砂体油气输导优势路径分布预测方法及其应用

Prediction Method for the Distribution of Dominant Paths for Oil and Gas Transmission in Sand Bodies and Its Application

为了厘清松辽盆地北部巴彦查干地区葡萄花油层P_(Ⅰ)^(1-1)小层油气分布规律,在砂体油气输导条件和优势路径形成机理研究的基础上,通过砂体孔隙连通分布区和砂体所在地层顶面古构造脊分布,确定砂体油气输导主优势路径;基于砂体孔隙连通分布区和优势相砂体分布,确定砂体油气输导次优势路径,形成了适用于断裂不发育的含油气盆地砂体油气输导优势路径分布预测方法。研究结果表明:砂体油气输导优势路径受砂体连通性和油气势能差共同影响,巴彦查干地区葡萄花油层P_(Ⅰ)^(1-1)小层发育5条砂体油气输导主优势路径,中部和东部各发育1条规模相对较大的南北向砂体油气输导主优势路径;北部和东南部发育砂体油气输导次优势路径。规模较大的2条砂体油气输导主优势路径范围内,有利于下伏青山口组烃源岩生成油气在P_(Ⅰ)^(1-1)小层内聚集成藏,与目前已发现的油气分布相吻合,表明该方法用于预测砂体油气输导优势路径是可行的。准确预测砂体油气输导不同级别优势路径,对于厘清含油气盆地砂体中的油气分布规律和指导油气勘探具有重要意义。

In order to clarify the oil and gas distribution law of P_(Ⅰ)^(1-1)sub-bed of Putaohua Reservoir in Bayantsagaan Area of northern Songliao Basin,on the basis of the research on the conditions of oil and gas transport in sand bodies and the formation mechanism of the dominant paths,the main dominant path for oil and gas transport in the sand body is determined by the distribution of sand body pore-connected distribution zones and the distribution of paleotectonic ridges on the top surface of the layer where the sand body is located;based on the sand body pore-connected distribution zone and the distribution of dominant-phase sand bodies,the subdominant paths for oil and gas transport in sand bodies are determined,thus forming a method for predicting the distribution of dominant paths for oil and gas transport in sand bodies in oil and gas-bearing basins with undeveloped fractures.The study results show that the dominant paths for oil and gas transport in sand bodies are affected by the connectivity of sand bodies and the difference in potential energy of oil and gas.Five main dominant paths for oil and gas transport in sand bodies have been developed in the P_(Ⅰ)^(1-1)sub-bed of Putaohua Reservoir in Bayantsagaan Area,and there is one relatively large-scale north-south oriented main dominant path for oil and gas transport in sand bodies in the center and east of the area;and there are two subdominant paths for oil and gas transport in sand bodies in the northern and southeastern parts of the area.The two relatively large-scale main dominant paths for oil and gas transport in sand bodies are conducive to the accumulation of hydrocarbons from the source rocks of the underlying Qingshankou Formation within the P_(Ⅰ)^(1-1)sub-bed,which is consistent with the distribution of hydrocarbons discovered so far,indicating that this method is feasible for predicting dominant paths for oil and gas transport in sand bodies.Accurately predicting the advantageous pathways of oil and gas transmission in sand bodies at different levels is of great significance for clarifying the distribution patterns,it will guide oil and gas exploration.