Productivity formula of horizontal well with gas and water production in ultra-high pressure and low permeability gas reservoir

The determination of gas well productivity is the basis of scientific and reasonable development of gas fields and has important guiding significance for gas well production allocation. According to the change of gas-water two-phase seepage law, the productivity equation of horizontal well with gas-water production in low permeability gas reservoir was established based on the theory of steady seepage, which was affected by stress sensitivity, formation damage and high-speed non-Darcy. The results show that the effective thickness, horizontal section length, permeability and well radius are positively correlated with productivity, while the water saturation, stress sensitivity, well control radius, skin factor and formation temperature are negatively correlated, and the water saturation and stress sensitivity have a greater impact on productivity.