四川盆地长宁示范区地质条件对页岩有机质的影响

The Influence of Geological Condition of Sichuan Basin Changning Demonstration Area on the Development of Organic Matters in Shale

以四川盆地长宁示范区志留系龙马溪组泥页岩层段为研究对象,在单井岩心观察、有机地球化学特征、地球物理测井和古生物标志等分析的基础上,根据该地区构造特征和沉积环境演化特征这两个方面,分析长宁示范区地质条件对其页岩段有机质的影响。结果表明:川东南地区虽经多期次构造运动,但总体构造格局未受明显破坏,页岩保存完好,为龙马溪组页岩展布广泛、厚度大、有机质保存提供环境保障。本区龙马溪组富含有机质,泥页岩累积厚度大,有机质类型以I型腐泥型为主,是川东南地区海相地层中的优质烃源岩,研究区的沉积环境和构造地质条件为龙马溪组页岩有机质富集保存提供了有利条件,龙马溪组的浅海陆棚闭塞缺氧的沉积环境和缓慢的沉积速率是其优质烃源岩发育主要影响因素。证明区域地质条件对泥页岩层段有机质含量、类型、成熟度、页岩有效厚度、保存条件具有重要意义。

For the study of Changning demonstration area in Sichuan Basin Longmaxi Silurian shale clay, based on the analysis of observation of single well, the characteristic of organic geochemical characteristics, geophysical logging, paleontology flag, according to these two aspects of the environment of the construction characteristics of the region and sedimentary evolution, Changning demonstration geological conditions on the shale organic matter were analyzed. Despite Siehuan Southeast experiences multi-stage tectonic movement, the overall structure of the pattern are not damaged. Shale preserved for Longmaxi shale widely spread, thick, organic matter preservation of environ- mental safeguards. The Longmaxi is rich in organic matter, shale accumulation of large thickness, the type of or- ganic matter is the I-sapropelic based, is high quality source rocks in Southeast Sichuan marine strata. Depositional environments and tectonic conditions provided Longmaxi shale organic matter enrichment favorable conditions, Longrnaxi occlusion of shallow shelf sedimentary environment of hypoxia and slow deposition rate are the main factor of its high-quality source rocks, regional geological conditions prove that mud shale organic matter content, type, maturity, the effective thickness of the shale, storage conditions are important.