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塔河-轮南地区是我国最大的海相油气富集区,但在多源多期生烃、多幕多类型油气藏调整、改造背景下,对于该区奥陶系储层烃类充注史的准确厘定尚存争议.基于烃源岩生烃史、奥陶系岩溶缝洞储集体的形成时间、奥陶系油气藏的空间分布特征及其流体性质的综合分析,认为寒武系烃源岩发生于加里东晚期的油气充注过程已遭破坏,而奥陶系主力烃源岩发生于石炭系沉积初期的油气充注事件形成了轮南低凸起现今黑油资源的主体,且由于封盖条件较差,油气在发生充注的同时遭受氧化降解形成广泛分布的重质稠油,包裹体均一温度的定年结果有力地佐证了这一结论.同时,基于喜马拉雅期气洗相分馏作用的定量化研究结果,证实了喜马拉雅期捕获的第二期烃类包裹体并非源自奥陶系烃源岩晚期高成熟度原油的二次充注,而是经强烈气洗相分馏改造后饱含大量轻质馏分的天然气遭捕获的结果.因此,塔河-轮南地区大型油气田的形成受控于两期油气充注过程,石炭系沉积初期是现今奥陶系油藏的形成期,而喜马拉雅期过量干气侵入所诱发的相分馏改造导致了现今奥陶系内部多种类型油气藏共存的复式油气聚集特征.
The Tahe-Lunnan area is the largest marine oil and gas accumulation area in China. However, under the background of adjustment and reconstruction of multi-source and multi-period hydrocarbon generation and multi-curtain multi-type reservoirs, Based on the hydrocarbon generation history of source rocks, the formation time of Ordovician karst seam reservoirs, the spatial distribution characteristics of Ordovician reservoirs and their fluid properties, it is considered that the Cambrian source rocks The process of oil and gas filling occurred in the late Caledonian was destroyed. However, the hydrocarbon filling events occurred in the early Carboniferous sediments of the main Ordovician source rocks formed the main body of the current black oil resources in the southern part of the Ordos Basin. The conditions of cap formation are poorer and the oil and gas are oxidized and degenerated to form widely distributed heavy heavy oil during filling, and the dating result of homogenization temperature of inclusions strongly supports this conclusion.At the same time, based on the gas phase fractionation in Himalayan Quantitative results confirmed that the second phase of hydrocarbon inclusions captured in the Himalayan period did not originate from the secondary charge of late mature high-matured crude oil from Ordovician source rocks. Instead, Lightweight As a result, the formation of large-scale oil and gas fields in the Tahe-Lunnan area is controlled by two stages of oil and gas filling, the early Carboniferous deposition is the formation of the present Ordovician reservoirs, while the excessively dry in the Himalayan period The facultative fractionation retrofit induced by gas intrusion has resulted in the complex hydrocarbon accumulation of many types of reservoirs in the Ordovician.