摘要
本文通过系统研究该区低熟油的物理化学特征,总结了低熟油的标志特征。在此基础上进行了精细的油岩对比,确定了济阳坳陷低熟油主要来自咸水—半咸水的沙四段和沙一段烃源岩。通过模拟实验和自然演化剖面对比研究发现,济阳坳陷的沙四段和沙一段烃源岩之所以在埋藏较浅的情况下形成了大规模的低熟油资源,有以下几方面的重要原因:①沙四段、沙一段烃源岩中存在富含藻类的有机质富集层,它是形成低熟油的物质基础;②富含有机酸、钾离子、铝离子的地层流体特征加速了粘土矿物的成岩演化,促进了低熟油的生成;③可溶有机质是形成低熟油的主要贡献者;④咸化环境有利于可溶有机质的保存。通过对其成油体系的剖析发现,低熟油成藏具有早生、早排、成藏期晚、运移距离短等特点,油藏展布受有效烃源岩体的控制,故低熟油的勘探应紧紧围绕低熟烃源岩体进行。
Based on oil-source correlation, and comparison ofexperimental profile of thermal simulation and naturalevolution profile, it is determined that immature oil ofJiyang depression was mainly from saline-brackishEs_4 and Es_1 source rocks. Some significant reasons are as follows. In Es_4 and Es_1 source rocks, there are con-centrated organism layers rich in algae Which are thebase of forming immature oil. Formation water rich inorganic acid, K^+ and Al^(3+) can accelerate diagenesisevolution of the clay mineral and forming of immatureoil. The soluble organic matter is the main contributorto immature oil generation. The saline environment isfavorable to the preservation of the soluble organicmatter. By means of the analysis of petroleum systems,it is believed that immature oil is characterized byearly generation, early expelling, late formation of oilpool, migration of short distance,with the spatial dis-tribution of oil pool controlled by the effective sourcerock.
关键词
低熟油
半咸水
生油
有机质
济阳坳陷
烃源岩
immature oil
brackish water
algae organism
soluble organic matter
regularity of pool formation
Jiyang depression.
