further research on rock microfacies,the Ma 4 Member of this area can be divided into five typical types of paleontological communities(community paleoecology).The evolutionary sequence also represe

关 键 词：鄂尔多斯盆地 马家沟组 生物扰动 群落古生态 豹皮灰岩 

分 类 号：P631[天文地球—地质矿产勘探]