鄂尔多斯盆地镇原地区延长组长8段致密砂岩油藏差异油气充注历史

Differential Hydrocarbon Charging History of Chang 8 Tight Sandstone Reservoir of Yanchang Formation in Zhenyuan Area,Ordos Basin

受多种成藏要素控制,鄂尔多斯盆地镇原地区延长组长8段致密砂岩油藏在研究区不同地区油藏面貌和勘探成果均存在较大差异。运用流体包裹体系统分析的技术和方法,从微观上探究了镇原地区长8油层组油气充注历史,并结合宏观上油气成藏条件特征,综合分析了研究区长8段致密砂岩油藏差异油气充注历史。研究结果表明,镇原地区东部长8段油充注较为活跃,油充注成藏主要发生在早白垩世早期(133~124Ma)、早白垩世中期(115Ma)以及晚白垩世早期(95Ma);镇原地区西部长8段油充注较弱,气充注成藏主要发生在晚白垩世早期(96 Ma)。镇原地区长8段致密砂岩油藏东、西部成藏差异性主要受距盆地生烃中心距离、储层成岩作用以及构造调整作用等多种因素的共同影响。

The reservoir characteristics and the exploration result are greatly different in different areas of Chang 8 tight sandstone reservoir of Yanchang Formation in Ordos Basin owing to the multiple reservoirforming factors.In this paper,the fluid inclusion technical method is employed to explore the oil charging history in the micro aspect.Combing with the characteristic of hydrocarbon accumulation conditions,the paper analyzes the diversity hydrocarbon reservoir forming process of Chang 8 interval of Yanchang Formation.The results indicate that there was active oil charging history in the eastern region of Chang 8 interval in Zhenyuan area,and the oil charging events mainly occurred in the early period of Early Cretaceous（133-124 Ma）,the middle period of Early Cretaceous（115 Ma）and the early period of Late Cretaceous（95 Ma）.But the oil charging history was very weak in western region of Chang 8 interval in Zhenyuan area,and the oil charging events mainly occurred in the early period of Late Cretaceous（96 Ma）.The different hydrocarbon accumulation process of Chang 8 interval in Zhenyuan area is impacted by the distance to the hydrocarbon generation center,the diagenesis of reservoir and the tectonic movement.