A combined geochemical and μCT study on the CO2 reactivity of Surat Basin reservoir and cap-rock cores: Porosity changes, mineral dissolution and fines migration

Abstract

16 17 Geological storage of CO2 generally involves injection of a CO2 stream into a high porosity and 18 permeability reservoir, contained by one or more overlying low permeability formations. 19Sandstone reservoirs and associated cap-rocks of targeted CO2 storage sites therefore have 20 distinct properties such as porosity and mineral contents. Their geochemical response or 21 reactivity to injected supercritical CO2 and associated changes in porosity, and permeability 22 trapping of CO2 as ferroan carbonates such as siderite, ankerite and dolomite over longer time 46 scales when pH is buffered. 47Changes to porosity, mineral content, and water chemistry after pure CO2 reaction observed here 48 and in other published studies were dependent on mineral content and fluid accessibility. These 49 results could be generalized to other sandstone reservoirs where it is expected to inject CO2. The 50 results can also be used to validate geochemical models to build longer term predictions. 51 52 Keywords 53 54 Surat Basin 55 Precipice Sandstone 56 Evergreen Formation 57 Hutton Sandstone 58 CO2 sequestration 59 60 25-60 %) after CO2 core-flooding at 60 -69°C and 19 -25 MPa pore pressure (Saeedi et al., 131 2016). Porosities however remained similar, with the permeability changes attributed to the 132 decreased pH destabilizing kaolinite which migrated plugging pore throats. 133While the above studies at high salinity conditions demonstrate generally higher reactivity of 134 calcite cements and potentially clay-rich cap-rocks that reservoir sandstone, changes in water 135 chemistry, porosity or permeability can be more complex. The different conditions used in each 136 study, especially temperature, and batch or flow conditions complicate direct comparisons 137

Enhancing geological and hydrogeological understanding of the Precipice Sandstone aquifer of the Surat Basin, Great Artesian Basin, Australia, through model inversion of managed aquifer recharge datasets

“…This smaller scale fracturing is observed in Precipice Sandstone, for example in the Chinchilla 4 well core (Fig. 3b), with both high and low core permeabilities reported (Pearce et al 2015(Pearce et al , 2019.…”

“…Thus, the two units are distinct from one another, and Wang et al (2019) suggests that this is sufficient reason not to group them. Sequence stratigraphy using logs and seismic also supports this subdivision of the Precipice-Evergreen succession as does mineralogical analysis (Grigorescu 2011;Bianchi et al 2018;La Croix et al 2019;Pearce et al 2019). Precipice Sandstone drill core is generally up to 90-95% quartz, whereas the overlying Evergreen Formation is more mineralogically diverse with higher proportions of clays and feldspars-an example is the Geological Survey of Queensland Roma 8 well ( Fig.…”

Wood distillate as an alternative bio-based product against lichens on sandstone

“…Accordingly, calcite dissolution in static conditions is remarkably lower than in flowing solutions, particularly in the case of rock structural features limiting a reactive fluid infiltration (e.g. Brand et al, 2017;Pearce et al, 2019). Therefore, combination of single and repeated impact measures with Equotip did not show changes in Pietra Serena sandstone after the poultice application of 10% WD, compared with those treated with tap water.…”

Experimental and Modelled Reactions of CO2 and SO2 with Core from a Low Salinity Aquifer Overlying a Target CO2 Storage Complex

“…Core air permeability, mercury intrusion porosimetry (MICP), and Helium porosity of the Chinchilla 4 well cores described here were performed at Weatherford. MICP, He pychnometry, permeability, and X-ray diffraction of West Wandoan 1 core was performed at the University of Queensland (UQ) by methods reported previously [10,23,24]. Scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) in back scatter detection mode (BSE) with both a low-vacuum JEOL 6460LA environmental SEM (Peabody, MA, USA), and Hitachi TM3030 (Tokyo, Japan) with a Bruker EDS (Billerica, MA, USA) was performed on polished thin sections and blocks.…”