Interfacial, pore geometry and saturation effect on complex resistivity of shaly sandstone: dispersion and laboratory investigation

Khairy, Hilfan; Harith, Zuhar Zahir Tuan

doi:10.1007/s12303-011-0033-9

Cited by 4 publications

(7 citation statements)

References 10 publications

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“…Compared with other geophysical approaches, it can obtain more electrical parameters and geoelectric information, so has attracted the attention of many scholars. The complex resistivity logging method in frequency domain was based on the dispersion characteristics of complex resistivity of coal and rock (Chen, Zhao and Zhu Khairy and Harith (2011) found the effect of pore geometry, con nement pressure and partial water saturation on coal-rock complex electricity. Li et al (2019) studied the in uence of water content of coal and rock and pear type on the electrical recovery.…”

Section: Introductionmentioning

confidence: 99%

WITHDRAWN: Experimental Study on Characteristics of Reactance Dispersion of Water Bearing Coal

Lei

Meng

et al. 2020

Preprint

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As an emerging geophysical exploration method, complex resistivity method is a potential non-invasive one for evaluating hydrofracturing effect. Reactance X is an important parameter of complex resistivity method. Compared with the traditional parameter resistance R, reactance has advantages such as distinct dispersion characteristics, clear conduction mechanism and rich information. In this paper, reactance X of four kinds of coal sample with different water saturation was tested, their dispersion characteristics were analyzed, and their conductive mechanism was studied. The results show that, (1) the characteristic curve of reactance dispersion presents a three-stage law when the water saturation is low, and a two-stage law when the water saturation is high,to some extent, the water content of coal body and the effect of hydraulic fracturing are distinguished;(2) polarization is the cause of dispersion, in which low frequency is induced polarization, high frequency is dielectric polarization, and electromagnetic induction is the interference phenomenon in the frequency band of induced polarization; (3) spectrum extremum frequency point is sensitive to changed water saturation. Extremum points of different coal rank are concentrated in 100-1000Hz. This frequency band can serve as the dominant frequency band for evaluating coal seam water saturation. This paper gives new insight into the evaluation of coal seam hydrofracturing effect by complex resistivity method.

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Section: Introductionmentioning

confidence: 99%

WITHDRAWN: Experimental Study on Characteristics of Reactance Dispersion of Water Bearing Coal

Lei

Meng

et al. 2020

Preprint

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“…These free ions move within the fluid to create a diffusion layer. Upon the application of an electric field, ions within the double layer facilitate charge transport along the interface Figure illustrates a schematic diagram of the double electric layer.…”

Section: Resultsmentioning

confidence: 99%

“…35 Upon the removal of the external electric field, the double electric layer slowly reverts to its original state, generating a secondary field that results in polarization phenomena. 33,34 Additionally, as the ion concentration increases, Na + moves rapidly in narrow pores while Cl − moves quickly in wide pores. In narrow pores, anions serve as the current inflow end and cations as the current outflow end, whereas the reverse occurs in wide pores.…”

Section: Low-frequency Polarization Mechanism Of Coalmentioning

confidence: 99%

Experimental Study on the Relationship Among Complex Resistivity, Water Saturation, and Salinity in the Jiaozuo Anthracite Reservoir

Li,

Lei

et al. 2024

ACS Omega

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In order to investigate the electrical response characteristics of anthracite coal reservoirs and their correlation with water saturation, salinity, and porosity, the complex resistivity of Zhaogu No. 2 mine anthracite coal was measured across a frequency range of 1 Hz to 100 kHz. The experimental findings indicate that as water saturation, salinity, and porosity increase, the amplitude of both the real and imaginary components of the complex resistance of the coal sample gradually decreases, leading to a decrease in the dispersion degree and an increase in the interface polarization frequency. By analyzing the experimental data and studying the polarization mechanism of coal in a sodium chloride solution, this study proposed an enhanced model that integrates the aspects of the Cole−Cole model and the Warburg model to overcome the limitations of the traditional first-order model, which can fit only single-peak curves. The second-order series Cole−Cole model not only delves into microscopic mechanisms underlying the low-frequency polarization effect of coal samples but also provides a highly accurate fit for complex resistivity dispersion curves under varying conditions. This research offers both an experimental foundation and a theoretical framework for leveraging the electrical properties of anthracite coal reservoirs in assessing the pore structure and permeability of coal seams.

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“…Rock's complex resistivity provides both resistivity and dielectric constant information about formations [2], which changes with variations in measurement frequency, displaying a pattern known as the complex resistivity spectrum (CRS). Experiments have shown that reservoir parameters such as porosity, permeability, water saturation, and water salinity influence the CRS characteristics of the formation [3][4][5][6][7][8]. Consequently, numerous evaluation methods for reservoir parameters based on CRS have emerged [9][10][11], showing promising potential in the exploration of oil and gas resources [12].…”

Section: Introductionmentioning

confidence: 99%

Coil System Design for Multi-Frequency Resistivity Logging Tool Based on Numerical Simulation

Jia,

Ke,

Rezaee

2023

Water

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A coil-type resistivity logging tool has been proposed for multi-frequency operation (250 kHz to 8 MHz) based on electromagnetic wave propagation. Different frequencies are matched with specific transmission coils, while the same two reception coils are used to achieve a consistent depth of investigation (DOI). By analyzing the electromagnetic attenuation and phase difference of induced signals at different frequencies, the complex resistivity can be jointly inverted. The coil systems were designed with four DOI options (0.3 m, 0.5 m, 1 m, and 1.5 m) and six measurement frequencies (250 kHz, 500 kHz, 1 MHz, 2 MHz, 4 MHz, and 8 MHz). Their detection performance was evaluated using the finite element method on the COMSOL platform. For higher frequencies or a deeper DOI, a coil system with a larger source-receiver distance was selected. These designed coil systems can provide qualitative identification of formations with thicknesses greater than 0.05 m and quantitative identification of formations with thicknesses greater than 1.5 m. In the single-transmission, dual-reception coil system, response signals are distorted at the formation boundary, and this distortion increases with the source-receiver distance. Adding a secondary transmission coil can reduce the distortion of response signals at the formation interface without increasing the overall length of the coil system. This research enriches the theoretical framework of complex resistivity spectrum (CRS) logging and contributes to the commercial development of CRS logging tools.

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Interfacial, pore geometry and saturation effect on complex resistivity of shaly sandstone: dispersion and laboratory investigation

Cited by 4 publications

References 10 publications

WITHDRAWN: Experimental Study on Characteristics of Reactance Dispersion of Water Bearing Coal

WITHDRAWN: Experimental Study on Characteristics of Reactance Dispersion of Water Bearing Coal

Experimental Study on the Relationship Among Complex Resistivity, Water Saturation, and Salinity in the Jiaozuo Anthracite Reservoir

Coil System Design for Multi-Frequency Resistivity Logging Tool Based on Numerical Simulation

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