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泥岩涂抹是断层封闭的主要机制之一,为了建立合理的断层封闭性评价方法,系统研究了泥岩涂抹类型、形成和演化规律.结果表明:泥岩涂抹主要有3种类型:即研磨型、剪切型和注入型.泥岩、页岩、煤层、膏岩、泥质盐岩、碳酸盐岩和粉砂岩均可成为涂抹的原岩,由原岩与周围岩石的强度差异所决定的拉张型叠覆带是泥岩涂抹形成的关键地质因素.叠覆区的几何学特征、断距与泥岩厚度的比率、有效正应力控制着泥岩涂抹的连续性,亚地震断层(断距小于15m)泥岩涂抹连续临界SSF值范围很大,最大可达到50,规模较大的断层(断距大于15m)临界SSF值一般为5～8,有效正应力越大,临界SSF值越大.连续的泥岩涂抹导致断层在盖层段垂向封闭.断层侧向封闭取决于多次涂抹形成断层泥含量,可建立SGR,SSF和CSP与过断层面压力差之间的关系,从而计算断层所能封闭的最大油气柱高度,实现断层侧向封闭性定量评价.
Mudstone smear is one of the main mechanisms of fault sealing. In order to establish a reasonable method of fault sealing evaluation, the types, formation and evolution of mudstone are systematically studied.The results show that there are mainly three types of mudstone smear: grinding, shearing Shale, coal seam, gypsum, argillaceous salt rock, carbonate rock and siltstone can all be coated original rock, which is determined by the difference in strength between the original rock and the surrounding rock The overburden zone is the key geological factor for the formation of mudstone smear.The geometric characteristics of overburden zone, the ratio of breakage to mudstone thickness, effective normal stress control the continuity of mudstone smear, the sub-seismic fault (less than 15m) mudstone smear Continuous critical SSF values range widely, up to 50, and the critical SSF values for large-scale faults (with a breakage greater than 15 m) are typically 5 to 8. The larger the effective normal stress, the greater the critical SSF value. The fault is vertically confined in the caprock, and the lateral sealing of the fault depends on the amount of fault mud formed by multiple smears to establish the relationship between the SGR, SSF and CSP and the pressure difference across the fault and thus the maximum oil and gas trapped by the fault Column height, Quantitative evaluation of fault lateral sealing.