Dawsonite and ankerite formation in the LDX-1 structure, Yinggehai basin, South China sea: An analogy for carbon mineralization in subsurface sandstone aquifers

Abstract

The geochemistry and petrology of the LDX-1 structure of the Yinggehai basin, a natural analog of a sedimentary carbon storage site, was investigated to understand the consequences of the charging of CO2 gas in this system. The rocks in this structure are dominated by subarkose and sublitharenite sandstones. The authigenic minerals formed after CO2 injection are dawsonite, microcrystalline quartz, kaolinite and ankerite.Dawsonite and ankerite are formed just beneath a CO2 bearing anticlinal structure due to the reactions between silicate minerals (feldspars and clay minerals) and the fluid phase. Carbon and oxygen isotopic analyses indicate that the main carbon source for dawsonite and ankerite formation was mantle magmatic CO2. The aqueous activities of sodium and calcium, the partial pressure of CO2, pH and temperature are the key factors influencing the stability of the dawsonite and ankerite. The presence of the anticlinal structure maintaining a locally high CO2 partial pressure in the waters beneath this structure is likely responsible for the observed long-term persistence of dawsonite and ankerite in this system.

Carbonate geochemistry and its role in geologic carbon storage

“…The carbonate mineral ankerite ((Mg,Fe,Ca)CO 3 ), however, may be favored in conditions at ambient to moderate temperatures [110,111] . Both dawsonite (NaAl(CO 3 )(OH)) and ankerite have been observed in sedimentary formations at high CO 2 pressures and temperatures >60°C [112,113].…”

Reactive Transport Modeling and Sensitivity Analysis of CO2–Rock–Brine Interactions at Ebeity Reservoir, West Kazakhstan

“…The selection of the secondary minerals could affect the results of the subsequent simulations; therefore, the most relevant minerals were selected based on their reaction mechanisms and previous studies. Dawsonite, anhydrite, and ankerite were included as secondary minerals and were allowed to precipitate to evaluate the possible mineral inclusion of CO 2 in the deposit [35][36][37]. Anhydrite is an anhydrous calcium sulfate that can reduce the amount of CO 2 trapped in the solid phase and can negatively affect rock permeability [38].…”

“…It has also been reported that dawsonite is more stable at low pH values (acidity is equilibrated by buffering); therefore, the range of dawsonite stability is limited given the boundaries of the albite dissolution effect. Moreover, significant care must be taken to preserve the dawsonite and ankerite formation under in-situ conditions by maintaining an increased pressure of the injected CO 2 [37]. These minerals may not provide CO 2 fixation at low partial pressure, unlike calcite.…”

Geochemical Negative Emissions Technologies: Part I. Review

“…These are stable enough to be stored for long time periods. Other carbonate minerals such as siderite (FeCO 3 ), dawsonite (NaAl(CO 3 )(OH) 2 ), and ankerite (Ca(Fe,Mg,Mn)(CO 3 ) 2 ) can act as stores of carbon, but may only be stable in subsurface environments (Hellevang et al, 2005;Snaebjörnsdóttir et al, 2014;Yu et al, 2020). Besides carbonates, other products of mineral carbonation and weathering include silica, iron oxides, and clays.…”