鄂尔多斯盆地延长组下组合油气来源及成藏模式_李相博

石油勘探与开发

172 2012年4月PETROLEUM EXPLORATION AND DEVELOPMENT Vol.39 No.2 文章编号：1000-0747(2012)02-0172-09

鄂尔多斯盆地延长组下组合油气来源及成藏模式

李相博1，刘显阳2，周世新3，刘化清1，陈启林1，王菁1，廖建波1，黄军平1

（1. 中国石油勘探开发研究院西北分院；2. 中国石油长庆油田公司勘探开发研究院；

3. 中国科学院地质与地球物理研究所油气资源研究重点实验室）

基金项目：国家自然科学基金项目（41172131）；中国科学院重要方向项目（KZCXZ-EW-104-02）；

国家科技重大专项“大型油气田及煤层气开发”（2008ZX05044-2-8-2）

摘要：通过生物标志化合物对比、流体包裹体分析及盆地模拟研究，对鄂尔多斯盆地延长组长9与长10油层组的油源、成藏期次及成藏模式进行了探讨。陇东与姬塬地区长9油层组的原油分为2种类型，第Ⅰ类来源于长7烃源岩，第Ⅱ类来源于长9烃源岩；陕北地区长10油层组的原油主要来源于长9烃源岩。陇东与姬塬地区长9油藏均发生过2期油气充注，但前者在第1期（中侏罗统直罗组沉积期）就达到了油气充注的高峰期，而后者在第2期（下白垩统志丹组沉积期）才达到油气充注高峰期；陕北长10油层组也存在2期成藏，但2期油气呈连续充注，大致从中侏罗统直罗组沉积早期一直持续到下白垩统志丹组沉积中后期。长9与长10油藏有“上生下储”、“侧生旁储”及“自生自储”3种成藏模式。图10参22 关键词：油源对比；成藏主控因素；成藏模式；长9油层组；长10油层组；鄂尔多斯盆地

中图分类号：TE122 文献标识码：A

Hydrocarbon origin and reservoir forming model of the Lower Yanchang

Formation, Ordos Basin

Li Xiangbo1, Liu Xianyang2, Zhou Shixin3, Liu Huaqing1, Chen Qilin1, Wang Jing1, Liao Jianbo1, Huang Junping1

(1. Northwest Branch, PetroChina Research Institute of Petroleum Exploration & Development, Lanzhou 730020, China; 2.

Exploration and Development Institute of PetroChina Changqing Oilfield Company, Xi’an 710018, China; 3. Key Laboratory of Petroleum Resources Research, Geology and Geophysics Institute, Chinese Academy of Sciences, Lanzhou 730000, China) Abstract:According to the comparison of biomarkers in source rocks and crude oil, fluid inclusion analysis, and basin modeling, this paper discusses the oil source, hydrocarbon accumulation period and reservoir forming model of the Chang 9 and Chang 10 oil-bearing formations, Yanchang Formation, Ordos Basin. The crude oil of Chang 9 in the Longdong and Jiyuan areas can be divided into two types, type crude oil originated from the source rocks within Chang 7, while type crude oil came from the source rocks within Chang 9.

ⅠⅡ

The crude oil of Chang 10 in Northern Shaanxi originated mainly from the source rocks of Chang 9. The Chang 9 oil reservoirs in both the Longdong and Jiyuan areas experienced two periods of hydrocarbon injection. The former reached the peak period of hydrocarbon injection in the first period (the depositional period of Middle Jurassic Zhiluo Formation), while the latter in the second period (the depositional period of Lower Cretaceous Zhidan Formation). There are two periods of continuous hydrocarbon injection in Chang 10 of Northern Shaanxi, generally from the early depositional period of the Middle Jurassic Zhiluo Formation to the middle-late depositional period of the Cretaceous Zhidan Formation. There are three types of hydrocarbon accumulation models in Chang 9 and Chang 10, i.e.

“upper generation and lower storage”, “adjacent generation and lateral storage” and “self-generation and self-storage”.

Key words:oil-source correlation; reservoir controlling factor; reservoir forming model; Chang 9 oil-bearing formation; Chang 10 oil-bearing formation; Ordos Basin

0 引言

鄂尔多斯盆地是中国陆上重要的含油气沉积盆地，三叠系延长组为其主要含油层位。前人根据沉积旋回特征，将延长组自上而下划分为长1—长10共10个油层组[1]（长1—长6为延长组上组合，长7—长8为延长组中组合，长9—长10为延长组下组合）。由于以往的油气勘探主要集中在长8油层组以上，所以对长9 油层组与长10油层组的认识程度较低，且存在争议。在油气来源方面，段毅等[2]与张文正等[3]认为鄂尔多斯盆地长9原油主要来自长7段烃源岩，只有志丹地区长9原油来自于长9段烃源岩，但笔者认为陇东地区长9原油明显存在自身油源的贡献。杨华等[4]认为陕北地区长10 原油来自长7段烃源岩，但李士祥等[5]认为这一地区长10