Mechanical and acoustic behaviors of brine-saturated sandstone at elevated temperature

Yan-Hua Huang and Sheng-Qi Yang

Abstract

The mechanical behavior of rock is essential to estimate the capacity and long-term stability of CO2 storage in deep saline aquifers. As the depth of reservoir increases, the pressure and temperature that applied on the rock increase. To answer the question of how the confining pressure and temperature influence the mechanical behavior of reservoir rock, triaxial compression experiments were carried out on brine-saturated sandstone at elevated temperature. The triaxial compressive strength of brine-saturated sandstone was observed to decrease with increasing testing temperature, and the temperature weakening effect in strength enhanced with the increase of confining pressure. Sandstone specimens showed single fracture failures under triaxial compression. Three typical regions around the main fracture were identified: fracture band, damaged zone and undamaged zone. A function was proposed to describe the evolution of acoustic emission count under loading. Finally, the mechanism of elevated temperature causing the reduction of strength of brine-saturated sandstone was discussed.

Key Words

sandstone; elevated temperature; strength; acoustic emission; ultrasonic velocity

Address

Yan-Hua Huang: 1.) State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, P.R. China 2.) School of Resources and Geosciences, China University of Mining and Technology, Xuzhou 221116, P.R. China Sheng-Qi Yang: State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, P.R. China

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