To evaluate the lateral sealing mechanism of extensional fault based on the pressure difference between fault and reservoir, an integral mathematical-geological model of diagenetic time on diagenetic pressure considering the influence of diagenetic time on the diagenetic pressure and diagenetic degree of fault rock has been established to quantitatively calculate the lateral sealing ability of extensional fault. By calculating the time integral of the vertical stress and horizontal in-situ stress on the fault rock and surrounding rock, the burial depth of the surrounding rock with the same clay content and diagenesis degree as the target fault rock was worked out. In combination with the statistical correlation of clay content, burial depth and displacement pressure of rock in the study area, the displacement pressure of target fault rock was calculated quantitatively. The calculated displacement pressure was compared with that of the target reservoir to quantitatively evaluate lateral sealing state and ability of the extensional fault. The method presented in this work was used to evaluate the sealing of F₁, F₂ and F₃ faults in No.1 structure of Nanpu Sag, and the results were compared with those from fault-reservoir displacement pressure differential methods without considering the diagenetic time and simple considering the diagenetic time. It is found that the results calculated by the integral mathematical-geological model are the closest to the actual underground situation, the errors between the hydrocarbon column height predicted by this method and the actual column height were 0–8 m only, proving that this model is more feasible and credible.

为基于断层与储层压力差评价伸展断层的侧向封闭机制，考虑成岩时间对断层岩成岩压力和成岩程度的影响，建立了成岩时间对成岩压力的整体数学-地质模型。定量计算伸展断层的侧向封闭能力。通过计算断层岩和围岩上的竖向应力和水平地应力的时间积分，计算出与目标断层岩具有相同粘土含量和成岩程度的围岩埋深。结合研究区粘土含量、埋藏深度和岩石位移压力的统计相关性，定量计算了目标断层岩的位移压力。将计算出的驱替压力与目标储层压力进行对比，定量评价横向封闭状态和伸展断层的能力。本工作中介绍的方法用于评估 F 的密封性₁、南堡凹陷1号构造F ₂和F ₃断层，与不考虑成岩时间和单纯考虑成岩时间的断层-储层置换压差法的结果进行了对比。发现积分数理模型计算的结果最接近地下实际情况，该方法预测的烃柱高度与实际柱高的误差仅为0-8 m，证明该模型更具可行性和可信度。