A New Fluid Mobility Calculation Method Based on Frequency-Dependent AVO Inversion

Xin Luo,Yingkai Qi,Fei Huo,Yinghao Duan,Xuehua Chen,Shizhen Chen

doi:10.3389/feart.2022.829846

Abstract

Fluid mobility (i.e., permeability to viscosity ratio) is a key parameter that can evaluate the reservoir permeability and delineate the fluid characteristic in hydrocarbon-saturated reservoirs. Based on the asymptotic representation for the frequency-dependent reflections in the fluid-saturated pore-elastic media and frequency-dependent AVO inversion, we propose a novel method for estimating fluid mobility from poststack seismic data. First, we establish the relationship between fluid mobility and frequency-dependent AVO analysis. Then, the fluid mobility is estimated using the theory of frequency-dependent AVO inversion. Tests on synthetic data reveal that the fluid mobility shows excellent imageability for the fluid-saturated reservoirs and can accurately delineate the spatial distribution shape of the gas-saturated reservoir. The application of field data examples demonstrates that the fluid mobility calculated by the proposed method produces less background interferences caused by elastic layers compared with the conventional frequency-dependent fluid indicator. The frequency-dependent fluid mobility takes into account the dispersion features associated with hydrocarbon reservoirs, and it provides a new way to detect the location of hydrocarbon reservoirs and characterize their spatial distribution.

Highlights

The reservoir permeability is a key parameter for measuring the capacity of fluid flow in porous rock and it is commonly measured through laboratory experiments
In comparison with the LF-FM method, the fluid mobility calculated by the proposed method can better delineate the spatial distribution shape
In addition to significant computation time reductions, the fluid mobility calculated by the proposed method has a higher accuracy for reservoir characteristics compared with the dispersion attribute, which can better delineate the reservoir location

Summary

INTRODUCTION

The reservoir permeability is a key parameter for measuring the capacity of fluid flow in porous rock and it is commonly measured through laboratory experiments. To illustrate the effectiveness of the proposed method, we design a simple gas-saturated permeable reservoir model (Figure 1A) to test the feasibility of the frequency-dependent fluid mobility to delineate reservoirs. The test for the synthetic data illustrates that the fluid mobility calculated by the frequency-dependent inversion method can accurately delineate the location of the gas-saturated reservoir. The fluid mobility slice clearly delineates the spatial distribution and the edge of the gassaturated reservoirs

DISCUSSION AND CONCLUSION

DATA AVAILABILITY STATEMENT