초록 ▼

연차목표
◦ CO₂ 이동/ 반응 모니터링 현장 시범적용
◦ CO₂ 거동 기반 지하 물성변화 모델개발 및 현장적용
◦ CO₂ 저장 안정성 평가 프로그램 개발 및 성능 시험
◦ CO₂ 주입/관측 테스트베드 구축 및 배경 모니터링(baseline survey)

개발내용 및 결과
▪ 불균질 매질에서의 CO₂ 이동특성 평가기술 개발
▪ Mg 동위원소를 이용한 CO₂-물-암석

연차목표
◦ CO₂ 이동/ 반응 모니터링 현장 시범적용
◦ CO₂ 거동 기반 지하 물성변화 모델개발 및 현장적용
◦ CO₂ 저장 안정성 평가 프로그램 개발 및 성능 시험
◦ CO₂ 주입/관측 테스트베드 구축 및 배경 모니터링(baseline survey)

개발내용 및 결과
▪ 불균질 매질에서의 CO₂ 이동특성 평가기술 개발
▪ Mg 동위원소를 이용한 CO₂-물-암석 반응 추적 기술개발
▪ CO₂모니터링 장비 및 시스템 개발 및 현장적용 테스트(항압 시료채취,고압환경 pH-meter, 광케이블을 이용한 온도·압력 모니터링 장비)
▪ 암석 시료에서의 CO₂ 주입에 따른 탄성파 물성변화 측정
▪ CO₂주입에 따른 단층 재활성 평가 프로그램 개발
▪ 주입정/관측정 기밀성 관리 및 누출 제어 기술개발
▪ 탄성파 자료처리 기술 고도화 및 테스트베드 지질모델 개선
▪ CO₂ 주입/관측 시나리오 개발 및 현장 실험계획 수립
▪ CO₂저장/모니터링 테스트베드내 CO₂주입정/관측정 완결
▪ CO₂관측정내 CO₂모니터링 장비 설치 및 성능시험
▪ CO₂주입정/관측정 주변 배경모니터링

기대효과
◦ CO₂ 모니터링 기술 자립도 향상을 통한 국내 산업 기반 및 경쟁력확보
◦ CO₂ 모니터링 핵심기술개발을 통해 CO₂ 배출권 확보를 위한 산업경제적 독립성 확보
◦ 저장 안정성 평가 기반기술 개발을 통한 CO₂ 지중저장의 대중적 인정(public acceptance) 확인

적용분야
◦ 파일럿 규모 CO₂저장 실증
◦ CO₂포집 연계 상용화 규모 통합 CCS 플랜트

Abstract ▼

We present the results of core-flooding experiments by assessing the impact of capillary heterogeneity on residual and dissolution CO₂ trapping. Two types of injection tests with different rates are conducted: single-phase(supercritical CO₂) injection and co-injection (equilibr

We present the results of core-flooding experiments by assessing the impact of capillary heterogeneity on residual and dissolution CO₂ trapping. Two types of injection tests with different rates are conducted: single-phase(supercritical CO₂) injection and co-injection (equilibrated CO₂ and brine) cases are considered for drainage tests. In case of the single-phase injection, CO₂ builds up at a low capillary pressure (P_c) zone located upstream of a high P_c zone as CO₂ was hindered to transport across the barriers. The experiments were conducted under capillary-dominated condition, and as capillary number (N_c) was increased with greater injection rate, the increased viscous force led higher CO₂ saturation in fine matrix implying that high P_c zone was more sensitive to the injection rate than the low P_c zone. The co-injection, however, leads to greater CO₂ saturation at the high P_c zone. The observed disparity of CO₂ saturation patterns in these two experiments resulted from the induced pressure gradient across the core as well as the greater capillary forces in high P_c zone. The following imbibition test, which was designed to reproduce conditions for the post-injection period, characterized three regimes of spatio-temporal variation of trapping mechanisms as follows: (1) displacement of mobile CO₂ by the injected brine and concurrent CO₂ dissolution into the fresh brine; (2) preservation of immobile CO₂ as a residual trapping; and (3) gradual CO₂ dissolution into the fresh brine.

In order to trace CO₂-water-rock interactions using Mg isotope, the dissolution experiment of Mg-rich biotite under high pressure and temperature has been conducted. The experiment shows that the concentration of Mg increases with the dissolution of biotite and Mg isotope value is enriched. This indicates that if the fractionation of Mg isotope is quantified, Mg isotope can be used as a tracer evaluating the change in Mg concentration and the contribution of Mg sources to Mg contents in groundwater. In addition, we have carried out the batch experiment to evaluate the change in groundwater quality and microbial communities by CO₂ leakage into aquifers. The results of analysis of microbial communities show that the distribution of microbial communities is related with the geochemical characteristics of groundwater.

The changes in characteristics of seismic wave have been studied using samples of the Berea sandstone. As pore and confining pressures changes, the velocity and amplitude of P-wave also changes, but the velocity of S-wave does not change with some change of amplitude. As the amount of injected CO₂ increases, the amplitude and velocity of P-wave decreases. At this time, the change of amplitude is quite larger than that of velocity. It is possible to use the change of velocity and amplitude of seismic wave to monitor the migration of injected CO₂. However, further studies are needed for quantification of this method.

Faults may be reactivated when reservoir overpressure resulted from CO₂injection into the subsurface reservoir exceeds the critical limit of reservoir pressure build-up. The fault reactivation potential needs to be assessed prior to injecting CO₂. We have developed a semi-analytical method which can be used for the assessment of fault reactivation potential. The methodology requires inputs that include in-situ stress orientation and magnitude, initial reservoir pressure, 3D fault geometry, friction coefficient of fault plane. Fault reactivation analysis using the solution involves multiple stress transformations one coordinate system to another. Three coordinate systems are defined, including global coordinate system, in-situ stress coordinate system, and fault plane coordinate system. Stresses acting on individual fault elements, which are generated by discretizing the fault plane, are resolved by the stress transformation. The critical perturbation is then calculated.

Cement dehydration can cause the volume reduction and result in the failure of cement-casing or cement-formation bondage and is one of important problems against well integrity. In this year, we collected the quantitative data on the cement dehydration along with temperature rising (105~200°C).

The quality of seismic exploration data, acquired last year, are identified as low, due to topographic effects and nearby artificial noise. In this year, we try to enhance signal-to-noise ratio through diverse data processing including static correction, frequency-wavenumber filtering and stacking. In addition, the sequential frequencywavenumber filter design method has applied in order to solve data pollution due to casing wave problem in the course of VSP data processing.

The two-stage numerical modeling, for the injection design in field test, was done. In the first stage, the constant-pressure injection was applied in the numerical mode, with the simplified geologic model, based on the field investigation. In the second stage, various injection rates, which were deduced from results of the first stage model, were applied. Based on results of two-stage numerical models, 65~80% of injected CO₂ is distributed in aqueous phase. Finally, the field test procedure in the Pohang test-bed was derived, considering results of numerical models and field investigations.

Fall-off data, acquired last year have been reinterpreted. In this year, we assume the dissected reservoir by intersecting faults. According to reinterpretation, it is presumed that the permeability of the reservoir is about 40 md, and that the distances between injection hole and two faults are 11.5 ft and 12.5 ft, respectively, and that intersecting angle between two faults is about 20°.

Test bed for CO₂ injection and monitoring has been constructed in the Pohang branch of KIGAM. Both monitoring and injection wells have been drilled. Integrated monitoring systems, consisting of VSP sensors, ERT sensors, P/T sensors, pH sensors and optic cable, have been installed in both injection and monitoring wells. Surface facilities for CO₂ injection have partly been built. In addition, functional test for VSP sensor array has been conducted.

The distribution and behavior of baseline soil CO₂ were investigated in a candidate geologic CO₂ storage site in Pohang prior to the CO₂ injection test in 2018. This investigation aims to assess the baseline CO₂ levels and to build the soil environment monitoring system before injecting CO₂. The gas in the vadose zone was collected using a peristaltic pump from the depth of 50 cm below ground surface, and stored at gas bags. Then the gas components (CO₂, O₂, N₂, CH₄) and δ¹³C_CO2 were analyzed using GC and CRDS(cavity ringdown spectroscopy) respectively in laboratory. CO₂ fluxes and CO₂ concentrations through ground surface were measured using Li-COR in field. In result, the median of the CO₂ concentrations in the vadose zone was about 5,200 ppm, and the δ¹³C_CO2 were in the wide range between –30.7 ‰ and –6.5 ‰. The median CO₂ flux through ground surface was 10.4 g/m²/d which is similar to the reported soil CO₂ fluxes in areas with temperate climates.

목차 Contents

• 표지 ... 1제 출 문 ... 2연차보고서 요약서 ... 4요약문 ... 5SUMMARY ... 10CONTENTS ... 13목차 ... 14제 1 장 연구개발과제의 개요 ... 16 1.1 연구개발의 필요성 ... 16 1.2 연구개발의 목적 ... 17 1.3 연구개발의 내용 ... 18 1.4 연구개발의 중요성과 파급효과 ... 20제 2 장 국내외 기술개발 현황 ... 22 2.1 국내 CO2 저장/모니터링 연구개발 현황 ... 22 가. 국내 CCS 저장 프로젝트 개요 ... 22 나. 미래창조과학부 CO2 저장 프로젝트 ... 23 다. 산업통상자원부 CO2 저장 프로젝트 ... 24 라. 해양수산부 CO2 저장 프로젝트 ... 25 마. 환경부 CO2 저장 프로젝트 ... 25 바. 국내 CO2 저장 프로젝트 진행상황 요약 ... 27 2.2 국외 CO2저장/모니터링 연구개발 현황 ... 28 가. 국외 CCS저장 현황 개요 ... 28 나. 노르웨이 북해 CO2 저장 프로젝트 ... 30 다. 캐나다 원유회수증진(EOR) CO2 저장 프로젝트 ... 34 라. 알제리 In Salah 프로젝트 ... 36 마. 기타 CCS 저장 프로젝트 ... 37제 3 장 연구개발수행 내용 및 결과 ... 40 3.1 심지층내 CO2 이동 및 CO2-물-암석 반응 규명 고도화 ... 40 가. 불균질 매질에서의 이산화탄소 이동특성 평가기술 개발 ... 40 나. Mg 동위원소와 미생물을 이용한 CO2-물-암석 반응 추적자 활용 연구 ... 50 3.2 CO2 거동에 따른 지하 물성변화 예측 모델링 기술개발 ... 61 가. CO2 거동에 따른 암석샘플의 물성(탄성파 속도) 변화 ... 61 3.3 CO2 저장 특성 및 안전성 평가 기술개발 ... 69 가. CO2 주입에 따른 단층 재활성 평가 기술개발 ... 69 나. CO2 주입/관측 시스템/지질매체 기밀성 평가/관리 기술개발 ... 73 3.4 시추공 기반 CO2 주입/관측 기술개발 ... 79 가. 탄성파 탐사 자료 재처리를 통한 실증부지 지질모델 개선 ... 79 나. 부지특성 평가 및 모델링 기반 CO2 주입/관측 시나리오 도출 ... 88 다. 테스트베드 관측공/주입공 구축 및 모니터링 설비 성능 시험 ... 120 라. 토양 CO2 배경 모니터링 ... 128제 4 장 목표달성도 및 관련분야에의 기여도 ... 142 4.1 당해연도 연구성과 ... 142 가. 논문, 지재권, 기술이전 성과물 ... 142 나. 연구성과 달성을 위해 추진한 대내외 활동(교육훈련, 워크샵, 자문 등) ... 144 4.2 연구실적의 파급효과 ... 148 가. 정부 정책적 측면 ... 148 나. 과학기술적·학술적 측면 ... 148 다. 경제·산업적 측면 ... 148 라. 국민생활과 사회 수준 향상에 기여 측면 ... 148제 5 장 연구개발결과의 활용계획 ... 150 5.1 기대 효과 ... 150 5.2 활용계획 ... 151제 6 장 참고문헌 ... 152부록 위탁연구 보고서 ... 156끝페이지 ... 255