Quantitative characterization of tight gas sandstone reservoirs using seismic data via an integrated rock-physics-based framework

作     者：Zhi-Qi Guo Xiao-Ying Qin Cai Liu 

作者机构：College of Geoexploration Science and TechnologyJilin UniversityChangchun130026JilinChina 

出 版 物：《Petroleum Science》 (石油科学（英文版）)

年 卷 期：2023年第20卷第6期

页      面：3428-3440页

核心收录：

学科分类：0820[工学-石油与天然气工程] 08[工学] 0817[工学-化学工程与技术] 0818[工学-地质资源与地质工程] 0708[理学-地球物理学] 0705[理学-地理学] 082002[工学-油气田开发工程] 

基　　金：supported by the National Natural Science Foundation of China(Grant numbers 42274160 and 42074153). 

主　　题：Tight gas sandstone reservoirs Quantitative reservoir characterization Rock-physics-based framework Microfracture porosity Rock physics template 

摘      要：Seismic characterizing of tight gas sandstone (TGS) reservoirs is essential for identifying promising gas-bearing regions. However, exploring the petrophysical significance of seismic-inverted elastic properties is challenging due to the complex microstructures in TGSs. Meanwhile, interbedded structures of sandstone and mudstone intensify the difficulty in accurately extracting the crucial tight sandstone properties. An integrated rock-physics-based framework is proposed to estimate the reservoir quality of TGSs from seismic data. TGSs with complex pore structures are modeled using the double-porosity model, providing a practical tool to compute rock physics templates for reservoir parameter estimation. The VP/VS ratio is utilized to predict the cumulative thickness of the TGS reservoirs within the target range via the threshold value evaluated from wireline logs for lithology discrimination. This approach also facilitates better capturing the elastic properties of the TGSs for quantitative seismic interpretation. Total porosity is estimated from P-wave impedance using the correlation obtained based on wireline log analysis. After that, the three-dimensional rock-physics templates integrated with the estimated total porosity are constructed to interpret microfracture porosity and gas saturation from velocity ratio and bulk modulus. The integrated framework can optimally estimate the parameters dominating the reservoir quality. The results of the indicator proposed based on the obtained parameters are in good agreement with the gas productions and can be utilized to predict promising TGS reservoirs. Moreover, the results suggest that considering microfracture porosity allows a more accurate prediction of high-quality reservoirs, further validating the applicability of the proposed method in the studied region.