Study On Productivity And Stable Production Capacity Of High-angle Gas Wells

High-angle gas wells are widely used in gas field development.The inclined well mining technology can economically and effectively develop gas fields with limited geological conditions and engineering conditions,and it is of great significance to accurately predict the productivity and stable production capacity of high-angle gas wells.In this paper,the high-angle gas well is taken as the research object.The gas reservoir engineering principle,the seepage mechanics theory(Mechanics of Fluids in Porous Media theory)and the numerical analysis method are used to establish the binomial equation of the high-angle gas well productivity.The calculation method of the pseudo-skin factor generated by the deviation angle is studied.A high-angle gas well production prediction method was developed and software was compiled.The main work done is as follows:(1)Established the productivity equations of high angle gas well under considering the impact of high-speed non-Darcy effect,under considering threshold pressure gradient,under considering stress sensitivity.Obtained the binomial productivity equation by introducing pseudo pressure.Programmed the software by using iterative methods and calculated the inflow performance relationship curve of the well bottom and then compared it with the common method.At the same time,analyzed the impact of threshold pressure gradient,permeability,terminal pressure and deviation angle on the inflow performance relationship curve of well bottom.(2)For the high angle gas wells,studied the pseudo-skin factors produced by the deviation angle of the well.The Cinco-Lee method,the Besson method,the Rogers-Economides method,the Zhang Zhenhua calculation method and the steady state model method are introduced to calculate the influencing factors of the skin factor and the anisotropy of the reservoir.At the same time,the calculation results of the five calculation methods are compared.(3)Combining the material balance equation and the binomial productivity equation,the production prediction calculation methods and steps of different working systems for high-angle gas wells are studied,which can calculate bottom flow pressure,daily output,cumulative production and formation pressure changes in high-angle gas wells.(4)Completed the writing and debugging of high-angle gas well production prediction software.Analyzed the impact of initial stable production yield,post-pressure pressure,start pressure gradient,stress sensitive effect,deviation angle,reservoir permeability and reservoir thickness on the high-angle gas well production and stable production capacity.Based on the previous research on the productivity of high-angle gas wells,this paper further deepens the research on the production and stable production capacity of high-angle gas wells,and provides a theoretical basis for the production prediction of high-angle gas wells.