Productivity Calculation for Fractured Wells in Low Permeability Gas Reservoirs

PH gas field, which located in East China Offshore, has the characteristic: Prematurely Senile Appearance. That means it is currently in the middle period of development, but has many features of the later period of the gas field's life. In order to compensate the reduction of gas production, the development of low permeability gas reservoirs has been carried out these years. Low permeability gas reservoirs which distributed in the lower stratum have the permeability ranges between 0.3 mD similar to 1 mD. Developing practice shows that the reservoirs with permeability lower than 1 mD haven't natural productivity to maintain regular production. As a result, researches and practices of reconstruction and fracturing had been implemented during the past years. In recent researches, calculation methods related to productivity, reservoir selection and fracturing design etc. were developed and applied, while the equations and analysis methods in accordance with the practice were presented in this paper.