Reservoir Fluid Substitution Effect in Heterogeneous Seismic Model

Abstract

Based on the difference of wave impedance between sand layer and surrounding rock, the seismic wave numerical simulation software, Tesseral-2D is used to establish the sandstone formation model containing water, oil and gas respectively, and the three models are treated by post-stack time offset under the conditions of defined channel spacing, wavelet frequency and wave velocity of different rock mass, and the root means square amplitude difference attribute profile under the condition of water-filled oil-filled and gas-filled oil-filled is obtained. From this, it can be obtained that after oil-gas substitution occurs in weak non-mean reservoirs, the root-mean-square amplitude difference from the reservoir to the lower part of the reservoir experiences a mutation process from a positive maximum to a negative maximum, while after oil-water substitution, the root-mean-square amplitude difference from the reservoir to the lower part of the reservoir experiences a mutation process from zero to a positive maximum. For a strong heterogeneous reservoir. Therefore, for Weak inhomogeneous media similar to tight sandstone, the root-mean-square amplitude difference attribute can be used to detect the distribution of fluid in the actual gas drive or water drive oil recovery process.