Joint inversion method for NMR dual-TW logging data and fluid typing
核磁共振双TW测井数据联合反演与流体识别

For the analysis of dual-TW activation of NMR logging and fluid typing,a joint inversion method is proposed based on genetic algorithm(GA),a global searching method,and damping least square(LSQR)method,a local optimization method.Firstly,multi-exponential response mechanism of NMR spin echo trains of dual-TW activation in reservoir filled with oil,water and gas is deduced and discussed in detail.Then,GA method is applied to global optimization of differential echo trains of NMR dual-TW Logging and T2 values of oil and gas,oil porosity,gas porosity are calculated.Finally,LSQR method is run for dual-TW echo trains based on the results of GA,and gives T2 distributions of dual-TW activation data,component porosity,effective porosity and hydrocarbon saturation.From above calculating results,fluid types of reservoirs are interpreted and summarized successfully.The inversion results of synthesized echo trains from forward modeling of various ideal models indicate that the joint inversion method is correct and effective.Furthermore,the interpretation conclusion from the inversion results in oil field case agrees well with well testing.So,the joint inversion method based on GA and LSQR is effective and suits to dual-TW activation data processing of NMR logging and fluid typing.