A decomposition method of nuclear magnetic resonance T2 spectrum for identifying fluid properties

作者：ZHONG Jibin,YAN Ronghui,ZHANG Haitao,FENG Yihan,LI Nan,LIU Xingjun

摘要：Based on analysis of NMR T2 spectral characteristics,a new method for identifying fluid properties by decomposing T2 spectrum through signal analysis has been proposed.Because T2 spectrum satisfies lognormal distribution on transverse relaxation time axis,the T2 spectrum can be decomposed into 2 to 5 independent component spectra by fitting the T2 spectrum with Gauss functions.By analyzing the free relaxation response characteristics of crude oil and formation water,the dynamic response characteristics of the core mutual drive between oil and water,the petrophysical significance of each component spectrum is clarified.T2 spectrum can be decomposed into clay bound water component spectrum,capillary bound fluid component spectrum,micropores fluid component spectrum and macropores fluid component spectrum.According to the nature of crude oil in the target area,the distribution range of T2 component spectral peaks of oil-bearing reservoir is 165-500 ms on T2 time axis.This range can be used to accurately identify fluid properties.This method has high adaptability in identifying complex oil and water layers in low porosity and permeability reservoirs.

发文机构：Exploration and Development Research Institute of PetroChina Changqing Oilfield Company National Engineering Laboratory for Exploration and Development of Low-Permeability Oil&Gas Fields PetroChina Changqing Oilfield Company Changqing Branch Technology Center

关键词：nuclearmagneticresonancefreerelaxationT2spectrumdecompositionmethodfittedT2spectrumcomponentspectrumfluididentification

分类号： P618.13[天文地球—矿床学]