The Application Study Of NMR In Daqing Oil Field

Nuclear Magnetic Resonance (NMR) logging technology is one of thegreatest technology advances of the world logging industry in 1990s.it providesus with new answers to many problems of hydrocarbon exploration anddevelopment. Since first introduced, it has been widely applied in oil field .In2000, Wireline logging Company of Daqing Petroleum Administration Bureauintroduced the advanced MRIL-P NMR equipments and relevant loggingtechnology from Halliburton Inc. and applied them in Daqing oil field withprovided new ideas and methods for solving some problems unsolvable byconventional wireline logging methods, and obtained good profits from itsapplication. But Daqing oil field and its outskirts filed are belong to continentalsedimentation model with complex geologic conditions, some empiricalparameters and interpretation procedures that are already applied in and outchina are not suitable for Daqing oil field, which limited the application ofNMR in Daqing to some extend;In order to solve them, It is thoroughlydiscussed about the principle, logging methods ,data interpretation procedureand the application problems of NMR logging technology in this paper, theinterpretation models and data interpretation procedure are given, which areapplied well in Daqing .Considering the characters of Daqing geology, this study is focus on : first,to improve the accuracy of porosity with NMR technology in Daqing outskirtsoil fields, which are complex in geology conditions;second, to improve theaccuracy of permeability with different T_2cutoff method, especially in Halar oilfield with uneven lithology;third, to identify layers and fluid traits in difficultreservoir;fourth, since over years developing with water injection in Daqing oilfield, the reservoirs are highly water out ,how to calculate residual oil saturationin quantification with NMR logging technology.On the basis of studying, this paper get some achievements: first, NMRcan provides more accurate porosity than that calculated by conventionallogging methods, In order to get more improvement in the accuracy of NMRporosity, using the porosity form core analysis to graduate the porosity fromNMR, and we also get the relevant normalized formula in different area;Second, in Halar oil field, lithology is complex and contain uneven paramagnetsubstances, so there is big different in T2cutoff , we take a method to solve thisproblem, that is, we determine T2cutoff layer by layer for even bed and point bypoint for uneven bed;then we figure out permeability with T2cutoff;Third,indifficult beds, conventional logging methods hardly identify layers precisely itcan do it by applying the information of the distribution of pore size andpermeability provide by NMR logging technology;Fourth, because of thediffusion coefficient of water is bigger than high viscosity crude oil, we takeadvantage of DIFAN method to identify fluid character;Fifth, we can calculateresidual oil saturation in quantification with diffusion coefficient weightingmethod providing residual oil saturation unaffected by mineralization ofinjected water and undependable on formation water for water out layer, so wecan know the situation of water out in quantificationAll these achievements are applied in Daqing and its outskirts oilfieldnow, but there are still some problems existed in NMR logging, for example,the identification of fluid character in special layer, the calculation of porosityand the establishment of saturation model of pyrogenetic rock, the determineradius of NMR equipments, and so on. All of them need to study in the future.