摘要
运用地球化学数据结合地质研究成果,重点介绍了海塔盆地中部断陷带下白垩统铜钵庙组—南屯组二段泥岩的基本地球化学指标和发育情况。泥岩中有机质丰度普遍较高,从下部的铜钵庙组到上部的南屯组二段有机质丰度平均值有逐步增加的趋势,有机质类型Ⅲ、Ⅱ_2、Ⅱ_1型比例相当,少部分为Ⅰ型,Ⅰ型主要集中在特殊岩性段和南一段上部。铜钵庙组主要分布于乌尔逊凹陷,复合旋回段泥岩则主要分布于乌尔逊和贝尔凹陷,从特殊岩性段开始泥岩全区分布,暗色泥岩比例和泥地比较前期明显增加,有机质丰度和I型有机质比例也同步增加,因此特殊岩性段时期开始了海塔盆地中部断陷带烃源岩的广泛发育期。综合泥岩有机质丰度、类型、成熟度及其分布分析认为,研究区内有生烃能力的泥岩集中在下白垩统的南屯组,最好的烃源岩发育于被动裂谷期、辫状河三角洲和滨浅湖环境较为发育的特殊岩性段;这也同时说明好的烃源岩的形成并不一定要求深湖一半深湖环境,在一定的盆地背景条件下,辫状河三角洲和滨浅湖环境同样可以形成好的烃源岩。
With the application of geochemical data and geologic research results, emphasis is laid on introducing basic geochemical indicators and development of mudstone of K1t group to K1n group of lower cretaceous of graben zone in the middle part of Hailar-Tamtsag Basin. Generally, mudstone is abundant with organic matter,which is found to be gradually increasing from lower K1t group to upper K1n group. Type Ⅲ, Ⅱ1, Ⅱ 2 of organic matter are justly proportioned, whereas type Ⅰ makes up a small proportion that mainly concentrates along K1n^12 and K1n^13 K1t group is primarily distributed along Wurxun depression,whereas K1n^11 is distributed along Wurxun and Beier depression. Mudstone of K1n^12 group starts spreading all over the depression. Proportion of black mudstone and mud/stratum value is significantly higher than that of former period. Organic matter abundance and type I organic matter advance in parallel,thus source rock of graben zone in the middle part of Hailar-Tamtsag Basin starts to widespread during K1n^12 period. With comprehensive research on organic matter abundance, types, maturity and distribution,it is thought that mudstone with hydrocarbon-generation potential is centered at Kin group of the lower cretaceous and the best source rock is formed at K1n^12 groupduring passive rift basin period under developed braid delta and shore-shallow lacustrine facies, which at the same time indicates that high quality source rock is not always developed at deep and semi-deep lake environment, but also at braid delta and shore-shallow lacustrine environment under given conditions.
出处
《地质科学》
CAS
CSCD
北大核心
2011年第4期994-1008,共15页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
国家油气重大专项(编号:2008ZX05007-03)资助
关键词
有机质丰度
类型
成熟度
深湖-半深湖环境
海塔盆地
Organic matter abundance, Types, Maturity, Deep and semi-deep lake, Hailar-Tamtsag Basin
