• Economic and Environmental Geology
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• v.48 no.4
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• pp.361-369
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• 2015

Interest of unconventional Oil and Gas, which is produced in a different way, has been increasing due to exhaustion of traditional oil and gas. However production of unconventional Oil and Gas is closely related to its technology level. Accordingly in this research, we can analyze technology level of unconventional Oil and Gas with country/sector/year patent analysis. Through the result of this research, U.S is highest patent application national, patent application in oil sand is increasing. In addition, oil sands-realated patents and shale oil-realated patents applying actively in early 1970's and since the mid-1980's showed a decreasing trend. And patent application in unconventional oil and gas has been increasing due to the rise in the oil price 2000's.

• Journal of the KSME
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• v.57 no.2
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• pp.46-50
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• 2017

이 글에서는 최근 관심이 증가하고 있는 셰일가스를 포함한 비전통 자원과 기존의 석유 가스 개발을 위한 자원플랜트 기술에 대해서 소개하고자 한다.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.4
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• pp.209-218
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• 2021

Studies of pore structure in shale gas reservoirs are essential to increase recovery rates, which is in the spotlight concerning unconventional resources. In this study, the distribution of pores in shale gas reservoir sample were observed using Scanning Electron Microscope Particle Analysis (SELPA), which is appropriate to analyze the distribution of particle or shape for sample in large area. A sample from the A-068 borehole drilled in the Liard Basin was analyzed; calcite is the main mineral. The pore size ranges from tens of nanometers to hundreds of micrometers and the contribution of each pore size to overall sample porosity was determined using SELPA. The distribution of pores was determined by observing the surface in the same area at magnifications of ×1000, ×3000 and ×5000. Pores less than 100 nm were observed at high magnifications and confirm that small-scale pore distribution can be analyzed and identified rapidly using SELPA. The method introduced in this study will be useful to understand pore structures in unconventional reservoirs.

• Journal of the KSME
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• v.56 no.1
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• pp.41-45
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• 2016

이 글에서는 최근 관심이 증가하고 있는 셰일가스를 포함한 비전통자원과 기존의 석유 가스 개발을 위한 자원플랜트 기술에 대해서 소개하고자 한다.

• Tunnel and Underground Space
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• v.23 no.6
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• pp.538-546
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• 2013

This paper deals with a hydraulic fracturing technique, which is one of the methods to maximize the recovery rate and productivity of oil and gas in the petroleum industry. In the hydraulic fracturing, typically water mixed with sand and chemicals is injected into a wellbore in order to create artificial fractures along which formation fluids migrate to the well. In recent years, it is widely used in non-conventional oil and gas such as oil shale and shale gas. Three main stages of the hydraulic fracturing process, the proposed design models for the effective hydraulic fracturing and diagnostics after fracturing treatment are introduced. In addition, this paper introduces reservoir geomechanics to solve various problems in the process of hydraulic fracturing.

• 해운
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• s.99
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• pp.14-20
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• 2013

석유생산이 정점을 짝은 후 감소한다는 피크오일(Peak Oil)의 대표사례로 지목되던 미국에서 원유생산이 39년 만에 증가세로 전환됐다(<그림 1> 참조). 2012년에는 WTI 유가 1% 하락에도 불구하고 미국은 주요 신유국 중에서 이라크에 이어 세계 두 번째로 빠른 석유생산 증가율(8.9%)을 기록하면서 세계 최대 석유 생산국으로 발돋움했다. 최근 들에서는 멜릴린치와 삭소은행 등 일부 투자은행들이 2년 내에 WTI 유가가 배럴당 50달러로까지 하락할 수 있다는 견해를 내 놓았다. 석유 생산 확대세가 이어지면서 미국내에서 거래되는 유가가 절반 가까이 하락할 수 있다는 것이다. 미국이 빠른 석유 생산 확대를 보이는 데에는 비전통 석유인 타이트 오일(Tight Oil)의 역할이 크다. 타이트 오일은 셰일가스가 매장된 셰일층, 즉 모래와 진흙이 굳어진 지하 퇴적암층에 존재하는 원유다. 탄소 함유량이 많고 황 함량이 적은 경질유이기 때문에 LTO(Light Tight Oil)라고 지칭되기도 한다. 일부에서는 셰일층이라는 매장위치를 감안해 셰일오일(Shale Oil)이라 부르기도 한다. IEA와 EIA 등 주요 에너지 기관들은 동식물의 사체가 원유로 변하기 전 단계인 케로젠(Kerogen)이 주성분인 오일셰일(Oil Shale)과 오일셰일에 열을 가해 합성 석유로 만든 셰일오일을 타이트 오일과 구분하고 있다. 타이트 오일의 잠재력을 평가하고 중장기 생산 전망과 이로 인한 국제석유시장 파급효과를 살펴본다. 다음은 엘지경제연구원에서 발표한 '셰일혁명으로 부상한 Tight Oil, 유가 안정 역할 커진다'의 주요 내용을 요약 정리한 것이다.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.4
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• pp.419-426
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• 2020

Understanding the pore structure including pore shape and connectivity in unconventional reservoirs is essential to increase the recovery rate of unconventional energy resources such as shale gas and oil. In this study, we found analysis condition to probe the nanoscale pore structure in shale reservoirs using Focused Ion Beam (FIB) and Ion Milling System (IMS). A-068 core samples from Liard Basin are used to probe the pore structure in shale reservoirs. The pore structure is analyzed with different pretreatment methods and analysis condition because each sample has different characteristics. The results show that surface milling by FIB is effective to obtain pore images of several micrometers local area while milling a large-area by IMS is efficient to observe various pore structure in a short time. Especially, it was confirmed that the pore structure of rocks with high content of carbonate minerals and high strength can be observed with milling by IMS. In this study, the analysis condition and process for observing the pore structure in the shale reservoirs is established. Further studies are needed to perform for probing the effect of pore size and shape on the enhancement of shale gas recovery.

• Journal of the Korean Institute of Gas
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• v.21 no.3
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• pp.61-69
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• 2017

The commercial development of unconventional gas is pursued in North America because it is more feasible owing to the technology required to improve productivity. Shale reservoir have low permeability and gas production can be carried out through cracks generated by hydraulic fracturing. The decline rate during the initial production period is high, but very low latter on, there are significant variations from the initial production behavior. Therefore, in the prediction of the production rate using deterministic decline curve analysis(DCA), it is not possible to consider the uncertainty in the production behavior. In this study, production rate of the Eagle Ford shale is predicted by Arps Hyperbolic and Modified SEPD. To minimize the uncertainty in predicting the Estimated Ultimate Recovery(EUR), Monte Carlo simulation is used to multi-wells analysis. Also, kernel density function is applied to determine probability distribution of decline curve factors without any assumption.

• Economic and Environmental Geology
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• v.48 no.1
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• pp.65-75
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• 2015

The CBM(Coalbed Methane) development technology being developed in mid 1980s is the technology to produce the methane gas absorbed in the coal bed. CBM is easy to be developed and its coal deposit is abundant. Therefore, the CBM industry has a large potential as an energy source as well as to deal with the global regulations for reducing greenhouse gas emission. In order to produce coal, the CBM should first be developed as a preliminary action for mine security. So CBM is advantageous in reducing the global greenhouse gas as well as its advantage not being influenced by the changes in gas market. The ECBM (Enhanced Coalbed Methane) is a new technique producing the methane gas which is substituted and disorbed from coal by injecting $CO_2$ or $N_2$ gas into a coal bed. Especially, $CO_2$-ECMB is a low-carbon, green-growth technology, so can expect to the effect of green gas reduction as well as the improved productivity of methane gas. CBM technology is being developed in about 40 nations including Canada, Australia, China, India, Indonesia and Viet Nam, and the coal output using this technology is continually being increased. The CBM is expected to contribute in changing the energy source paradigm from current coal & petroleum energy to unconventional gas.

• Tunnel and Underground Space
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• v.31 no.1
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• pp.41-51
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• 2021

The hydraulic fracturing developed to improve permeability of tight reservoir is one of key stimulation technologies for developing unconventional resources such as shale gas and deep geothermal energy. The experimental study was conducted to improve disadvantage of hydraulic fracturing which has simple fracture pattern and poor fracturing efficiency. The fracturing experiments was conducted for tight rock using various fracturing fluids, water, N2, and CO2 and the created fracture pattern and fracturing efficiency was analyzed depending on fracturing fluids. The borehole pressure increased rapidly and then made fractures for hydraulic fracturing with constant injection rate, however, gas fracturing shows slowly increased pressure and less fracture pressure. The 3D tomography technic was used to generate images of induced fracture using hydraulic and gas fracturing. The stimulated reservoir volume (SRV) was estimated increment of 5.71% (water), 12.72% (N2), and 43.82% (CO2) respectively compared to initial pore volume. In addition, permeability measurement was carried out before and after fracturing experiments and the enhanced permeability by gas fracturing showed higher than hydraulic fracturing. The fracture conductivity was measured by increasing confining stress to consider newly creating fracture and closing induced fracture right after fracturing. When the confining stress was increased from 2MPa to 10MPa, the initial permeability was decreased by 89% (N2) and 50% (CO2) respectively. This study shows that the gas fracturing makes more permeability enhancement and less reduction of induced fracture conductivity than hydraulic fracturing.