NMR derived capillary pressure and relative permeability curves as an aid in rock typing of carbonate reservoirs

Hosseinzadeh, Sirous; Kadkhodaie, Ali; Yarmohammadi, Saeed

doi:10.1016/j.petrol.2019.106593

Cited by 28 publications

(10 citation statements)

References 22 publications

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“…The gas–water permeability curves in the study area were divided into three categories. The relative permeability curve corresponds to the permeability of the reservoir in an actual reservoir. − The tight sandstone reservoirs in the study area have poor seepage capacity, and no reservoirs with slow decay, long stable production periods, and late water breakthroughs in gas wells have been found. It can be seen from the division results of the gas–water phase permeability curves that the distribution of various types of curves is relatively concentrated, indicating that the division results are more reasonable.…”

Section: Experimental Resultsmentioning

confidence: 99%

Research on the Relationship between Electrical Parameters and Relative Permeability of Tight Sandstone

Zhao

Song

et al. 2022

ACS Omega

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The relationship between the electrical properties and relative permeability of tight sandstones with complex pore-throat structures is still unclear. In this study, a relationship model between the electrical parameters and pore-throat structure and the relative permeability of tight sandstone based on experimental data was established by combining theoretical derivation and experimental comparison. The model has typical three-terminal element characteristics. Porosity had little effect on relative permeability, whereas saturation index had a significant control effect on relative permeability. The relative permeability curve deduced based on the electrical parameters was quite different from the experimental fitting curve. Because irreducible water could conduct electricity but not flow, the relative permeability of the gas phase derived from the theory was higher than the experimental one, while the relative permeability of the water phase was lower. The isotonic point saturation of the phase permeability curve derived from the rock electrical parameter theory was larger than that obtained from the experiment. This research could help us obtain accurate relative permeability curves through electrical parameters and provide a basis for the fine evaluation of tight sandstone two-phase flow.

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Section: Experimental Resultsmentioning

confidence: 99%

Research on the Relationship between Electrical Parameters and Relative Permeability of Tight Sandstone

Zhao

Song

et al. 2022

ACS Omega

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“…Based on the previous methods [13][14][15][16], with the iterative least-square method, the conversion coefficient corresponding to the minimum area difference and the maximum correlation coefficient was iteratively and automatically searched to calculate the pseudo-capillary pressure curve in the study. Based on the absolute error between the pseudo-capillary pressure curve and the core capillary pressure curve, the inversion method of the pseudo-capillary pressure curve was optimized.…”

Section: Introductionmentioning

confidence: 99%

Fluid Identification Based on NMR Apparent Free Water Porosity Inversion: A Case Study of Paleozoic Tight Sandstone Gas Reservoirs in Western Ordos

et al. 2022

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Tight sandstone reservoirs are affected by various factors such as pore structure, formation water salinity, and siliceous cementation, which lead to the abnormal phenomenon of high-resistivity water layers and increase the difficulty in identifying gas and water layers by conventional logging. In this study, the pore types and pore size distribution characteristics of tight sandstone reservoirs were firstly determined by NMR and high-pressure mercury injection experiments, and then the iterative least-square method was used to automatically optimize the inversion method of pseudo-capillary pressure curve and search for the optimal conversion coefficient. Finally, the apparent free water porosity was inversed and the fluid identification standard was obtained and applied. The results showed that the reservoirs mainly developed intergranular pores, cutting solution pores, and intergranular pores. The pore throats were poorly sorted, and the displacement pressure was high. The median radius ranged from 0.01 to 0.48 μm, and the main peak range was from 0.02 to 0.06 μm. Pores were of mainly small-hole fine throat type. In the inversion results of the optimal conversion coefficient, the correlation coefficient between the aperture parameters and the results of high-pressure mercury injection experiments was greater than 0.93. According to the fluid property identification standard based on nuclear magnetic apparent free water porosity, the high-resistivity water layers were effectively identified and its coincidence rate with the final field test was 10.7% higher than that of the conventional method. This identification method can be used to identify complex fluids in tight sandstone reservoirs.

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“…26 On the basis of the capillary pressure curves and relative permeability curves converted from the NMR T 2 distribution combined with conventional core analysis data, the reservoir type was determined using the flow zone index method. 27 The paper presents a method for automatic classification of tight sandstone reservoirs based on the NMR T 2 distribution. The NMR T 2 distribution acquired from tight sandstone samples taken from the Shaximiao Formation in the Sichuan Basin is employed in the study.…”

Section: Introductionmentioning

confidence: 99%

“…The criteria were established for classification of tight sandstone reservoirs based on the NMR T 2 distribution . On the basis of the capillary pressure curves and relative permeability curves converted from the NMR T 2 distribution combined with conventional core analysis data, the reservoir type was determined using the flow zone index method …”

Section: Introductionmentioning

confidence: 99%

Classification of Tight Sandstone Reservoirs Based on the Nuclear Magnetic Resonance T₂ Distribution: A Case Study on the Shaximiao Formation in Central Sichuan, China

et al. 2022

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The classification of tight sandstone reservoirs is of significance for hydrocarbon exploration and production. Different from conventional reservoirs, tight sandstone reservoirs are characterized by a complex pore structure and strong heterogeneity. Tight sandstone reservoir classification may not be reliable with conventional reservoir classification methods. In this paper, a classification method of tight sandstone reservoirs was proposed on the basis of the nuclear magnetic resonance (NMR) transverse relaxation (T 2 ) distribution, and it was employed for reservoir classification on the Shaximiao Formation in central Sichuan, China. As a result of the complex pore structure of a tight sandstone reservoir, the NMR T 2 distribution is characterized by the presence of multiple peaks. Therefore, the three-peak Gaussian function was used to fit the T 2 distribution and obtain the characteristic parameters. On the basis of high-pressure mercury intrusion (HPMI) experiments, the correlation between the characteristic parameters of the NMR T 2 distribution and pore structure parameters and petrophysical properties was analyzed, and then the optimal characteristic parameters of the NMR T 2 distribution were selected according to the results of correlation analysis and used to establish the pore structure index. In combination of petrophysical properties with the pore structure index, the model for classification of tight sandstone reservoirs was established by the naive Bayesian method based on hierarchical clustering, and the accuracy of the model was verified by k-fold cross-validation. Finally, the effectiveness of the proposed method was verified using the actual NMR logging data in conjunction with the oil test data. The results showed that the method for classification of tight sandstone reservoirs based on the NMR T 2 distribution can provide effective guidance for production capacity evaluation.

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NMR derived capillary pressure and relative permeability curves as an aid in rock typing of carbonate reservoirs

Cited by 28 publications

References 22 publications

Research on the Relationship between Electrical Parameters and Relative Permeability of Tight Sandstone

Research on the Relationship between Electrical Parameters and Relative Permeability of Tight Sandstone

Fluid Identification Based on NMR Apparent Free Water Porosity Inversion: A Case Study of Paleozoic Tight Sandstone Gas Reservoirs in Western Ordos

Classification of Tight Sandstone Reservoirs Based on the Nuclear Magnetic Resonance T₂ Distribution: A Case Study on the Shaximiao Formation in Central Sichuan, China

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NMR derived capillary pressure and relative permeability curves as an aid in rock typing of carbonate reservoirs

Cited by 28 publications

References 22 publications

Research on the Relationship between Electrical Parameters and Relative Permeability of Tight Sandstone

Research on the Relationship between Electrical Parameters and Relative Permeability of Tight Sandstone

Fluid Identification Based on NMR Apparent Free Water Porosity Inversion: A Case Study of Paleozoic Tight Sandstone Gas Reservoirs in Western Ordos

Classification of Tight Sandstone Reservoirs Based on the Nuclear Magnetic Resonance T2 Distribution: A Case Study on the Shaximiao Formation in Central Sichuan, China

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Classification of Tight Sandstone Reservoirs Based on the Nuclear Magnetic Resonance T₂ Distribution: A Case Study on the Shaximiao Formation in Central Sichuan, China