A pilot project of CO2Carbon dioxide storage(CO2Carbon dioxide) A process for retaining captured CO2Carbon dioxide, so that it does not reach the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) was conducted at an onshore site in Nagaoka, Japan. The target aquiferAn underground layer of fluid-bearing permeable rock or unconsolidated materials (gravel, sand, or silt) with significant permeability to allow flow was early Pleistocene sandstoneSand that has turned into a rock due to geological processes, which is around 60 m thick and found at 1100 m below the ground surface. During the 554-day injectionThe process of using pressure to force fluids down wells period, which commenced in 2003, around 10,400 tonnes of CO2Carbon dioxide were stored. Three monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions wells were completed around an injectionThe process of using pressure to force fluids down wells wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injectionThe process of using pressure to force fluids down wells of fluids and several monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions schemes, including continuous measurements of pressure and temperature, wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injectionThe process of using pressure to force fluids down wells of fluids logging, crosswell tomography, and in situ fluid sampling, were employed (Sato et al., 20102010 - K. Sato, S. Mito, T. Horie, H. Ohkuma, H. Saito, J. Watanabe and T. YoshimuraMonitoring and simulation studies for assessing macro- and meso-scale migration of CO2 sequestered in an onshore aquifer: Experiences from the Nagaoka pilot sitesee more). Flow simulation provided valuable insights into the process of macro- and meso-scale migrationThe movement of fluids in reservoir rocks.
The 4 km × 4.4 km area was taken as the simulation space domain and was discretised using LGR (local grid refinement) with the 5 m × 5 m grid blocks covering the test area. To represent formationA body of rock of considerable extent with distinctive characteristics that allow geologists to map, describe, and name it heterogeneity, the aquiferAn underground layer of fluid-bearing permeable rock or unconsolidated materials (gravel, sand, or silt) with significant permeability to allow flow was split into seven grid layers, based on the layering by wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injectionThe process of using pressure to force fluids down wells of fluids correlation. The total number of grid blocks of the model was approximately 100,000. Pore volume modifiers were applied to the boundary grid blocks representing the exterior extension of the formationA body of rock of considerable extent with distinctive characteristics that allow geologists to map, describe, and name it.
In the early years of the project, simulation studies were performed to examine the technical feasibility of the planned injectionThe process of using pressure to force fluids down wells scheme and to optimise the locations of three observation wells, as wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injectionThe process of using pressure to force fluids down wells of fluids as to examine the technical feasibility of the injectionThe process of using pressure to force fluids down wells scheme. The simulation studies using the petro-physical data from the injector (IW-1) showed the injected CO2Carbon dioxide would spread in a nearly circular area. The provisional locations of the observation Wells were determined based upon the numerical simulation results.
To interpret the observation data collected from various monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions tools and assess probable distributions of the injected CO2Carbon dioxide, history matching was carried out during the injectionThe process of using pressure to force fluids down wells period and then repeatedly after 3 years of monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions. The observed data used in the history matching were monitored bottomhole pressures, free CO2Carbon dioxide arrival times to the observation wells, and approximate CO2Carbon dioxide distributions, which was estimated through crosswell seismic tomography (Sato et al., 20102010 - K. Sato, S. Mito, T. Horie, H. Ohkuma, H. Saito, J. Watanabe and T. YoshimuraMonitoring and simulation studies for assessing macro- and meso-scale migration of CO2 sequestered in an onshore aquifer: Experiences from the Nagaoka pilot sitesee more).