• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.283-286
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• 2003

국내의 12개소 저산출 우물을 대상으로, 외국의 유정들에서의 산출량 증대를 위하여 많이 사용되고있는 인공수압파쇄 방법을 적용하여 산출성 증대 효과를 검증하였다. 12개소에 대하여 수압파쇄시험 전후로 양수 시험을 실시하여 투수성 증대 등의 효과와 비양수량을 정량적으로 평가한 결과, 비양수량의 경우 전체적으로 평균 약 45%의 증가하였으며 투수량계수 또한 약 26%가 증가하였다. 이러한 결과는 인공수압파쇄 방법이 대수층내 열극의 생성 혹은 확장 및 균열내의 막힘(clog) 물질 제거를 통해 투수성을 상당히 개선시킨 것으로 평가된다. 특히, 현재까지의 시험 결과, 퇴적암류 지역에서 보다 화성암류 지역에서의 시험 결과가 양호하게 나타났다. 화성암 지역에서 개발된 홍천에서의 사례를 볼 때, 고압의 주입을 통하여 상부 및 하부의 파쇄대가 확장 연결되고, 이들 파쇄 열극에 부착된 광물학적, 생물학적 막힘 물질이 제거되면서 산출성이 증대되는 것으로 나타났다.

• The Journal of Engineering Geology
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• v.14 no.2
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• pp.189-197
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• 2004

For a long time, groundwater has been used for a substitution for surface water but recently many problems have risen due to shortage of water resources and decrepitude of waterwells. Pneumatic fracturing technique is likely to be an efficient way to solve the problem of tile wells, in which pressure under the ground is applied to increase the amount of ground water. When applied pressure is given artificially to unstabilize the rock stress or to remove substances between fractures the groundwater can inflow. As the air pressure applied on the base rocks is stronger, permeability is getting higher, thus producing much groundwater than ever before. The result of this study show 15% increase of pumping rate in the P-5 well. After pneumatic fracturing pumping rate changed from 26m3/day to 30m3/day, drawdown rate increase from 51.12m to 56.58m, and specific yield also increased from 0.51m3/day to 0.53m3/day.

• Tunnel and Underground Space
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• v.29 no.3
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• pp.157-171
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• 2019

The fracturing by liquid carbon dioxide ($LCO_2$) as a fracking fluid has been an alternative to mitigate the environmental issues often caused by the conventional hydraulic fracking since it facilitates the fluid permeation owing to its low viscosity. This study presents how $LCO_2$ injection influences the breakdown pressure, acoustic emission, and fracture morphology. Three fracturing fluids such as $LCO_2$, water, and oil are injected with different pressurization rate to the synthetic and porous mortar specimens. Also, the shale which has been a major target formation in conventional fracking practices is also tested to examine the failure characteristics. The results show that $LCO_2$ injection induces more tortuous and undulated fractures, and particularly the larger fractures are developed in cases of shale specimen. On the other hand, the relationship between the fracturing fluids and the breakdown pressure shows opposite tendency in the tests of mortar and shale specimens.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.443-446
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• 2004

이동장수 먹는샘물 공장부지내에 파쇄대에 위치한 관정에서 인공수압파쇄 및 인공함양 시험을 실시하여 대수성 산출 증대효과와 저장 증대효과를 살펴보았다. 인공수압파쇄 시험은 두개의 관정(MW-2, O-7)에 실시하였고, 마찬가지로 인공함양 시험도 다른 두개의 관정(O-7a, MW-7)에 대해서 실시하였다. 또한 대수성 산출능의 효과를 살펴보기 위하여 인공수압파쇄 및 인공함양시험 전후에 각각 양수 시험을 실시하여 비양수량, 투수계수, 및 수위강하를 구하였다. 따라서 사전 사후 대수성 시험 비교 결과 인공수압파쇄 시험에서는 평균적으로 약 367 %의 투수계수의 증가율과 271 %의 비양수량의 증가를 나타내었다. 마찬가지로 인공함양 시험 결과 O-7a는 약 110%의 투수계수의 증가와 약 75%의 비양수량의 증가를 보였다. 반면에 MW-7는 거의 변화가 없었다. 인공함양시험은 인공수압파쇄시험보다 낮은 투수계수 증가율을 보이거나 거의 변화를 일으키지 못했지만 주변에 있는 관정에 주입압과 비슷한 양상를 갖는 수위변화를 일으키는 것으로 보아서 함양된 주입수가 주변의 대수층에 널리 퍼져 있을 것으로 추측된다.

• 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.

• Tunnel and Underground Space
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• v.26 no.4
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• pp.327-337
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• 2016

In this study, laboratory hydraulic fracturing tests are carried out to evaluate the effects of the cleavage anisotropy of Pocheon granite. Breakdown pressure is smaller when cracks are generated to the direction of rift plane in constant pressurization rate condition because of higher microcracks density. Besides not only injection rate changes but also the amount of injection pressure for fracture initiation and crack expansion is detected while testing due to internal deformation. Pressurization rate is higher while hydraulic fracture testing with constant injection rate condition in case of the specimen which has rift plane perpendicular to borehole because there are much flow paths to penetrate compared to the specimen which has hardway plane perpendicular to borehole. Observation by X-ray CT scanning shows that almost all of cracks due to hydraulic fracturing are generated to the direction of plane which has higher microcrack density that is rift plane or grain plane.

• The Journal of Engineering Geology
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• v.16 no.2 s.48
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• pp.125-134
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• 2006

In order to establish the in-situ application of the artificial storage and recovery (ASR) technology which is used the property of the aquifer storage of groundwater. We carried out to the in-situ experiments such as borehole TV logging, pumping test and artificial hydraulic fracturing in volcanic island, Ulleungdo. In-situ experiments were conducted to divide the before- and after-hydraulic fracturing. Pumping test was achieved to confirm the two fracture zones, GL-13m and GL-21m, which are determined by the borehole TV logging. From the results of the before- and after-pumping tests, the hydraulic connectivity was confirmed to locate at GL-13m in the residual deposit zone of pumice media as alluvium. However, in the bedrock tone at GL-21m the hydraulic connectivity could be considered to faulty. Consequently, in this study area the artificial recharge has a little unsatisfied to geo-structural condition and desired to more detail investigation works.

• Journal of Korea Foundry Society
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• v.43 no.1
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• pp.31-36
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• 2023

• Tunnel and Underground Space
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• v.15 no.2 s.55
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• pp.111-118
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• 2005

The area of investigation belongs to Okchon metamorphic zone and the fault fractured zone runs parallel to the tunnel direction. It causes the independent decline of tunnel face and the slackness of the tunnel surrounding base so, after all, the severe displacement has occurred within the tunnel. Accordingly, the TSP(Tunnel Seismic Prediction) survey has been performed to investigate the extent of fault fractured zone and to analize its characteristics. Also, we have analized the behavior causes by performing the tunnel face mapping and drilling investigation, and confirmed the position and scale of geological anomaly area and front fractured zone which influences tunnel excavation and supporting. Collected data analyzed ground layer condition through 3 dimensional modeling. Several variables included in the modeling were analyzed by geostastistics. The analysis of the modeling data shows that the belt of weathering by fault fractured zone is developing on the basis of the right side of tunnel and that is decreasing to the left side. The fault fractured zone was confirmed that it has strike, $N0\~5^{\circ}E$ dip NW, and it is consisted of large-scale fractured zone including several anomalies. The severe displacement in tunnel is probably caused by asymmetrical load that n generated by the crossing of discontinuity and the rock strength imbalance of tunnel's both side by fault fractured zone, and judge that need tunnel reinforcement method of grouting etc.

• Proceedings of the KSEG Conference
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• 2002.04a
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• pp.285-290
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• 2002

조사지역은 전라남도 함평군 함평읍으로부터 남쪽으로 엄다면 화양리, 학야리, 성천리 일대에 발달한 충적층으로서. 이 지역에는 남서-북동방향으로 광주단층이 통과하고 있는 것으로 추정된다. 충적층 하부에 발달한 단층을 포함한 대규모 파쇄대 파악에는 지표지질조사로서 한계가 있다. 따라서 이 연구에서는 물리탐사방법을 적용하여 충적층 하부의 대규모 파쇄대의 방향과 연장성을 파악하고자 하였으며, 사용된 물리탐사법은 전기비저항 2차원탐사, 전자탐사 그리고 자력탐사이다. 전기비저항 탐사결과 충적층 내에서 남북방향의 연장성을 갖는 전기비저항 이상대가 파악되었으나, 자력탐사와 전자탐사의 측정자료에는 이 이상대에대한 반응을 관찰할 수 없었다. 이는 전자탐사의 경우, 가탐심도가 매우 작은 EM31을 사용하였고, 또한 자력탐사는 주변 지질매체 간의 대자율 차이가 없는 것에 기인한 것으로 판단된다. 따라서 향후 지하심부의 탐사를 위해 전자탐사법중 TEM 탐사를 실시할 계획이며, 또한 낮은 전기비저항 이상대의 연장성을 정확히 파악하기 위하여 기 측정된 전기비저항 탐사 측선 사이를 탐사할 예정이다.