Experimental Investigation of Clay Content on Brittleness of Synthetic Shale

Abstract

Summary It is important to understand that the brittleness of shale is a combined response of minerals composition, pores, fluids in pores, and micro-structure of rock at certain temperature and pressure. However, clay content as a key parameter that affect the brittleness of shale, has not yet been well studied and understood. In this paper, we focus on impact of clay content on the brittleness of synthetic shale with different clay content. To reduce the number of unknown factors caused by multiple minerals, we made 8 samples each with a different weight percent of mineral: 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, instead of natural shale. The results indicate that with the higher clay content, samples show higher Young’s modulus, higher brittleness and lower Poisson’s ratio, which may be attributed to the increase of amount soft component (clay mineral). Besides, bedding plane has a significant impact on mechanical properties, E11 is always larger than E33 and B11 is always larger than B33. For the anisotropy of mechanical properties, ΔE and ΔB increase with the increase of clay content, contrarily, Δv decrease with the increase of clay content.