涠西南凹陷TY油田断层封闭性定量评价

涠西南凹陷低凸起TY油田的块1构造为涠洲组的断块圈闭，高部位F₂断层是成藏主控因素。从断层封闭机理及影响因素入手，综合考虑岩石泥质含量及压实强度，建立了岩石排驱压力与深度和泥质含量的定量关系式，利用该关系式分别计算目标储层和起封堵作用断层岩的排驱压力，对二者大小进行比较，实现定量评价断层封闭性。利用该方法对涠西南凹陷TY油田块1控圈断层F₂的侧向封闭能力进行了分析。结果表明，H1和H2两个目的层对接的断层岩的排驱压力大于储层的排驱压力，具有封闭能力； H3和H4两层对接的断层岩与储层的排驱压力差为负值，不具备封闭油气能力。

A Quantitative Evaluation of Fault Sealing of the TY Oilfield in the Weixinan Sag

Block 1 of the low uplifted TY Oilfield in the Weixinan Sag is within a fault trap of the Weizhou Formation and the F₂ fault at a higher position is the key factor in reservoir formation. This study assessed the mechanisms and influencing factors of fault sealing to comprehensively consider the mud content and compaction levels of rocks to establish the quantitative relationships between the driving pressure of rocks and their depth and mud content. Relationship equations were employed to calculate the driving pressure of the target reservoir layers and the fault rocks which serve as a blockage. The two values were compared in a quantitative evaluation of fault sealing. The proposed method was used to analyze the lateral sealing ability of the F₂ fault of Block 1 of the TY Oilfield in the Weixinan Sag. The results suggest that the driving pressure of the fault rocks connecting the two target layers H1 and H2 is greater than that of the reservoir layers; thus, the fault rocks are capable of sealing. Meanwhile, the faults rocks connecting H3 and H4 have a smaller driving pressure to that of the reservoir layers; thus, they cannot seal oil and gas.