Impact of slippage effect and start-up pressure gradient on deliverability of low-permeability gas reservoirs

Based on the low-permeability gas reservoirs,through considering the slippage effect and start-up pressure gradient,the conformal transformation and mirror reflection and superposition principle methods are used to obtain a calculation model for the horizontal wells in this paper.By using the models,the influence of the slippage effect and start-up pressure gradient on deliverability of low-permeability gas reservoirs is contrasted,and the impact of the pressure squared differences on gas production and gas productivity index is analyzed and studied.The result shows that the deliverability of horizontal wells in low permeability gas reservoirs decreases with start-up pressure gradient at linear relationship,which increases with slippage effect at linear relationship.In the early stages of development,the effect of the starting pressure gradient is greater than slippage effect,and in the later stage of the development,the effect of the slippage effect is greater.