鄂尔多斯盆地五蛟西地区长6段单砂体叠置特征研究  

Superposition characteristics of single sand body of Chang‑6 formation in Wujiaoxi area,Ordos Basin

作　　者：武芳芳 瞿璇 周宁杰 朱薇 李彦兵 周小平 张东阁 张庆军 郭岭[1] Wu Fangfang;Qu Xuan;Zhou Ningjie;Zhu Wei;Li Yanbing;Zhou Xiaoping;Zhang Dongge;Zhang Qingjun;Guo Ling(State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi'an 710069;Changqing Industrial Group Co.,Ltd.,Changqing Oilfield Company,PetroChina,Xi'an 710018)

机构地区：[1]西北大学大陆动力学国家重点实验室,西北大学地质学系,西安710069 [2]中国石油长庆油田分公司长庆实业集团有限公司,西安710018

出　　处：《地质科学》2024年第4期1034-1047,共14页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金重点基金项目(编号:42103206);长庆油田重大科技专项(编号:ZDZX⁃2021⁃03)资助。

摘　　要：沉积微相控制下的单砂体发育类型、频率和叠置样式,控制了储层的连通性和井间剩余油的分布。本次研究综合利用丰富的岩心、测井和分析测试资料,在沉积微相精细刻画基础上,对鄂尔多斯盆地五蛟西地区三叠系延长组长6段单砂体发育特征和叠置样式进行精细研究。结果表明:五蛟西地区长6段岩性以粉砂岩、细砂岩、含泥砾或泥岩撕裂屑的细砂岩和泥岩为主,发育沉积微相类型主要为砂质碎屑流、浊流和半深湖泥3种。长6段垂向上可识别出5~8期单砂体,单砂体叠置类型包括孤立型、叠加型以及切叠型3种;平面上单层砂体多以枝状、网状、局部片状展布。湖平面升降导致的可容纳空间(A)变化及沉积物供给速度(S)匹配关系是控制单砂体空间发育特征的关键性因素。研究区长6段自下而上,随着A/S比值的变化,单砂体类型垂向上由叠加型、切叠型逐渐向孤立型、局部叠加型变化,平面上由网状、枝状向局部片状演化。The type,frequency and stacking style of single sand body development under the control of sedimentary microphase control the reservoir connectivity and the distribution of residual oil between wells.In this study,we comprehensively utilized abundant core,logging and analytical test data to study the development characteristics and stacking style of single sand body in the Chang-6 formation of the Triassic extension formation in the Wujiaoxi area of the Ordos Basin on the basis of fine depiction of the sedimentary microphase.The results show that the lithology of Chang-6 is dominated by siltstones,fine sandstones,fine sandstones and mudstones with mud gravels or mudstone laccoliths,and the types of sedimentary microfacies developed are sandy debris flow,turbidite flow,and semi-deep lake mud.In the vertical direction of the Chang-6 formation,5~8 phases of single sand bodies can be recognized,and the stacking types of single sand bodies include isolated,stacked and cut-and-stacked types;on the planar surface,the single sand bodies are mostly spread in the form of dendrites,nets,and local flakes.The change of accommodation space(A)and the matching relationship of sediment supply rate(S)caused by the rise and fall of lake level are the key factors controlling the spatial development characteristics of single sand bodies.From the bottom to the top of Chang-6 formation in the study area,with the change of the A/S ratio,the type of single sand body gradually changes from superposition type and cut-and-stack type to isolation type and localized superposition type vertically;and it evolves from reticulation and dendritic to localized lamellar on the planar surface.

关 键 词：单砂体 重力流沉积 叠置样式 鄂尔多斯盆地 五蛟西地区 长6段 

分 类 号：TE122[石油与天然气工程—油气勘探]