Novel Beneficial Use of Oil Field Brine and Bauxite Residue for Carbon Sequestration

Peng Lu¹, Robert Dilmore², Yee Soong², and Chen Zhu^1
1Department of Geological Sciences, Indiana University, Bloomington, IN
²National Energy Technology Laboratory, US Department of Energy, Pittsburgh, PA

Currently, 20-30 billion barrels of oil field brine are produced annually associated with the production of oil and gas in the USA. Many of the gas/oil-field brines have high concentrations of dissolved ions such as Ca, Mg, and Fe ions, which make the treatment and disposal costly. At the same time, over 70 million tons of bauxite residues are generated annually when aluminum is extracted from bauxite. The pH of the liquid is as high as 13.5, and the solids contain high alkalinity. The caustic nature of the residue has resulted in damages to the ecosystems and concerns with long-term environmental liability. Worldwide, there are about 200 million tons of bauxite residues that are stored in tailings ponds. Environmentally and economically sound methods and processes are still elusive. We conducted laboratory experiments of addition of CO₂ to bauxite residues and oil field brine mixtures as a way of beneficial use of industrial wastes and carbon sequestration. The use of bauxite residue/brine to capture and store CO₂ will serve to not only mitigate the impact of anthropogenic CO₂ on global warming but will also help safe storage and reuse of industrial wastes. Carbonation experiments were carried out over the full range of bauxite residue liquor/brine mixtures in 10% increments by volume. The capacity of reactant mixtures to absorb CO₂ is, primarily, a function of reactant mixture pH, with carbonation capacity decreasing with decreasing mixture bauxite residue concentration. A geochemical model was carried out to predict the effectiveness of bauxite residue liquor neutralization and potential CO₂ mineral sequestration capacity. Modeling results show that carbon trapping is accomplished through both CO₂ mineralization and dissolution. Dawsonite and calcite formation were predicted to be the dominant products of bauxite residue liquor/brine mixture carbonation.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas