Description
The sequestration of CO2 in shales, associated with an increase in gas production due to CO2 driven stimulation might be developed to an industrial-scale. Polish Lower Palaeozoic gas-bearing shales of the Pomeranian part of the Baltic Basin provide a natural research laboratory and test site for this technology. The main objective is to provide a comprehensive, multi-scale approach to estimate the CO2 storage capacity of the shale structures as well as the effectiveness of CO2 as the gas recovery medium. The development of research may result in growing number of scientific competence and improve Europe's position. Considering shales as common sealing rock for CO2 storage in saline aquifers the results of the project should be important for the safety assessment of conventional storage sites. The combined expertise of multidisciplinary Polish-Norwegian team will allow to create a comprehensive model of CO2 sequestration, capable of assessment of the storage capacity of Pomeranian shales. Decision makers, Petroleum industry and Energy producing sector; Researchers and scientists; Research centres and bodies concerned with lifelong learning issues.
Summary of project results
The main showstoppers for deployment of the CCS technology at industrial-scale are a high price of the process hidden, first of all, in the capture segment. Low prices of the CO2 emission allowances do not compensate for these costs. A possible way out of this dilemma is to combine CO2 sequestration with enhanced recovery techniques, which is proved to be both profitable and acceptable by the public. In our project we have explored a relatively new and not yet implemented option of i) the permanent storage of CO2 in unconventional reservoirs combined with ii) the enhanced gas recovery from the reservoir. The main aim of this Project was a development of a multi-scale model of CO2 sequestration in shales combined with simultaneous stimulation of natural gas production. Understanding of gas adsorption and desorption in shales requires the resolution of different spatial and temporal scales: from the atomic scale (adsorption of CO2 by kerogen), through the nanoscale (transport of CO2 and methane in the pores), to the larger scale processes of flow and transport in the fractures. Our results indicate that the CO2 has a larger affinity to the shale matrix than methane and thus can be stored in the matrix, at the same time enhancing shale gas production. Nevertheless, the overall capacity of the Pomeranian shale formations is not large enough to provide an effective alternative to conventional storage in porous saline aquifers. At the same time, the perspectives for shale gas exploitation in Poland have become rather bleak, which further defers the implementation of CO2 sequestration in Polish shales. However, the results of the project will undoubtedly be useful for the practitioners provided the idea of shale production in Poland resurfaces. For example: (i) our experimental investigations of CO2-rich brine interaction with mudrocks are potentially useful for oil industry in design fracking fluid composition, (ii) reactive flow simulations carried out within the project suggests that acidization should be implemented to maximize the gas extraction out of shale formations with calcite veins, (iii) results of ab initio studies indicate that CO2 can be chemisorbed to many carbon systems and minerals has potential to pave the way toward solving the carbon capture problem. Additionally, many of these results are not limited to the Pomeranian shales and can be used in the implementation of CO2 sequestration in other active shale plays.
Summary of bilateral results
Within the ShaleSeq Project, we built an interdisciplinary team, comprising a mix of geologists and physicists. Both disciplines were represented on the Polish and Norwegian side. One of our main objectives was to enhance the cooperation between the researches representing different fields. We believe that the benefits of cooperation between the Polish and Norwegian partners were mutual. The Polish partner provided geological and geophysical data and rock samples that were necessary for conducting laboratory experiments and for inferring the in-situ conditions. On the other hand, 4 PhD students from Poland spent up to 4 months in Oslo, which gave them opportunities to follow various academic courses at the UiO, develop new scientific skills and gain new experiences by staying within the international community at PGP. The physicist from the University of Warsaw have benefited from the contacts with the group in Oslo. In particular, they were inspired by them to use double-coated tape in the microfluidic dissolution experiments, which resulted in a perfect control of the flow rate in the system and a full repeatability of the experiments. While visiting Norwegian colleagues the team has also learned that another group from the University of Oslo, performs similar dissolution experiments in the Hele-Shaw cell. This resulted in collaboration between the two groups, and a joint paper is planned. The team from the Computational Geology Laboratory at PGI has benefited from the expertise of the colleagues at PGP in the field of laboratory experiments, and in particular microfluidics. A collaboration focused on roughness measurements in shales has been established between CGL and PGP. Highly accurate white light interferometry measurements have been already performed on one of the samples and will serve the purpose of a reference result to calibrate the microphotogrammetric method, which is currently developed at CGL. The cooperation between the Faculty of Mining and Geology of SUT and Department of Physics of University of Oslo has been developed in the field of diffusion processes studies both from the experimental and modeling point of view. It is planned to maintain contacts and apply for projects related to the gas storage or Compressed Air Energy Storage. Strong research ties have also been established between the physicists from the University of Warsaw and geologists from the Polish Geological Institute.