海拉尔盆地莫达木吉凹陷南屯组油气充注期次研究

摘要

Based on the pore casting thin sections,scanning electron microscopy (SEM)and X-ray diffraction,analysis of physical properties,hydrocarbon inclusions,combined with the results of thermal history reconstruction,diagenesis and classification of hydrocarbon accumulation phases of the Nantun formation in lower cretaceous in the Modamudi depression, Hailar basin were conducted in this paper.The results showed that the main rock types including feldspar lithic sandstone, tuffaceous debris sandstone,and the main interstitial material were associated with argillaceous siliceous,carbonate and a small amount of volcanicash.The pore types,including the hole and intergranular corrosion reap the hole,have been found.The diagenesis in this formation included compaction stage,cracking,cementation,metasomatism,dissolution,which usually is related with early diagenetic stage B to late diagenetic stage A.Combined fluid inclusion analysis,homogenization temperature as well as thermal evolution history,the late cretaceous(90~70 Ma)is the major period of hydrocarbon accumulations in the Nantun Formation.%利用岩石铸体薄片、扫描电镜、X衍射、常规物性、流体包裹体测试等分析方法,结合热史恢复结果,开展海拉尔盆地莫达木吉凹陷下白垩统南屯组成岩作用及油气充注期次研究.结果表明,南屯组砂岩主要岩石类型为长石岩屑砂岩、凝灰质岩屑砂岩;填隙物主要以泥质、硅质、火山灰和少量碳酸盐为主;孔隙类型主要为原生孔隙、晶间孔和溶蚀粒内孔.砂岩储层经历的成岩作用类型有压实作用、破裂作用、胶结作用、交代作用、溶蚀作用,综合多种成岩作用阶段判断指标,认为南屯组砂岩目前处于早成岩阶段B期晚期-中成岩阶段A期.此外,结合流体包裹体分析、均一温度测定及南屯组热演化史,确定南屯组油气充注时代约为90~70 Ma,大致对应晚白垩世.