A Practical Algorithm of the Steady Development Period and the Declined Production in the Deep Gas Reservoir

Deep gas reservoirs are characterized by high temperature and high pressure, when the gas reservoir is developed, the development indexes should be reasonably controlled. Gas production velocity and steady development period are two important indexes which influence the exploitation scale and economic efficiency in the gas field development, deepening the theoretical understanding of them has the important practical significance. This paper carries out the research into functional relationship between the gas production velocity and steady development period of high pressure gas reservoir by making use of numerical simulation software, obtains the functional relationship and analytical expressions between them by combining the deliverability equation and the material balance equation of high pressure gas reservoir. The research shows that, when the gas reservoir pressure is greater than 13.79 MPa at the end of steady development period, the gas production velocity is roughly in double-curve relationship with the steady development period; when the gas reservoir pressure is less than 13.79 MPa at the end of steady development period, the gas production velocity is roughly in straight-line relationship with the steady development period, The above functional relationship can further predict the declined production of the gas reservoir.