Uncertainties in the Measurement of Rock Porosity Obtained from Laplace Inversion of NMR Relaxation Logs

摘要

Calculation of uncertainties from the Laplace inversion of NMR data used in the determination of rock porosity is an important and under-valued area. Recently, Parker and Song have reported a method to evaluate the error bounds of the inversion results based on the noise statistics. However, this method often resulted in bounds that were unrealistically large due to uncertainty in the noise amplitude characterization. This paper reports an improved technique for calculating the uncertainty of NMR data to yield tighter, more realistic values for the upper and lower porosity bounds. We also improved processing algorithms to reduce calculation time down to minutes.