In order to further study the EOR effect of condensate gas reservoir in Zhongyuan Oilfield

the lower third member of Shahejie Formation of a block is taken as an example. Based on the theoretical support of material balance equation and state equation

laboratory experiments such as PVT phase state and physical simulation are carried out to reveal the development rule and deeply analyze the reasons of low production

even no production

of this gas reservoir

so as to recognizes the current situation. For the first tim

e

a two-way EOR method by dry gas injection with pressure maintaining after plugging removing near wellbore area conforming to the geological characteristics of the condensate gas reservoir in this block is proposed. Physical simulation experiments of plugging removing by CO

2

flooding for natural cores at injection end and extraction end are conducted respectively. The corresponding permeability after plugging removing is 60.44 % and 63.15 %

showing that the effect of plugging removing by CO

2

injection is good. On this basis

experiment of core displacement with dry gas injection is conducted with the result that at the beginning

dry gas injection with pressure maintaining under the original formation pressure of 41.19 MPa for condensate gas reservoir can make the condensate oil recovery ratio up to 91.41 %; when the pressure decline to the plugging pressure of 21.14 MPa

using this method again

the recovery ratio can be 44.28 %. By the researches

the formation physical model of oil-water emulsification plugging

because that the near wellbore area pressure is lower than the dew point pressure in the development process

is further clarified

providing technical support for the benefit development of low permeability tight condensate gas reservoir in Zhongyuan Oilfield.