Abstract: A pressure-sensitive effect affects unfavorably the production performance of fractured low-permeability reservoirs with horizontal fractures. With continuing an oilfield development, its formation pressure tends to decline along with the horizontal fractures being closed, the permeability drawdown and the productivity being damaged. Based on the core lab data, this paper presents the affected trend of varied pressure on core permeability, the differences of pressure-sensitive features between low-permeability sand cores with/ without horizontal fractures, and develops a model for steady-state productivity prediction considering the pressure-sensitive effect. Furthermore, the influences of pressure sensitivity on permeability, pressure distribution and productivity of such reservoirs are discussed with calculated example. These results have important instructional significance to highly efficient exploitation of fractured low permeability reservoirs with horizontal fractures.

Key words: pressure-sensitive effect, fracture, permeability, pressure, productivity