An analytical model for pore volume compressibility of reservoir rock

The analytical model shows that pore volume compressibility of reservoir rock is related not only to porosity but also to elastic modulus and Poisson's ratio. There is a positive correlation between pore volume compressibility and porosity. The compressibility value of our model is much lower than that measured using volume method. The reason of the improper results from volume method is the micro interstice in core holder. Without the effects of micro interstice (mercury immersion method or loading and unloading stress treatment before the test), the measured pore volume compressibility shows a relatively low value and a positive correlation between pore compressibility and porosity, which validate the results of our analytical model. The pore volume compressibility calculated by volume method and Hall plot will overestimate the elastic energy of the reservoir and bring substantial errors in evaluation of original oil in place and the flow radius.