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Brachiopods present a key fossil group for Phanerozoic palaeo-environmental and palaeo-oceanographical reconstructions, owing to their good preservation and abundance in the geological record. Yet to date, hardly any geochemical proxies have been calibrated in cultured brachiopods and only little is known on the mechanisms that control the incorporation of various key elements into brachiopod calcite. To evaluate the feasibility and robustness of multiple Element/Ca ratios as proxies in brachiopods, specifically Li/Ca, B/Ca, Na/Ca, Mg/Ca, Sr/Ca, Ba/Ca, as well as Li/Mg, we cultured Magellania venosa , Terebratella dorsata and Pajaudina atlantica under controlled experimental settings over a period of more than two years with closely monitored ambient conditions, carbonate system parameters and elemental composition of the culture medium. The experimental setup comprised of two control aquariums (pH 0 = 8.0 and 8.15, T = 10 °C) and treatments where pCO 2 − pH (pH 1 = 7.6 and pH 2 = 7.35), temperature (T = 16 °C) and chemical composition of the culture medium were manipulated. Our results indicate that the incorporation of Li and Mg is strongly influenced by temperature, growth effects as well as carbonate chemistry, complicating the use of Li/Ca, Mg/Ca and Li/Mg ratios as straightforward reliable proxies. Boron partitioning varied greatly between the treatments, however without a clear link to carbonate system parameters or other environmental factors. The partitioning of both Ba and Na varied between individuals, but was not systematically affected by changes in the ambient conditions. We highlight Sr as a potential proxy for DIC, based on a positive trend between Sr partitioning and carbonate chemistry in the culture medium. To explain the observed dependency and provide a quantitative framework for exploring elemental variations, we devise the first biomineralisation model for brachiopods, which results in a close agreement between modelled and measured Sr distribution coefficients. We propose that in order to sustain shell growth under increased DIC, a decreased influx of Ca2+ to the calcifying fluid is necessary, driving the preferential substitution of Sr2+ for Ca2+ in the crystal lattice. Finally, we conducted micro-computed tomography analyses of the shells grown in the different experimental treatments. We present pore space – punctae – content quantification that indicates that shells built under increased environmental stress, and in particular elevated temperature, contain relatively more pore space than calcite, suggesting this parameter as a potential novel proxy for physiological stress and even environmental conditions. [ABSTRACT FROM AUTHOR]

During carbonated water injection and CO 2 -WAG scenarios for enhanced oil recovery, dynamic transfer of CO 2 from aqueous phase into resident oil can cause complex pH variations, which can affect mineral dissolution around wellbore and precipitation in reservoir. Also, transfer of CO 2 from carbonated water into live oil can liberate light components of the oil, which would create gas phase in-situ. In this investigation, a novel methodology was developed to numerically simulate these complex processes in an integrated approach. This study could present one step closer to realistic evaluations of dynamic CO 2 transfer from carbonated water to resident oil and consequent interactions with the reactive minerals in a carbonate reservoir. Taking account of the data of coreflood experiments performed on a carbonate rock under 3100 psi and 100 °C, profiles of ionic concentration of produced brine and rock weight during carbonated water injection into a dry core (in the absence of oil) were history-matched to tune reaction parameters. Calcite reaction parameters (surface area and activation energy) were tuned to match profile of concentration of Ca ++ . Also, for additional oil recovery and dP profiles, secondary and tertiary carbonated water injection experiments were matched simultaneously to obtain relative permeability curves and CO 2 mass transfer parameters. This new approach is called co-history-matching. Using the tuned parameters in a radial sector model, a series of simulations was performed to analyse change in rock porosity and enhanced oil recovery for large scales for carbonated water injection. Results of the large-scale model have demonstrated that minerals dissolution takes place mostly in vicinity of the injection wellbore. However, the simulation results demonstrated that injection of short cycle of carbonated water followed by plain water would alleviate the dissolution issue, while significant additional oil recovery is achieved. Image 1 • EOR and rock dissolution during carbonated water injection in carbonate formation were studied. • Using multiple experiments, co history matching technique was employed to obtain reliable CO 2 transfer to resident oil. • Geochemical parameters were tune to match rock dissolution. • Carbonated water injection in a radial model demonstrated intense dissolution of carbonate rock near injection wellbore. • To prevent wellbore failure, short cycle injection of carbonated water followed by plain water injection is implemented. [ABSTRACT FROM AUTHOR]