A review of theories to calculate pore pressures when fluids penetrate into rocks

Quantifying the pore pressures that build up inside of the rock matrices when fluids are injected inside of them is very important. In fact, the effective stresses that a rock is subject to either decrease or increase, when a fluid is filling or is being drained out of the rock matrix, respectively, due to the simple fact the fluid pore pressure vary. Several theories have been developed to better understand the pore pressure distributions in the Earth layers. Thus, this review will allow the reader to have a better understanding of the evolution of those theories, in a single manuscript, rather than in multiple documents which, in turn, is time consuming and not user friendly. Important also to separate this review paper into two parts, depending on the study the reader needs to make when fluids are considered: (1) quantification of fracturing pressures and (2) quantification of the pore pressures due to the fluid penetration.