Study on the Imbibition Characteristics of Different Types of Pore-Throat Based on Nuclear Magnetic Resonance Technology

“Fracturing network+imbibition oil production” is a new attempt to effectively develop low-permeability tight reservoirs. Fracturing fluid not only carrier for sand carrying but also tool in the process of imbibition. On basis imbibition experiments, combined with nuclear magnetic resonance and pseudo-color processing technology, this paper clarified dominant forces different types pore-throat quantitatively characterized contribution levels recovery. The results show that gravity main controlling force reservoirs higher permeability. Fluid replacement mainly occurs early period Macropores contribute most recovery, mesopores have weak contribution, micropores pinholes can be ignored. For low permeability, capillary later recovery rate, small part factor, This macropores are sources efficiency, content connectivity key factors efficiency.