渤海湾盆地东濮凹陷上古生界烃源岩成烃特征及成藏意义

为了明确渤海湾盆地东濮凹陷上古生界油气成藏条件和规律，采用烃源岩评价、生烃热模拟实验和盆地模拟相结合的研究方法，定量研究石炭系—二叠系烃源岩生烃历史和强度，并探讨其成藏意义。结果表明：东濮凹陷石炭系—二叠系烃源岩显微组成中富氢的壳质组、基质镜质体含量高（>10%），烃源岩具有较高生油潜力，成烃演化过程以多阶段性、生气带宽为特征；石炭系—二叠系在燕山期埋藏深度小，R_o在0.6%~0.8%，生气量较小，在喜马拉雅期呈差异化的热演化特征，凹陷西部至西斜坡地区生气强度整体较低，为（1~20）×10⁸ m³/km²，东部深洼带烃源岩埋深大、演化程度高、生气量大，生气强度达（60~110）×10⁸ m³/km²。已有勘探成果分析显示，生气强度大于40×10⁸ m³/km²的区域才能形成天然气富集，前梨园洼陷带生气强度在（60~110）×10⁸ m³/km²，具备形成原生煤成气藏和古生新储煤成气藏的有利条件，是下步有利勘探区带。

Hydrocarbon generation characteristics and significance of accumulation of Upper Paleozoic source rocks in Dongpu Sag,Bohai Bay Basin

In order to clarify the conditions and rules of hydrocarbon accumulation of the Upper Paleozoic in the Dongpu Sag of Bohai Bay Basin, source rock evaluation, pyrolysis experiment and basin modelling were carried out in this paper, the history of hydrocarbon generation and intensity of source rocks have been quantitatively studied, consequently, the significance of hydrocarbon accumulation in this area has also been discussed. The micro-composition of the Carboniferous-Permian source rocks in the Dongpu Sag is featured by high contents of hydrogen-rich exinite and matrix vitrinite (>10%), and the source rocks have a high oil-generating potential. The hydrocarbon generation process is characterized by multiple stages and wide gas generation band. During the Yanshanian period, the Carboniferous-Permian source rocks were shallowly buried, the R_o value ranged between 0.6%-0.8%, and only a little gas has been generated. In the Himalayan period, due to the differential thermal evolution of the Paleogene deposits, from the western part of the sag to the western slope, gas generation was significantly decreased, with an average of (1-20)×108 m3/km2. While in deep sag of the eastern part, source rocks were deeply buried with a high thermal degree, and a large amount of gas was generated with an intensity of (60-110)×108 m3/km2. Past exploration results have shown that the area with a gas generation intensity greater than 40×108 m3/km2 is favorable for natural gas accumulation. The gas generation intensity of the Qianliyuan sub-sag ranges (60-110)×108 m3/km2, which has favorable conditions for the formation of primary as well as paleogenetic and new-storage coal-derived gas reservoirs, and is a favorable exploration zone for the future exploration.