The perforation tunnel is the channel for transporting the hydrocarbon to the well bore. The shaped charge perforation operation

however

usually leads to some damage to the surrounding sandstone. Based on the perforation efficiency tests and numerical simulations

a new method is developed to quantitatively evaluate the porosity and permeability damage degree of the compacted zone. The kinematic-hardening plastic flow law is used to describe the sandstone deformation under high strain rate loading. Then dynamic responses of near-tunnel sandstone during perforation process are simulated by using the explicit dynamic analysis code LS-DYNA. Some key data

such as the sandstone matrix stress

plastic strain and volumetric strain are obtained. Subsequently

the damage degree of compacted zone is quantitatively analyzed by using these data together with the porosity and permeability evolution models. By comparing numerical results with the experimental results of core flow efficiency and CT scanning data from the interparticle pore sandstone targets in Shengli oil field; good agreements are achieved

the validaty of the proposed method is verified. It is shown that

during shaped charge perforation

there are two major damage mechanisms for the compacted zone

namely

the plastic squeezing and shear swelling. Near the tunnel’s inner wall

the sandstone matrix mainly suffers dilatancy actions

which enhances the porosity; meanwhile

the original structure of pore are changed due to plastic squeezing

which brings a jam to the tunnels

resulting in a reduction in permeability.