Experimental study on threshold pressure of extra low permeability reservoir during gas injection;

A research on the seepage flow pattern of low-permeability reservoirs under consideration of threshold pressure and pressure-sensitive effect:a case of Member L1 in Weixi'nan depression

The viewpoint of there isn’t threshold pressure is doubted

which is contradictory to the fact that the JBN method presently used for relative permeability curve correction is based on the Darcy's Law without consideration of start-up pressure gradient effect.

Four classification evaluation parameters for extra-low permeability reservoir are proposed,including effective porosity,mainstream throat radius,movable fluid saturation and start-up pressure gradient.

We have researched the relation between reservoir permeability and pore structure,and its decisive role in reservoir recovery of Wendong oilfield,and have researched the effect of start-up pressure on development.

The study and analysis of starting pressure gradient in low permeability gas reservoirs;

The relationships are derived between the effective permeability and the effective viscosity of power law fluid versus the feature parameters of the fluids and formation media and between the starting pressure gradient of Bingham fluid and fluid feature parameters versus the feature parameters of the fluids and formation media.

Through numerical simulation methods, influence of starting pressure gradient on production indexes of fractured producers in diamond shaped well pattern was studied.

The generalization mechanism and variation law of triggering pressure differential in a lowpermeability reservoir, as well as the generalization condition and percolation law of nonDarcy flow, was demonstrated.