摘要:
迄今为止,莺歌海盆地古近-新近系烃源岩研究及烃源条件分析均主要局限于中新统海相,而对于古近系尚未涉及。根据莺歌海盆地区域地质背景及构造沉积演化特征,首次系统地研究了古近系陆相沉积分布特征及其湖相及煤系烃源岩特点与烃源条件。通过对上覆新近系及第四系海相坳陷沉积较薄、古近系埋藏较浅的盆地西北部临高凸起和盆地周缘斜坡带的地震分析解释和探井钻探结果,采用地质地球物理与地球化学分析相结合的研究方法,综合判识和确定了古近系陆相地层及其湖相及煤系烃源岩的存在,在此基础上深入剖析了古近系烃源条件及其重要的石油地质意义。强调指出,盆地不同区域古近系陆相烃源岩有机质丰度、生源母质类型及成熟演化程度等,均存在明显差异。鉴此,根据古近系陆相烃源岩分布特征及烃源条件的控制影响因素,初步评价预测了古近系油气藏和古潜山油气藏勘探的有利区域。
Abstract:
Good source conditions are the material basis and basic prerequisite for hydrocarbon formation, according to the theories of petroleum system and the pool-forming dynamics. However, the research of Paleogene hydrocarbon sources is lack in the Yinggehai Basin. This paper has, for the first time, made a systematic analysis on the distribution of Paleogene continental deposits and the characteristics of the lacustrine and coal-bearing source rocks based on regional geology and tectono-sedimentary evolutionary histories in the Yinggehai Basin. Using comprehensive geophysical and geochemical methods and the results of seismic interpretation in the slope zones and on the Lingao bulge, where the overlying Neogene-Quaternary sediments are thin and Paleogene buried shallowly, the paper confirms the existence of Paleogene hydrocarbon Source. On the basis, Paleogene hydrocarbon source condition and its petroleum geological significance were analyzed in details. The results show that the abundance and maturity of the organic matter and the type of source materials differ from place to place. Moreover, in the light of the distribution and the controlling factors of the Paleogene source rock, the paper made a forecast of favorable exploration areas of Paleogene reservoirs and buried hill reservoirs preliminarily.
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