The Evolutionary Characteristics of Reservoir Microstructure under Long-Term Waterflooding Development and Its Fractal Description

Generally, long-term waterflooding development often leads to the change of reservoir pore and clay mineral composition, which results in permeability wettability. In order explore relationship between core micropore structure water cut, based on physical simulation experiments fractal theory, we proposed a evolutionary model describe evolution characteristics microstructure driving reservoirs. this paper, by SEM was first conducted analyze before after under conditions magnification 200 times, 800 2000 respectively. Then, conventional constant rate mercury injection tests were combined perform comparative analysis structural parameters waterflooding. Finally, micropore-throat established. Research shows that connectivity larger pores becomes better driving, degree heterogeneity weakens, micro small stronger stronger. The throat complex manner, radius tends increase, sorting better, while changes complex. general, increases with time reservoirs low porosity permeability. On basis theory variation rock reservoirs, have established pore-throat characteristics. This quantitatively characterized complexity law clarified dimension cut different stages driving.