The field of research for this project belongs to the exploration and development of oil and natural gas. The phenomenon of nuclear magnetic resonance was first independently discovered by Bloch from Stanford University and Purcell from Harvard University in 1945. In 1952, due to the discovery of nuclear magnetic resonance, Bloch and Purcell shared the Nobel Prize in Physics that year. It is precisely because the discoverers received the Nobel Prize that numerous researchers have devoted great effort to the application of nuclear magnetic resonance in scientific research and production activities, achieving fruitful results. Similarly, the application of nuclear magnetic resonance in the petroleum industry has also made exciting progress. The research achievements of Tarr and Yakov et al. have laid the theoretical and practical foundation for nuclear magnetic resonance (NMR) in evaluating rock pore structure and fluid identification. Relying on project research, this project has proposed four innovative points: the mechanism of NMR evaluation reflecting rock pore structure, the frequency modulation NMR logging data acquisition scheme, the quantitative interpretation technology research of complex lithology logging and development of logging interpretation platform, as well as the quantitative calculation of rock pore structure parameters based on the ball tube model. 1. Proposing the physical mechanism for NMR evaluation reflecting rock pore structure The characteristic solution of the hydrogen nucleus relaxation equation in pores is related to the boundary conditions of the pores, which are part of the boundary conditions of the rock pore structure. This is precisely the basis for the relationship between the NMR relaxation process and the pore structure. 2. Propose the acquisition method of frequency-modulated nuclear magnetic resonance logging data The hydrogen nuclei of oil and gas molecules have different molecular environments, that is, they have different chemical shifts. The difference in chemical shift causes different molecular hydrogen nuclei to have different resonance frequencies. Using specific frequencies of magnetic pulses to cause resonance signals from oil and gas molecules alone can be expected to improve the direct recognition ability of nuclear magnetic resonance for oil and gas. 3. Propose the quantitative calculation method of rock porosity structure parameters using a sphere-tube model Decompose the rock porosity structure into spherical pore distribution and tubular pore distribution, and apply the sphere-tube model method to analyze the storage performance and permeability characteristics of rocks. Scaling the evaluation method of the sphere-tube model with mercury intrusion data ensures that the analysis results of the sphere-tube model are more practical. 4. Research on Quantitative Interpretation Technology of Complex Lithology Logging and Development of Logging Interpretation Platform Through artificial core and actual core NMR experiments, the applicability of NMR logging in volcanic rock reservoirs was analyzed, and a complete set of quantitative evaluation methods for volcanic rocks was proposed. This method has been applied in the Santanghu Basin with good application results. A program for analyzing the porosity structure of reservoirs using NMR logging quantitative evaluation was compiled and completed its integration with the logging interpretation platform. The analysis program of project research results has already interpreted logging data from 6 wells, adding an additional value of 1.2 million yuan. On the basis of integrating and optimizing the research results, a comprehensive application platform for logging data was formed. This platform has become an integrated platform for logging data analysis and application, equipped with various processing and interpretation functions such as conventional logging, imaging logging, special logging, and production logging. The research results of the project have achieved a quantitative evaluation of rock pore structure and a classification evaluation of reservoir permeability characteristics and storage properties. Among them, the study on the relaxation mechanism of rocks saturated with two-phase fluids and the pore structure evaluation method based on the sphere tube model are original innovations. There have been 14 research articles published related to the content of the study, including 7 that were indexed by SCI and 7 by Ei. The 'NMR Rock Analysis Software V2.1' reflecting the research results has been completed and software copyright registration has been carried out. The project research results have been applied in the technical center of China National Petroleum Corporation Logging Technology Co., Ltd., with a contract fee of 300,000 yuan. The application of these research results in the Logging Co., Ltd. has formed a series of high-tech domestic products in terms of both hardware and software, enhancing the bidding competitiveness of state-owned enterprises in the international market. Relying on project research, one master's graduate has been trained. Currently, there are four master's students enrolled.