层序地层地球化学——地球化学研究的新进展

SEQUENCE STRATIGRAPHIC GEOCHEMISTRY——A NEW PROGRESS OF GEOCHEMISTRY

层序地层地球化学是地球化学研究的新进展,它主要研究基于层序地层格架的烃源岩分布及其地球化学特征。层序地层地球化学的概念由Peters等人(2000)提出,并在勘探实践中取得了良好的效果。层序地层地球化学将地球化学方法与层序地层学研究相结合,主要用于研究;a)基于层序格架下的烃源岩分布特征和地球化学性质;b)烃源岩地球化学特征随海(湖)平面的变化规律;c)在油源对比和油油对比的基础上进行基于地层格架的原油成出分类;d)最终研究油气聚和成藏特征并指导勘探。在研究中,层序地层格架的建立是基础,高分辨率的生物标志化合物分析是关键。在以寻找隐蔽油气藏、深层和非常规油气藏为主的中国东部陆相断陷湖盆的勘探中,开展层序地层地球化学研究具有重要的实践意义。

Sequence stratigraphic geochemistry is a new progress of geochemistry. It mainly studies the occurrence, distribution and geochemical characteristics of source rocks under a sequence stratigraphic framework. The concept of sequence stratigraphic geochemistry was proposed by Peters et al. in 2000, and was effectively used in hydrocarbon exploration practice. Combining geochemistry with sequence stratigraphy, it can be used to study the distribution and geochemical characteristics of source rocks from a sequence standpoint and the changing rules of the geochemical characteristics of source rocks with the sea (lake) level. It can also make the genetic classification of crude oil under a sequence stratigraphic framework on the basis of oil-oil and oil-source correlation, and study the characteristics of hydrocarbon migration and accumulation. It can be eventually used to direct hydrocarbon exploration. During the course of sequence-stra-tigraphic-geochemical research, the setup of a sequence stratigraphic framework is the base, and the high-resolution analyses of biomarkers are the key. The study of sequence stratigraphic geochemistry is necessary in the exploration of continental fault lake basins in East China, where the exploration is focused on seeking for unconventional hydrocarbon accumulations such as subtle or deep reservoirs.