中文摘要：

天然气在微间隙中的气窜流动特征比较复杂，一旦发生环空气窜，就会造成生产损失，甚至影响施工安全。针对目前封堵材料粒径选择方法的不足，国内外公司做了大量的研究，但国内油田在此方面的研究还未成熟，气体上窜问题仍未得到根本解决。引入分形理论，建立微间隙封堵的物理模型，结合激光粒度测试得到的材料粒径分布状况及分形维数的合理筛选（D=2．556mm），假定在小于1．68mm、（1．68—56．8）mm、大干56．8μm三个粒径范围内分别填充微硅、水泥和漂珠，设计出水泥、微硅和漂珠的质量配比为100：22．068：12．973。并对封堵体系进行试验测定，结果表明该堵剂有良好的固结强度、造壁性和封堵效果。从而为微间隙封堵工艺提供技术指导，减少气窜事故的发生。

英文摘要：

The flow behavior of the gas breakthrough in the microgap is complex, production losses caused and construction safety affected by gas breakthrough. The companies research a lot at home and abroad for the optimum selection of grain diameter of plugging material, but this study is not mature at home, This shows that the gas channeling has not been fundamentally resolved. The fractal theory is introduce, the physical model of the plugging microgap was established. The grain-size distributions of the slurry materials are measured by a laser grain-size test machine, and an appropriate fractal dimension is screened （D = 2. 556）. Suppose that the grain sizes of micro-silica, cement and floating beads distribute respectively in 〈 1.68 μm, 1.68 - 56.8μm and 〉 56.8 μm, and the mass ratio of cement, micro-silica and floating beads is 100：22. 068：12.973. And this sealing system has been determined by testing, the test result indicates that the system has good consolidation strength, building capacity and sealing characteristics. It provided guidance for option of the plugging technology and low possibility for accidents.