凹陷区上生下储油侧向运移模式及油聚集——以松辽盆地三肇凹陷扶杨油层为例

为了研究三肇凹陷扶杨油层油成藏规律,采用油分布与源岩、断裂空间叠合研究的方法,对扶杨油层油侧向运移模式及其对油成藏与分布的控制作用进行了研究。结果表明,上覆青一段源岩生成的油向下伏扶杨油层侧向运移的模式为:断裂错断使上覆青一段源岩与下伏扶杨油层中的不同油层组对接,青一段源岩生成的油在浮力作用下侧向运移进入扶杨油层的不同油层组中;断裂错断阶数越多,青一段源岩生成的油侧向运移进入扶杨油层中油层组的层位越深,反之则越浅。青一段源岩生成的油向扶杨油层侧向运移对其油成藏与分布的控制作用主要表现在2个方面:①断裂密集带两侧的地垒构造是扶杨油层油成藏的有利部位;②扶一油层组是青一段源岩生成的油向扶杨油层侧向运移的主要层位。这一研究成果对于指导三肇凹陷扶杨油层石油勘探具有推广价值。

Lateral migration model of oil in combination of upper source rock and lower reservoir and oil accumulation in depressed area:An example from Fuyu and Yangdachengzi oil layer in Sanzhao Depression,Songliao Basin

In order to study the oil accumulation rule of Fuyu and Yangdachengzi oil layer in Sanzhao Depression,the method of studying space distribution relation among oil distribution,source rocks and faults was applied to study the oil lateral migration model and its control action on oil accumulation and distribution.The result shows that the lateral migration model is that oil generated from the overlying K1 qn1 source rocks migrates into underlying different horizons of Fuyu and Yangdachengzi oil layer under the action of buoyancy,because faults make the overlying K1 qn1 source rocks touch with underlying different horizons of Fuyu and Yangdachengzi oil layer.The more the fault step in fault is,the more horizons of Fuyu and Yangdachengzi oil layer the oil migrated into.This lateral migration model of oil generated from the overlying K1 qn1 source rocks controls the oil accumulation and distribution of Fuyu and Yangdachengzi oil layer,and it mainly displays in the following two aspects:①The horst structures in two sides of fault condensed belts are favorable places for oil of Fuyu and Yangdachengzi oil layer to accumulate.②Fu I oil group is the main horizon for oil generated from the overlying K1 qn1 source rocks to migrate and accumulate in Fuyu and Yangdachengzi oil layer.The study result is of extend value for guiding oil exploration of Fuyu and Yangdachengzi oil layer in Sanzhao Depression.