• Journal of the Korean Geophysical Society
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• v.5 no.4
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• pp.271-281
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• 2002

Interpretation of high-resolution seismic profiles collected from the inner shetf of the Korea Strait reveals that the shelf sequence in this area consists of three sedimentary units (I, II, and III in a descending order) formed after the last glacial maximum. Lower two units (II and III) represent the transgressive systems tract formed during the Holocene transgression, Unit III above the sequence boundary is interpreted to be the transgressive estuarine deposit, whereas Unit ll above the ravinement surface forms a thin transgressive sand which consists of the sediment produced through shoreface erosion and winnowing during the transgression. Unit I above the maximum flooding surface is the highstand systems tract consisting mainly of recent muds derived from the Nakdong River.

• Ocean Systems Engineering
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• v.6 no.3
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• pp.289-303
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• 2016

With more than 100 years exploration and development of offshore oil, more and more offshore oil fields will gradually lose the economic profit to operate. In this article, to take the target oil field for example, the procedure of decommissioning for FPSO, TCMS, subsea system and well abandonment have been analyzed. Meanwhile, the environment impact and mitigation measure have been proposed. The successful project experience will provide a guide line for the offshore facilities decommissioning and abandonment.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1991.07a
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• pp.47-50
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• 1991

With increasing offshore oil exploration, drilling, and production activities, and with a huge amount of petroleum being transported by tankers and pipelines through the ocean and coastal environment and resoures has been realized among government decision makers, oil industry personnel, and the general public. Assessment must be made of the potential risk of damage resulting from the exploration, development and transportation activities, based on predictive impact evaluations of the fate of hypothetical or real oil spills.(omitted)

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.261-266
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• 2007

An efficient three-dimensional (3D) inversion of magnetotelluric (MT) data can be carried out by using approximate sensitivities or avoiding the calculation of a full sensitivity matrix. In this paper, we propose approximate sensitivities for efficient 3D MT inversion based on the Gauss-Newton method and test and compare four kinds of sensitivities. Applying the four sensitivities to both synthetic and field data shows that the effects of sensitivities are highly dependent on data and thus applying various combinations of sensitivities is recommended for efficient inversion and good images.

• Korean Journal of Remote Sensing
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• v.8 no.1
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• pp.45-58
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• 1992

The study is aimed at extraction of the groundwater potential area using the Geographic Information System. The study was to develop techniques of the thematic mapping such as slope map, geologic map, soil map and suitability mapping for grotential area. There thematic maps were combined and weightages were given to produce suitability map for groundwater potential area. The results of this study are as follows. 1) The 78% of cased wells have releation to lineament coincided with the appraisement point of the suitability map. 2) The 9 sites of 18 test sites produced over than 200 m$^3$/day. The with the highest appraisement point of the suitability map. 3) Suitability map is effective to extract groundwater potential area which can not be extracted from the remotely sensed data. The developed suitability mapping techniques are expected to do as an important tool for exploration and development of the newable and unnewable resources such as groundwater, petroleum etc.

• The Korean Journal of Petroleum Geology
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• v.14 no.1
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• pp.36-44
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• 2008

Natural gas in tight reservoirs, one of unconventional hydrocarbon resources, has become a significant exploration and exploitation targets. Tight gas reservoirs are the gas-bearing rocks that commonly have a permeability of less than 0.1 millidarcy (mD). Tight gas reservoirs are characterized by extensive and deep locations as well as abnormal pressure such as over- or under-pressure. The tight gas reservoirs are independent of structural or stratigraphic traps, whereas conventional gases normally occur at these traps. Tight gas reservoirs can be productive when stimulated by hydraulic fracturing. Better production areas within the tight reservoir beds are referred to as sweet spots that are commonly caused by natural fractures, which should be understood and identified to enhance the recovery of the gas from tight reservoirs. The exploration and production techniques allow the commercial production of tight gas, one of environmentally friendly resources. Slant and horizontal wells have best production when they intersect the fractures. Gas production from the tight reservoirs has rapidly grown in U.S. and Canada. Indeed, the U.S. gas production of tight sandstones increases from 11.1% in 1990 to 24.1% in 2005. The presence of tight gas reservoirs has been suggested on the Korean offshore block 6-1. Paradigm shift from conventional to unconventional tight reservoir is required to develop the tight gas from the block.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.113-117
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• 2007

Sub-salt imaging is an unsolved hot issue in subsurface imaging area. We tested several important properties in imaging sub-salt structures to provide a clue to this problem. Reverse time migration using velocity models obtained by waveform inversion produced better results than that of stacking velocity analysis. Sub-salt imaging results were highly dependent on the size and shape of a salt structure. The results were not clear when the velocity of a salt structure is significantly higher than that of adjacent layers.

• Journal of Information Processing Systems
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• v.20 no.3
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• pp.399-408
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• 2024

The moisture content of crude oil notably affects various aspects of oil production, storage, transportation, and exploration. However, accurately measuring this moisture content is challenging because of numerous influencing factors, leading to a lack of precision in existing detection methods. This inadequacy hinders the progress of China's petroleum industry. To overcome these challenges, this paper proposes a conductivity-based method for measuring crude oil moisture content. By employing an embedded system, we designed a sensor comprising five electrodes. Additionally, we developed signal excitation and signal processing circuits. Moreover, a software program was designed to analyze and compute the output signal using fast Fourier transform operations. This facilitated the identification of flow patterns, computation of relevant flow rates, and establishment of correlation rates based on frequency spectral characteristics. Based on experimental results, we established a functional relationship between measurement parameters and crude oil moisture content. This study enhanced the precision of moisture content measurement, thereby addressing existing limitations and fostering the advancement of China's petroleum industry.

• Journal of Computational Design and Engineering
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• v.3 no.3
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• pp.226-249
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• 2016

The symbiotic organisms search (SOS) algorithm is an effective metaheuristic developed in 2014, which mimics the symbiotic relationship among the living beings, such as mutualism, commensalism, and parasitism, to survive in the ecosystem. In this study, three modified versions of the SOS algorithm are proposed by introducing adaptive benefit factors in the basic SOS algorithm to improve its efficiency. The basic SOS algorithm only considers benefit factors, whereas the proposed variants of the SOS algorithm, consider effective combinations of adaptive benefit factors and benefit factors to study their competence to lay down a good balance between exploration and exploitation of the search space. The proposed algorithms are tested to suit its applications to the engineering structures subjected to dynamic excitation, which may lead to undesirable vibrations. Structure optimization problems become more challenging if the shape and size variables are taken into account along with the frequency. To check the feasibility and effectiveness of the proposed algorithms, six different planar and space trusses are subjected to experimental analysis. The results obtained using the proposed methods are compared with those obtained using other optimization methods well established in the literature. The results reveal that the adaptive SOS algorithm is more reliable and efficient than the basic SOS algorithm and other state-of-the-art algorithms.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.151-156
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• 2007

In December 2006, 2D surface streamer and Ocean Bottom Seismometer (OBS) data were acquired in the Ulleung basin in Korea where strong Bottom Simulating Reflectors (BSR) were shown as a result of 2D and 3D multichannel (MCS) reflection survey. The aim of this study is to provide another reliable source for estimating P wave velocity around BSR depth using OBS data in addition to velocity information from 2D surface seismic data. Four OBSs were deployed and four 20-km shot lines which pass two OBSs respectively were designed. To derive P wave velocity profile, interactive interval velocity analysis using ${\tau}$-p trajectory matching method (Kumar, 2005) was used for OBS data and semblance analysis was used for surface data. The seismic profiles cross the OBS instruments in two different directions yield recordings for four different azimuths. This raised the confidence for the results. All velocity profiles in the vicinity of BSR depth of four OBS sites show almost definite velocity changes which we could consider as upper BSR and free gas layer. Making comparison between velocity from OBS and that from 2D seismic semblance velocity analysis gives consistency in result.