Abstract: Effective permeability is one of the key parameters to characterize shale reservoirs. Due to the density of shale reservoir, it is of great difficulty to obtain the effective permeability through by core flow experiment. In order to solve the problem, a method to predict the effective permeability of rock based on imbibition experiment is established in this paper. Firstly, the spontaneous imbibition coefficient is obtained through shale spontaneous imbibition experiment, and the effective permeability prediction method based on the spontaneous imbibition coefficient is established by comprehensively considering the permeability pressure, tortuosity and dynamic capillary force of shale. The results show that the effective permeability prediction method established in this paper takes into account all factors, requires fewer parameters, and has a clear calculation process, which is more in line with the real formation situation. Osmotic pressure and tortuosity have obvious influence on effective permeability. Ignoring osmotic pressure will lead to a higher prediction of effective permeability, and ignoring tortuosity will lead to a lower prediction of effective permeability. This paper provides a new way to evaluate effective permeability of shale reservoir effectively and quickly.

Key words: shale reservoir, spontaneous imbibition experiment, osmotic pressure, dynamic capillary force, spontaneous imbibition coefficient, effective permeability