由地震资料预测断—盖配置有效封闭部位

Effective sealed part prediction in the fault-caprock configuration on seismic data

当盖层受到断裂破坏后,其能否封闭油气不再取决于其本身的封闭能力,而取决于断—盖配置的封闭能力,即:断层岩石排替压力大于或等于下伏储层岩石排替压力,则油气被断—盖配置封闭;相反,油气则不被断—盖配置封闭。基于上述原理,研究了含油气盆地断—盖配置对油气的控制作用。从断—盖配置封闭油气机理及其影响因素研究入手,通过计算一条断裂不同点处的断—盖配置封闭油气所需的最大破坏程度值,比较断—盖配置破坏程度与其封闭油气所需的最大破坏程度的相对大小,建立了一套利用地震资料预测断—盖配置有效封闭部位的方法。该方法在渤海湾盆地南堡凹陷南堡5号构造的NP5-1断裂与东二段泥岩盖层配置封闭部位的预测结果与已发现油气藏分布相吻合,表明该方法是可行的。

When the caprock is damaged by a fracture,the sealing ability of the capcock is no longer dependent on the sealing ability of the caprock itself,but depends on the sealing ability of the fault-caprock configuration.That is,if the displacement pressure of the fault rock is greater than or equal to the displacement pressure of the lower reservoir rock,the oil and gas are sealed by the fault caprock configuration.On the contrary,the oil and gas are not sealed.Based on the above principles,the control effect of the fault-caprock configuration on oil and gas in a basin is studied.We first discuss the oil and gas sealing mechanism with the fault-caprock configuration and its influencing factors.Then we calculate the maximum damage values required for oil and gas sealing at different points of the fracture.After that we compare the damage value of the fault-caprock configuration to the maximum value required by the sealing of oil and gas.So an effective sealed part prediction approach in the fault-caprock configuration on seismic data is established.The prediction of NP5-1 fault and Ed_2 of Nanpu No.5 structure in Nanpu Sag,Bohai Bay Basin with the proposed approach coincides well with the distribution of the discovered oil and gas reservoirs,which shows that the proposed approach is feasible.