关键词: 循环荷载；导流能力；支撑剂层；应力敏感性；渗流&ndash, 应变耦合

Abstract: Alternating load damages fracture conductivity. Alternating load is caused by stress shadow effect between artificial fractures during the process of shale-gas well multistage fracturing or caused by gas extraction and stop production during the period of production. Ceramic proppants with different thicknesses are tested via the DL-2000 diversion tester under cyclic loading to study deformation and seepage characteristics of proppant. The results show that with the number of cyclic loading increasing, elastic strain is basically stable, the plastic strain continues producing. Plastic strain is the basic reason of the decreasing permeability. The trends of plastic strain along with closure pressure coincide well with that of permanent permeability loss. Elastic strain and recovery permeability increase with closure pressure increasing. Elastic strain decreases with sand thickness increasing; but recovery permeability has no significant change. Along with the thickness of sanding increasing, fracture stress sensitivity reduces; particle breakage degree decreases; so increasing sanding thickness can decrease crack width loss and permeability loss; and then reduce the harm of fracture conductivity caused by cyclic loading.

Key words: cyclic loading, conductivity, proppant, stress sensitivity, coupled seepage and strain