Temperature Sensitivity of Ottawa Sand and Massillon Sandstone Intrinsic Permeabilities

摘要

Aquifer Thermal Energy Storage (ATES) involves the seasonal storage of surplus, low enthalpy energy. A typical scheme might involve withdrawing a few hundred gallons per minute of water from an aquifer, passing the groundwater through a heat exchanger where its temperature is increased via indirect contact with surplus heat from an electric generating or industrial processing plant, and then reinjecting and storing the heated groundwater in the original aquifer. The heat might be ultimately withdrawn and used for space heating or commercial applications. It has been estimated that it may be technically feasible to supply about 7.5% of the nation's total energy demand through aquifer thermal energy storage. However, certain unknowns remain including cost effectiveness, institutional and legal problems, and the physicochemical stability of the storage aquifer. This paper is a summary of a laboratory study focused on the component of the reservoir stability question, the temperature sensitivity of sand and sandstone intrinsic permeabilities. Ottawa sand and Massillon sandstone samples were exposed to a hydrostatic confining pressure of 150 bars, a pore fluid pressure of 60 bars, and temperatures between 25 and 150 exp 0 C. Permeability to deionized, deaerated, prefilitered water and calcium chloride solution, bulk volumetric strain, fluid chemistry, and particle carryover were monitored as a function of temperature and time. Potential permeability damage mechanisms were investigated including porosity reduction via bulk compaction, porosity reduction due to thermal expansion of constituent minerals, and thermally-induced internal and/or external particle plugging. (ERA citation 07:050522)