Observation of Cement/Sandstone Interface after Reaction with Supercritical CO₂Using SEM-EDS,  μ-XRD, and  μ-Raman Spectroscopy

Abstract

We observed cement/sandstone interfaces after reaction with supercritical CO2 using SEM-EDS, µ-XRD, and µ-Raman spectroscopy in order to evaluate chemical reactions of well-cement in CO2 storage site. To model actual well in geological formation, we prepared a well composite sample consisting of steel casing, Portland cement, and Berea sandstone. The batch experiment was performed for 56 days under a condition of 10 MPa and 50• C. After the batch experiment, a carbonation zone appeared at the cement/sandstone interface, however, the carbonation depth was limited within a few millimeters and the inner part of the cement was not altered. The Ca concentration in the carbonation zone increased 13% in comparison to that in the unaltered cement zone while the Mg, Si, and S concentrations decreased significantly. The predominant crystalline phases in the carbonation zone were calcite, aragonite, and vaterite. In addition, sparse precipitation of CaCO3 was observed in the pore spaces of the sandstone along the cement/sandstone interface.

Wellbore integrity in a saline aquifer: Experimental steel-cement interface degradation under supercritical CO2 conditions representative of Brazil’s Parana basin

“…For these specimens, cement and steel integrity in the interface were preserved, meaning that the wellbore integrity is assured. Similar results were found from field (Carey et al, 2007;Duguid et al, 2014) and laboratory scale experiments (Mito et al, 2015;Nakano et al, 2016;Ren et al, 2016) indicating that perfectly bonded cement-casing interfaces may efficiently protect the casing against CO 2 induced degradation and act as a barrier to prevent CO 2 leakage from the geological formation (Beck et al, 2016;Carroll et al, 2016). However, other studies indicate that the cement-casing interface may lose its integrity over time in aggressive environments (Lorek et al, 2016;Ren et al, 2016) whereas field data show that interfacial defects are present to some extent of all wells evaluated (Carey et al, 2007;Duguid et al, 2014;Hawkes and Gardner, 2013).…”

“…Studies of cement carbonation (Bihua et al, 2018;Koukouzas et al, 2017) and steel casing corrosion (Nešić, 2007) are numerous. However, the evaluation of the cement-casing interface integrity is significantly limited (Asahara et al, 2013;Carey et al, 2010Carey et al, , 2009Mito et al, 2015;Nakano et al, 2016Nakano et al, , 2014Ren et al, 2016;Wolterbeek et al, 2016Wolterbeek et al, , 2013Wolterbeek and Raoof, 2018). Among them, only three works simulate interface degradation in the presence of wellbore defects (microannuli) and CO 2 -rich fluids in dynamic (Carey et al, 2010(Carey et al, , 2009 or static (Wolterbeek et al, 2013) systems, considering the simultaneous occurrence of cement carbonation and steel corrosion.…”

Elucidation of Calcite Structure of Calcium Carbonate Formation Based on Hydrated Cement Mixed with Graphene Oxide and Reduced Graphene Oxide

“…However, the XRD patterns show sharp calcite reflections, confirming the effective formation of calcite. 20,24−26,48,51,59 Further, a comparison of the XRD patterns for the CaCO 3 particles acquired using GO and/or rGO reveals that the XRD peaks for the hydrated cement mixed with GO and/or rGO are sharper than those of the hydrated cement without any additives.…”

“…14−17 In addition, multiple studies have been committed to investigate the carbonation effects on the reinforced cement durability, 2,18−26 and environmental factors such as temperature, relative humidity, and partial pressure of carbon dioxide have been found to have enormous effects on the carbonation of hydrated cement. 19,20,24−26 Indeed, the carbonation of hydrated cement implies an intricate effect on the microstructure; 27−30 mild CO 2 exposure enhances the compressive strength, while extended exposure might negatively influence the mechanical properties. More importantly, Pavlik 21,22 demonstrated that the reaction of the hydrated cement with atmospheric CO 2 is generally a slow process and is highly dependent on some environmental factors such as the concentration of atmospheric CO 2 , temperature, and permeability of the material.…”

“…Recently, the increased attention on civil infrastructure enhancement has motivated research on the possible modification of cement-based materials to fulfill the growing requirements for sustainability in the construction field. , Modification is performed by some selective additives and adjusting the cement composition. Several attempts have been done to enhance the hardness, durability, and tensile properties of the cement by utilizing different kinds of reinforcing materials, from carbon fibers, steel fibers, and polymer fibers − to nanomaterials, , such as carbon nanotubes, graphene derivatives, and nanosilica. − In addition, multiple studies have been committed to investigate the carbonation effects on the reinforced cement durability, ,− and environmental factors such as temperature, relative humidity, and partial pressure of carbon dioxide have been found to have enormous effects on the carbonation of hydrated cement. ,,− Indeed, the carbonation of hydrated cement implies an intricate effect on the microstructure; − mild CO 2 exposure enhances the compressive strength, while extended exposure might negatively influence the mechanical properties. More importantly, Pavlik , demonstrated that the reaction of the hydrated cement with atmospheric CO 2 is generally a slow process and is highly dependent on some environmental factors such as the concentration of atmospheric CO 2 , temperature, and permeability of the material.…”