核磁共振（NMR）在石油测井和地层油气评价中已经得到应用，是当前地球物理勘探的前沿领域之一。介绍了NMR测井的测量原理、应用基础和地层信息的表达方式，并讨论了NMR测井的主要应用和实例。

NMR has been widely applied to well logging and formation evaluation since 1990's. NMR core analysis, NMR wireline logging, NMR logging while drilling,as well as down hole NMR laboratory have been developed and available to the industry, which provide unique information to fluids identification and Petrophysical analysis. The NMR information provides： 1,lithology-independent porosity; 2,clay bound water, capillary bound water, and free fluids; 3,permeability; 4,oil and gas in free fluids; 5,fluids NMR properties at down hole conditions, etc. The availability of the NMR information dramatically enhances the accuracy of well logging fluids evaluation and makes the reserve calculation, Producibility estimation and stimulation evaluation feasible and much reliable. In this paper, referred to author´s new publication, NMR logging principles are briefly introduced, applications case studies to porosity, permeability, and oil and water saturation are discussed in details.