中国沉积盆地火山岩油气藏形成与分布

中国火山岩油气藏勘探经历了偶然发现、局部勘探、全面勘探3个发展阶段.中国沉积盆地内发育石炭系-二叠系、侏罗系-白垩系和古近系-新近系3套火山岩,以火山熔岩、火山角砾岩和风化壳岩溶型储集层为主,储集层物性基本不受埋深限制.火山岩自身不能生成有机烃类,与有效烃源岩匹配是成藏的关键,近源组合最有利于成藏,生烃中心控制油气分布,远源组合需断层或不整合面沟通.中国东部断陷盆地火山岩油气藏以近源组合为主,沿断裂高部位爆发相储集层发育,形成构造-岩性油气藏,斜坡部位喷溢相大面积分布,经裂缝改造的储集层有利,主要形成岩性油气藏;中西部发育两种成藏组合,近源大型地层油气藏最有利,沿不整合面分布的风化淋滤型储集层亦可形成大型地层油气藏.图9表6参44

Formation and distribution of volcanic hydrocarbon reservoirs in sedimentary basins of China

Volcanic hydrocarbon exploration in China experienced three phases, accidental discovery, local prospecting and all-round exploration. There are mainly Carboniferous-Permian, Jurassic-Cretaceous, Paleogene-Neogene volcanic rocks and lava, pyroclastics, karst reservoirs in oil- and gas-bearing basins in China. Volcanic rocks can not generate organic hydrocarbons, and the combination of volcanic rocks, source rocks and seals is the key controlling factor of the primary lava plays. The near-source play is most favorable for hydrocarbon accumulation. Distribution of oil and gas is controlled predominantly by the hydrocarbon-generating center. The distal play requires communication with faults or unconformities. Near-source plays are in the faulted basins in eastern China. Structural-lithologic hydrocarbon reservoirs are formed in the higher place of faults and lithologic hydrocarbon reservoirs are formed in the slope. Two types of plays are developed in central and western China. The near-source play is most favorable for the formation of large stratigraphic hydrocarbon reservoirs.