Forecast of fractured horizontal well productivity in dual permeability layers in volcanic gas reservoirs

In view of the flow particularity of fractured horizontal wells in dual permeability layers in volcanic gas reservoirs, based on the equivalent flowing resistance method and superposition principle, a new productivity forecasting method for fractured open-hole horizontal wells with multi-transverse fractures in volcanic gas reservoirs is established using a new pseudo-pressure function, with the comprehensive effect of gas slippage effect, starting pressure gradient, stress sensitivity effect and turbulence effect in fractures taken into consideration. The simulation results show that in the production process of fractured open-hole horizontal wells, and the starting pressure gradient has the most remarkable impact on gas well productivity, followed by pressure-sensitive effect and turbulence effect. The slippage effect has the lowest influence. Production pressure difference in gas reservoirs with strong pressure-sensitive effect should be reduced. Gas well production increases as the fracture half-length increases. With the increase of fracture number, the increase of gas production slows down, there exists an optimal number of cracks. The factor affecting gas well production most significantly is fracture conductivity capacity. Different gas reservoirs have different optimal fracture conductivity capacity.