• 한국가스학회지
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• 제27권3호
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• pp.98-107
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• 2023

본 연구에서는 인도네시아 북부 칼리만탄 섬 임의의 광구에서 취득한 석탄시료의 메탄가스 흡착량 측정 실험 결과를 활용하여 석탄층 메탄가스 저류층의 적정 생산정 간격 설계 연구를 수행하였다. 가스 생산성 분석결과, 랭뮤어 부피가 증가할수록 누적 가스생산량도 증가하며 이는 최대 가스 흡착량이 가스생산량에 직접적인 영향을 주는 것으로 판단된다. 또한 탄리투과도가 증가할수록 최대 가스생산량이 증가하고 배출수 기간(dewatering period)이 단축되는 것을 확인하였다. 특히 생산 영향영역이 넓어짐에 따라 누적 가스생산량은 증가하지만 단위 가스정 당 생산성 비교 시, 심도 2,000 ft, 영향영역 80-160 acres 사이에서 최대 누적 가스생산량이 산출되었다. 탄층 심도와 생산 영향영역을 동시에 고려하여 적정 생산정 심도 및 간격 산출 결과, 600-2,000 ft 사이에서 가스 생산성이 가장 높게 나타나며, 이때 생산정 간격은 80-160 acres 범위 내로 설계 하는 것이 적정하다. 따라서 탐사 시추 시 회수된 코어 시료 이외의 시추 자료가 없는 미개발 CBM 저류층에서 석탄시료의 가스흡착 실험 결과를 활용함으로써 탄층심도를 고려한 생산정 간격 설계를 수행할 수 있음을 제시하였다.

• 지질공학
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• 제18권2호
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• pp.159-166
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• 2008

지각 천부인 취성변형의 조건 하에서도 지표에서 발달하는 절리들의 방향성 분포가 지하 심부로 가면서 지하 몇 미터에서부터 불연속면의 변화를 보이는지에 대해 의문이 생긴다. 이에 대한 의문의 해결을 위해 본 연구에서는 지표지질조사를 통해 측정한 불연속면의 자료와 BIPS 및 Televiewer에 의해 측정된 불연속면의 자료들을 두 개 지역에 대해 비교 분석하였다. 호남탄전지역은 지하 심부로 가면서 지표에서 30 m와 40 m 지점에서 불연속면의 방향성이 변하며 수원지역의 경우는 20 m에서 불연속면의 방향들이 변화하였다. 이와 같은 변화가 등방성의 암석에서 변화를 관찰함이 심도별 변화를 대비 할 수 있으나 호남탄전의 경우는 퇴적암으로 측정된 암반이 세립질의 사암과 세일이 교호하는 이방성의 암반이며 스르스트단층이 통과하고 있다. 그러나 수원지역의 경우는 대개 운모편암들로 호남탄전 지역보다는 암질의 변화가 적다. 그러나 두 지역 공히 지하 20 m와 30 m 이하에서 이미 지표와는 달리 불연속면의 분포특성이 바뀜을 시사하고 있다.

• Geomechanics and Engineering
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• 제23권2호
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• pp.93-102
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• 2020

The excavation broken zones (EBZ) of gateways is a significant factor in determining the stability of man-made opening. The EBZ of 55 gateways with variety geological conditions were measured using Ground Penetrating Radar (GPR). The results found that the greatly depth of EBZ, the smallest is 1.5 m and the deepest is 3.5 m. Experimental investigations were carried out in the laboratory and in the coal mine fields for applying the combined arch support theory to large EBZ. The studies found that resin bolts with high tensile strength and good bond force could provide high pretension force with bolt extensible anchorage method in the field. Furthermore, the recently invented torque amplifier could greatly improve the bolt pretension force in poor lithology. The FLAC3D numerical simulation found that the main diffusion sphere of pretension force was only in the free segment zone of the surrounding rock. Further analysis found that the initial load-bearing zone thickness of the combined arch structure in large EBZ could be expressed by the free segment length of bolt. The using of high mechanical property bolts and steel with high pretension force will clearly putting forward the bolt length selection rule based on the combined arch support theory.

• 설비공학논문집
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• 제16권9호
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• pp.863-871
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• 2004

The use of fossil fuels like coal, oil and natural gases around the world causes an increase of the carbon dioxide content in the atmosphere. In order to reduce the concentration of the greenhouse gas, the idea of carbon dioxide sequestration in the ocean is proposed to be an effective mitigation strategy to counteract potential global warming due to the greenhouse effect. Therefore, in the present study, calculations of the dissolution behavior of carbon dioxide when liquid carbon dioxide is released at 1,000m and 1,500m in depth by fixed pipeline are performed. The results show that carbon dioxide droplets change to carbon dioxide bubbles in gas phase around 500m in depth, and the droplets are completely dissolved below 500 m in depth if the liquide carbon dioxide is released both at 1,000 m in depth with the initial diameter of 0.007m or less and at 1,500m in depth with the diameter of 0.011m or less.

• Geomechanics and Engineering
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• 제22권2호
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• pp.133-142
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• 2020

The evolution of the mining-induced fracture network formed during longwall top coal caving (LTCC) has a great influence on the gas drainage, roof control, top coal recovery ratio and engineering safety of aquifers. To reveal the evolution of the mining-induced stress and fracture network formed during LTCC, the fracture network in front of the working face was observed by borehole video experiments. A discrete element model was established by the universal discrete element code (UDEC) to explore the local stress distribution. The regression relationship between the fractal dimension of the fracture network and mining stress was established. The results revealed the following: (1) The mining disturbance had the most severe impact on the borehole depth range between approximately 10 m and 25 m. (2) The distribution of fractures was related to the lithology and its integrity. The coal seam was mainly microfractures, which formed a complex fracture network. The hard rock stratum was mainly included longitudinal cracks and separated fissures. (3) Through a numerical simulation, the stress distribution in front of the mining face and the development of the fracturing of the overlying rock were obtained. There was a quadratic relationship between the fractal dimension of the fractures and the mining stress. The results obtained herein will provide a reference for engineering projects under similar geological conditions.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.335-340
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• 2002

By the recently, Environmental pollution is serious by the highly economic growth and expansion of lively country basic industry. Especially, in case of industrial waste and life waste leaped into a pollution source. Also, research for processing of waste and recycling countermeasure is a pressing question on national dimension because it is prohibited an ocean disposal and reclamation. In this study, it looked for fracture characteristic value of recycling a coal ash to decrease environmental pollution by picky and exhaustion of natural resources and to reduce self-weight to prepare for a tall building and earthquake. So a coal ash examined to be possible to do as construction material. It achieved compressive strength test and three points bending test with initial notch depth rate and age for variables to show a basic research data. From the basis of the three points bending test, the fracture parameters - notch sensitivity, fracture energy, initial compliance were experimentally proposed. From the results of the compressive strength test, the elastic modulus was experimentally proposed. Also on the basis of the three points bending test, the fracture parameters - notch sensitivity, fracture energy, initial compliance were experimentally proposed. The results that the strength and fracture energy value are lower than concrete or mortar is described in this paper. Also, it shows that the deflection at fracture decreases as the age increases and the notch sensitivity decrease. However, it is judged to be available to construction material if research is continuously gone forward.

• 대한기계학회논문집B
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• 제29권12호
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• pp.1321-1328
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• 2005

The burning characteristics of interacting coal particles in a convective flow are numerically investigated at various Reynolds numbers. The transient combustion of 2-dimensionally arranged particles, both the fixed particle distances of 5 radii to 20 radii horizontally and 4 radii to 24 radii vertically, is studied. The results obtained from the present numerical analysis indicate that the transient flame configuration and retardation of particle temperature augmentation with the horizontal or vertical particle spacing substantially influence devolatilization process and carbon conversion ratio of interacting particles. Volatile release and carbon conversion ratio of the second particle with decreasing horizontal and vertical particle spacing decrease gradually, whereas those of the first particle with decreasing vertical particle spacing increase due to flow acceleration. When the vertical particle spacing is smaller than $6R_0$, volatile release and carbon conversion ratio of the second particle decrease due to reduction of flame penetration depth and interference of oxygen diffusion by the first particle.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제29회 KOSCI SYMPOSIUM 논문집
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• pp.117-123
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• 2004

The burning characteristics of interacting coal particles in a convective flow are numerically investigated at various Reynolds numbers. The transient combustion of 2-dimensionally arranged particles, both the fixed particle distances of 5 radii to 20 radii horizontally and 3 radii to 24 radii vertically, is studied. The results obtained from the present numerical analysis reveal that the transient flame configuration and retardation of particle temperature augmentation with the horizontal or vertical particle spacing substantially influence devolatilization process and carbon conversion ratio of interacting particles. Volatile release and carbon conversion ratio of the second particle with decreasing horizontal and vertical particle spacing decrease gradually, whereas those of the first particle with decreasing vertical particle spacing increases due to flow acceleration. When the vertical particle spacing is smaller than $6R_{o}$, volatile release and carbon conversion ratio of the second particle decrease greatly due to reduction of flame penetration depth.

• 자원환경지질
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• 제27권3호
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• pp.313-321
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• 1994

Structural interpretation by using subsurface attitude of coal seam and outcrop patterns of folds and faults shows that wrench and thrust tectonics took place simultaneously in the study area. From the interference patterns of fold axes, three generations of folding are suggested: $F_1$ (NE-SW), $F_2$ (N-S), and $F_3$ (E-W). Differential displacement of rock mass from north to south yields to E-W fold and Osypcheon Fault. Geometry of subsurface coal seam show different patterns comparing to those of surface outcrop because of shallow-depth crustal shortening which took place post Cretaceous.

• Geomechanics and Engineering
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• 제21권1호
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• pp.23-33
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• 2020

An advancing cutting roof for gob-side entry retaining with no-pillar mining under specific geological conditions is more conducive to the safe and efficient production in a coalmine. This method is being promoted for use in a large number of coalmines because it has many advantages compared to the retaining method with an artificial filling wall as the gateway side filling body. In order to observe the inner structure of the gateway cutting roof and understand its stability mechanism, an equivalent material simulation experiment for a coalmine with complex geological conditions was carried out in this study. The results show that a "self-stabilization bearing structure" equilibrium model was found after the cutting roof caving when the cut line deviation angle was unequal to zero and the cut height was greater than the mining height, and the caving roof rock was hard without damage. The model showed that its stability was mainly controlled by two key blocks. Furthermore, in order to determine the optimal parameters of the cut height and the cut line deviation angle for the cutting roof of the retaining gateway, an in-depth analysis with theoretical mechanics and mine rock mechanics of the model was performed, and the relationship between the roof balance control force and the cut height and cut line deviation angle was solved. It was found that the selection of the values of the cut height and the cut line deviation angle had to conform to a certain principle that it should not only utilize the support force provided by the coal wall and the contact surface of the two key blocks but also prevent the failure of the coal wall and the contact surface.