东濮凹陷文留地区油气相态类型及分布规律

Distribution and phase type of hydrocarbon resources in Wenliu area,Dongpu depression

根据烃源岩热压模拟实验,结合温度—压力相图分析,研究了东濮凹陷文留地区油气资源在生排、运聚阶段相态的类型及演化特点。结果表明:沙三段烃源岩因埋深不同导致热演化程度不同,生、排油气相态的类型各异,主要包括重质油、常规油、挥发性油、凝析气和湿气—干气相态;运聚过程中油气相态的演化主要体现为油溶天然气出溶、原油稠化、原油裂解成气和原油逆蒸发反溶于气,其中中浅层主要为油溶天然气出溶,受温压和烃类组分双重因素控制,深层则主要为原油裂解成气,受温压条件的影响明显。在生排、运聚过程中油气相态演化特征研究的基础上,结合已发现油气藏相态类型的统计结果,确定了文留地区不同相态类型油气藏的垂向展布规律,深层以气藏为主,中浅层以油藏及临界态油气藏为主。

According to heat-press simulation experiment of source rock and phase diagram,we studied the phase type of hydrocarbon and its evolution characteristics during the stage of generation-discharge and migration-accumulation in Wenliu area,Dongpu depression.The results show that the Es3 source rock hydrocarbon phase stages are varying in different depth attribute to the difference in thermal evolution degree,the phase stages are heavy oil,conventional oil,ethereal oil,condensate oil and wet gas-dry gas.The changes during generating and transporting including gas ex-solution,oil thickening,oil cracking,oil inverse evaporating into gas.Controlling by temperature,pressure and composition,the middle and upper layer major transform is gas ex-solute from oil,and the lower layer transform is oil cracking dominated by temperature and pressure.Based on the former information,combining with the GOR data and hydrocarbon phase state,the law of phase state in vertical sequence is studied,reservoirs in the deeper layer are mainly gas pool,while reservoirs in the middle and upper layer are mainly oil reservoirs and the critical state of oil and gas reservoirs.