A new quantitative evaluation method for fluid constituents with NMR T1-T2 spectra in shale reservoirs

Gu, Mingxuan; Xie, Ranhong; Jin, Guowen

doi:10.1016/j.jngse.2022.104412

Cited by 7 publications

(4 citation statements)

References 21 publications

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“…20 Gu et al divided the T 1 −T 2 spectrum into different regions using NMF and classified the overlapping regions according to the T 1 /T 2 value of the fluid. 21 The weak signal in the T 1 −T 2 spectrum is then transferred to accurately obtain the saturation of fluid. Gu et al applied the geometrybased unmixing method for the quantitative evaluation of fluids and discussed the effectiveness of the proposed method based on 2D NMR logging, including T 2 -D logging and T 1 −T 2 logging.…”

Section: Introductionmentioning

confidence: 99%

“…To date, the T 1 – T 2 interpretation scheme ,− and the blind source separation (BSS) method − have been the two methods most often used for saturation evaluation in shale. Via drying, centrifugation, extraction, and pyrolysis at various temperatures, the T 1 – T 2 spectrum of a few cores at different states is analyzed and the T 1 – T 2 interpretation scheme is drawn to obtain the regions of different fluids.…”

Section: Introductionmentioning

confidence: 99%

“…The weak signal in the T 1 – T 2 spectrum is then transferred to accurately obtain the saturation of fluid. Gu et al applied the geometry-based unmixing method for the quantitative evaluation of fluids and discussed the effectiveness of the proposed method based on 2D NMR logging, including T 2 -D logging and T 1 – T 2 logging . In the BSS method, the statistical independence of different fluid types is utilized to extract the fluid features.…”

Section: Introductionmentioning

confidence: 99%

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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%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Xie

Guo

et al. 2023

Energy Fuels

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“…Moreover, blind source separation (BBS) algorithm and non-negative matrix factorization (NMF) have been employed to determine free oil saturation in recent studies (Venkataramanan et al, 2018). Base on blind source separation (BBS) algorithm, the volume fractions of shale oil can be computed by hierarchical clustering; a method of fast independent component analysis (FastICA) was proposed for the inverted NMR spectrums to obtain the fluid components of shale oil; a method of two-dimensional (2D) principal component analysis (PCA) was proposed to quantitative evaluate the T 1 -T 2 signatures of different fluids (Zhang H. et al, 2020;Gu et al, 2021;Gu et al, 2022). However, none of these studies dealt with the influence of complex lithology on the 2D NMR evaluation model for shale oil.…”

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confidence: 99%

Nuclear magnetic resonance response characteristics and quantitative evaluation method of fluid saturation of lacustrine shale oil

Fan

Liao²,

Mao³

et al. 2023

Front. Earth Sci.

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The quantitative evaluation of fluid saturation is important for formation evaluation of shale oil. However, there is currently no effective method to identify the fluid occurrence state and quantitative evaluate the fluid saturation of lacustrine shale oil because of the complexity of diagenetic minerals and pore types. In this paper, a method is proposed for the quantitative evaluation of fluid saturation based on nuclear magnetic resonance (NMR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements for shale samples of Fengcheng Formation, Mahu sag in Junggar Basin, China. These studies revealed that the shale oil rocks mainly contain quartz, feldspar, dolomite, calcite and clay minerals, both develop organic and inorganic pores. The fluids mainly occur in the form of bitumen, clay bound water, bound water, bound oil and movable oil in this study area. Based on the findings from these experiments, a mixed rock index (MI) and mud index (SI) were proposed to divide the shale oil formations into three types, including sand shale, dolomitic shale and mudstone. A T1−T2 2D NMR fluid occurrence state characterization map was established to identify the different fluids by the MI, SI and NMR characteristics. Furthermore, a method was proposed to quantitatively calculate the coefficient distribution of bound and movable fluids for shale oil in different formations. Finally, the proposed method was successfully applied into the lacustrine shale oil in the Fengcheng Formation to identify fluid occurrence state and evaluate fluid saturation quantitatively.

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