Application Of Nuclear Magnetic Resonance In Shale Reservoir Evaluation

Nuclear magnetic resource（NMR）is an important researching tool. It could achieve reservoir geologic evaluation by measuring the ¹H relaxation characteristics in the rock. For the purpose of the application of NMR log in geological interpretation,the laboratory study of the NMR parameters of various formations has been carried out.The NMR property of rock and the interpretation models of NMR log data have been studied. The NMR porosity, permeability, Through the core analysis, optimization of imaging logging parameters, mainly in reservoir rocks the best measured parameters selection, so as to provide the actual measured parameters experimental basis. By studying a rock NMR petrophysical parameters and the analysising of the relationship, we can perfected the NMR measurements for petrophysical parameters （porosity, permeability） analysis computation model. According to the calculation model, we can obtained porosity, permeability and saturation, and conventional analysis results relationship by NMR T₂ spectrum.Using NMR method standard samples, NMR curve fitting method and conventional gas measurement method measured the porosity of the sample, obtain fitting curves, the NMR method degree of fitting are better than conventional gas measurement method.The methods were introduced that rock’s permeability is derived from NMR T₂ relaxation distribution of rock. Three models （SDR, Tim-Coates） were analyzed. the SDR model is sensitive to the the fluid viscosity in core’s pores, and The Tim-Coates model and Coates-sbvi model are greatly affected by calculation of moveable/irreducible fluid volume. Through core analysis, the SDR,selecting Tim-Coates parameters,calculate permeability and conventional gas logging method of permeability good get consistent relationship.