石油学报 ›› 2019, Vol. 40 ›› Issue (9): 1069-1084.DOI: 10.7623/syxb201909005

• 地质勘探 • 上一篇    下一篇

四川盆地震旦系灯影组丘滩体发育分布及对储层的控制

兰才俊1,2, 徐哲航1,2, 马肖琳1,2, 胡超1,2, 陈浩如3, 邹华耀1,2   

  1. 1. 油气资源与探测国家重点实验室 北京 102249;
    2. 中国石油大学(北京)地球科学学院 北京 102249;
    3. 中国地质大学(武汉)资源学院 湖北武汉 430074
  • 收稿日期:2019-04-08 修回日期:2019-06-19 出版日期:2019-09-25 发布日期:2019-10-15
  • 通讯作者: 邹华耀,男,1963年12月生,1985年获江汉石油学院学士学位,2002年获中国地质大学(武汉)矿产普查与勘探专业博士学位,现为中国石油大学(北京)教授、博士生导师,主要从事油气成藏机理与富集规律教学与科研工作。Email:huayaozou@cup.edu.cn
  • 作者简介:兰才俊,男,1995年5月生,2016年获中国石油大学(北京)地质工程专业学士学位,现为中国石油大学(北京)博士研究生,主要从事四川盆地碳酸盐岩沉积与储层研究。Email:lonedaniel@163.com
  • 基金资助:

    国家自然科学基金项目(No.U1663210)、中国科学院战略性先导科技专项(XDA14010306)和中国石油化工股份有限公司项目(P16108)资助。

Development and distribution of mound-shoal complex in the Sinian Dengying Formation, Sichuan Basin and its control on reservoirs

Lan Caijun1,2, Xu Zhehang1,2, Ma Xiaolin1,2, Hu Chao1,2, Chen Haoru3, Zou Huayao1,2   

  1. 1. State Key Laboratory of Petroleum Resources and Prospecting, Beijing 102249, China;
    2. College of Geosciences, China University of Petroleum, Beijing 102249, China;
    3. Faculty of Earth Resources, China University of Geosciences, Hubei Wuhan 430074, China
  • Received:2019-04-08 Revised:2019-06-19 Online:2019-09-25 Published:2019-10-15

摘要:

四川盆地震旦系灯影组储层主要发育于微生物丘滩体中,但不同成因类型丘滩体对储层的影响尚不明确。通过钻井岩心和野外露头观测、岩石薄片分析和物性测试等手段,将丘滩体划分为丘基、丘核、丘翼和丘坪4种微相,并根据微相的组合划分出台缘并进型丘滩体、台缘追补型丘滩体和台内饥饿型丘滩体3种丘滩体类型。台缘并进型丘滩体的生长速率快,与可容空间的增加速率相同步,其微相组合以"丘基+丘核"垂向加积为主,在海平面升降过程中易暴露于大气淡水环境,造成海水胶结作用弱、淡水溶蚀作用强,形成以格架溶蚀孔洞为主的储集空间,储层物性好,储集性能最优。台缘追补型丘滩体的生长速率次之,其早期的生长速率滞后于可容空间增长速率但后期逐渐同步,呈现出"丘基+丘核+丘翼/丘坪"侧向加积的微相组合;由于暴露于大气淡水环境的几率减小,其海水胶结作用强,淡水溶蚀作用减弱,储集性能稍差。台内饥饿型丘滩体的生长速率最慢,严重滞后于可容空间的增长速率,呈"云坪(丘基)+丘核+丘坪"微相组合,难以暴露于大气淡水环境,淡水溶蚀作用最弱,储集性能也最差。台缘带古地貌对丘滩体的生长速率影响较大,可控制丘滩体的沉积样式。陡坡台缘带有利于台缘并进型丘滩体发育,缓坡台缘带主要发育台缘追补型丘滩体,台内高地中发育台内饥饿型丘滩体。胡家坝-阆中-安岳地区一带的震旦系灯影组四段发育于典型的陡坡台缘带,是储层发育的最有利相带。

关键词: 丘滩体, 台缘带, 发育机理, 灯影组, 四川盆地

Abstract:

The reservoirs of the Sinian Dengying Formation in Sichuan Basin are mainly developed in the microbial mound-shoal complex, but the influence from the complex of different genetic types on reservoirs remains unclear. By means of drilling core and field outcrop observation, thin-section analysis and physical property test, the mound-shoal complex is divided into the mound-base, mound-core, mound-flank and mound-flat microfacies; based on the microfacies assemblage, three types of mound-shoal complexes can be identified as below:platform-margin keep-up mound-shoal, platform-margin catch-up mound-shoal and intra-platform give-up mound-shoal. The growth rate of platform-margin keep-up mound-shoal is fast, synchronous with the growth rate of the accommodation space. The microfacies assemblage of platform-margin keep-up mound-shoal is mainly shown as the vertical accretion of "mound-base+mound-core", which is easy to be exposed to the meteoric fresh water during sea level eustacy, resulting in weak seawater cementation and strong freshwater dissolution, and forming reservoir space dominated by lattice dissolution pores, with good physical property and optimal reservoir performance. The platform-margin catch-up mound-shoal has the second fastest growth rate that lagged behind but gradually synchronized with the rate of accommodation space and presents laterally aggradation of "mound-base + mound-core+mound-flank/mound-flat" in microfacies assemblage. Due to the reduced probability of exposure to meteoric fresh water, the reservoir performance in platform-margin catch-up mound-shoal is quite poor as the result of strong seawater cementation and weakening fresh water dissolution. The intra-platform give-up mound-shoal shows the slowest growth rate, seriously lagging behind that of the accommodation space. Its microfacies assemblage is "dolomitic flat (mound-base)+mound-core+mound-flat", which is difficult to be exposed to the meteoric freshwater, with the weakest freshwater dissolution and the poorest reservoir performance. The paleo-geomorphology of the platform margin has a great influence on the growth rate and controls sedimentary pattern of the mound-shoal complex. The platform margin of steep slope is conducive to the development of platform-margin keep-up mound-shoal, platform-margin catch-up mound-shoal and intra-platform give-up mound-shoal are mainly developed in the platform margin of gentle slope and the highland within the platform, respectively. The Member 4 of Sinian Dengying Formation in the Hujiaba-Langzhong-An'yue area is developed in the platform margin of typical steep slope and is the most favorable facies belt for reservoir development.

Key words: mound-shoal complex, platform margin, development mechanism, Dengying Formation, Sichuan Basin

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