A method to construct high-precision complex pore digital rock

Dong, Huaimin; Sun, Jianmeng; Golsanami, Naser; Cui, Likai; Jiang, Liming; Yan, Guoliang; Yan, Wei; Li, Yafen

doi:10.1088/1742-2140/aae04e

Cited by 24 publications

(15 citation statements)

References 18 publications

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“…From the current numerous digital rock modeling methods, the CT scanning method is the most accurate method for constructing digital rock, which can best reflect the microscopic pore structure of real cores. However, even when the resolution is as high as 1 µm, the porosity of the three-dimensional digital rock is still less than the results of laboratory porosity measurements, indicating that there are micro-pores in the rock core whose size is less than the CT scanning resolution [50]. The existence of micro-pores makes the porosity of the digital core lower than that of the experiment, which affects the pore connectivity of the digital rock and is not conducive to subsequent numerical simulation research.…”

Section: Methodsmentioning

confidence: 91%

Microscopic Conductivity Mechanism and Saturation Evaluation of Tight Sandstone Reservoirs: A Case Study from Bonan Oilfield, China

et al. 2022

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Core samples of the tight sandstone reservoir in the Bonan Oilfield were analyzed by using multiple petrophysical experimental techniques, then a multi-scale three-dimensional digital rock model was constructed. The pore structure parameters of tight sandstone and homogeneous Berea sandstone were compared. The electrical simulation method based on the digital rock model was utilized to quantitatively reveal the influence of five micro-pore structure parameters (pore size, throat size, pore-throat size, coordination number, and shape factor) on the rock’s electrical properties. In addition, the saturation of tight sandstone reservoirs was evaluated in combination with the three-component automatic mixed-connection conductivity model. The results show that the “non-Archie” phenomenon in sandstone is obvious, which is mainly caused by the small radius of the maximum connected pore throat and the complex structure of the pore throat. We noted that: with an increase in pore radius, throat radius, and coordination number, the formation factor decreases and tends to be stable; the pore-throat size increases and the formation factor decreases in the form of power function; the shape factor increases, and the formation factor increases; the larger the pore–throat ratio and shape factor, the greater the resistivity index; with an increase in coordination number, the resistivity index decreases; and the pore-throat size has no effect on the resistivity index. The calculation accuracy of oil saturation is improved by 6.54% by constructing the three-component automatic mixed-conductivity saturation model of tight sandstone.

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Section: Methodsmentioning

confidence: 91%

Microscopic Conductivity Mechanism and Saturation Evaluation of Tight Sandstone Reservoirs: A Case Study from Bonan Oilfield, China

et al. 2022

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“…Besides, there are still many unknown aspects of applying the new interdisciplinary investigation techniques in assessing the gas solubility, bubble point pressure, bottom hole pressure or temperature, gas injection rate, etc., throughout dual gradient drilling or other deepwater drilling tasks. These techniques include fractal geometry theory [52][53][54][55], digital rock technology [56][57][58], one-dimensional [59][60][61][62] and two-dimensional nuclear magnetic resonance [63,64], numerical methods [65][66][67], artificial intelligence [68][69][70][71][72] especially the deep learning technique [73][74][75], which could be used individually or in a joint manner during well planning, design, engineering, operations, and technology application, etc. This wide range of topics is suggested as the potential areas of future research.…”

Section: Limitations and Future Extensionsmentioning

confidence: 99%

Evaluating the Effect of New Gas Solubility and Bubble Point Pressure Models on PVT Parameters and Optimizing Injected Gas Rate in Gas-Lift Dual Gradient Drilling

2022

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Gas-lift dual gradient drilling (DGD) is a solution for the complex problems caused by narrow drilling windows in deepwater drilling. Investigations are lacking on using oil-based drilling fluid in DGD, which is the principal novel idea of the present study. This research compares the results obtained from two new models with those of Standing’s correlations for solubility and bubble point pressure. Nitrogen was selected as the injection gas, then the PVT behavior of drilling fluid (oil/water/Nitrogen) in gas-lift DGD was evaluated and compared by coding in MATLAB. Then, these results were used to calculate the bottom hole pressure and finally investigate the optimization of injected gas flow rate. According to the achieved results, the Standing model has some errors in evaluating the PVT behavior of “Nitrogen and oil-based drilling fluids” and is not recommended for the mixtures in the gas-lift DGD. Regarding optimizing gas flow rate, a discrepancy was observed between pressure values obtained from the new models and the Standing model for the case of high liquid flow rates at low gas flow rates because of the difference in PVT parameters. The developed codes are deposited on an online data repository for future users. This study lays the foundation for better planning of drilling in deepwater drilling projects.

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“…have been modeled with fractal geometry theory. In these models, the pore space is either simulated [18,19], captured by NMR [20][21][22][23][24], or obtained through computed 2 Geofluids tomography (CT) scanning and digital rock technology [25][26][27]. However, in most cases, a part of the microscopic pore space could not be captured by NMR or micro-CT.…”

Section: Introductionmentioning

confidence: 99%

Fractal Properties of Various Clay Minerals Obtained from SEM Images

et al. 2021

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Clay minerals significantly alter the pore size distribution (PSD) of the gas hydrate-bearing sediments and sandstone reservoir rock by adding an intense amount of micropores to the existing intragranular pore space. Therefore, in the present study, the internal pore space of various clay groups is investigated by manually segmenting Scanning Electron Microscopy (SEM) images. We focused on kaolinite, smectite, chlorite, and dissolution holes and characterized their specific pore space using fractal geometry theory and parameters such as pore count, pore size distribution, area, perimeter, circularity, and density. Herein, the fractal properties of different clay groups and dissolution holes were extracted using the box counting technique and were introduced for each group. It was observed that the presence of clays complicates the original PSD of the reservoir by adding about 1.31-61.30 pores/100 μm2 with sizes in the range of 0.003-87.69 μm2. Meanwhile, dissolution holes complicate the pore space by adding 4.88-8.17 extra pores/100 μm2 with sizes in the range of 0.06-119.75 μm2. The fractal dimension ( D ) and lacunarity ( L ) values of the clays’ internal pore structure fell in the ranges of 1.51-1.85 and 0.18-0.99, respectively. Likewise, D and L of the dissolution holes were in the ranges of, respectively, 1.63-1.65 and 0.56-0.62. The obtained results of the present study lay the foundation for developing improved fractal models of the reservoir properties which would help to better understand the fluid flow, irreducible fluid saturation, and capillary pressure. These issues are of significant importance for reservoir quality and calculating the accurate amount of producible oil and gas.

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A method to construct high-precision complex pore digital rock

Cited by 24 publications

References 18 publications

Microscopic Conductivity Mechanism and Saturation Evaluation of Tight Sandstone Reservoirs: A Case Study from Bonan Oilfield, China

Microscopic Conductivity Mechanism and Saturation Evaluation of Tight Sandstone Reservoirs: A Case Study from Bonan Oilfield, China

Evaluating the Effect of New Gas Solubility and Bubble Point Pressure Models on PVT Parameters and Optimizing Injected Gas Rate in Gas-Lift Dual Gradient Drilling

Fractal Properties of Various Clay Minerals Obtained from SEM Images

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