Calculation Methods of the Dynamic Reserves for Gas Wells in a Low-Permeability Gas Reservoir

Accurately calculating dynamic reserves for single well in a low-permeability gas reservoir has an important guiding significance to high efficiency development of the gas reservoir. During the development of the gas reservoir, dynamic analysis methods were often used to calculate dynamic reserves. Dynamic analysis methods mainly include the material balance method, the gas production method in unit pressure drop, the flexible two-phase method and the production unstable method. Dynamic reserves for four types of gas wells in a low-permeability gas field were calculated using these four methods. Calculation results show that dynamic reserves from big to small are respectively obtained using material balance method, gas production method in unit pressure drop, flexible two-phase method and production unstable method. Calculating dynamic reserves obtained by flexible two-phase method and production unstable method are utilized to production dynamic data of gas well, and those obtained by material balance method and gas production method in unit pressure drop are utilized to the reservoir parameters of different state. Therefore, the values of dynamic reserves obtained using flexible two-phase method and production unstable method in the low-permeability gas reservoir may be more accurate than those obtained using the other methods.