【作者】 郭峰；

【导师】 孟祥化； 葛铭；

【作者基本信息】 中国地质大学（北京） ， 矿产普查与勘探， 2007， 博士

【摘要】 本文是中石化石油勘探项目《华北地台及两大裂谷系烃源岩研究》部分研究成果。以大量野外地质露头剖面的详测、描述分析为基础,结合室内研究总结,通过沉积学及层序地层学分析,研究贺兰拗拉谷寒武-奥陶系岩石学特征、沉积特征及层序地层学特征,并在此基础上,通过大量的样品测试分析,初步评价了拗拉谷海相烃源岩。拗拉谷寒武-奥陶系以海相碳酸盐沉积为主,其次为泥质岩及砂砾岩,结合海平面变化分析认为,贺兰拗拉谷寒武-早中奥陶世地层可划分为2个超层序,11个二级层序和48个三级层序。拗拉谷寒武系主要发育潮坪、滨海浅滩、局限台地、开阔台地、台地边缘浅滩、台地前缘斜坡及深水陆棚等沉积相类型。奥陶系则主要发育局限台地、开阔台地、浅海陆棚、海底扇及生物礁相等。贺兰拗拉谷早古生代沉积相模式可表示为:由陆向海依次为大陆区-海陆过渡区-局限台地-开阔台地-台地边缘斜坡-广海陆棚。贺兰拗拉谷寒武-奥陶系海相烃源岩有机质为I、IIA型。寒武系烃源岩热解峰温Tmax值多在460℃以上,有机质演化程度都达到了高成熟至过成熟阶段。下奥陶统烃源岩热演化程度以高成熟为主,部分为过程熟阶段。中奥陶统除甘肃平凉地区处于成熟度相对较低阶段外,其他地区均达到高成熟至过成熟阶段。大部分地区为较差烃源岩,而桌子山、香山、平凉及铜川地区有机质含量较高,可作为较好的源岩。拗拉谷寒武-奥陶系受海平面快速上升控制所发育的较好烃源岩多位于层序中下部甚至底部的海侵体系域或凝缩层;烃源岩的发育与沉积环境密切相关,局限台地、开阔台地台凹、深水相等是形成好烃源岩的有利场所。更多还原

【Abstract】 The paper is part results of“The Research on Hydrocarbon of NorthChina Platform and Two Rift Systems”. The results come from detail measurements, descriptions and analysis on lots of outcrops and painstakingly work indoor. Based on the research of sedimentology and sequence stratigraphy, the lithology, depositional environment and sequence stratigraphy features are concluded. In addition, the marine carbonate source rocks of Helan Aulacogen were preliminary assessment.The main deposition of Cambrian (ε) and Ordovician (O) in Helan Aulacogen is marine carbonates; The second is argillaceous rocks and glutenite rocks. And the stratigraphy ofε-O1-2 can be divided into 2 super sequences, 11-second order sequences and 48 third order sequences.The sedimentary facies ofεin Helan Aulacogen are as follows: tidal flat, offshore fords, restricted platform, open platform, plateau boundary shallows, plateau foreslope, et al. Restricted platform, open platform, neritic continental shelf, abyssal fan and biohermal facies are mainly facies of Ordovician. The sedimentary facies pattern of Eopaleozoic from land to sea can be regard as: land-transition area-ristrict platform-open platform- plateau foreslope-continental shelf.Carbonate source rocks organic matter ofε-O in Helan Aulacogen belong to IIA model or I. The value of Rock Eval Tmax mainly over 460℃which mean that organic matter evolution attain high or post mature period. The thermal evolution of Lower Ordovicion source rocks mainly fall in high mature, some in over mature. Except Pingliang area source rocks of Middle Ordovician attains maturity period, others are all accomplish high or over mature period. Most of them are relatively bad source rocks, but source rocks of several areas as Zhuozishan, Xiangshan, Pingliang and Tonghcuan have high organic content that can be regard as preferable source rocks.Preferable source rocks mostly locate at the middle-lower part or bottom of the sequence, transgression system or condense stratigraphy, which is controlled by the seal level fast ascend. Source rocks deposition has osculated links to sedimentaryenvironment, restrict platform, bight of open platform and deep-water facies are the better area for the development of good source rocks.更多还原