Molecular Interactions of Major Mineral Constituents with Kerogen in Green River Oil Shale

Abstract

AbstractOil shales are sedimentary rocks containing kerogen, a precursor to crude oil trapped in the inorganic mineral matrix. Green River formation in Utah, Wyoming, and Colorado is the largest deposit of oil shale in the world. The current extraction of shale oil involves the pyrolytic extraction of kerogen from the mineral matrix, which is expensive and detrimental to the environment. A better understanding of kerogen-mineral interactions could lead to more efficient extraction techniques. Our experiments indicate that the size of kerogen “pockets” is of the order of 10s of nanometers in the mineral matrix and also, the in situ kerogen is strongly influenced by molecular interactions with the surrounding minerals. A three-dimensional molecular kerogen model of Type I has been developed to determine the molecular interactions with predominant minerals (Na-montmorillonite clay, quartz, and calcite) of Green River oil shale. These molecular interactions are analyzed based on the seven fragments and associated independent ammonium ions that constitute kerogen. The results indicate that the interactions of kerogen molecules vary with the mineral in proximity, and also the underlying mechanisms are different. Techniques for the efficient extraction of kerogen can be developed by understanding the binding interactions between the kerogen and minerals.KeywordsSedimentary rocksKerogenMolecular interactions