GEOLOGICAL FACTORS AFFECTING GAS WELL DELIVERABILITY OF THE CARBONIFEROUS GAS RESERVOIRS IN EAST SICHUAN

The methods of determining gas well deliverability and of choosing and calculating geological parameters are introduced in the paper.The initial binomial open flow capacity,stable production and primary gas productivity index are adopted as the criteria of evaluating gas well deliverability.The parameters are:①reservoir effective thickness;②reservoir porosity;③reservoir volume efficiency;④fair pay′s reservoir volume efficiency;⑤distance to the fault;⑥reciprocal of the square root of the distance to the fault);⑦apparent fold strength coefficient;⑧maximum principal curvature of structural plane;⑨transversal section line curvature;and ⑩ longitudinal section line curvature.The characteristics of the geological parameters affecting gas well deliverability are analyzed and a correlation analysis of the gas well deliverability with the geological parameters is finished.On the basis of graphic cluster analysis of the gas well deliverability with the geological factors,the gas wells are classified and two models of high production wells are proposed,including①the wells in a reservoir with large thickness and medium porosity and a medium apparent fold strength coefficient;and ② the wells in a reservoir with medium thickness and high porosity and a large apparent fold strength coefficient.