论冀中地区O、C—P凝析气藏的形成条件

据凝析油轻烃组成、甲烷及其同系物碳同位素组成、天然气与源岩吸附气指纹时比、双环倍半萜组合特征及地质结构的综合分析，查明O、C—P大多数提析气藏的油气主要来源于石炭—二叠系煤系腐植型有机质，混入了部分下第三系的油气。对石炭—二叠系成烃特点的分析表明，R。=0.6%～1.3%，以成气为主，生油为辅，原始油气比一般大于1OOCm3/t。成熟期的石炭—二叠系有机质的成烃特点和具备油气富集的良好地质条件是O、C—P凝析气藏形成的基本条件。

FORMATION CONDITIONS OF O AND C-P CONDENSATE GAS RESERVOIRS IN JIZHONG AREA

According to the comprehensive analysis of light hydrocarbon composition of condensates, carbon isotopic composition of methane and its homologues，fingerprint correlation of natural gases with absorbed gases of source rocks, assemblage features of double-cycle serquiterpenes and geologic framework, this paper demonstrates that oil and gas in most O and C-P condensate gas reservoirs mainly come from humic organic matter of C-P coal seams and are mixed with a portion of oil and gas from Paleogene. The authors analyze the characteristics of hydrocarbon generation in C-P, and suggest that gas generation is main，oil generation is subordinate，and original gas-oil ratio is more than 100Cm3/t in general within vitrinite reflectance values of 0.6% —1.3%,The basic formation conditions of O and C-P condensate gas reservoirs are both the characteristics of hydrocarbon generation in C-P coal organic matter during mature stage anp the favorable geologic conditions for oil and gas accumulation.