渤海湾盆地黄骅坳陷古生界煤成凝析气藏特征、主控因素与发育模式

近年来，黄骅坳陷乌马营潜山二叠系碎屑岩和歧北潜山奥陶系碳酸盐岩取得高产煤成凝析气流，证实古生界潜山具有良好的凝析油气勘探潜力。系统分析了黄骅坳陷古生界凝析气藏的地质特征、流体性质、成藏主控因素等，剖析了典型古生界凝析气藏储-盖组合、煤系烃源岩生烃期次、油气充注期次及凝析气藏成因，明确了古生界煤成凝析气藏的发育模式。研究认为黄骅坳陷古生界发育多套优质储-盖组合，为凝析气藏的形成提供了优越的储集与保存条件。石炭系—二叠系煤系烃源岩于早白垩世、晚新生代两期生烃，具有"早油晚气、晚期为主"的生烃特点，是形成凝析气藏的关键因素。油气两期充注成藏，早期以原油充注为主，晚期以天然气充注为主，以晚期充注为主，晚期天然气对早期古油藏进行气侵改造，形成凝析气藏。建立了"两期生烃、早油晚气、气侵成藏"的成藏演化模式，构造稳定期与生烃高峰期相匹配，利于凝析气藏的大规模保存。黄骅坳陷古生界煤成凝析气藏的勘探发现与理论认识，对于渤海湾盆地石炭系—二叠系发育区开展凝析油气勘探具有重要指导与借鉴意义。

Characteristics,main controlling factors and development mode of Paleozoic coal-formed condensate gas reservoirs in Huanghua depression,Bohai Bay Basin

In recent years, high-yield coal-formed condensate gas flow has been found in Permian clastic rocks and Ordovician carbonate rocks in Wumaying buried hill and carbonate rocks in Qibei buried hill, proving that Paleozoic buried hills have good potential for oil and gas exploration in Huanghua depression. This paper systematically analyzes the geological characteristics, fluid properties and main controlling factors of Paleozoic condensate gas reservoir in Huanghua depression, dissects the reservoir-cap assemblage of typical Paleozoic condensate gas reservoir, hydrocarbon generation stages of coal-bearing source rocks, oil and gas charging stages and the genesis of condensate gas reservoir, and determines the development mode of Paleozoic coal-formed condensate gas reservoir. Research suggests that multiple high-quality reservoir-cap assemblages are developed in Paleozoic of Huanghua depression, providing superior accumulation and preservation conditions for the formation of condensate gas reservoirs. Carboniferous-Permian coal-bearing source rocks generated hydrocarbons in Early Cretaceous and Late Cenozoic, with the hydrocarbon generation characteristics of "oil in early stage and gas in late stage, dominated by late stage", which is the key for the formation of condensate gas reservoirs. Oil and gas reservoirs are formed by two-stage charging, mainly filled by crude oil in the early stage and natural gas in the late stage, and the late-stage charging plays a dominant role. Condensate gas reservoirs are formed through gas cut transformation by late-stage natural gas on early-stage paleo oil reservoirs; the accumulation evolution model has been established, with the characteristics of "hydrocarbon generation in two stages, oil in early stage and gas in late stage, accumulation by gas cut". The period of structural stability matches with the peak of hydrocarbon generation, which is conducive to the large-scale preservation of condensate gas reservoirs. In conclusion, the exploration discovery and theoretical understanding of Paleozoic coal-formed condensate gas reservoir in Huanghua depression are of great guidance and reference significance for oil and gas exploration in other Carboniferous-Permian stratigraphic regions of Bohai Bay Basin.