An investigation of the reactions of supercritical CO 2 and brine with the Berea sandstone, muscovite, and iron bearing minerals

Abstract

The reduction of anthropogenic CO 2 emissions while still generating energy is a challenge that society faces. Most current energy production comes from fossil fuels that increase atmospheric CO 2 concentrations. Pending a breakthrough in clean energy production, technological solutions that increase efficiency and sequester CO 2 are required. Carbon Capture and Storage (CCS) or carbon sequestration technology can provide part of the solution by providing disposal of point source CO 2 emissions. The research described in this thesis aims to aid development of CCS technology. There are three parts to the thesis. First, is an experimental study of the Berea sandstone to determine the reactivity of its minerals, as these could impact its potential as a reservoir for CO 2 storage. Cores of Berea were placed in a "flow-through reactor" that pumped a continuous stream of supercritical CO 2 (scCO 2) mixed with simulated groundwater through the rock. Chemical and physical changes to the solid, liquid and gas phases were monitored. Second, batch experiments were conducted to study the behavior of pyrite, magnetite, hematite, and muscovite when subjected to simulated groundwater and scCO 2. Third, is an outcrop study of the Devonian Jefferson Formation, a carbonate formation to serve as an analog to the same formation in the subsurface where it is the target of a Department of Energy CCS pilot project. The field study provided analysis of the mineralogy, sedimentology, and stratigraphy so as to better understand its potential as a reservoir for CO 2 storage. The flow-through experiments on the Berea sandstone demonstrated that carbonate cement and iron oxides were reactive phases. It was equivocal as to whether muscovite was reactive. The batch experiments quantified the reactivity of iron oxides and pyrite and demonstrated significant dissolution of the scCO 2, such that supercritical conditions were not maintained for the duration of the experiment. The batch experiments also showed that muscovite was not reactive within the time frame of the Berea flow-through experiments (72 hours), but was reactive over longer time periods (500+ hours). The field study indicated that the best potential reservoir zones of the Jefferson Formation are altered reef complexes composed mostly of dolomite.