CO2 uptake in the Wilhelmøya Subgroup reservoir section using X-ray micro-CT, Svalbard, Norway

• Main Authors: Van Stappen, Jeroen, De Kock, Tim, Boone, Marijn, Olaussen, Snorre, Cnudde, Veerle
• Format: Conference Object
• Language: English
• Published: International Society for Porous Media (Interpore) 2014
• Subjects: Earth and Environmental Sciences; fracture characterization; CO2 uptake; multiphase fluid flow; Svalbard; Longyearbyen; Norway; Wilhelmøya; Konusdalen; Spitsbergen
• Online Access: https://biblio.ugent.be/publication/5810396; http://hdl.handle.net/1854/LU-5810396

Wilhelmøya Subgroup rocks in Central Spitsbergen, Svalbard, form a potential storage reservoir for CO2 below Longyearbyen. These rocks are characterized by a moderate porosity and low permeability within which fractures are considered to facilitate fluid flow [1]. However, hard data on fracture parameters and pore characteristics were necessary to understand reservoir characteristics and assess the storage potential of the layers. Therefore, sandstone and conglomerate samples from the Wilhelmøya Subgroup were sampled and characterized with traditional laboratory test, such as Mercury Injection Porosimetry and permeability measurements, and non-destructive High Resolution X-ray Computed Tomography (HRXCT) [2] at the Centre for X-ray Tomography at Ghent University, Belgium (UGCT). The analysed dataset includes samples taken from drill holes in the vicinity of Longyearbyen, constructed during the pilot phase of the Longyearbyen CO2 project, as well as from the Wilhelmøya Subgroup outcrops at two valleys, Konusdalen and Criocerasdalen, North-East of the drill sites. Doing so, the fracture and pore parameters obtained during analysis can be compared in both settings. A multiscale approach was applied on the samples analysed with HRXCT. A first investigation was carried out on samples with diameters of 4 to 5 cm so that resolutions of approximately 50 μm were obtained in the CT images. Subsequently, subsamples were taken and examined at higher resolutions (2.8 μm to 4.0 μm). Quantitative information on the pore networks and fractures within the rocks were determined and pore networks were extracted from the HRXCT images. These were used for multiphase fluid simulations, performed to replicate CO2 injection at reservoir conditions in specific samples. The obtained data, in combination with information from classical laboratory tests, can be directly used for a better understanding of flow in the Wilhelmøya Subgroup.