Abstract: The hydraulic fracturing breccia, sandstone vein, hydraulic fracture and activation synsedimentary fracture were recognized as the hydraulic fracturing products in the lower first member of Shahejie Formation in Dagang beach by observation of core and microscope. Hydraulic fracturing breccia can be joggled joint and the veins have clear fluid evidence. It is found that the fractures were developed in the crust around the uncompacted belt. Hydraulic fracturing experiments were conducted by using composite samples consisting of micrite(muddy siltstone)and sandstone. The relationship between hydraulic fracturing and rock type in sedimentary basin was analyzed. The low-permeability rocks and micrite(muddy siltstone)for modeling the crust of the overpressure system were broken under the action of overpressure fluid, while the sandstone for modeling the uncompacted belt of overpressure system was not broken. The experimental results coincide with the theoretical analysis and field observation of hydraulic fracturing made by others.

Key words: Dagang beach, the first member of Shahejie Formation, hydraulic fracturing, compaction, lithologic features, physical modeling

摘要： 通过对大港滩海区沙一段下部岩心观察和薄片分析,识别出水力破裂角砾、砂岩脉、水力破裂裂缝及活化同沉积裂缝4种水力破裂作用产物,水力破裂角砾之间具有可拼合性,脉体具有明显流体作用痕迹;本区水力破裂发生于欠压实带周围的“壳”中。利用三轴实验系统,对泥晶灰岩(泥质粉砂岩)—砂岩复合试件进行了水力破裂实验。在实验过程中,模拟超压系统“壳”的低渗透岩石—泥晶灰岩(粉砂质泥岩)发生了破裂,而模拟超压系统“欠压实带”的高渗透砂岩却未发生破裂。该实验结果与理论分析和水力破裂裂缝露头特征具有明显的可比性。

关键词: 大港滩海区, 沙一段, 水力破裂, 压实作用, 岩石学特征, 物理模拟