Two-Step Inversion Method for NMR Relaxometry Data Using Norm Smoothing and Artificial Fish Swarm Algorithm

Gu, Mingxuan; Xie, Ranhong; Xiao, Lizhi

doi:10.1007/s00723-021-01403-5

Cited by 4 publications

(1 citation statement)

References 30 publications

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“…Low-field NMR T 1 – T 2 instruments are commonly used in the NMR logging field, but the resolution of fluid in the T 1 – T 2 spectrum is poor. In addition, the signal-to-noise ratio (SNR) of field-collected echo data is low, and the inversion of NMR echo data based on the inverse Laplace transform is an ill-posed problem. − In the inverted T 1 – T 2 spectrum, different fluids overlap significantly, making it difficult to extract fluid features and calculate fluid saturation. Therefore, it is necessary to develop a saturation evaluation method to provide guidelines for geologists to calculate reserves and determine the perforation location in shale.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Fluid Saturation in Shale Using 2D Nuclear Magnetic Resonance

Xie

Guo

et al. 2023

Energy Fuels

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Two-dimensional (2D) nuclear magnetic resonance (NMR) has become an indispensable tool for fluid saturation evaluation in shale reservoir. NMR spectrum derived from echo data with a low signal-to-noise ratio, however, cannot be effectively used for fluid feature extraction and saturation calculation. In this study, we proposed a fluid saturation evaluation method that combines morphology, nonnegative matrix decomposition, and fully constrained least squares. Moreover, an Akaike information criterion (AIC)-based method was proposed to determine the number of fluid types. A shale formation data set with varying fluid saturation was processed to validate the effectiveness of the proposed method. The results show that the proposed method can efficiently and accurately obtain the NMR T 1 −T 2 feature and saturation of different fluid types and has advantages over the comparable method in both computational efficiency and accuracy. Furthermore, the impact of the structure size was investigated, demonstrating that the proposed method is very fault tolerant.

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Section: Introductionmentioning

confidence: 99%