The flowing mechanism of a low permeability gas reservoir is different from a conventional gas reservoir,especially for that with higher irreducible water saturation the threshold pressure gradient exists. At present,...The flowing mechanism of a low permeability gas reservoir is different from a conventional gas reservoir,especially for that with higher irreducible water saturation the threshold pressure gradient exists. At present,in all the deliverability equation,the additional pressure drop caused by the threshold pressure gradient is viewed as constant,but this method has big error in the practical application. Based on the non-Darcy steady flow equation,the limited integral of the additional pressure drop is solved in this paper and it is realized that the additional pressure drop is not a constant but has something to do with production data,and a new deliverability equation is derived,with the relevant processing method for modified isochronal test data. The new deliverability equation turns out to be practical through onsite application.展开更多
Calculating the absolute open flow potential timely and investigating production capacity so as to adjust working system of production wells is one of main means to effectively recovery gas reservoirs during intermedi...Calculating the absolute open flow potential timely and investigating production capacity so as to adjust working system of production wells is one of main means to effectively recovery gas reservoirs during intermediate and late development stage.In order to obtain the open flow potential of gas wells accurately,a new method which utilized a single steady point was proposed in this research,which was based on deliverability formula of a gas well in pseudo-steady state flow with pseudo-pressure form.The influence on factor B in binomial productivity equation caused by the changed permeability was taken into consideration.According to the stable production data,reservoir permeability K can be determined by iterative method firstly,and the coefficient A,B in binomial productivity equation can be calculated with the open flow potential subsequently.It illustrated clearly by a practical example that the new method was suitable for gas wells especially when the producing pressure drop is large.Additionally,the error between the open flow potential value and interpretation result from the multi-point test was small,which proved it to be more simple,economic and effective than the common one.展开更多
基金National Basic Research Program of China(2007CB209506)
文摘The flowing mechanism of a low permeability gas reservoir is different from a conventional gas reservoir,especially for that with higher irreducible water saturation the threshold pressure gradient exists. At present,in all the deliverability equation,the additional pressure drop caused by the threshold pressure gradient is viewed as constant,but this method has big error in the practical application. Based on the non-Darcy steady flow equation,the limited integral of the additional pressure drop is solved in this paper and it is realized that the additional pressure drop is not a constant but has something to do with production data,and a new deliverability equation is derived,with the relevant processing method for modified isochronal test data. The new deliverability equation turns out to be practical through onsite application.
基金Fund project:National Basic Research Program of China(973 Program-2014CB239205).
文摘Calculating the absolute open flow potential timely and investigating production capacity so as to adjust working system of production wells is one of main means to effectively recovery gas reservoirs during intermediate and late development stage.In order to obtain the open flow potential of gas wells accurately,a new method which utilized a single steady point was proposed in this research,which was based on deliverability formula of a gas well in pseudo-steady state flow with pseudo-pressure form.The influence on factor B in binomial productivity equation caused by the changed permeability was taken into consideration.According to the stable production data,reservoir permeability K can be determined by iterative method firstly,and the coefficient A,B in binomial productivity equation can be calculated with the open flow potential subsequently.It illustrated clearly by a practical example that the new method was suitable for gas wells especially when the producing pressure drop is large.Additionally,the error between the open flow potential value and interpretation result from the multi-point test was small,which proved it to be more simple,economic and effective than the common one.
