## 4 Discussion  
This study establishes a significant correlation between static and dynamic moduli of elasticity. The linear or power-law correlation is the best correlation between the static and dynamic moduli of elasticity. Meanwhile, [PERSON] [9] established a power-law correlation between dynamic and static moduli of elasticity by conducting experimental studies on different types of rocks, with R\({}^{2}\) = 0.96\(\sim\)0.99. [PERSON] and [PERSON] [10] analyzed a mass of data and concluded that a better correlation for predicting static elastic modulus is a nonlinear logarithmic correlation, with R\({}^{2}\) = 0.92. [PERSON] et al. [33] conducted a similar study and established a nonlinear empirical equation between static and dynamic elastic moduli for various types of rocks, with R\({}^{2}\) = 0.99. [PERSON] et al. [43] studied various rock samples and found R\({}^{2}\) = 0.99. [PERSON] et al. [49] investigated the relationship between dynamic and static elastic parameters of different types of composite resins under other light time conditions, with R\({}^{2}\) = 0.92, and [PERSON] and [PERSON] [30] conducted a correlation study for crystalline rocks, with R\({}^{2}\) = 0.75. This study established the correlation between igneous, sedimentary, and metamorphic rocks. According to the type of rock, the best correlation for static and dynamic elastic moduli is a power-law relationship for igneous and metamorphic rocks; there are linear and nonlinear logarithmic correlations for sedimentary rocks. However, many scholars hold different views on the difference between dynamic and static elastic moduli. According to reports in the literature, the static and dynamic elastic moduli have different values. Many reasons have been suggested to account for this discrepancy, from strain amplitude effect to viscoelastic behavior. In addition, this difference is described as static measurements are more susceptible to the influence of fractures, cracks, voids, weak surfaces, and foliation structures [4; 5; 12; 13; 61]. Academic researchers have different opinions on the reasons for the discrepancy between the static and dynamic elastic moduli of rocks. [PERSON], et al. [62] mentioned in the article that the core samples are multiphase composite media, and it is believed that there are microcracks distributed in the samples, and there is fluid inside the microcracks, which is the inherent reason for the differences in dynamic and static elastic parameters. [PERSON] et al. [32] have the same view that the rock's cracks and voids decay process can lead to the deviation between dynamic and static values. [PERSON] [7] also reached the same conclusion in  
Figure 15: Dynamic and static Poisson’s ratio fitting relationships for different types of rocks.  
his research, stating that this was due to the existence of microcracks or microfractures. The external reason is the strain amplitude [63]. [PERSON] [17] indirectly demonstrated through experiments that strain amplitude is the cause of the discrepancy between static modulus and dynamic modulus. [PERSON] and [PERSON] [64] conducted experimental research on granite. They believed that stress-induced anisotropy (caused by differences in stress states) is the primary cause of the difference between static and dynamic moduli of elasticity.  
This paper reviews the essential viewpoints and results in the dynamic and static interrelation field. Although there are differences in some aspects among different studies, the results show that the dynamic elastic modulus of rock has a good correlation with the static elastic modulus. In contrast, the correlation between the dynamic and static Poisson's ratios could be clearer. This study provides an experimental basis for the application of the acoustic properties of rocks in petroleum engineering.