Analysis and modification of Biot poro-elastic theory for application in flow modeling of oil reservoirs

Key words:  oil reservoir  flow in porous media  porous media  low frequency vibration oil extraction technology  improved wave equation

Abstract:

A poro-elastic model can be derived for flow modeling in porous media of oil reservoirs, in which the Darcy flow in porous media and the elastic wave theory are considered in the process of oil production assisted by a low frequency vibration technique. A general poro-elastic model for fluid flow and wave propagation in porous media saturated with single-phase fluid was established in combining different mechanisms and considering various factors, including the oil extraction mechanism via low frequency vibration technology and the Biot poro-elastic model. In the new model the coupling flow equation, the state equation of porosity and oil viscosity under low-frequency vibration, and specifi conditions were improved. The solution of the new poro-elastic model was described and the use of the model was verified in a case study. The simulation results show that an increase of pressure in the middle of the rock and the flow rate at the inlet induced by vibration can be identified, which is in line with the observation in laboratory experiments. The low frequency vibration oil extraction technology can improve oil recovery in low porosity and permeability reservoirs. The modified model can lay foundation for the establishment of a general poro-elastic model for multi-phase flows.