Study On Productivity Evaluation Of Gas Wells In X Volcanic Condensate Gas Reservoirs

As a new development field, volcanic rock gas resources are abundant and have a broad prospect. Compared with conventional gas reservoirs, volcanic rock gas reservoirs developed a multiple media including pore, vug and fracture. There are no suitable percolation mathematical models and productivity prediction methods for volcanic rock gas reservoirs with multiphase flow for the poor reservoirs property and complex percolation mechanism.With the study of the X volcanic gas reservoir, researches on the nonlinear percolation mechanism have been done. Considering its characteristics of condensation and water production, nonlinear percolation mathematical models and productivity prediction methods for volcanic rock gas reservoirs have been established in this paper. In this paper, the author based on investigation and research on the productivity of gas condensate wells and fractured gas wells, combined with the basic characteristics of X volcanic gas reservoir and percolation mechanism, established the gas-water and oil-gas seepage flow model which considered stress sensitive effect and start-up pressure in matrix and stress sensitive effect and high-speed non-Darcy effect in fracture. On the basis of those mechanisms, the productivity models for fractured vertical well and fractured horizontal well were established respectively by introducing elliptical coordinates and pseudopressure, using superposition principle of potency and equivalent wellbore diameter. The productivity models were validated through X volcanic gas reservoir typical wells, and then analyzed factors that affect the production capacity. Finally, based on the analysis of principle of empirical method, system analysis curve method, gas recovery curve method and liquid carrying calculation method, combined with productivity models and wellbore pressure calculation model, the rational proration for fractured wells have been calculated and selected.The research in this paper can offer some theoretical guidance for productivity prediction and rational proration of low permeability volcanic gas reservoir fractured vertical wells and fractured horizontal wells. And provide valuable references for the development of similar gas reservoirs.