Study on the Optimization of Intermittent Production for Hydraulic Fractured Vertical Wells in Tight Gas Reservoirs
摘要
The formation of tight sandstone reservoirs is characterized by low porosity, low permeability, high water saturation, and strong heterogeneity. In the later stage of tight gas well production, the gas supply rate of the low-permeability area is lower than the gas production rate of gas wells, which leads to the failure of continuous production of the gas well. The recovery of the gas reservoir will be seriously affected. The recovery of gas reservoirs and the producing reserves of gas wells can be improved by reasonable intermittent production working system, which was proved by the development practice. Consequently, it is of great significance to study the optimization theory of tight sandstone gas well intermittent production working system, which can improve the management level and recovery rate of tight sandstone gas wells. Based on the full investigation and laboratory experiments of the fluid flow through the porous medium mechanism of tight sandstone reservoirs, a mathematical model was established, which considered the threshold pressure gradient and stress sensitivity. Then the model was solved by Laplace transformation, perturbation method, and Stehfest numerical inversion method. And the optimization method of seepage theory of intermittent production working system is established. The intermittent production working system of different types of parameters was demonstrated. Finally, a series of charts for the optimization of the gas well intermittent production was formed, which provided a theoretical basis for the management of the tight gas wells. The following understandings have been obtained by the research of this paper.