A New Method for Forecast the Productivity of Gas Well under the Consideration of Pressure Sensitive Effect

In the development process of gas reservoirs, the effective stress increases with the decline in reservoir pressure, resulting in decreasing in the permeability and gas well productivity. Based on the rock body effective stress theory, the permeability stress sensitivity state equation which is under the Terzaghi effective stress has been modified. Based on Darcy percolation theory, com-bined with core stress sensitivity experiments, the gas well deliverability calculation equation considering the permeability stress sen-sitivity has been derivated; new gas productivity forecast method has been put forward. The influence of stress sensitive on the gas well productivity has been discussed with an example. The results show that the permeability stress sensitivity damage has influenced the gas well productivity significantly. When the stress sensitive effect becomes stronger, the production of gas well decreases more serious.