## 1 Introduction
### Shale Interactions (Multi-Mineral)
These authors noted that any relative increase in quartz content was most likely caused by the dissolution of other minerals (such as feldspar and clay minerals), whereas a decrease was attributed to the dissolution of quartz itself. The kinetics of quartz dissolution is slow; therefore, this reaction is only observed in experiments conducted over long periods of time [49] or at higher temperatures. As determined by CO\({}_{2}\) and N\({}_{2}\) adsorption isotherms, the volumes of micropores and fine mesopores in the Longmaxi shale significantly decreased, with a corresponding increase in volumes of larger meso- and macropores, following treatment. The opposite trend was observed for terrestrial Chang-7 shale. Both the surface fractal dimension and the pore structure fractal dimension of the Longmaxi sample showed a significant decrease with treatment, which again was opposite to that observed for terrestrial Chang-7 shale. [PERSON] et al. [36; 55] considered that the changes they observed were due to a combination of three mechanisms, namely, (1) organic matter extraction, (2) dissolution and precipitation of the minerals, and (3) adsorption-induced expansion. Two experiments of note were reported by [PERSON] et al. [56]). Both were conducted on two New Albany shales containing pyrite, apatite, dolomite, illite, chlorite, and quartz. One shale had a low TOC, of about 6%, whereas that of the other was higher, at about 15%. The first experiment combined treatment with CO\({}_{2}\) and distilled water at low pressure (3.8 MPa) and a temperature of 150 \({}^{\circ}\)C with a duration of 3-42 days. Control tests were conducted without CO\({}_{2}\), using only distilled water or brine. They found that injecting CO\({}_{2}\) in a small amount did not change the porosity or structure relative to the control tests. However, the second experiment involved treatment with CO\({}_{2}\) and brine, at higher pressures ranging from 0.69 to 24.13 MPa and with a temperature of 80 \({}^{\circ}\)C, for 21 days. Testing the brine chemistry periodically, they observed an increase in carbonate minerals entering the solution. Ca and Mg ion concentrations increased with pressure due to further lowering of the brine pH level. Ion ratios suggested that dolomite/ankerite were the dissolving phases, along with variable amounts of calcite. Although most investigations in the literature have used batch reactors, [PERSON] and [PERSON] [57] used a flow reactor. Batch reactors are more representative of the static CO\({}_{2}\) found pooling under the caprock or shale interlayers in the Sleipner case. Flow reactors model areas where CO\({}_{2}\) is more mobile, such as when passing through the shale layers. Shale samples were pressure-saturated with simplified artificial pore water from a 30,000 ppm NaCl solution, before being held in a pressurised cell at 13.8 MPa and 60 \({}^{\circ}\)C for nine months. Wet scCO\({}_{2}\) was then dynamically flowed throughout this time. The shales tested were Eneabba Basal shale and claystone-rich facies of the Yalgorup Member. Ten samples were tested, and an initial XRD analysis before treatment showed varying amounts of quartz, microcline, alibite, anorthite, illite/mica, kaolinite, chlorite, gewdite, hematite and halite. However, after treatment, XRD then revealed the dissolution of quartz, and aluminosilicates such as K-feldspar, as well as clay minerals such as kaolinite, were seen. Precipitation of muscovite (illite) was also detected. These changes resulted in an increase in the porosity of most samples. Mercury intrusion porosimetry showed a shift towards larger pore throat sizes. [PERSON] et al. [58] investigated the interactions of wet CO\({}_{2}\) over 32 days at 15 MPa and 50 \({}^{\circ}\)C, with Muderong shale. XRD analysis was used to track mineralogical changes over time, and the example data given in Figure 6 shows that a marked change was observed after 6 days in illite and K-feldspar content. Although illite content decreased and K-feldspar content increased, [PERSON] et al.