This study aims to apply Shannon entropy to analyze and compare facies and petrophysical heterogeneity in the K1 and K2 units of the Kangan Formation. Facies were first classified into twelve groups based on petrographic studies, and facies entropy was calculated from their relative frequencies. Subsequently, core porosity and permeability were categorized into value classes, and Shannon entropy was computed independently for each parameter. Diagenetic features were also examined to interpret data distribution patterns. The results demonstrate that Shannon entropy can quantitatively express structural differences between the two units. While facies entropy values are similar in both units, their facies distribution patterns differ. Porosity entropy in K2 is 1.58 compared to 1.12 in K1, indicating a wider porosity distribution in K2. Permeability entropy values are 1.95 in K2 and 1.60 in K1, reflecting greater diversity in permeability classes within K2. The higher porosity and permeability entropy in the K2 unit is consistent with its diagenetic characteristics, where intergranular and intragranular dissolution has created or expanded secondary pore spaces, distributing porosity and permeability values across multiple classes. In contrast, more extensive microcrystalline dolomitization, cementation, and particularly anhydrite cementation in K1 have resulted in pore filling or throat tightening, concentrating data in low-permeability and low-porosity classes. Thus, porosity-reducing diagenetic processes in K1 yield lower entropy, while porosity-enhancing or pore-preserving processes in K2 produce higher entropy. This relationship indicates that Shannon entropy can effectively reflect the differentiating effects of various diagenetic styles through a quantitative index. Based on these findings, Shannon entropy provides a simple, reliable, and appropriate approach for assessing heterogeneity in carbonate reservoirs and can serve as a valuable complement to conventional petrophysical and sedimentological methods for analyzing reservoir units and modeling reservoir behavior.