摘要
以二连盆地下白垩统为例,研究了小型断陷湖盆有效烃源岩分布特征与分布模式。根据烃源岩热解分析指标S1与有机碳含量的关系,建立了有效烃源岩有机质丰度的下限标准,对二连盆地有效烃源岩进行了识别,研究了有效烃源岩的分布。研究发现小型断陷湖盆有效烃源岩分布特征明显不同于大型湖盆有效烃源岩主要分布在深湖—半深湖区的特征,其有效烃源岩的分布有3种模式,即深洼型、近洼缓坡型和深洼—缓坡型。边界断层规模大、活动性强的小型断陷湖盆一般深洼带宽度与盆地宽度比值大,有效烃源岩主要分布于深洼带;边界断层规模小、活动性弱的小型断陷湖盆深洼带宽度与盆地宽度比值小,有效烃源岩主要分布于近洼缓坡带;边界断层规模中等、活动性适中的小型断陷湖盆深洼带宽度与盆地宽度比值居中,有效烃源岩在深洼带和近洼缓坡带均有分布。小型断陷湖盆凹陷结构和形成机制的差异控制了湖盆的沉积速率、古生产力和水体氧化-还原条件,决定了有效烃源岩的形成和分布。
Taking the Lower Cretaceous in Erlian Basin as an example, distribution characteristics and distribution pattern of effective source rock in small faulted lacustrine basin have been studied. Lower limit of the organic matter abundance parameters of effective source rock is determined based on the relationship between the pyrolysis parameter $1 and organic carbon content. According to this discrimination standard, the effective source rock in Erlian Basin is recognized and its distribution is studied. Research shows that the distribution of effective source rock in small faulted lacustrine basin is significantly different with large-scale lacustrine basin, where the effective source rock is mainly distributed in deep or semi-deep lake. There are three distribution patterns in small faulted lacus- trine basin, i. e. , ＂deep sag type＂, ＂gentle slope type＂, and ＂deep sag-gentle slope type＂. The small faulted lacustrine basins with large-scale boundary faults and strong fault activities usually have high ratio of deep-sag width to basin width, and the effective source rock is mainly distributed in deep sag; while those with small-scale boundary faults and weak fault activities have lower ratio of deep-sag width to basin width, and the effective source rock is mainly distributed in gentle slope belt near the sag; between these two types are basins with medium boundary faults and moderate fault activity, they have the medium ratios and the effective source rock is distributed in both deep sag and gentle slope belt. The difference in depression structure and formation mechanism of small faulted lacustrine basin has a controlling effect on deposition rate, paleo-productivity and water redox conditions, which determine the formation and distribution of effective source rock.
出处
《石油学报》
EI
CAS
CSCD
北大核心
2015年第6期641-652,共12页
Acta Petrolei Sinica
基金
国家重大科技专项(2011ZX05006-005)
中国石油天然气股份有限公司科技项目(2014E-035)资助
关键词
有效烃源岩
古生产力
小型断陷湖盆
下白垩统
腾格尔组
二连盆地
effective source rock
paleoproductivity
small faulted lacustrine basin
Lower Cretaceous
Tengger Formation
Erlian Basin
