断层封堵能力定量评价

断层封堵性分析是断层构造圈闭评价的重要内容，断层封堵能力的优劣将直接决定其成藏的可能性。依据对接封堵机理，将砂岩视为渗透性地层，泥岩视为非渗透性地层，通过地震及区域地质资料，确定目的盘和封堵盘整体高度、各层厚度及砂地比等参数。通过随机模拟建立断层两侧岩性柱子，对砂岩储集层进行逐层判断，统计每层被封堵的百分比，将出现概率最大的封堵百分比值视为该目的层的封堵百分比。从定量计算结果可总结出断层两侧砂岩含量、地层层数等参数对封堵能力的影响规律：目的盘含砂量越低、层数越多，砂岩被封堵的百分比越高；封堵盘含砂量越低、层数越少，目的盘砂岩被封堵的百分比越高。将该方法应用于珠江口盆地深水区构造圈闭断层封堵性研究，认为目的盘砂岩的封堵百分比为40％～50％，属于中等封堵。图9表3参18

Quantitative evaluation of fault sealing capacity

Fault sealing analysis is an important aspect of the fault trap evaluation. Probability statistics is used to quantitatively evaluate fault sealing. According to the fault sealing mechanism, sands are permeable strata and clay stones are impermeable strata. The paper determines the sedimentary facies and sand content of target stratum and plugged zone using seismic data and regional geological data, and then establishes the lithologic columns on both sides of the fault using random simulation, counts the sealing percentage of every sand layer, and confirms the sealing percentage of the whole reservoir rocks by probability statistics calculation. The results show: the lower content of sand and the more strata reservoir rocks contain, the higher the percentage of the fault sealing sandstones; the lower content of sand and the less strata sealing rocks contain, the higher the percentage of the fault sealing reservoir rocks. The method is applied in the deepwater area of the Pearl River Mouth Basin without wells and indicates that its sealing percentage is 40%-50%.