Effect of Temperature and Pressure on the Bulk Modulus of a Poroelastic System

Pressure and temperature are ubiquitous physical parameters that affect subsurface porous systems both under ambient geologic conditions and under engineering operations related to fluid injection and thermal operations. Consequently, for efficient planning of subsurface operations, trends in elastic parameter variations with temperature and pressure need to be understood. In the petroleum literature, measurements have been made on the effect of temperature and pressure on bulk modulus of saturated porous systems. Reported experimental results predict interesting and definite trends. In this paper, the effect of pressure and temperature on the bulk modulus of the saturated porous system under undrained conditions, mostly applicable to low permeability environments has been mathematically, investigated. The equation presented has been found to predict experimental observations under different combinations of pressure and temperature as found in published works. Also, the model predicts higher bulk moduli for poroelastic systems with lower initial porosities for a given set of temperature and pressure conditions and this has been substantiated using literature source experimental data. By using this model, the combined effect of temperature and pressure on bulk moduli of igneous and sedimentary rocks can be compared analytically.