http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
개별검색 DB통합검색이 안되는 DB는 DB아이콘을 클릭하여 이용하실 수 있습니다.
통계정보 및 조사
예술 / 패션
<해외전자자료 이용권한 안내>
- 이용 대상 : RISS의 모든 해외전자자료는 교수, 강사, 대학(원)생, 연구원, 대학직원에 한하여(로그인 필수) 이용 가능
- 구독대학 소속 이용자: RISS 해외전자자료 통합검색 및 등록된 대학IP 대역 내에서 24시간 무료 이용
- 미구독대학 소속 이용자: RISS 해외전자자료 통합검색을 통한 오후 4시~익일 오전 9시 무료 이용
※ 단, EBSCO ASC/BSC(오후 5시~익일 오전 9시 무료 이용)
CO2-EOR is considered as a promising solution for enhanced oil recovery (EOR) and is attracting attention as being a more economical CO2 geological sequestration solution along with oil recovery enhancement. However, injecting CO2 at high pressure may cause many geomechanical changes and potential instabilities in surrounding formation such as ground uplift, caprock fracturing, and nearby fault reactivation. Such instabilities could significantly influence the stability of both surface facilities and subsurface structures. Especially, miscible CO2-EOR, by which recovers more oil than immiscible one but, uses less CO2, requires an injection pressure exceeding the minimum miscible pressure (MMP), which is determined by characteristics of reservoir conditions and oil compositions. Thus, for successful and safe CO2-EOR operation, injection pressure interval between MMP and the maximum pressure that could be tolerated from geomechanics safety concerns should be appropriately designed considering site-specific reservoir conditions. In this study, we perform a numerical simulation of coupled multiphase fluid flow and geomechanical analysis using TOUGH-FLAC simulator for the potential CO2-EOR site in Indonesian oil field, and demonstrate how much fault reactivation is sensitive to fault structure, slip-weakening property of faults, reservoir permeability, and in situ stress conditions. The model site consists of impermeable shale and permeable sandstone reservoir units so that the potential for fault slip through this multilayered formation is highlighted in the simulations. Our simulation results showed that fault slip initiation can be reached earlier period when in situ stress is anisotropic and reservoir is more permeable, because the stress state at the faults is near the frictional strength limit and the pore pressure buildup reaches to the fault much faster. The analysis shows that multilayered formations with high- and low-permeability layers are advantageous in CO2-EOR since intense pore pressure buildup and subsequent fault reactivation could be impeded by pressure dissipation in high-permeability layers. However, we noted that fault reactivation may become substantial when the fault has a slip-weakening property and the residual frictional coefficient of the site-specific fault is very low.
This paper presents a numerical modeling study of coupled thermodynamic, multiphase fluid flow and heat transport associated with underground compressed air energy storage (CAES) in lined rock caverns. Specifically, we explored the concept of using concrete lined caverns at a relatively shallow depth for which constructing and operation costs may be reduced if air tightness and stability can be assured. Our analysis showed that the key parameter to assure long-term air tightness in such a system was the permeability of both the concrete lining and the surrounding rock. The analysis also indicated that a concrete lining with a permeability of less than 1x10<SUP>-18</SUP>m<SUP>2</SUP> would result in an acceptable air leakage rate of less than 1%, with the operation pressure range between 5 and 8MPa at a depth of 100m. It was further noted that capillary retention properties and the initial liquid saturation of the lining were very important. Indeed, air leakage could be effectively prevented when the air-entry pressure of the concrete lining is higher than the operation air pressure and when the lining is kept at relatively high moisture content. Our subsequent energy-balance analysis demonstrated that the energy loss for a daily compression and decompression cycle is governed by the air-pressure loss, as well as heat loss by conduction to the concrete liner and surrounding rock. For a sufficiently tight system, i.e., for a concrete permeability of less than 1x10<SUP>-18</SUP>m<SUP>2</SUP>, heat loss by heat conduction tends to become proportionally more important. However, the energy loss by heat conduction can be minimized by keeping the air-injection temperature of compressed air closer to the ambient temperature of the underground storage cavern. In such a case, almost all the heat loss during compression is gained back during subsequent decompression. Finally, our numerical simulation study showed that CAES in shallow rock caverns is feasible from a leakage and energy efficiency viewpoint. Our numerical approach and energy analysis will next be applied in designing and evaluating the performance of a planned full-scale pilot test of the proposed underground CAES concept.
Permeability and its change due to a fluid injection in jointed rock mass is an important factor to be well identified for a safe and successful implementation of Carbon Capture and Sequestration (CCS), Enhanced Geothermal System (EGS) and Enhanced Oil Recovery (EOR) projects which may accompany injection-induced hydromechanical deformation of the rock mass. In this technical report, we first reviewed important issues in evaluating initial permeability using borehole hydraulic tests and numierical approaches for understanding coupled hydromechanical properties of rock mass. Recent SIMFIP testing device to measure these hydromechanical properties directly through in-situ borehole experiments was also reviewed. The technical significance and usefulness of the device for further applications was discussed as well. 최근의 이산화탄소 심지층 처분, 인공지열저류층 형성 및 발전, 원유회수증진 사업 등에는 고압의 유체를 주입하는 과정이 수반되고 이들 사업의 안전하고 성공적인 수행을 위해서는 대상 부지 절리 암반의투수 특성 및 주입압에 의한 역학적 변형에 기인한 변화를 정확하게 평가하는 것이 중요하다. 본 고에서는 절리 암반 수리-역학 특성 파악을 위한 해석적 및 실험적 평가 방법에 대해 검토하였다. 먼저 유체 주입 전 절리 암반 초기 투과 특성 및 수리-역학 특성 평가에 고려해야 할 기술요소를 분석하고 현장 시추공실험을 통해 이들 수리-역학 특성을 직접 측정하기 위한 최근의 SIMFIP 실험장치의 특징 및 활용방안에대해서도 검토하였다.
In this study, we carried out numerical modeling to investigate the impact of air tight liner within the concrete linings of underground lined rock cavern for compressed air energy storage (CAES). For the numerical modeling, TOUGH-FLAC that can simulate coupled non-isothermal multiphase (air and groundwater) fluid flow and geomechanical behavior of both concrete linings and rock mass as well as within the cavern, was used. The calculated results of pressure, temperature and stress for two different lining options with and without impermeable inner liner showed that the installation of an inner air tight liner reduced the maximum effective tensile stress of the concrete linings which results in the increase of geomechanical stability as well as air tightness performance of the storage cavern. 본 연구에서는 수치해석을 통해 복공식 지하 압축공기에너지 암반 저장 공동의 콘크리트 라이닝 내부에 설치되는 비투과성의 기밀라이너의 시공효과를 검증하였다. 수치해석기법으로는 저장공동 내부, 콘크리트 라이닝 및 주변 암반에서의 압축공기 및 지하수 유동, 열전달, 역학적 변형의 복합 거동을 시뮬레이션할 수 있는 TOUGH-FLAC 연계해석을 이용하였다. 저장공동 내부에 기밀라이너 시공유무에 따른 콘크리트 라이닝 내 압력, 온도, 응력 계산결과를 비교․분석한 결과, 비투과성의 기밀라이너는 저장 압축공기의 누출을 방지하는 기밀성능 뿐만 아니라 콘크리트 라이닝 내 인장응력을 감소시켜 역학적 안정성을 증대하는 효과가 있는 것으로밝혀졌다.
<P>Underground compressed air energy storage (CAES) in lined rock caverns (LRCs) provides a promising solution for storing energy on a large scale. One of the essential issues facing underground CAES implementation is the risk of air leakage from the storage caverns. Compressed air may leak through an initial defect in the inner containment liner, such as imperfect welds and construction joints, or through structurally damaged points of the liner during CAES operation for repeated compression and decompression cycles. Detection of the air leakage and identification of the leakage location around the underground storage cavern are required. In this study, we analyzed the displacement (or strain) monitoring method to detect the mechanical failure of liners that provides major pathways of air leakage using a previously developed numerical technique simulating the coupled thermodynamic and geomechanical behavior of underground CAES in LRCs. We analyzed the use of pressure monitoring to detect air leakage and characterize the leakage location. From the simulation results, we demonstrated that tangential strain monitoring at the inner face of sealing liners could enable one to detect failure. We also demonstrated that the use of the cross-correlation method between pressure history data measured at various sensors could identify the air leak location. These results may help in the overall design of a monitoring and alarm system for the successful implementation and operation of CAES in LRCs.</P>