|Publisher||Society of Petroleum Engineers||Language||English|
|Content Type||Conference Paper|
|Title||The influence of pore space geometry on the entrapment of carbon dioxide by capillary forces|
Pentland, C.H., Shell Global Solutions International BV, Iglauer, S., Curtin University, Gharbi, O., Imperial College London, Okada, K., Tokushima University, Suekane, T., Tokyo Institute of Technology
SPE Asia Pacific Oil and Gas Conference and Exhibition, 22-24 October 2012, Perth, Australia
2012. Society of Petroleum Engineers
|6.8 Fundamental Research in Reservoir Description and Dynamics
6.3.2 Multi-phase Flow
We analyse a series of saturated and unsaturated porous media using μCT; four glass bead packs, a sand pack and a sandstone. In the saturated images the pore space contains brine and residual CO2 (Sr) at subsurface storage conditions. We quantify Sr and cluster size distributions and determine characteristic properties of the porous media through image analysis and the extraction of representative networks. We show that media with narrower pore throats, such as sandstones, trap more CO2 than media with wider pore throats. Numerical simulations performed on the extracted networks do not accurately predict the measured residual CO2 saturations. We discuss the important implications of these results for CO2 storage site selection, containment security assessments, and storage capacity appraisal.
Capillary trapping has been studied for decades due to its importance in the petroleum industry and in soil remediation, and more recently also in the context of CO2 storage (e.g. Jerauld, 1997, Conrad et al., 1992, Iglauer et al., 2011a respectively). Historically experiments were performed on centimetre scale samples (e.g. Oak et al., 1990) but recently such experiments have been performed on millimetre scale samples enabling the pore space and the fluids contained therein to be imaged on the micro-meter scale with micro-computed tomography (μCT) [Prodanović et al., 2007; Iglauer et al., 2010, 2011b, 2012a, 2012b; Kumar et al., 2010; Georgiadis et al., 2011; Suekane et al., 2011; Porter et al. 2010].
Here we perform additional analysis on the storage condition (i.e. high pressure and elevated temperature) CO2-brine results of Iglauer et al., 2011b and Suekane et al., 2011. Table 1 summarises the conditions of these experiments. Our objective is to understand which characteristic properties of the porous media have the greatest influence upon capillary trapping, and to investigate the characteristic properties of the trapped clusters. We employ a multi stage approach: rock properties are determined from the unsaturated scans through image analysis and the generation of representative pore network models; cluster properties are determined by analysing the saturated scan images; and trapped CO2 saturations from the experiments are compared with those predicted by dynamic simulations on the pore network models.
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