• Geophysics and Geophysical Exploration
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• v.18 no.3
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• pp.125-132
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• 2015

The water saturation ($S_w$), which is very important to estimate hydrocarbon reserves in the reservoir, has been determined from resistivity index (RI) by using the Archie's formula. However, in many cases, it has been reported that n is not constant for a given formation and it could be varied with water saturation. In addition, it frequently happens that the line obtained by linear regression analysis on log-log scale does not pass through the origin. In order to overcome these drawbacks, we suggested a modified Archie's formula, which can handle almost all the RI vs. $S_w$ cross-plots whether the trend is straight or curved and whether it passes through the origin or not. We also demonstrated that how to determine conductivity exponent ${\mu}$, critical water saturation $S_c$, and saturation distribution factor b in the laboratory to use the modified Archie's formula. Since the modified Archie's formula takes into account pore structure, pore water distribution, and wettability of reservoir such as clean sandstone and carbonate rocks, it might improve field applicability.

• Cross-Cultural Studies
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• v.25
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• pp.131-158
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• 2011

In the Sakha(Yakutia) Republic, culture and politics continue to be interwined. Shamanism recently has come out of hiding after Soviet repression, and into fashion. Images of the shaman are changing in villages, where traditional healers have maintained their practices in difficult conditions, and in cities, where a resurgence of spirit belief and healing has led to the revitalization of their nationalism. Shamans and folk healers manipulate their own images, and in turn are changed by the upheavals of politicized cultural revitalization. In this complex and interactive context, folklore about traditional shamans has become especially rich and accessible. I argue here that religion has become an idiom through which competing definitions of homeland and national pride are being shaped. Until September 2002, Yakutsk had never had a 'temple' devoted to the practice of traditional shamanic beliefs. Indeed the whole concept that a building 'Archie Jiete' could contain or represent the beliefs, values and rituals of the Sakha people was new, and highly controversial.

• Journal of Information Management
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• v.26 no.4
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• pp.28-62
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• 1995

This paper introduced Internet totally, which is continuously changing, for the aspect of service-improvement to users. Particulary, the concepts, the features and methods of Gopher, Veronica, Archie, WAIS and WWW which are used broadly in the aspect of information retrieval, have been introduced with command-language in Internet. Among them, this paper intends not only to describe in detail the use of Web-browser's method but also to explain about the search engine which is provided in the large online service on the base of actual experience.

• Journal of the Korean Geotechnical Society
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• v.31 no.6
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• pp.45-58
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• 2015

The aim of this study is to suggest a semi-empirical equation for estimating the hydraulic conductivity of sands using geoelectrical measurements technique. The suggested formula is based on the original Kozeny-Carman equation; therefore varying factors affecting the Kozeny-Carman equation were selected as the testing variables, and six different sands with varying particle sizes and particle shapes were used as the testing materials in this study. To measure both hydraulic and electrical conductivities, a series of constant head permeameter tests equipped with the four electrodes conductivity probe was conducted. Test results reveal that the effects of both pore water conductivity and flow rate in relation between hydraulic conductivity and formation factor (=pore water conductivity / measused conductivity of soil) of tested materials are negligible. However, because the variations of hydraulic conductivity of the tested sands according to particle sizes are significant, the estimated hydraulic conductivity using the formation factor varies with particle sizes. The overall comparison between the measured hydraulic conductivity and the estimated hydraulic conductivity using the suggested formula shows a good agreement, and the variation of hydraulic conductivity with varying Archie's m exponents is smaller compared with varying porosities.

• Journal of the Korean Geotechnical Society
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• v.39 no.8
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• pp.29-39
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• 2023

The degree of saturation determines the connectivity of void space and the particle surface. Thus, it greatly affects the electrical conductivity of soils. This study aimed to analyze the electrical conductivities of coarse grains with a high relevance of pore water conduction and fine grains with a high relevance of surface conduction based on the degree of saturation. It also aimed to express the electrical conductivity of unsaturated soils as a combination of surface and pore water conductions using the modified Archie's equation. Samples were prepared in a plastic cell equipped with four electrodes, and the electrical conductivity was measured based on the porosity at various degrees of saturation (40%~100%). The results demonstrate that Archie's equation can be used to express the electrical conductivity of coarse grains, with a saturation exponent of ~1.93 regardless of the pore water conductivity. However, the saturation exponent of fine grains varied considerably with pore water concentration. This variation can be attributed to the relative magnitude of surface conduction with respect to the electrical conductivity of soils at different pore water concentrations. Thus, the degree of saturation has varying effects on pore water conduction and surface conduction. Therefore, different saturation exponents must be used for pore water conduction and surface conduction to predict the electrical conductivity of unsaturated soils using the modified Archie's equation.

• Journal of the Korean Geotechnical Society
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• v.25 no.2
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• pp.45-54
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• 2009

The electrical characteristics of soils have been used for investigating soil properties. The purpose of this study is the development and application of the electrical resistivity cone probe (ERCP) for the evelation of the porosity in the field with high precision. The shape of the probe tip is a cone shape to minimize the disturbance during penetration. In addition, the four terminal pair configuration is adopted to minimize the electrical interference. The electrical resistances are continuously measured during penetration of the ERCP using penetration rigs with 0.33 mm/sec penetration rate at Incheon and Busan sites. With the measured resistance profile and electrical resisivity of electrolyte of undisturbed samples, soil porosity profiles are obtained by using Archie's law. The empirical coefficients for the Archie's law are obtained based on the electrolyte extracted from the undisturbed samples. The estimated porosity profiles show similar trends to those of in-situ penetration tests such as SPT, CPT, and DMT. This study suggests that the ERCP may be an effective tool for the porosity estimation in the field with minimum disturbance.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.127-133
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• 2008

The electrical resistivity methods have been commonly used for figuring out the ground layers. The purpose of this paper, differently from previous methods, is not only to figure out the layers but also to develope a equipment and a method to analyze ground porosity. Equipment has a shape of cone, which can be coupled with drilling rods. A field penetration test was performed to test application in Incheon Chungla area. Through the field test soil resistances were measured. To calculate soil porosity along the depth, Archie's law is applied. The results show that a new equipment and porosity analysis method using Archie's law can distinguish soil layers and precisely measure soil porosity.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.464-475
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• 2009

Electrical resistivity can be used for porosity estimation. In order to improve previously developed ERCP(Electrical Resistivity Cone Probe), 4ERP(4 Electrical Resistivity Probe), which has Wenner array at the tip of probes, has been developed. In properties of current flow Wenner array measures electrical properties of undisturbed area during penetration and relatively correct measurements are guaranteed without polarization. Furthermore, Wenner array equation can estimate electrical resistivity without extra calibration. 4ERP is developed into 2 types, penetration and fixation. Penetration type has wedge-shaped tip. Considering disturbance minimization, fixed type has plane tip. Fixed type 4ERP in consolidation cell measure electrical resistivity increment along porosity decrease, and penetration type 4ERP measured resistivity profile along the depth in chamber. Applying Archie's law, porosity profile was estimated with electrical resistivity. The tests result suggests that 4ERP can be new site investigation equipment with little disturbance.

• Geophysics and Geophysical Exploration
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• v.15 no.2
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• pp.102-115
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• 2012

The purpose of this paper is to review several different methods calculating gas hydrate saturations. There are three methods using downhole log data, core data (including pressure core), and seismic velocity data. Archie's equation using electrical resistivity of downhole log data is widely used for saturation calculation. In this case, Archie's parameters should be defined accurately. And the occurrence types of gas hydrate significantly affect to saturation calculation. Thus saturation calculation should be carefully conducted. The methods using chlorinity and pressure core data are directly calculated from core sample. So far, the saturation calculated from pressure core gives accurate and quantitative values. But this method is needed much more time and cost. Thus acquisition of the continuous data with sediment depth is realistically hard. The recent several results show that the saturation calculated from resistivity data is the highest values, while the value calculated from pressure core is the lowest. But this trend is not always absolutely. Thus, to estimate accurate gas hydrate saturation, the values calculated from several methods should be compared.

• Geophysics and Geophysical Exploration
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• v.7 no.2
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• pp.130-135
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• 2004

This paper describes the physical properties of the factors controlling the electrical resistivity of the subsurface. Resistivities of various types of soil and rock samples saturated with sodium chloride solutions having nine different concentrations were measured, and the measured resistivities of these samples were compared with calculated resistivities obtained using the conventional empirical formulas. From the results obtained, we observed that the resistivity of the soil and rock samples increases with increasing in pore-fluids resistivity regardless of the media type. However, between 20 and 200 ohm-m, which is the normal range of resistivity of groundwater, the resistivity of the pore-fluids have little or no effect on the resistivities of the samples used. Below 10 ohm-m, the resistivities of the samples are mainly controlled by the pore-fluids, whereas, in the normal range of resistivity of groundwater, the sample resistivities are controlled by their intrinsic matrix resistivity more than by the pore-fluids resistivity. Also, the measured resistivity of rock and soil samples having more than $20\%$ clay contents showed a good agreement with the calculated resistivity using the parallel resistance model whereas, the calculated resistivities of glass beads correlate with that obtained using Archie's formula. When the pore-fluid resistivity is high, the computation of the resistivity values of the samples using the Archie's formula could not be carried out. Through this study, we were able to confirm that the tests are only applicable to the parallel resistance model considering the intrinsic matrix resistivity within the normal resistivity range of groundwater in the subsurface.