Pre-Stack Seismic Data-Driven Pre-Salt Carbonate Reef Reservoirs Characterization Methods and Application

Xingda Tian,Handong Huang,Jun Gao,Tong Zhu,Gang Cui,Jing Zeng,Yaneng Luo

doi:10.3390/min11090973

Abstract

Carbonate reservoirs have significant reserves globally, but the substantial heterogeneity brings intractable difficulties to exploration. In the work area, the thick salt rock reduces the resolution of pre-salt seismic signals and increases the difficulty of reservoir characterization. Therefore, this paper proposes to utilize wavelet frequency decomposition technology to depict the seismic blank reflection area’s signal and improve the pre-salt signal’s resolution. The high-precision pre-stack inversion based on Bayesian theory makes full use of information from various angles and simultaneously inverts multiple elastic parameters, effectively depicting reservoirs with substantial heterogeneity. Integrating the high-precision inversion results and the Kuster-Toksöz model, a porosity prediction method is proposed. The inversion results are consistent with the drilling rock samples and well-logging porosity results. Moreover, the reef’s accumulation and growth, which conform to the geological information, proves the accuracy of the above methods. This paper also discusses the seismic reflection characteristics of reefs and the influence of different lithological reservoirs on the seismic waveform response characteristics through forward modeling, which better proves the rationality of porosity inversion results. It provides a new set of ideas for future pre-salt carbonate reef reservoirs’ prediction and characterization methods.

Highlights

The world has undergone millions of years of sedimentation, development, and evolution
The heterogeneity carbonate and the overlying salt rock cause the seismic signal in the BVE layer to be weak, and it is difficult to reflect the detailed information in the target layer
The results prove that the high-resolution seismic reflection results obtained by the wavelet frequency decomposition processing are closer to the actual underground data

Summary

Introduction

The world has undergone millions of years of sedimentation, development, and evolution. Most reef reservoirs have a carbonate background, while the pore types of carbonate rocks are complex and accompanied by substantial heterogeneity [1,2,3]. It is difficult for conventional research procedures to accurately construct the relationship between elastic parameters and physical property parameters, thereby affecting the results of seismic reservoir prediction [4]. The composition of reservoir fluids is relatively complex, and there are some complex physical and chemical effects in oil and gas exploitation These characteristics have brought significant challenges to seismic reservoir description and quantitative characterization [6,7,8]

Methods

Results

Discussion

Conclusion