尼日尔三角洲富泥型浊流沉积储层特征  

Characteristics of Mud-rich Turbidite Reservoir in Niger Delta

作　　者：陈国宁 陈筱 李晨曦 段瑞凯 康博韬 CHEN Guoning;CHEN Xiao;LI Chenxi;DUAN Ruikai;KANG Botao(Development Institute,CNOOC Research Institute Co.,Ltd.,Beijing 100028,China;Technical Support Center,CNOOC International Co.,Ltd.,Beijing 100027,China)

机构地区：[1]中海油研究总院有限责任公司开发研究院,北京100028 [2]中国海洋石油国际有限公司技术支持中心,北京100028

出　　处：《西安石油大学学报（自然科学版）》2021年第5期13-21,共9页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：国家科技重大专项(2011ZX05030-005)。

摘　　要：西非尼日尔三角洲F区发育深水沉积体系,储层以砂泥岩薄互层为主,与尼日尔三角洲典型深水沉积储层差异较大。为厘清研究区砂泥岩薄互层沉积成因、沉积特征及储层品质主控因素,通过岩相识别及分类,识别出4类10种岩相。基于岩相分析岩石类型及沉积构造,结果表明,研究区是在限制性环境转变为半限制—非限制性环境中发育的远端极低能—低能富泥型浊流沉积。构造坡度的变化及限制性环境的减弱导致浊流流速减弱,沉积物在陆坡上沉积形成浊积水道-天然堤复合体。水道是主要的储集空间。不同期次水道-天然堤沉积体表现为垂向加积、侧向迁移,晚期沉积体会侵蚀早期沉积体。储层为极细粒至细粒长石砂岩和亚长石砂岩,物性较好,为中高孔渗储层。由于薄层泥岩夹层普遍存在,储层品质及储层连通性受到一定影响。Deepwater turbidite is developed in F block of Niger Delta in West Africa.The reservoir is mainly composed of thin interbeds of sandstone and mudstone,and it is quite different from the typical deepwater reservoir in Niger Delta.This paper is meant to clarify the origin and characteristics of the thin interbeds of sandstone and mudstone.In F block,ten kinds of lithofacies are identified,and based on lithofacies analysis,the study area is interpreted to represent very low to low-energy distal turbidite flows in confined environment turning to half confined--unconfined environment.Based on seismic attribute,lithofacies analysis and seismic facies identification,it is held that the decrease of tectonic slope and the loss of confined environment lead to the formation of channel-levee complex deposit.Channel is the main reservoir space.The sedimentary bodies of channel-levee in different periods are characterized by vertical aggradation and lateral migration,and the late deposition will erode the early deposition.The reservoir is very fine to fine unconsolidated feldsarenites and subfeldsarenites with medium-high porosity and permeability.As the thin mudstone interlayer is widespread,reservoir quality and reservoir connectivity are affected in a certain area.

关 键 词：富泥型浊流沉积 砂泥岩薄互层 水道-天然堤 尼日尔三角洲 

分 类 号：TE122.1[石油与天然气工程—油气勘探]