摘要
陆源碎屑与碳酸盐(岩)混合沉积现象普遍发育并已成为有利的油气勘探类型,但陆相断陷盆地混合沉积类型多样、成因复杂,是当今沉积地质学的研究热点和难点.基于渤海油田大量勘探实践及国内外研究成果的调研,归纳总结了陆相断陷盆地混合沉积研究所取得的主要进展,提出了目前混合沉积研究面临的主要问题.陆相混合沉积研究历程可划分为起步阶段、快速发展阶段和综合研究阶段.由于地质条件的差异性,混合沉积岩性鉴定方案并未形成统一的标准.陆相断陷盆地混合沉积具有复杂的成因类型,包括近源混合沉积、远源混合沉积2大类及6种具体沉积类型.渤海油田首次建立了独立的陆相断陷盆地混合沉积相体系.陆相混合沉积形成的主控因素包括稳定的宏观构造背景与局部强断裂活动、盆内局部凸起碎屑供给的不稳定性、相对干旱的气候与较高盐度的水体条件、正向的古地貌背景.近源扇三角洲混合型、近源扇三角洲侧翼型、近源辫状河三角洲侧翼型、远源高能粗粒型混合沉积优质储层是目前较为有利的混合沉积勘探类型.古地理条件约束、地质模式主导是有效的混积型储层预测思路.现阶段陆相混合沉积研究中需要重视的关键性问题主要包括以下几个方面:混合沉积岩性分类方案,钙质壳体生物发育规律及微生物白云岩化作用,细粒混合沉积与页岩油气储层的关系,混积型储层地球物理预测技术.
Mixed siliciclastic and carbonate sediment formations are widely developed and recently have become favorable petroleum exploration targets with the emergence of unconventional oil and gas plays.It becomes a research focus on continental basin,considering the complex geological conditions and various types of mixed deposition.Based on numerous exploration practices in the Bohai Bay oil field and research investigations in other parts of China and overseas,in this paper,it summarizes the main advances of the deposition of mixed sediments in continental rift basins and discusses several critical issues.The research process of continental mixed sediments can be divided into three stages:(1)infancy stage;(2)stage of rapid development;(3)stage of systematical research.There are various but no universal criteria of petrographic classifications for the mixed sediments because of different geological settings.The genetic types of mixed sediments are various and generally include proximally mixed sedimentation and distally mixed sediments,which could be further divided into 6 specific mixed types.An independent continental sedimentary facies system has been established in the Bohai Bay oil field.The mixing processes are mainly controlled by stable macroscopical tectonic setting and locally intense fault activity,arid climate and saline water,unstable siliciclastic supply of local uplift inside basin and positive paleogeomorphologic unit.Types of proximal fan-delta mixing,proximal fan-delta flank mixing,proximal braided river delta flank mixing and distal high-energy mixing could be excellent lacustrine reservoirs and are the advantageous exploration targets.At present,the relatively effective approach for predicting mixed sediment reservoirs is through investigating the paleogeographic environment and understanding the dominant geological model.Current researches on mixed sediments should be focused on the following key issues:(1)lithologic classification of mixed sediments;(2)growth habit of calcareous shell paleobiology and microbial dolomitization;(3)relationship between fine-grained mixed sediments and shale reservoirs;and(4)seismic prediction technology for mixed sediment reservoirs.
作者
杜晓峰
徐长贵
朱红涛
解习农
朱筱敏
刘可禹
姜在兴
曾洪流
Du Xiaofeng;Xu Changgui;Zhu Hongtao;Xie Xi'nong;Zhu Xiaomin;Liu Keyu;Jiang Zaixing;Zeng Hongliu(Tianjin Branch of China National Offshore Oil Corporation Limited,Tianjin 300459,China;School of Earth Resources,China University of Geosciences,Wuhan 430074,China;College of Geosciences,China University of Petroleum,Beijing 1022A9.China;School of Geosciences,China University of Petroleum,Qingdao 266580,China;College of Energy,China University of Geosciences,Beijing 100083,Chitia;Bureau of Economic Geology,Jackson School of Geosciences,The University of Texas at Austin,Texas 78712,USA)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2020年第10期3509-3526,共18页
Earth Science
基金
国家科技重大专项(No.2016ZX05024-003)
国家自然科学基金项目(No.41772111)。
关键词
混合沉积
岩性界定
混合沉积相
沉积模式
成因机制
储层预测
渤海海域
沉积
mixed sediment
lithologic identification
mixed sedimentary facies
sedimentary model
genetic mechanism
reservoir prediction
Bohai Sea area
sedimentation
