论文部分内容阅读
济阳坳陷深层裂解气藏成因较为复杂,影响了深层天然气的认识和勘探。利用天然气组分和碳同位素等鉴别了原油裂解气和干酪根裂解气,进一步分析了2类成因的成藏差异性。原油裂解气表现为Ln(C2/C3)值随Ln(C1/C2)值增大而增大;干酪根裂解气随Ln(C1/C2)值的增大,Ln(C2/C3)值基本不变。在有机质类型和热演化程度大致相当的情况下,原油裂解气δ13C1值、δ13C2值、δ13C3值与相应的干酪根裂解气的最大差值分别为-12.4‰、-8.8‰和7.5‰;随着δ13C1值或(δ13C1-δ13C2)值的增大,干酪根裂解气(δ13 C2-δ13 C3)值快速减小,而裂解气(δ13 C2-δ13 C3)值变化微弱。干酪根裂解气藏表现为早期油气扩散、断裂活动停止和后期天然气充注,原油裂解气藏体现为早期油气充注、岩性侧向封堵和后期古油藏裂解的成藏规律。2种裂解气成因开启了深层天然气勘探的新思路,并指出了其勘探方向,对深层勘探具有重要的指导意义。
The genesis of the deep pyrolysis gas pool in Jiyang Depression is complicated and affects the understanding and exploration of deep natural gas. The natural gas components and carbon isotopes were used to identify the pyrolysis gas of crude oil and pyrolysis gas of kerogen. The differences of hydrocarbon accumulation between the two types of genesis were further analyzed. The value of Ln (C2 / C3) increased with the increase of Ln (C1 / C2) value. The value of Ln (C2 / C3) increased with the increase of Ln constant. The δ13C1 values, δ13C2 values and δ13C3 values of cracked gas of crude oil are -12.4 ‰, -8.8 ‰ and 7.5 ‰, respectively, with the organic matter type and thermal evolution roughly equivalent. (δ13C2-δ13C2) increased rapidly, the value of kerogen pyrolysis gas (δ13C2-δ13C3) rapidly decreased and the value of pyrolysis gas (δ13C2-δ13C3) changed little. The kerogen pyrolyzed gas reservoirs are characterized by early oil and gas diffusion, cease of the fault activity and filling of natural gas in later period. The crude oil pyrolysis gas reservoir is characterized by hydrocarbon accumulation, lateral seal of lithology and later reservoir fracturing. Two kinds of pyrolytic gas genesis opened a new idea of deep natural gas exploration, and pointed out its exploration direction, which has important guiding significance for deep exploration.