Experimental Study on Multi-Layer Waterflooding in Low-Permeability Carbonate Reservoirs by NMR

In consideration of the heterogeneity of low-permeability carbonate reservoir in M reservoirs of H oilfield, carried out multi-layer waterflooding physical simulation experiment, and based on the nuclear magnetic resonance (NMR) technique, studied the micro-distribution of residual oil and recovery degree of three different permeability combination. Results show that to the different pore structure types, NMR tests have different The greater permeability, NMR T2 relaxation spectrum further to right, the higher the peak, indicating more movable fluid. The difference of permeability range has certain influence on residual oil and recovery degree of multi-layer waterflooding, residual oil, and recovery degree in absolute and relative values of different permeability combination are quite different. The larger the permeability contrast, small pores have less residual oil relative value and greater recovery degree relative value; residual oil and recovery degree absolute values are mainly distributed in large pores, less in small pores. In same permeability contrast, the low-permeability samples of residual oil are greater than high-permeability samples, and the exploitation potential of large pores is still enormous.