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对东濮凹陷古近系凝析气的多样相态类型及成因进行研究.基于油气的轻烃组成并结合试油结果,利用方框图法、因子法、秩数法和Z值法等多种判别方法,对东濮凹陷古近系凝析气藏的相态类型进行了综合判识;并利用ln(C_1/C_2)-ln(C_2/C_3)关系及苯/正庚烷与正庚烷/甲基环己烷关系,结合研究区的地质特征,对凝析气的成因进行了分析,认为东濮凹陷不同类型凝析气藏的分布具有一定的差异,由富生烃洼陷向中央隆起带、由古近系深部向浅部层系,依次发育原生型凝析气藏、原油裂解型凝析气藏和运移分馏型凝析气藏,兰聊断裂、黄河断裂等基底大断裂附近的中浅层还发育煤成气气侵富化凝析气藏.研究结果表明:东濮凹陷古近系凝析气藏主要表现为带大油环、带小油环和无油环等3种相态类型,成因类型包括原生型、原油裂解型、运移分馏型和气侵富化型等4种,且二者之间存在一定的对应关系.原生型凝析气藏通常无油环,轻质组分含量高,C_(5+)质量分数小于1.75%,主要分布于埋深4 200m以下深层洼陷带;原油裂解型凝析气藏多带有大油环,重质组分含量较高,C_(5+)质量分数大于1.75%,且随着ln(C_1/C_2)增加,ln(C_2/C_3)变化较大,主要分布于深层环洼斜坡带,剖面上与原生凝析气藏相邻,但深度稍浅于原生型凝析气藏;运移分馏型凝析气藏通常带有小油环,具有较高的正庚烷/甲基环己烷比值和较低的苯/正庚烷比值,主要分布于构造高部位;气侵富化型凝析气藏往往无油环,其形成与石炭—二叠系煤成气的向上侵入有关,~(40)Ar/~(36)Ar介于630~803,δ~(13)C_1介于-38‰~-34‰之间,属油型气和煤型气的混合气范畴,主要分布于存在气源断裂沟通深部石炭—二叠系烃源岩的区域.
Based on the light hydrocarbon composition of oil and gas combined with the test oil results, the paper uses the block diagram method, factor method, rank method and Z value method to judge the diversity phase of the condensate gas in Paleogene in Dongpu Sag. Method, the phase state types of the Paleogene condensate gas reservoirs in Dongpu Depression are comprehensively identified. The relationship between ln (C 1 / C 2) -1n (C 2 / C 3) Methylcyclohexane and the geological characteristics of the study area, the causes of condensate gas are analyzed. The distribution of different types of condensate gas reservoirs in Dongpu Depression shows that there is a certain difference in the distribution of gas condensate from the hydrocarbon-rich hydrocarbon-bearing depression to the central uplift zone , From the Paleogene deep to shallow layer system, followed by the development of the primary condensate gas reservoir, crude oil cracking condensate gas reservoir and migration fractionated condensate gas reservoir, Lan chat fault, the Yellow River fault near the basement fault In the middle and shallow layers, gasification and enrichment condensate gas reservoirs are also developed. The results show that the Paleogene condensate gas reservoirs in Dongpu sag are mainly characterized by large oil ring, small oil ring and oil-free ring There are four types of facies and types of genesis, including primary type, crude oil cracking type, migration fractionation type and gas intrusion enrichment type There is a certain correspondence between the primary condensate gas reservoirs. There is usually no oil ring in the primary condensate gas reservoirs. The content of light components is high, the content of C 5+ is less than 1.75%, mainly distributed in the deep subsidence zone below 4 200 m, Most of the pyrolysis condensate gas reservoirs have large oil rings with high contents of heavy components and C_ (5 +) mass fraction of more than 1.75%. With the increase of ln (C_1 / C_2), the change of ln (C_2 / C_3) Which is mainly distributed in the deep annular depression zone and is adjacent to the primary condensate gas reservoir in profile, but slightly shallower than that of the primary condensate gas reservoir. The migration-fractionated condensate gas reservoir usually has a small oil ring, With a higher n-heptane / methylcyclohexane ratio and a lower benzene / n-heptane ratio, which are mainly distributed in the high positions of the structure. Gas-in-enrichment condensate gas reservoirs often lack oil rings and are formed with carbon (40Ar) ~ (36Ar) is between 630 ~ 803, δ ~ (13) C_1 is between -38 ‰ ~ -34 ‰, and is an oil type Mixtures of gas and coal gas are mainly distributed in the areas where there are gas source faults that communicate with deep Carboniferous-Permian source rocks.