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Oh, Seok-Hoon;Chung, Ho-Joon;Suh, Baek-Soo
- 한국지구물리탐사학회:학술대회논문집
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- 2007.06a
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- pp.48-53
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- 2007
A new way to integrate various geophysical information for evaluation of RQD was developed. In this study, we did not directly define the RQD value where borehole data are not sampled. Instead, we infer the probability of RQD values with prior probability from borehole direct data, and secondary supporting probability from resistivity and seismic tomography data. For the integration, we applied the geostatstical indicator kriging to get prior probability of RQD value, and indicator kriging with soft data to get the supporting probability from resistivity and seismic data. And we finally use the permanence ratio rule to integrate these information. The finally obtained result was also analyzed to fully utilize the probabilistic features. We show the probability of wrongly classifying the RQD evaluation and vice versa. This result may be used for decision making process based on the geophysical exploration.
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Tsourlos, Panagiotis;Kim, Jung-Ho;Vargemezis, George;Yi, Myeong-Jong
- 한국지구물리탐사학회:학술대회논문집
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- 2007.06a
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- pp.87-92
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- 2007
This work describes the installation and preliminary measurements of an electrical resistivity tomography (ERT) system to monitor the injection of recycled water into a confined aquifer in the area of Sindos (Thessaloniki N. Greece). The aim is to provide, through time-lapse ERT measurements and processing, geoelectrical images of rather increased volumetric sampling around and between the holes and to obtain improved understanding of the flow and transport of the injected water. The details about the general setting, the construction and installation of the ERT cables into the boreholes are explained in full. Preliminary measurements involving single and cross-hole ERT measurements were obtained and processed with a 2D inversion algorithm to produce images of the subsurface. Results depict a very good correlation between ERT images and the lithology and resistivity logs; an indication of the reliability of the approach.
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Choi, Jae-Ho;Lim, Hyo-Jae;Kong, Hyoung-Jin;Sohn, Byong-Hu
- Proceedings of the SAREK Conference
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- 2008.11a
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- pp.33-38
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- 2008
A ground-loop heat exchanger in a ground source heat pump system is an important unit that determines the thermal performance of a system and its initial cost. The Size and performance of this heat exchanger is highly dependent on ground thermal properties. A proper design requires certain site-specific parameters, most importantly the ground effective thermal conductivity, the borehole thermal resistance and the undisturbed ground temperature. This study was performed to investigate the effect of some parameters such as borehole lengths, various grouting materials and U-tube configurations on ground effective thermal conductivity. In this study, thermal response tests were conducted using a testing device with 9-different ground-loop heat exchangers. From the experimental results, the length of ground-loop heat exchanger affects to the effective thermal conductivity. Among the various grouting materials, the bentonite-based grout with silica sand shows the largest thermal conductivity value.
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Chang Hyun-Sam;Lim Hae-Ryong;Hong Jae-Ho
- 한국지구물리탐사학회:학술대회논문집
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- 1999.08a
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- pp.176-201
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- 1999
Principles, data acquisition, data processing of four frequently used borehole seismic methods, i.e., downhole seismic, vertical seismic profiling(VSP), crosshole seismic, and seismic tomography, are reviewed briefly. Field data examples are presented and their application to civil engineering area was also discussed.
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Rasouli, Fatemeh S.
- Nuclear Engineering and Technology
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- v.54 no.9
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- pp.3390-3397
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- 2022
Among the different techniques available, nuclear methods, including gamma-gamma logging tools, are of special importance. Though the real environment which surrounds the drilled borehole is a complex fractured medium which the fluid can flow through the porosities, simulation studies generally use the traditional model of a homogeneous mixture of formation and the liquid. Considering a previously published study, which shows that modeling of fluid flow in fractured reservoirs and simulating the formation as an inhomogeneous fractured medium leads to different results compared with those of homogeneous mixture, here we study the effect of the presence of drilling fluid (mudcake) on the response of the detectors in both the models. To study this effect, a typical gamma-gamma logging tool was modeled by using the MCNPX Monte Carlo code. The results show that the responses of the detectors in the mixture model in the presence of various thicknesses of mudcake are sensitive to the density of the formation material. However, this effect is not notable in the inhomogeneous fractured medium. These results emphasize the importance of the model employed for simulation of the medium in gamma-gamma well-logging.
https://doi.org/10.1016/j.net.2022.03.028 인용 PDF KSCI