Study On Processing Method Of MREx Logging Data

Nuclear Magnetic Resonance logging technology is a major progress of well logging industry in the 1990s. It provides new answers to hydrocarbon exploration and development in complex reservoirs. MREx nuclear magnetic resonance logging is an advanced one, which is imported from foreign Companies. Because this tool is launched in a short time, both hardware and software of this instrument are imperfect, and geological conditions are different in and out of China, some problems, maily on the data processing and interpretation, are encountered, If these problems are not solved, will greatly influence the application of this technology in China.Through plenty of investigation on NMR logging research and application at home and abroad, this paper studies the entire process of data processing on the basis of NMR basic theory and key technologies.In data extraction and echo generation aspects, the feature, activation, data recording format of MREx tool are analyzed. Making clear data acqusition and storage details, original record data are extracted. A series of key technologies of echo generation from MREx original data are formed, including phase-correction, echo stack, standard echo combinations, time-to-depth conversion, etc. The original orhogonal signals in time domain are processed to echo signals in depth domain.In echo inversion aspects, the mathematical model of echo-T₂ inversion and Singular Value Decomposition algorithm are disscused. An improved singulare value decomposition to obtainning the T₂ spectrum from echo is used.In reservoir parameter calculation aspects, methods to calculate the porosity and permeability from NMR data are researched and improving the accuracy of parameters through variable T₂ cutoff values and DMR, SMR technologies.In fluid qualitative analysis and quantitative calculation aspects, analyze the feature of Shift Spectrum Method(SSM), Differential Spectrum Method (DSM) of the typical oil, gas and water reservoir as well as the theories and application conditions of these methods. Quantitative calculation based on echos uses echo difference between dual-TW echos. Quantitative calculation based on T₂ spectrum include three methods: diffusion analysis of dual-TE T₂ spectra, diffusion analysis of multi G·TE T₂ spectra, joint inversion of multi G·TE T₂ spectra. Among them, the use of Very Fast Simulated Annealing algorithm for dual-phase T₂ research on echo gets good results.Bases on this study, these methods are verified by the treatment of wells.