油气二次运移方向模拟及有利区带预测:以束鹿凹陷西斜坡沙二段为例

Simulation of Secondary Hydrocarbon Migration Direction and Prediction of Favorable Zones: An Example from the Second Member of Shahejie Formation of West Slope,Shulu Sag

束鹿凹陷位于冀中坳陷南部,为一典型的断陷湖盆。凹陷古近系发育多套生储盖组合,具有良好的勘探前景。为了寻求油气勘探的突破口,进一步明确勘探的主攻方向和区带,急需深化对研究区油气二次运移的认识。以束鹿凹陷西斜坡沙二段为例,基于Arcgis软件对目的层的油源区、输导体系、构造及流体势特征等多种地质信息进行处理,在大尺度条件下以流体势模型为油气二次运移动力模型模拟油气二次运移方向。模拟结果揭示,油气在砂体发育状况的约束下,鼻状构造控制油气相对运移方向,油气向其脊部运移汇聚。最后,依据油气二次运移方向模拟结果及对成藏条件的认识,优选出台家庄鼻状构造带、雷家庄南部鼻状构造带以及西曹固南、北鼻状构造带4个长期继承性的鼻状构造带为成藏有利区带。

The Shulu sag in the south of Jizhong depression is a typical rift basin. Paleogene formation develops many sets of source-reservoir-cap assemblage,showing good exploration prospects. In order to seek the breakthrough in oil and gas exploration and to clarify the main exploration direction and zones,it’s urgent to deepen the understanding of the secondary hydrocarbon migration of the study area. Taking the Second Member of Shahejie Formation as an example,based on the Arcgis software platform,we could manage the various geological information,such as source kitchen,conducting system,structural features,fluid potential,etc. After then,we simulate the direction of the secondary hydrocarbon migration with fluid potential model under the large scale conditions. The simulation results reveal that the secondary hydrocarbon migration is dominated by nose-structural belt under the restraint of development status of sandbody,and the oil and gas gather in its spine. Finally,four nose-structural belts are selected to be the favorable accumulation zones based on the understanding of simulation results and reservoir-forming conditions.