| Sulige belongs to tight gas reservoir,gas well fracturing is widely used,in order to maintain a high yield,the large production pressure difference,so the production yield rapid decline;Initial production yield includes the supply of high conductivity fracture,yield decreasing trend including the energy depletion of the near wellbore and the lack of formation supply;The deceleration decline characteristics in the later period reflect the balance of supply capacity and the increase of the effect caused by the failure of Downhole Throttle in different degrees.It is of great significance to study the variation law of gas well production and optimize the stimulation measures to improve the productivity of gas wells and optimize the engineering operation.In this paper,Sulige gas field is taken as the research object,the production casing is 3.5 inches,and the fracturing is put into operation at the initial stage of production.The early production of the pipe string is in the production of the 3.5 inch casing with the throttle.This kind of production string causes most of the oil well casing pressure data,in order to obtain these data a few wells have been used to obtain the pressure monitoring,there is gas effusion phenomenon.Dynamic analysis of gas well production in low permeability gas reservoir is used.The analysis of causes and characteristics of water gas reservoir of low permeability,this paper analyzes the mechanism of gas water two phase flow in low permeability reservoir is analyzed based on gas slippage effect,high velocity non Darcy flow,starting pressure gradient and stress sensitivity.The value of the effective gas permeability,the average viscosity of formation fluid and the control radius of gas wells in the low permeability gas reservoir are analyzed.The calculation of gas flow boundary and evaluation of gas well productivity are analyzed.The effluent gas well production decline analysis,The reasons for the decline of production and the geological cause of the decline are analyzed.Wellbore lift model is established,the calculation principle and example analysis of liquid carrying critical production are carried out.The method of calculating the pressure loss of the liquid filled wellbore and the evaluation of the liquid lift capacity is carried out.The dynamic analysis method of gas well and gas well is carried out.The integrated dynamic analysis method includes the following steps:the subsection decline analysis of production based on geological origin,the production history fitting and dynamic prediction based on stratum condition,and the comprehensive decline analysis to evaluate the development potential of gas well.The principle,advantages,limitations,improvement and analysis steps of the complex production decline analysis method are discussed.The example calculation of the production dynamic prediction of decline method is carried out.The results show that the fitting accuracy is improved.The typical single well numerical simulation parameter adjustment principle is the variation of the initial production reflects the formation of supply speed,by adjusting the permeability(0.01-2.5mD)to the fitting;In the middle and later stages of production,the change of the formation energy,which is the degree of depletion of reserves,by adjusting the width of the geological model(20-1000m)to achieve based on the distribution characteristics of sand bod.The numerical simulation shows that there is a good agreement between the single well controlled reserves and the test flow.The fitting results of typical wells show that the fitting degree is 97.4%,the minimum is about 63%,the average is about 89.5%,and the fitting degree of the 67 wells is more than 80%,accounting for the total number of wells,which meets the design requirements.The research method and the obtained knowledge have certain guiding significance to the production decline rule,the production history fitting,the dynamic forecast and the speed pipe string and the pressurization mining optimization design. |
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