摘要
为了研究鄂尔多斯盆地长7油层组沉积物变形构造时空展布规律,对盆地西南部镇原地区20口井的岩心进行了精细观察与描述,综合分析了沉积物变形构造的形态特征和形成机制,共识别出7种常见的沉积物变形构造类型,即滑塌变形、液化卷曲变形、泥质撕裂屑、液化砂岩脉、球枕构造、火焰构造和重荷模等。垂向上,沉积物变形构造在长72小层最为发育,长71小层次之,长73小层较少;平面上,在镇原地区中部集中发育,西部和东部局部发育。斜坡背景下沉积物变形构造的形成机制和展布规律为:①盆山耦合激活了沉积物变形构造的触发因素;②湖进与湖退转换期是沉积物变形构造最为集中发育的阶段;③不同类型沉积物变形构造的分布与坡折带的发育关系密切,随着向半深湖—深湖沉积区推进,其类型发生规律性演化。该研究成果对于探讨沉积物变形构造的分布模式、重力流砂体分布预测及事件沉积等研究具有参考价值。
In order to study the spatio-temporal distribution of soft-sediment deformation structures of Chang 7 oil reservoir of Upper Triassic Yanchang Formation,the detailed observation and description of core from 20 wells in Zhenyuan area,southwestern Ordos Basin,were carried out. Combined with morphological characteristics and formation mechanism of the soft-sediment deformation structures,seven common types of soft-sediment deformation structures were recognized,including slump deformation,liquefied curled deformation,torn mud intraclasts,liquefaction sandstone dikes,sandy ball-pillow structures,flame structures and load casts. Vertically,softsediment deformation structures are most frequently observed in Chang 72 sublayer,followed by Chang 71 and Chang 73 sublayers. Horizontally,the soft-sediment deformation structures mainly distribute in the deep-water slope-break zone and semi-deep and deep lake where is located in the central and eastern of the study area. The formation mechanism and distribution of soft-sediment deformation structures on slope is that:(1)Basin-mountain coupling has activated triggers for the occurrence of soft-sediment deformation structures.(2)The transition period between the lake transgression and lake regression is the stage when the soft-sediment deformation structures are most concentrated.(3)The distribution of the soft-sediment deformation structures is closely related to the development of slope break zone. From the slope to the semi-deep lake-deep lake environment,various types of softsediment deformation structures have evolved regularly. The results of this study have important reference for the distribution pattern of sedimentary deformation structures,the prediction of gravity flow sand body distribution and the study of sedimentary events.
作者
何维领
罗顺社
李昱东
吴悠
吕奇奇
席明利
HEWeiling;LUO Shunshe;LI Yudong;WU You;LYU Qiqi;XI Mingli(School of Geosciences,Yangtze University,Wuhan 430100,China;Hubei Cooperative Innovation Center of Unconventional Oil and Gas(Yangtze University),Wuhan 430100,China;Research Institute of Exploration and Development,PetroChina Yumen Oilfield Company,Jiuquan 735000,Gansu,China;Department of Development,PetroChina Changqing Oilfield Company,Xi'an 745000,China)
出处
《岩性油气藏》
CSCD
北大核心
2020年第6期62-72,共11页
Lithologic Reservoirs
基金
国家自然科学基金项目“鄂尔多斯盆地延长组湖泊重力流沉积特征及形成机理研究”(编号:41672099)
国家重点基础研究发展计划“973”项目“淡水湖盆细粒沉积与富有机质页岩形成机理”(编号:2014CB239003)联合资助。
关键词
沉积物变形构造
火焰构造
分布模式
长7油层组
鄂尔多斯盆地
soft-sediment deformation structures
flame structure
Distribution pattern
Chang 7 oil reservoir
Ordos Basin
