TIGHT Dynamic Single Well Gas Reservoir Reserve Calculation Method

Accurate prediction and analysis dynamic reserves of single well in the low permeability gas reservoir, affect the low permeability gas reservoir objective synthetic evaluation gas well reasonable production, working system establishment as well as the low permeability gas field development well deployment and adjustment. It is the base to highly effectively and scientifically develop the low permeability gas fields. It is also the prerequisite to realize the low permeability gas fields’ long-term high production and stable production.The dynamic reserves calculation methods of gas or gas well is much, However, these methods for low permeability gas reservoir is poor applicable. Through literature research, this paper analyzes the basic principles and its adaptability of the widely used gas reserves calculation methods, including material balance method, pressure drop test method, pressure restore well test, production accumulation method. Material balance method is simple operation and widely used, but it is the poor practicability for low-permeability gas reservoirs. The pressure drop test method and pressure restore well test method need less information, and they are widely used, However, this method is applied to the choice of mobile phase is uncertain and limited. The production accumulation method can calculate reserves by use of gas production data, but this method is suitable for the late development of conventional gas reservoir, the research on the applicability of the low permeability gas reservoir has yet to be.Based on the study of dynamic reserves calculation method of the conventional gas well, the new method of the low permeability gas reservoir dynamic reserves of gas well is studied. The method of material balance equation combined with the productivity equation is very suitable for the low permeability gas reservoir which does not have steady well test and production data, it makes fitting both productivity and pressure to safeguard the final result. The method of transient pressure testing with material balance method, avoids the subjective choice of line and dependence of formation pressure; it makes sure the reliability of parameters by means of fitting pressure; in the process of calculation, it can constantly examine accuracy of the dynamic reserves to safeguard the final result. As productivities and pressures can’t always keep steady, the method of nonresistant with material balance method is based on Duhamel’s principle to safeguard the final result.Finally, the program of calculation of single gas well dynamic reservoir in the low permeability gas reservoir is compiled by Visual C++6.0, it is called prediction software. The western sichuan multiple gas Wells of low permeability gas reservoir dynamic reserves were analyzed by use of the software, the application effect is good, it proved that the results are reliable, and it is of important guiding significance for the low permeability gas reservoir.