Interpretation And Application Effect Of Nuclear Magnetic Resonance Logging In Chagan Depression Area

Nuclear magnetic resonance logging is a new type of logging technology developed in the1990 s.The NMR logging has a clear detection area.The raw data collected only contains the information of the hydrogen nuclei in the formation.The signal of the NMR logging only comes from the pore fluid of the formation,so the measurement result is not affected by the skeleton composition of the rock solid.And its observation range is optional,which can identify significant differences in the relaxation characteristics of oil,gas and water.The essence of nuclear magnetic resonance logging is the direct measurement of pore fluid information.This measurement method eliminates the problem that conventional logging data is evaluated by the formation mineral model.In order to change the potential energy of the nuclear magnetic moment in the magnetic field,energy must be absorbed.This can be achieved by adding an RF field in a plane perpendicular to the direction of the static magnetic field B.The RF field is an alternating magnetic field B1 in time.=2Bcos?0,B1>>B,so the precession is very slow,the result is that the angle ? between ? and B changes slowly,and the potential energy of ? in B also changes,?increases,potential energy increases,this energy Provided by the addition of alternating magnetic field B1.When ? decreases,the potential energy decreases,and the energy is transferred to the applied alternating magnetic field.This energy exchange can only occur when?=?B=?0 is satisfied.At this time,? and B1 rotate around the z-axis.This phenomenon is nuclear magnetic resonance,and ?0=?B is a resonance condition,as shown by the movement of the nucleus in an external magnetic field.NMR logging solves the shortcomings of conventional logging methods.Conventional logging methods are highly susceptible to wellbore,lithology,and salinity of formation water,making measurement results controversial.The nuclear magnetic resonance logging technology solves the problems of complex lithology,low porosity,low permeability and low resistivity of the oil and gas layer encountered by conventional logging methods,which makes the measurement results more realistic and reliable.Magnetic resonance logging is the only logging technology that can directly measure the free fluid porosity of reservoirs.Its technical advantages have been widely recognized at home and abroad,and the unique measurement mode of nuclear magnetic resonance logging,and its The application effects obtained in the stratumhave also been unanimously affirmed.In this paper,the quality of the original data of nuclear magnetic resonance logging is used to ensure the accuracy of the processing and interpretation of the subsequent nuclear magnetic resonance logging data.Combined with the actual situation of the geological features of the Chagan Sag,the stratum is classified to determine the different types of geomorphology.Different nuclear magnetic measurement modes,which lays the foundation for the subsequent data acquisition;through the analysis of the T2 spectral characteristics of different types of fluids in the dry depression,such as oil(including heavy oil),gas and water,understand the different types of fluids.The characteristics of T2 spectrum,difference spectrum and shift spectrum help nuclear NMR logging technology to identify fluids;NMR logging data combined with conventional logging data,using spectral characteristics to qualitatively analyze different fluid types,using DPP software TDA analysis and DIFAN analysis of nuclear magnetic resonance logging data,combined with nuclear magnetic resonance logging data and conventional logging data,MRIAN quantitative analysis to identify different types of fluids;fitting of core analysis data with nuclear magnetic resonance logging data,re-adjust the parameters in the NMR permeability model to establish NMR Well permeability interpretation model to optimize its interpretation parameters.Finally,based on the analysis of nuclear magnetic resonance logging data and geological data and conventional logging data,based on the fluid identification research,the advantages of nuclear magnetic resonance logging technology are fully applied to comprehensively evaluate the reservoir,and the test oil data is used to test the nuclear magnetic field.The application effect of resonance logging,thereby improving the interpretation rate of NMR logging permeability.