关键词: 裂隙砂岩;渗流特性;分形维数;渗流模型

Abstract: In order to study the influence of fracture on the seepage characteristics of sandstone , Laser Scanning Confocal Microscopy ( LSCM) was used to observe the fracture surface of sandstone with different particle sizes.The 3D fractal dimension D was used to characterize the fracture surface roughness.The rock pore-fracture seepage flow system was used to carried out sandstone specimen seepage experiment with different rough single fracture .And the model of sandstone seepage with single rough fracture was established .The results show that 3D fractal dimension D can characterize the surface roughness of sandstone fracture.The seepage flow of fracture is obviously affected by fracture surface roughness, and when the fracture width is same , the seepage flow decreases with the increase of fracture 3D fractal dimension D.There exists a fracture width threshold (b =175 μm), and the seepage flow increases rapidly when the fracture width is greater than 175 micrometer.The model of single fracture seepage was established based on 3D fractal dimension D, the model result has good agreement with the test law of fracture seepage, so the model is reasonable .

Key words: fracture sandstone;seepage characteristic;fractal dimension;seepage model