Petroelastic simulation as a method for analysing the anisotropy of elastic properties on the scale of seismic surveys

Abstract

Introduction. Reservoirs composed of thin layers with different elastic properties exhibit the anisotropy of elastic properties. Anisotropic environments are studied using special seismic positioning systems that require large financial and time resources. However, neglecting pronounced anisotropy leads to misinterpretation of the data. Evaluation of the degree of anisotropy of a thin-layer stratum allows researchers to determine whether anisotropy could be neglected by conditionally considering the stratum to be isotropic.Aim. To estimate the anisotropy of carbonate rocks on the scale of seismic surveys based on the data of geophysical well logging and petroelastic simulation.Materials and methods. Models of carbonate rocks with different characteristics of pore space were created based on the Berryman and Backus methods. For these models, an analysis of the degree of anisotropy by Thomsen parameters was carried out. Acoustic and density logging data of a well located in Western Siberia were used for comparison with actual data.Results. A numerical characteristic was found, the analysis of which helped to determine the significance of anisotropy before the application of the Backus method thus significantly reducing the number of necessary computational processes.Conclusion. The obtained parameter of the degree of rock heterogeneity correlates well with Thomsen parameters responsible for anisotropy, which indicates the possibility of its use for assessing the anisotropy of strata.