Abstract: Based on the experiments of hydrocarbon-generating simulation and the analysis on P-T phase diagram,the existing phase type of oil and gas products generated from source rocks was studied in the primary migration stage of oil and gas in Dongying Depression.The phase types of hydrocarbon-generated and hydrocarbon-expulsed from source rocks in the 4th member of Shahejie Formation varied with the increase of the buried depth of source rocks and included viscous oil,conventional oil,volatile oil,condensate gas and wet-to-dry gas.The source rocks in the 3rd member of Shahejie Formation only produced the conventional oil.The changes of phase type and its affecting factors were investigated in the secondary migration stage of oil and gas in Dongying Depression.The natural gas could be released from oils,and oil could be thickened in the secondary migration stage of oil and gas in Dongying Depression.The release of natural gas from oil was controlled by temperature,pressure and the components of oil and gas.The biodegradation could accelerate the release of natural gas from oil.Both the biodegradation and water washing could improve the thickening actions of oil in Dongying Depression.Based on the phase types of explored reservoirs,the existing depth range of hydrocarbon resources with various phase types was ascertained in Dongying Depression.

Key words: Dongying Depression, hydrocarbon resources, hydrocarbon phase type, hydrocarbon-generation and hydrocarbon-expulsion, natural gas release from oil, oil thickening, biodegradation, secondary migration

摘要： 根据生烃模拟实验,结合相图特征,研究了东营凹陷烃源岩生排油气相态类型演化特点。结果表明:沙四段烃源岩在不同演化阶段,生、排油气相态类型不同,其相态类型包括稠油、常规油、挥发性油、凝析气和湿气—干气相态;沙三段烃源岩则全部处于生排常规油相阶段。对二次运移过程中油气相态类型的变化及主要影响因素分析表明:二次运移过程中,油气相态类型变化主要包括油溶天然气出溶和原油稠化。油溶天然气出溶主要受地层温度、压力和油气流体组成控制,生物降解可加速油溶天然气出溶;原油稠化的主要地质作用为生物降解作用和水洗作用。在此基础上,结合对已发现油气藏相态类型的统计,确定了东营凹陷不同相态类型油气资源的垂向分布范围。

关键词: 东营凹陷, 油气资源, 油气相态, 生排烃, 油溶天然气出溶, 原油稠化, 生物降解, 二次运移