Main Controlling Factors Of Water/Gas Channeling In Tight-Low Permeability Reservoir

Aiming at the serious problem of water and gas channeling in the process of tight-low permeability reservoir exploitation,this paper studies the main controlling factors and relevant laws of influencing channeling by physical simulation experiment.By using the homogeneous columnar core model,the influence of core permeability,displacement velocity and displacement pressure on water and gas channeling caused by viscous fingering are studied;By using the two-layer heterogeneous core model,the influence of permeability ratio and displacement velocity on water channeling caused by heterogeneity are studied.The experimental results of water flooding in columnar cores show that the strength of water channeling decreases monotonously with the increase of core permeability,and the weakening range is greater when the permeability is less than17.88×10^-3μm².The strength of water channeling increases monotonously with the increase of displacement velocity,and the enhancement is greater when the displacement velocity is less than 2m/d.The experimental results of CO₂ displacement in columnar cores show that the strength of gas channeling increases monotonously with the increase of core permeability,and the enhancement is greater when the monotonously with the increase of displacement pressure,and the enhancement is greater when displacement pressure is more than 0.5MPa.In the homogeneous core with permeability of 1.72×10^-3μm²,the degree of gas channeling is much weaker than that of water channeling.So gas injection has more advantages in tight and low permeability reservoirs.The experimental results of water flooding in two-layer heterogeneous cores show that the strength of heterogeneous water channeling increases monotonously with the increase of permeability ratio,and the enhancement is greater when the ratio is less than 11.49.The strength of heterogeneous water channeling increases monotonously with the increase of displacement velocity,and the enhancement is greater when the displacement velocity is less than 2m/d.