Characterization of Pore Throat Size Distribution in Tight Sandstones with Nuclear Magnetic Resonance and High-Pressure Mercury Intrusion

Characterization of pore throat size distribution (PTSD) in tight sandstones is of substantial significance for tight sandstone reservoirs evaluation. High-pressure mercury intrusion (HPMI) and nuclear magnetic resonance (NMR) are the effective methods for characterizing PTSD of reservoirs. NMR T2 s...

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Bibliographic Details
Published in:Energies (Basel) 2019-04, Vol.12 (8), p.1528
Main Authors: Xu, Hongjun, Fan, Yiren, Hu, Falong, Li, Changxi, Yu, Jun, Liu, Zhichao, Wang, Fuyong
Format: Article
Language:English
Subjects:
capillary pressure
Computed tomography
Contact angle
Conversion
Enhanced oil recovery
HPMI
Intrusion
Mercury
Minerals
NMR
Nuclear magnetic resonance
Permeability
Pore size
pore throat size distribution
Porosity
Pressure
Quartz
Resonance
Sandstone
Scanning electron microscopy
Size distribution
T2 spectra
tight sandstone
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Summary:Characterization of pore throat size distribution (PTSD) in tight sandstones is of substantial significance for tight sandstone reservoirs evaluation. High-pressure mercury intrusion (HPMI) and nuclear magnetic resonance (NMR) are the effective methods for characterizing PTSD of reservoirs. NMR T2 spectra is usually converted to mercury intrusion capillary pressure for PTSD characterization. However, the conversion is challenging in tight sandstones due to tiny pore throat sizes. In this paper, the linear conversion method and the nonlinear conversion method are investigated, and the error minimization method and the least square method are proposed to calculate the conversion coefficients of the linear conversion method and the nonlinear conversion method, respectively. Finally, the advantages and disadvantages of these two different conversion methods are discussed and compared with field case study. The research results show that the average linear conversion coefficients of the 20 tight sandstone core plugs collected from Yanchang Formation, Ordos Basin of China is 0.0133 μm/ms; the average nonlinear conversion coefficient is 0.0093 μm/ms and the average nonlinear conversion exponent is 0.725. Although PTSD converted from NMR spectra by the nonlinear conversion method is wider than that obtained from linear conversion method, the nonlinear conversion method can retain the characteristic of bi-modal distribution in PTSD.
ISSN:1996-1073
1996-1073
DOI:10.3390/en12081528