This study focuses on the development of conglomerate reservoir in Mahu Block of Karamay Oilfield, and simulates the distribution and variation of the tectonic stress field in this block through two-dimensional finite element method to meet the challenges in the process of oil and gas exploration. The Mahu block has the characteristics of large reservoir thickness, strong heterogeneity, and significant differences in physical properties, resulting in complex fluid flow patterns within the reservoir. The study used seismic data to construct a geological model, combined with rock mechanics parameters, and used the Mohr Coulomb failure criterion for finite element modeling and simulation. The direct impact of the earth’s stress field on oil and gas migration and accumulation, as well as the specific mechanism of its effect on reservoir properties and permeability, were revealed through simulation. Research has found that high stress areas are often accompanied by dense fault systems, forming channels for rapid oil and gas migration, while low stress areas are conducive to oil and gas accumulation. In addition, the porosity and permeability of reservoirs are lower in high stress areas, which is not conducive to oil and gas storage and development. On the contrary, they are relatively higher in low stress areas, providing favorable conditions for oil and gas storage and development. The results of this study not only enhance the understanding of the geological characteristics of the Mahu block, but also provide strong technical support and decision-making basis for oil and gas exploration and development. At the same time, it has important theoretical significance and practical value for resource exploration, geological disaster prediction, and other fields.