Quantification of additional stresses caused by water level fluctuations in reservoirs

Abstract During the formation and triggering process of reservoir-induced seismicity (RIS), rock mass conditions, load conditions, and water occurrence conditions all have a significant impact. As the mechanism of RIS is the core and difficult problem in RIS measurement research, and the mechanism model of quantifiable calculation and analysis at any point of reservoir influence area is lacking, the additional stress model suitable for any location of reservoir were proposed and established in this paper. Based on the model, complete calculation of additional stress in reservoir space is realized, the distribution of additional stress on the reservoir section is obtained, and the influence of reservoir shape and size on the additional stress is discussed. The additional stress model of water level fluctuation considering the influence of water storage and drainage is established, then, the distribution of additional stress and the influence of water level fluctuation on induced seismic are analyzed, and a more simplified and general theory of additional stress coefficients is established. The results show that the variation of water level has a significant effect on the additional stress, and the increase of water level will lead to the increase of additional stress.