Study on Wettability and Static Imbibition Law of Tight Reservoir Based on Nuclear Magnetic Resonance Test

The research on tight oil is one of the hot spots nowadays. China has rich tight oil resources, with a wide distribution range and great development potential. For tight reservoirs, this paper proposes a method to test the rock wettability of tight reservoirs using the nuclear magnetic resonance (NMR) technology. Based on the idea of combining the NMR technology with indoor physical simulation, and on the basis of T2 relaxation time, the mixed wettability index is calculated through the limit of T2 relaxation time of 1 ms to evaluate the wettability of tight reservoirs. The design contrast experiment has studied the influence of wettability on the imbibition law, and concluded that the imbibition rate of hydrophilic rock samples is higher than that of lipophilic rock samples, but the ultimate recovery rate of lipophilic rock samples is higher than that of hydrophilic rock samples, which provides a basis for the development of tight reservoirs.