断-砂配置中油气运移方向的判别方法及其应用

Discriminatory method and its application of oil-gas migrating direction in fault-sand-body configuration

为了研究含油气盆地下生上储式生储盖组合中油气分布规律,在油气沿断裂垂向运移和沿砂体侧向运移机制及所需条件研究的基础上,通过比较利用模拟实验结果确定出的断裂填充物排替压力和砂体排替压力的相对大小,建立一套断-砂配置中油气运移方向的判别方法,并将其应用于南堡凹陷5个典型区块7条输导断裂与东营组53个砂层配置中油气是沿断裂垂向运移还是沿砂体侧向运移的判别中。结果表明:东营组53个砂层中有35个砂层的排替压力小于断裂填充物的排替压力,油气沿砂层侧向运移,油气钻探为油层或油水同层;有18个砂层的排替压力大于断裂填充物的排替压力,油气沿断裂垂向运移,油气钻探为水层或干层,这一研究结果与目前油气钻探所揭示的油气分布相吻合;该方法用于判别断-砂配置中油气是沿断裂垂向运移还是沿砂体侧向运移是可行的。

In order to study the oil-gas distribution patterns in lower generation-upper accumulation source rock-reservoir-cap rocks in oil-gas bearing basins,a set of discriminating methods for oi-gas migrating direction in fault-sand-body configuration were established. The methods were derived based on necessar conditions and mechanisms of oil-gas migrating both vertical-ly along faults and laterally along sand bodies,and by comparison of relative sizes of displacement pressures in fault filler and sand bodies. The new methods were then used to determine the vertical and horizontal directions of oil-gas migration in 7 transport faults of 5 typical blocks in Nanpu Depression, and 53 sand layers in Dongying Formation. The result show that in 53 sand layers of Dongying formation,the displacement pressure of 35 sand layers is less than that of fault filler,where oil-gas migrates laterally along sand layers; oil-gas drilling is oil layer or oil-water layer. The displacement pressure of the rest 18 sand layers is larger than that of fault filler,where oil-gas migrates vertically along fault and oilgas drilling is water layer or dry layer. The results are coincident with known well logs, and suggest that the method is feasible to be applied in discrimi-nation of oil-gas migrating vertically along fault or laterally along sand-bodies in fault-sand-body configuration.