- Email: [email protected]
An upgraded storage site model of the Shenhua CCS demonstration project
Available online at www.sciencedirect.com
ScienceDirect Availableonline onlineatatwww.sciencedirect.com www.sciencedirect.com Available Energy Procedia 00 (2018) 000–000
ScienceDirect ScienceDirect
www.elsevier.com/locate/procedia
Energy Procedia Procedia 00 154(2017) (2018)000–000 94–99 Energy www.elsevier.com/locate/procedia
Applied Energy Symposium and Forum, Carbon Capture, Utilization and Storage, CCUS 2018, 27–29 June 2018, Perth, Australia
An upgraded site model of the Shenhua CCS demonstration Thestorage 15th International Symposium on District Heating and Cooling project Assessing the feasibility of using the heat demand-outdoor a d e Yujie Diaoa *, Guowei Zhub, Xufeng , Bing Baic,district Yongsheng Wang , Bing Zhang , Hui temperature function for a Li long-term heat demand forecast a Long c c I. Andrić A. Geological Pina , P. Ferrão J. Hydrogeology Fournierband ., B. Lacarrière , O. LeChina Corre Key Laboratory of Carbon *, Dioxide Storage, Center, for Environmental Geology Survey, Geological a,b,c
a
a
a
Survey, No.1305 Qiyi Middle Road, Baoding 071051, China a IN+ Center for Innovation, Technology and Policy Research - Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal State Key Laboratory of Coal Resource and Mine Safety, China University of Mining & Technology, Ding No.11 Xueyuan Road, Beijing b Veolia Recherche & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France 100083, China c Département Systèmes Énergétiques et Environnement - IMT Atlantique, 4 rue Alfred Kastler, 44300 Nantes, France c Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, No.2 Xiaohongshan, Wuhan 430071, China d China Shenhua Coal Liquefaction Co., Ltd. Ordos, Shangwan Town, Yijinhuoluo County, Ordos 017209, China e China United Coalbed Methane Corporation, Ltd., Jia No.88 Andingmenwai Street, Beijing 100011, China
b
Abstract Abstract District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse emissions the building sector. These systems require high investments which are returned through the heat As the only gas project for COfrom 2 storage in deep saline aquifers in China, the Shenhua CCS demonstration project is of great sales. Due to the changed climate conditions and building renovation policies, heat demand the in designed the futureinjection could decrease, importance in the geological storage of CO2 in continental sedimentary strata. Despite achieving goal of prolonging the investment return period. 302,000 tons, the demonstration project currently does not have a widely accepted storage site geological model because of the The overall main scope of thisofpaper is to assess the feasibility of using the heat demand outdoor temperature function for heat demand large thickness the injection layers, low porosity and permeability, and –high heterogeneity. Based on geological study The site district of Alvalade, in Lisbon (Portugal), was(VSP) used seismic as a casemonitoring study. Thedata, district is consisted 665 offorecast. the storage system, combinedlocated with vertical seismic profiling we used the welloflogbuildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district constrained seismic inversion method to predict the lithology, porosity and permeability of the storage site. We constructed a new developedmodel (shallow, intermediate, deep). well. To estimate error, obtained heat demand were 5renovation km × 5 km scenarios × 1200 m were site geological centered on the injection Our newthe geological modeling method andvalues the related compared with results a dynamic heat demand model, studies previously and validated by the authors. reservoir parameters arefrom innovative compared with previous and developed enhance geological understanding of the site, providing a The results that when only weather change is considered, themonitoring margin of error acceptable for some applications reservoir simulation and deep geophysical in thecould futurebestages of the project. reference for showed CO2 migration (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation ©scenarios, 2018 The Authors. Published by Ltd. (depending on the weather and renovation scenarios combination considered). error value increased up toreserved. 59.5% Copyright ©the 2018 Elsevier Ltd. AllElsevier rights This an open accesscoefficient article under the CCon BY-NC-ND licensethe (http://creativecommons.org/licenses/by-nc-nd/4.0/) The isvalue slope increased average within range of up to Energy 8% perSymposium decade, thatand corresponds to the Selection andofpeer-review under responsibility of the scientific committee of 3.8% the Applied Forum, Carbon Selection and peer-review under responsibility of the scientific committee the Applied Energy and Forum, Carbon decrease in the number of heating hours of 22-139h during the heating of season (depending on Symposium the combination of weather and Capture, Utilization and Storage, CCUS 2018. Capture, Utilization andconsidered). Storage, CCUS 2018. renovation scenarios On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). Thesaline values suggested could bestorage; used to modify theproject; function Keywords: site model; deep aquifers; CO2 geological Shenhua CCS VSPparameters monitoring for the scenarios considered, and improve the accuracy of heat demand estimations. © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. * Corresponding author. Tel.: +86-312-5908833; fax: +86-312-5908611. E-mail address: [email protected] Keywords: Heat demand; Forecast; Climate change
1876-6102 Copyright © 2018 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the Applied Energy Symposium and Forum, Carbon Capture, Utilization and Storage, CCUS 2018. 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. 1876-6102 © 2018 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of the Applied Energy Symposium and Forum, Carbon Capture, Utilization and Storage, CCUS 2018. 10.1016/j.egypro.2018.11.016
2
Yujie Diao et al. / Energy Procedia 154 (2018) 94–99 Author name / Energy Procedia 00 (2018) 000–000
95
1. Introduction The Shenhua Group implemented the CCS demonstration project in the Ordos Basin of China, representing the only geological storage project of CO2 in deep saline aquifers in China. The demonstration project began its CO2injection experiment on May 9, 2011, and successfully completed the designed injection goal of 30.2 × 104 t in April 2015. The reservoirs are mainly terrestrial sedimentary strata, with low porosity and permeability, a high number of thin layers and thick mudstone interlayers, and the total thickness of the study layers is nearly 1000 m. The geology and insufficient data therefore represent a great challenge to reservoir characterization and modeling. As the only geological storage project of CO2 in deep saline aquifers in China, the Shenhua CCS demonstration project has drawn considerable attention in China; many experts have conducted geological modeling studies based on the storage site to lay the foundation for the numerical simulation of engineering design. Using well logging and 3D seismic exploration data (He, 2011), Zhang (2013) first used GOCAD software and geostatistical methods to construct a 3D geological model of the 3D seismic coverage area, but without comprehensive geological analysis or any further updates to the geological data. Guo (2014) and Kuang (2014) established an ideal 2D homogeneous model for numerical simulations of CO2 migration, dissolution, and mineralization, but without further in-depth reservoir characterization and geological modeling. Based on 3D seismic data of the demonstration project storage site, Xie (2015, 2016) and Li (2016) constructed a 3D geological model based on injection well parameters. However, only vertical inter-layer heterogeneities were considered; each layer was assumed to be homogeneous in the horizontal direction. However, none of the above models have been widely recognized. In addition, there is an overall lack of systematic geology and supplementary laboratory data, and a detailed analysis of 3D seismic data is required. To respond to these problems, we built a 3D geological model to provide support for future research and optimization of monitoring framework of the Shenhua CCS demonstration project. This model was constructed on the basis of previous studies, systematic geological study, porosity and permeability predicted by using well logconstrained seismic inversion method, and relative permeability and capillary pressure test data of actual cores and laboratory-configured formation water samples. 2 Description of the model framework 2.1. Model composition Using the top of the Triassic Heshanggou Formation (about 1310 m) and the upper part of the Ordovician Majiagou Formation (about 2500 m) as the top and bottom boundaries, we constructed a new 3D geological model with a boundary of 5 km × 5 km centered on the injection well. The new model consists of the following major components: (1) site tectonics, (2) formation lithology, (3) porosity, (4) permeability, (5) water chemistry, (6) temperature, (7) pressure, (8) capillary pressure, and (9) relative permeability. 2.2. Methodology The Shenhua CCS demonstration project storage site is located in the northeast of the Yimeng uplift tectonic unit in the Ordos Basin, with gentle tectonics and a dip angle of approximately 1°. Although there are well developed small-scale faults in the exploration area, there is no inter-layer interpretation fault in the injection well or within 1 km of the surrounding area (Wu, 2013). Therefore, the 2D VSP seismic data for monitoring of CO2 migration underground before or during CO2 injection can be used as important basic data to predict the stratigraphic attributes (Fig. 1). The detailed methodology and processes are as follows: (1) The model was based on the high-resolution stratigraphic framework, actual trajectories of three drilling wells and four 2D seismic lithology prediction profiles (Wu, 2013; Guo, 2014). By comprehensively analyzing the related geological data, such as investigation of formation outcrops, seismic exploration, and drilling logging, we performed fine classification and comparison of sedimentary formations and combined this with perforation position (Wu, 2013) to further refine the sandstone and fractured aquifer groups.
Yujie Diao et al. / Energy Procedia 154 (2018) 94–99 Author name / Energy Procedia 00 (2018) 000–000
96
3
(2) We predicted the lithology, porosity and permeability of the CO2 reservoirs based on the above-mentioned first and second phases VSP seismic data and drilling logging data in combination with laboratory tests, drilling logging and well logging data. Moreover, the pseudo-acoustic curve construction technology of LD-EPSTM (reservoir prediction and interpretation software) (LandOcean Energy Services, Beijing, China) is used for geophysical interpretation based on the well log-constrained seismic inversion principle (Xu, 1996; Shi, 2004). (4) Based on the storage site geological research, geophysical interpretation and reservoir flow unit prediction results, we performed reservoir characterization and 3D geological modeling using PETREL 2015 (Schlumberger, Beijing, China) with mature petroleum geology in combination with the corner grid subdivision method and Kriging interpolation.
Fig. 1 Time-lapse vertical seismic profiling (VSP) seismic profiles for 2011 and 2013
3 Primary parameters of the model 3.1. Stratigraphy and lithology The sedimentary formations of in the storage site (Diao, 2014; Zhang, 2015) from the old to the new in succession are the Middle Ordovician Majiagou Formation (O2m); the Upper Carboniferous Benxi Formation (C2b) and Taiyuan Formation (C2t); the Lower Permian Shanxi Formation (P1s), Middle Permian Shihezi Formation (P2sh) and the Upper Permian Shiqianfeng Formation (P3sh); the Lower Triassic Liujiagou Formation (T1l) and Heshanggou Formation (T1h). (1) Reservoir Once CO2 is injected underground, it will migrate and diffuse into reservoirs with higher porosity and permeability. The Shenhua CCS demonstration project contains a total of 21 perforation layers, 3 of which have poor permeability, i.e., are "dry layers". Based on the high-resolution stratigraphic framework analysis of the Shenhua CCS demonstration project storage site and combined with the CO2 geological storage mechanism, the general standard for reservoir division, and the perforation layer of injection wells, five saline aquifer groups were initially identified, mainly distributed in the bottom of the Liujiagou Formation, the upper part of the Shiqianfeng Formation, the middle and lower parts of Shihezi Formation and the upper part of the Majiagou Formation. A total of 33 layers of sand/carbonate fissure reservoirs were identified with a total thickness of approximately 200 m. (2) Cap rocks The bauxite shale of residual genesis that developed at the bottom of the Benxi Formation can have a good capping effect. However, because the unified injection and buoyancy driven of CO2 in reservoirs, the cap rocks above the sandstone layers at the bottom of Liujiagou Formation are most important for the geological security of the storage site. The middle and upper parts of Liujiagou Formation and the overall Heshanggou Formation are dominated by mudstone and sandy mudstone, which can be used as effective cap rocks in the storage site to seal CO2 leakage. 3.2. Porosity & permeability 3.2.1 Porosity
4
Yujie Diao et al. / Energy Procedia 154 (2018) 94–99 Author name / Energy Procedia 00 (2018) 000–000
97
The sandstones at the bottom of the Liujiagou Formation, the upper part of the Shiqianfeng Formation, and the middle and lower parts of the Shihezi Formation have relatively high porosity, generally ranging from 9% to 15%, and the porosity of the local sand bodies could reach 18%–20%. 3.2.2 Permeability The permeability increased exponentially with increasing porosity, and the fitted relationship between the two was (1) PERM = 9.678 + 1040.2/e(POR) where PERM is the permeability; POR is the porosity; the correlation coefficient reached 0.995. As a whole, the permeability of target reservoirs at the storage site was relatively low, generally 10–20 mD, and the horizontal heterogeneity is high. The permeability in the sandstones of the Shiqianfeng Formation and Shihezi Formation was relatively high in the direction of line L1. The permeability in the Liujiagou Formation, Majiagou Formation and Shihezi Formation in the direction of the L2 line was relatively high. The permeability in the sandstone of Liujiagou Formation, Shiqianfeng Formation, and the middle and lower parts of Shihezi Formation in the direction of L3 line was relatively high. The permeability in the direction of the L4 line was similar to that in the direction of the L1 line, where the permeability in the sandstones of the Shiqianfeng Formation and the middle and lower parts of the Shihezi Formation was relatively high. 3.3. Hydrochemistry With a depth of 800–3000 m, the Shenhua CCS demonstration project storage site belongs to the deep aquifer rock group of the Ordos Basin. It is the ideal target saline aquifer for CO2 geological storage because of its low porosity, low permeability, and very slow groundwater runoff. The chemical type of underground saline was mainly Cl–Ca·Na. The total dissolved solids content was higher in the Liujiagou Formation and Shiqianfeng Formation (65.1 g/L and 31.2 g/L, respectively), whereas it was much lower in the Shihezi Formation and Majiagou Formation (9.5 g/L and 7.1 g/L, respectively). 3.4. Pressure & Temperature The drilling test results showed that the pressure at the top of the Liujiagou–Majiagou Formation was between 16 MPa and 22.8 MPa, and the pressure coefficient was between 0.92 and 1.12. The pressure coefficient was the largest in the Shihezi Formation, with a local maximum of 1.12. The pressure coefficient of the carbonate formations was lowest at the top of the Majiagou Formation, generally less than 1. Stratum temperature ranged from 54.5°C– 69.1°C, and the geothermal gradient was small at about 1.45°C per 100 m depth. 4 Demonstration of the model The new geological model had an area of 5 km × 5 km (X, Y) centered on the injection well, of which the central 1 km × 1 km (X, Y) was controlled by VSP seismic data, and the reliability was high. The 3D geological modeling methods of corner grid subdivision and Kriging interpolation were used. In the vertical direction (Z), the Liujiagou and Heshanggou Formations were divided according to ~5 m resolution. The Shiqianfeng, Shihezi and Shanxi Formations were divided at ~10 m resolution. The Benxi and Taiyuan Formations were considered as mudstone cap rock in the simulation (designed with a layer of inactive grid). The Majiagou Formation was divided according to ~10 m resolution. In the vertical direction (Z), there were a total of 149 grids. For the range of 1 km × 1 km in the center of the model, there were 100 × 100 grids in the plane (X, Y) direction, and each grid size was 10 m × 10 m. In other areas, because there was no seismic data control, the grid was coarser: each grid size was 50 m × 50 m, and there were a total of 80 × 80 grids. The total model contained 180 × 180 × 149 = 4 827 600 grids.
Yujie Diao et al. / Energy Procedia 154 (2018) 94–99 Author name / Energy Procedia 00 (2018) 000–000
98
5
4.1 Lithological modeling With increasing depth, the shale content in the Shiqianfeng Formation and Shihezi Formation increased, mainly including interbedded sand and mud, especially the mudstones that developed in the upper Shihezi Formation and the carbonate rocks that developed mainly in the Majiagou Formation. In the horizontal direction, the continuity of sand distribution was good and consistent with the high-resolution sequence stratigraphic framework of the three wells. This also reflects the fluvial sedimentary characteristics from north to south of the Paleozoic and Mesozoic sand bodies in the storage site. 4.2 Porosity and permeability modeling Based on the storage site tectonics model and the stratum structure, 3D porosity and permeability models were constructed using four 2D porosity and permeability profiles. The value of porosity of the 3D model presented high heterogeneity in horizontal and vertical distribution (Fig. 2), the yellow zone has a relatively high porosity, generally higher than 10%. As shown in Fig. 3, in the 3D permeability model of the storage site, the permeability in the yellow zone is generally greater than 1 mD and that of the red zone is generally 10 mD. The overall porosity and permeability models are consistent with the predicted CO2 migration direction monitored by the time-lapse VSP seismic profile, i.e., overall migration to the northwesterly direction with relatively high porosity and permeability.
Fig. 2 The 3D porosity model of the demonstration project site
Fig. 3 The 3D permeability model of the demonstration project site
5 Conclusions Based on the results obtained from the existing data, we updated the geological model by supplying and improving the late-stage experimental data, deep geophysics and inside-well monitoring data of Shenhua CCS demonstration project storage site. This allowed the more accurate and scientifically supported prediction of CO2
6
Yujie Diao et al. / Energy Procedia 154 (2018) 94–99 Author name / Energy Procedia 00 (2018) 000–000
99
migration and provided geological support for late engineering monitoring and safety assessment. Through the construction of the geological model in the current study, we inferred the following conclusions: • Thick sandstone layers developed at 1600–2500 m in the Shanxi Formation, Shihezi Formation, Shiqianfeng Formation and Liujiagou Formation, and carbonate aquifers of Majiagou Formation can be divided into five good aquifer groups for CO2 storage. Among these, the sand bodies of Liujiagou Formation are thicker than the others and are mixed with thin layers of mudstones. The formation mud in Shiqianfeng Formation and Shihezi Formation increased with increasing depth, including mainly interbedded sand and mud, such as the mudstones that developed in the Upper Shihezi Formation and the carbonate rocks that mainly developed in the Majiagou Formation. • The middle and upper parts of the Liujiagou Formation and all of the Heshanggou Formation are dominated by mudstones and sandy mudstones, which can be used for the effective capping of the demonstration project to seal CO2 leakage. However, the model suggests that the alluvial bauxite shale with residual genesis that developed at the bottom of Benxi Formation can also be used as secondary effective cap rocks for the Majiagou Formation. • The sandstone porosity is mainly distributed in the range of 10%–18%. The bottom part of the Liujiagou Formation, the upper part of the Shiqianfeng Formation, and the middle and lower parts of the Shihezi Formation had a higher porosity at 9%–15%. The porosity of the local sand bodies reached 18%. The overall permeability was found to be low, and the target reservoir permeability range was generally 10–20 mD. • The advantages of 2D VSP seismic technology can be brought into full play in areas with geological conditions most favorable for CCS from an economic and long-term monitoring point of view. This research indicates that the well log-constrained VSP seismic attribute inversion technique can be used for fine reservoir prediction and CO2 monitoring purposes. Acknowledgements The authors gratefully acknowledge the financial support of the project of National Natural Science Foundation of China (Grant No. 41602270); the China Clean Development Mechanism Fund project of National Development and Reform Commission (Grant No. 2014088); the geological survey project of China Geological Survey (Grant No. 121201012000150010); and the National Key Research and Development Program of China (Grant No. 2016YFE0102500) under the cooperation framework of China-US Clean Energy Research Center (CERC). References [1]
Guo, J., Wen, D., Zhang, S., Xu T., 2014. Potential Evaluation and Demonstration Project of CO2 Geological Storage in China. Beijing: Geological Publishing House. [2] He, T., Ruan, Z., Guo, Q., Zhou, J., 2011. Interpretation results of 3D seismic data acquisition for Shenhua Ordos 100000 ton/year CCS project. Changqing Institute of BGP Inc., China National Petroleum Corporation. [3] Kuang, D., Li., Q., Wang, Y., Wang, X., Lin, Q., Wei, X., Song, R., 2014. Numerical simulation of distribution of migration of CO2 in Shenhua CCS carbon capture and storage demonstration project. Rock and Soil Mechanics, 35(9),2623-2641. [4] Li, C., Zhang, K., Wang, Y., Guo, C., Maggi, F., 2016. Experimental and numerical analysis of reservoir performance for geological CO2 storage in the Ordos Basin in China. International Journal of Greenhouse Gas Control, 45,216-232. [5] Shi, L., Wang, C., 2004. Do High Resolution Inversion by Using Simulated AC Curve. Journal of Southwest Petroleum Institute, 26(5),1820. [6] Wu X., 2013. Carbon dioxide capture and geological storage-The First Massive Exploration in China. Science Press Ltd. [7] Xie, J., Zhang, K., Hu, L., Pavelic, P., Wang, Y., Chen, M., 2015. Field-based simulation of a demonstration site for carbon dioxide sequestration in low-permeability saline aquifers in the Ordos Basin, China. Hydrogeology Journal, 23(7),1465-1480. [8] Xie, J., Zhang, K., Hu, L., Wang, Y., Chen, M., 2015. Understanding the carbon dioxide sequestration in low – permeability saline aquifers in the Ordos Basin with numerical simulations. Greenhouse Gases Science & Technology, 5(5),558-576. [9] Xie, J., Zhang, K., Wang, Y., Qin, L., Guo, C., 2016. Performance assessment of CO2 geological storage in deep saline aquifers in Ordos Basin, China. Rock and Soil Mechanics, 37(1),166-174. [10] Xu, S., White, R.E., 1996. A physical model for shear-wave velocity prediction[J]. Geophysical Prospecting, 44(4),687-717. [11] Zhang, D., Li, H., Chang, H., 2013. Potential evaluation and numerical simulation of CO2 migration. Peking University.
ScienceDirect Availableonline onlineatatwww.sciencedirect.com www.sciencedirect.com Available Energy Procedia 00 (2018) 000–000
ScienceDirect ScienceDirect
www.elsevier.com/locate/procedia
Energy Procedia Procedia 00 154(2017) (2018)000–000 94–99 Energy www.elsevier.com/locate/procedia
Applied Energy Symposium and Forum, Carbon Capture, Utilization and Storage, CCUS 2018, 27–29 June 2018, Perth, Australia
An upgraded site model of the Shenhua CCS demonstration Thestorage 15th International Symposium on District Heating and Cooling project Assessing the feasibility of using the heat demand-outdoor a d e Yujie Diaoa *, Guowei Zhub, Xufeng , Bing Baic,district Yongsheng Wang , Bing Zhang , Hui temperature function for a Li long-term heat demand forecast a Long c c I. Andrić A. Geological Pina , P. Ferrão J. Hydrogeology Fournierband ., B. Lacarrière , O. LeChina Corre Key Laboratory of Carbon *, Dioxide Storage, Center, for Environmental Geology Survey, Geological a,b,c
a
a
a
Survey, No.1305 Qiyi Middle Road, Baoding 071051, China a IN+ Center for Innovation, Technology and Policy Research - Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal State Key Laboratory of Coal Resource and Mine Safety, China University of Mining & Technology, Ding No.11 Xueyuan Road, Beijing b Veolia Recherche & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France 100083, China c Département Systèmes Énergétiques et Environnement - IMT Atlantique, 4 rue Alfred Kastler, 44300 Nantes, France c Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, No.2 Xiaohongshan, Wuhan 430071, China d China Shenhua Coal Liquefaction Co., Ltd. Ordos, Shangwan Town, Yijinhuoluo County, Ordos 017209, China e China United Coalbed Methane Corporation, Ltd., Jia No.88 Andingmenwai Street, Beijing 100011, China
b
Abstract Abstract District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse emissions the building sector. These systems require high investments which are returned through the heat As the only gas project for COfrom 2 storage in deep saline aquifers in China, the Shenhua CCS demonstration project is of great sales. Due to the changed climate conditions and building renovation policies, heat demand the in designed the futureinjection could decrease, importance in the geological storage of CO2 in continental sedimentary strata. Despite achieving goal of prolonging the investment return period. 302,000 tons, the demonstration project currently does not have a widely accepted storage site geological model because of the The overall main scope of thisofpaper is to assess the feasibility of using the heat demand outdoor temperature function for heat demand large thickness the injection layers, low porosity and permeability, and –high heterogeneity. Based on geological study The site district of Alvalade, in Lisbon (Portugal), was(VSP) used seismic as a casemonitoring study. Thedata, district is consisted 665 offorecast. the storage system, combinedlocated with vertical seismic profiling we used the welloflogbuildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district constrained seismic inversion method to predict the lithology, porosity and permeability of the storage site. We constructed a new developedmodel (shallow, intermediate, deep). well. To estimate error, obtained heat demand were 5renovation km × 5 km scenarios × 1200 m were site geological centered on the injection Our newthe geological modeling method andvalues the related compared with results a dynamic heat demand model, studies previously and validated by the authors. reservoir parameters arefrom innovative compared with previous and developed enhance geological understanding of the site, providing a The results that when only weather change is considered, themonitoring margin of error acceptable for some applications reservoir simulation and deep geophysical in thecould futurebestages of the project. reference for showed CO2 migration (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation ©scenarios, 2018 The Authors. Published by Ltd. (depending on the weather and renovation scenarios combination considered). error value increased up toreserved. 59.5% Copyright ©the 2018 Elsevier Ltd. AllElsevier rights This an open accesscoefficient article under the CCon BY-NC-ND licensethe (http://creativecommons.org/licenses/by-nc-nd/4.0/) The isvalue slope increased average within range of up to Energy 8% perSymposium decade, thatand corresponds to the Selection andofpeer-review under responsibility of the scientific committee of 3.8% the Applied Forum, Carbon Selection and peer-review under responsibility of the scientific committee the Applied Energy and Forum, Carbon decrease in the number of heating hours of 22-139h during the heating of season (depending on Symposium the combination of weather and Capture, Utilization and Storage, CCUS 2018. Capture, Utilization andconsidered). Storage, CCUS 2018. renovation scenarios On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). Thesaline values suggested could bestorage; used to modify theproject; function Keywords: site model; deep aquifers; CO2 geological Shenhua CCS VSPparameters monitoring for the scenarios considered, and improve the accuracy of heat demand estimations. © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. * Corresponding author. Tel.: +86-312-5908833; fax: +86-312-5908611. E-mail address: [email protected] Keywords: Heat demand; Forecast; Climate change
1876-6102 Copyright © 2018 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the Applied Energy Symposium and Forum, Carbon Capture, Utilization and Storage, CCUS 2018. 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. 1876-6102 © 2018 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of the Applied Energy Symposium and Forum, Carbon Capture, Utilization and Storage, CCUS 2018. 10.1016/j.egypro.2018.11.016
2
Yujie Diao et al. / Energy Procedia 154 (2018) 94–99 Author name / Energy Procedia 00 (2018) 000–000
95
1. Introduction The Shenhua Group implemented the CCS demonstration project in the Ordos Basin of China, representing the only geological storage project of CO2 in deep saline aquifers in China. The demonstration project began its CO2injection experiment on May 9, 2011, and successfully completed the designed injection goal of 30.2 × 104 t in April 2015. The reservoirs are mainly terrestrial sedimentary strata, with low porosity and permeability, a high number of thin layers and thick mudstone interlayers, and the total thickness of the study layers is nearly 1000 m. The geology and insufficient data therefore represent a great challenge to reservoir characterization and modeling. As the only geological storage project of CO2 in deep saline aquifers in China, the Shenhua CCS demonstration project has drawn considerable attention in China; many experts have conducted geological modeling studies based on the storage site to lay the foundation for the numerical simulation of engineering design. Using well logging and 3D seismic exploration data (He, 2011), Zhang (2013) first used GOCAD software and geostatistical methods to construct a 3D geological model of the 3D seismic coverage area, but without comprehensive geological analysis or any further updates to the geological data. Guo (2014) and Kuang (2014) established an ideal 2D homogeneous model for numerical simulations of CO2 migration, dissolution, and mineralization, but without further in-depth reservoir characterization and geological modeling. Based on 3D seismic data of the demonstration project storage site, Xie (2015, 2016) and Li (2016) constructed a 3D geological model based on injection well parameters. However, only vertical inter-layer heterogeneities were considered; each layer was assumed to be homogeneous in the horizontal direction. However, none of the above models have been widely recognized. In addition, there is an overall lack of systematic geology and supplementary laboratory data, and a detailed analysis of 3D seismic data is required. To respond to these problems, we built a 3D geological model to provide support for future research and optimization of monitoring framework of the Shenhua CCS demonstration project. This model was constructed on the basis of previous studies, systematic geological study, porosity and permeability predicted by using well logconstrained seismic inversion method, and relative permeability and capillary pressure test data of actual cores and laboratory-configured formation water samples. 2 Description of the model framework 2.1. Model composition Using the top of the Triassic Heshanggou Formation (about 1310 m) and the upper part of the Ordovician Majiagou Formation (about 2500 m) as the top and bottom boundaries, we constructed a new 3D geological model with a boundary of 5 km × 5 km centered on the injection well. The new model consists of the following major components: (1) site tectonics, (2) formation lithology, (3) porosity, (4) permeability, (5) water chemistry, (6) temperature, (7) pressure, (8) capillary pressure, and (9) relative permeability. 2.2. Methodology The Shenhua CCS demonstration project storage site is located in the northeast of the Yimeng uplift tectonic unit in the Ordos Basin, with gentle tectonics and a dip angle of approximately 1°. Although there are well developed small-scale faults in the exploration area, there is no inter-layer interpretation fault in the injection well or within 1 km of the surrounding area (Wu, 2013). Therefore, the 2D VSP seismic data for monitoring of CO2 migration underground before or during CO2 injection can be used as important basic data to predict the stratigraphic attributes (Fig. 1). The detailed methodology and processes are as follows: (1) The model was based on the high-resolution stratigraphic framework, actual trajectories of three drilling wells and four 2D seismic lithology prediction profiles (Wu, 2013; Guo, 2014). By comprehensively analyzing the related geological data, such as investigation of formation outcrops, seismic exploration, and drilling logging, we performed fine classification and comparison of sedimentary formations and combined this with perforation position (Wu, 2013) to further refine the sandstone and fractured aquifer groups.
Yujie Diao et al. / Energy Procedia 154 (2018) 94–99 Author name / Energy Procedia 00 (2018) 000–000
96
3
(2) We predicted the lithology, porosity and permeability of the CO2 reservoirs based on the above-mentioned first and second phases VSP seismic data and drilling logging data in combination with laboratory tests, drilling logging and well logging data. Moreover, the pseudo-acoustic curve construction technology of LD-EPSTM (reservoir prediction and interpretation software) (LandOcean Energy Services, Beijing, China) is used for geophysical interpretation based on the well log-constrained seismic inversion principle (Xu, 1996; Shi, 2004). (4) Based on the storage site geological research, geophysical interpretation and reservoir flow unit prediction results, we performed reservoir characterization and 3D geological modeling using PETREL 2015 (Schlumberger, Beijing, China) with mature petroleum geology in combination with the corner grid subdivision method and Kriging interpolation.
Fig. 1 Time-lapse vertical seismic profiling (VSP) seismic profiles for 2011 and 2013
3 Primary parameters of the model 3.1. Stratigraphy and lithology The sedimentary formations of in the storage site (Diao, 2014; Zhang, 2015) from the old to the new in succession are the Middle Ordovician Majiagou Formation (O2m); the Upper Carboniferous Benxi Formation (C2b) and Taiyuan Formation (C2t); the Lower Permian Shanxi Formation (P1s), Middle Permian Shihezi Formation (P2sh) and the Upper Permian Shiqianfeng Formation (P3sh); the Lower Triassic Liujiagou Formation (T1l) and Heshanggou Formation (T1h). (1) Reservoir Once CO2 is injected underground, it will migrate and diffuse into reservoirs with higher porosity and permeability. The Shenhua CCS demonstration project contains a total of 21 perforation layers, 3 of which have poor permeability, i.e., are "dry layers". Based on the high-resolution stratigraphic framework analysis of the Shenhua CCS demonstration project storage site and combined with the CO2 geological storage mechanism, the general standard for reservoir division, and the perforation layer of injection wells, five saline aquifer groups were initially identified, mainly distributed in the bottom of the Liujiagou Formation, the upper part of the Shiqianfeng Formation, the middle and lower parts of Shihezi Formation and the upper part of the Majiagou Formation. A total of 33 layers of sand/carbonate fissure reservoirs were identified with a total thickness of approximately 200 m. (2) Cap rocks The bauxite shale of residual genesis that developed at the bottom of the Benxi Formation can have a good capping effect. However, because the unified injection and buoyancy driven of CO2 in reservoirs, the cap rocks above the sandstone layers at the bottom of Liujiagou Formation are most important for the geological security of the storage site. The middle and upper parts of Liujiagou Formation and the overall Heshanggou Formation are dominated by mudstone and sandy mudstone, which can be used as effective cap rocks in the storage site to seal CO2 leakage. 3.2. Porosity & permeability 3.2.1 Porosity
4
Yujie Diao et al. / Energy Procedia 154 (2018) 94–99 Author name / Energy Procedia 00 (2018) 000–000
97
The sandstones at the bottom of the Liujiagou Formation, the upper part of the Shiqianfeng Formation, and the middle and lower parts of the Shihezi Formation have relatively high porosity, generally ranging from 9% to 15%, and the porosity of the local sand bodies could reach 18%–20%. 3.2.2 Permeability The permeability increased exponentially with increasing porosity, and the fitted relationship between the two was (1) PERM = 9.678 + 1040.2/e(POR) where PERM is the permeability; POR is the porosity; the correlation coefficient reached 0.995. As a whole, the permeability of target reservoirs at the storage site was relatively low, generally 10–20 mD, and the horizontal heterogeneity is high. The permeability in the sandstones of the Shiqianfeng Formation and Shihezi Formation was relatively high in the direction of line L1. The permeability in the Liujiagou Formation, Majiagou Formation and Shihezi Formation in the direction of the L2 line was relatively high. The permeability in the sandstone of Liujiagou Formation, Shiqianfeng Formation, and the middle and lower parts of Shihezi Formation in the direction of L3 line was relatively high. The permeability in the direction of the L4 line was similar to that in the direction of the L1 line, where the permeability in the sandstones of the Shiqianfeng Formation and the middle and lower parts of the Shihezi Formation was relatively high. 3.3. Hydrochemistry With a depth of 800–3000 m, the Shenhua CCS demonstration project storage site belongs to the deep aquifer rock group of the Ordos Basin. It is the ideal target saline aquifer for CO2 geological storage because of its low porosity, low permeability, and very slow groundwater runoff. The chemical type of underground saline was mainly Cl–Ca·Na. The total dissolved solids content was higher in the Liujiagou Formation and Shiqianfeng Formation (65.1 g/L and 31.2 g/L, respectively), whereas it was much lower in the Shihezi Formation and Majiagou Formation (9.5 g/L and 7.1 g/L, respectively). 3.4. Pressure & Temperature The drilling test results showed that the pressure at the top of the Liujiagou–Majiagou Formation was between 16 MPa and 22.8 MPa, and the pressure coefficient was between 0.92 and 1.12. The pressure coefficient was the largest in the Shihezi Formation, with a local maximum of 1.12. The pressure coefficient of the carbonate formations was lowest at the top of the Majiagou Formation, generally less than 1. Stratum temperature ranged from 54.5°C– 69.1°C, and the geothermal gradient was small at about 1.45°C per 100 m depth. 4 Demonstration of the model The new geological model had an area of 5 km × 5 km (X, Y) centered on the injection well, of which the central 1 km × 1 km (X, Y) was controlled by VSP seismic data, and the reliability was high. The 3D geological modeling methods of corner grid subdivision and Kriging interpolation were used. In the vertical direction (Z), the Liujiagou and Heshanggou Formations were divided according to ~5 m resolution. The Shiqianfeng, Shihezi and Shanxi Formations were divided at ~10 m resolution. The Benxi and Taiyuan Formations were considered as mudstone cap rock in the simulation (designed with a layer of inactive grid). The Majiagou Formation was divided according to ~10 m resolution. In the vertical direction (Z), there were a total of 149 grids. For the range of 1 km × 1 km in the center of the model, there were 100 × 100 grids in the plane (X, Y) direction, and each grid size was 10 m × 10 m. In other areas, because there was no seismic data control, the grid was coarser: each grid size was 50 m × 50 m, and there were a total of 80 × 80 grids. The total model contained 180 × 180 × 149 = 4 827 600 grids.
Yujie Diao et al. / Energy Procedia 154 (2018) 94–99 Author name / Energy Procedia 00 (2018) 000–000
98
5
4.1 Lithological modeling With increasing depth, the shale content in the Shiqianfeng Formation and Shihezi Formation increased, mainly including interbedded sand and mud, especially the mudstones that developed in the upper Shihezi Formation and the carbonate rocks that developed mainly in the Majiagou Formation. In the horizontal direction, the continuity of sand distribution was good and consistent with the high-resolution sequence stratigraphic framework of the three wells. This also reflects the fluvial sedimentary characteristics from north to south of the Paleozoic and Mesozoic sand bodies in the storage site. 4.2 Porosity and permeability modeling Based on the storage site tectonics model and the stratum structure, 3D porosity and permeability models were constructed using four 2D porosity and permeability profiles. The value of porosity of the 3D model presented high heterogeneity in horizontal and vertical distribution (Fig. 2), the yellow zone has a relatively high porosity, generally higher than 10%. As shown in Fig. 3, in the 3D permeability model of the storage site, the permeability in the yellow zone is generally greater than 1 mD and that of the red zone is generally 10 mD. The overall porosity and permeability models are consistent with the predicted CO2 migration direction monitored by the time-lapse VSP seismic profile, i.e., overall migration to the northwesterly direction with relatively high porosity and permeability.
Fig. 2 The 3D porosity model of the demonstration project site
Fig. 3 The 3D permeability model of the demonstration project site
5 Conclusions Based on the results obtained from the existing data, we updated the geological model by supplying and improving the late-stage experimental data, deep geophysics and inside-well monitoring data of Shenhua CCS demonstration project storage site. This allowed the more accurate and scientifically supported prediction of CO2
6
Yujie Diao et al. / Energy Procedia 154 (2018) 94–99 Author name / Energy Procedia 00 (2018) 000–000
99
migration and provided geological support for late engineering monitoring and safety assessment. Through the construction of the geological model in the current study, we inferred the following conclusions: • Thick sandstone layers developed at 1600–2500 m in the Shanxi Formation, Shihezi Formation, Shiqianfeng Formation and Liujiagou Formation, and carbonate aquifers of Majiagou Formation can be divided into five good aquifer groups for CO2 storage. Among these, the sand bodies of Liujiagou Formation are thicker than the others and are mixed with thin layers of mudstones. The formation mud in Shiqianfeng Formation and Shihezi Formation increased with increasing depth, including mainly interbedded sand and mud, such as the mudstones that developed in the Upper Shihezi Formation and the carbonate rocks that mainly developed in the Majiagou Formation. • The middle and upper parts of the Liujiagou Formation and all of the Heshanggou Formation are dominated by mudstones and sandy mudstones, which can be used for the effective capping of the demonstration project to seal CO2 leakage. However, the model suggests that the alluvial bauxite shale with residual genesis that developed at the bottom of Benxi Formation can also be used as secondary effective cap rocks for the Majiagou Formation. • The sandstone porosity is mainly distributed in the range of 10%–18%. The bottom part of the Liujiagou Formation, the upper part of the Shiqianfeng Formation, and the middle and lower parts of the Shihezi Formation had a higher porosity at 9%–15%. The porosity of the local sand bodies reached 18%. The overall permeability was found to be low, and the target reservoir permeability range was generally 10–20 mD. • The advantages of 2D VSP seismic technology can be brought into full play in areas with geological conditions most favorable for CCS from an economic and long-term monitoring point of view. This research indicates that the well log-constrained VSP seismic attribute inversion technique can be used for fine reservoir prediction and CO2 monitoring purposes. Acknowledgements The authors gratefully acknowledge the financial support of the project of National Natural Science Foundation of China (Grant No. 41602270); the China Clean Development Mechanism Fund project of National Development and Reform Commission (Grant No. 2014088); the geological survey project of China Geological Survey (Grant No. 121201012000150010); and the National Key Research and Development Program of China (Grant No. 2016YFE0102500) under the cooperation framework of China-US Clean Energy Research Center (CERC). References [1]
Guo, J., Wen, D., Zhang, S., Xu T., 2014. Potential Evaluation and Demonstration Project of CO2 Geological Storage in China. Beijing: Geological Publishing House. [2] He, T., Ruan, Z., Guo, Q., Zhou, J., 2011. Interpretation results of 3D seismic data acquisition for Shenhua Ordos 100000 ton/year CCS project. Changqing Institute of BGP Inc., China National Petroleum Corporation. [3] Kuang, D., Li., Q., Wang, Y., Wang, X., Lin, Q., Wei, X., Song, R., 2014. Numerical simulation of distribution of migration of CO2 in Shenhua CCS carbon capture and storage demonstration project. Rock and Soil Mechanics, 35(9),2623-2641. [4] Li, C., Zhang, K., Wang, Y., Guo, C., Maggi, F., 2016. Experimental and numerical analysis of reservoir performance for geological CO2 storage in the Ordos Basin in China. International Journal of Greenhouse Gas Control, 45,216-232. [5] Shi, L., Wang, C., 2004. Do High Resolution Inversion by Using Simulated AC Curve. Journal of Southwest Petroleum Institute, 26(5),1820. [6] Wu X., 2013. Carbon dioxide capture and geological storage-The First Massive Exploration in China. Science Press Ltd. [7] Xie, J., Zhang, K., Hu, L., Pavelic, P., Wang, Y., Chen, M., 2015. Field-based simulation of a demonstration site for carbon dioxide sequestration in low-permeability saline aquifers in the Ordos Basin, China. Hydrogeology Journal, 23(7),1465-1480. [8] Xie, J., Zhang, K., Hu, L., Wang, Y., Chen, M., 2015. Understanding the carbon dioxide sequestration in low – permeability saline aquifers in the Ordos Basin with numerical simulations. Greenhouse Gases Science & Technology, 5(5),558-576. [9] Xie, J., Zhang, K., Wang, Y., Qin, L., Guo, C., 2016. Performance assessment of CO2 geological storage in deep saline aquifers in Ordos Basin, China. Rock and Soil Mechanics, 37(1),166-174. [10] Xu, S., White, R.E., 1996. A physical model for shear-wave velocity prediction[J]. Geophysical Prospecting, 44(4),687-717. [11] Zhang, D., Li, H., Chang, H., 2013. Potential evaluation and numerical simulation of CO2 migration. Peking University.