Experiments and Analysis of Nonlinear Seepage Characteristics of Heavy Oil in Porous Media

Aiming at a problem of seepage characteristics and threshold pressure of heavy oil in porous media,a transient method was introduced to measure the threshold pressure of heavy oil,which considered the mass conservation theory and the modified Darcy's law to calculate pressure variation at unsteady state in 1D porous media.Then some experiments were carried out to measure the threshold pressure of heavy oil for three permeability levels and three oil viscosity levels. Finally,inflection temperatures were calculated according to the experimental results.The results showed that the threshold pressure gradually decreased as temperature increased and the inflection temperature exponentially increased as oil viscosity increased in the same porous media. For the same heavy oil,the inflection temperature gradually decreased as permeability increased. In III8- 9 Layer of Zone No. 1,Jinglou Oilfield,high inflection temperature mainly distributed at the north and central section of this reservoir,which made heavy oil lower flow ability. Lower inflection temperature distributed at the east of this reservoirs to make higher flow ability.