A review of variability of the effective mineral's elastic moduli in sandstones

Understanding the bulk and shear moduli of the background material (?_0, µ_0) from which the rock frame is built is crucial in rock physic models with a direct impact on rock frame modelling and Gassmann fluid substitution. Here, I describe different components of the background material and explain why the terms grain, matrix, solid or mineral do not solely represent ?_0 and µ_0 accurately. I explored the literature to gain a data-driven insight into variability of the elastic properties of the non-clay fraction of the sandstones, where quartz's elastic properties are typically used for. The results from unjacketed bulk compressibility measurements, along with two other empirical methods indicate the range of ?_0 and µ_0 vary over a rather large interval. It is shown that the effective medium theories - even using a detailed mineralogical description of the rock aggregate - do not guarantee an accurate estimation of ?_0 (and probably µ_0). It was also found that the quartz elastic properties, in particular its shear modulus, do not appear to be suitable for characterisation of the for non-clay fraction of the sandstones. Alternatively, unjacketed bulk compressibility measurements, or curve fitting is recommended for estimation of these parameters.