细粒沉积学研究动态及探讨

The research and discussion of fine-grained sedimentology

针对国内外细粒沉积研究现状与存在问题,采取文献调研与典型对象分析相结合的手段,得到研究结果:①页岩中存在大量生物石英与成岩石英,粉砂质纹层发育粗粒黏土矿物,以生物-化学成因的碳酸盐为主。有机质含量与生物石英呈正比,与陆源石英(或黏土)呈反比。②目前的岩相分类依据主要包括成分、结构、沉积构造、物质来源及非均质性等,分类方法尚未统一,符合组分成因机制且适用于页岩气评价的岩相分类体系有待提出。③古水深研究包括利用沉积特征和地化指标的定性分析及利用古生物法的定量分析,我国海相产气页岩中沉积速率与有机质含量呈负相关性。关于细粒沉积的动力学过程还需深化,综合性的沉积条件分析还需完善。④我国湖相产油页岩主要发育于半深湖-深湖相,海相产气页岩则发育于半深水-深水陆棚。

Considering about the current status and existing problems of domestic and foreign research of fine-grained sediments(FGS),this paper adopts a combination of literature research and typical object analysis to obtain the following results:①There are lots of biological quartz and diagenetic quartz in shale;clay minerals are enriched in silty laminae;biochemical carbonate is the dominant form in shales.The content of organic matter is positively proportional to the biological quartz and inversely proportional to terrestrial quartz(or clay minerals).②At present,the classification basis of lithofacies mainly includes composition,structure,sedimentary tectonics,material source and heterogeneity,etc.While,the classification method of FGS has not been unified,and the classification according with th eorigins of component and suitable forshale gas evaluation is needed to be put forward.③The study of paleo-water depth mainly includes qualitative analysis using sedimentary characteristics and geochemical indicators,and quantitative analysis using paleontological methods.The sedimentation rate and organic matter content in marine gas-producing shales in China are negatively correlated.The sedimentary dynamics process of FGS needs to be researched in-depth.The comprehensive analysis of sedimentary conditions needs to be refined.④It is found that Chinese lacustrine oil-producing shales are mainly developed in the semi-deep-deep lake facies,and marine gas-producing shales are mainly developed in the deep water shelf.