Abstract:

After the dry gas reservoir with low and extremely-low permeability,but without identified edged and bottom water has been produced for a period,the formation pressure of different areas decreases inhomogeneously,while the gas saturation (S_g) changes slightly,which can not be used to describe accurately the distribution of remaining gas.Therefore,the formation pressure in production process is usually used to describe qualitatively the distribution of remaining gas.According to the state equation of real gas and the definition of recoverable gas reserve,the functional relation between produced degree of recoverable gas reserve (K) and formation pressure (P) has been established,by which the formation pressure distribution during production process can be transformed to the distribution of produced degree of recoverable gas reserve, realizing the quantitative description of remaining gas distribution.

Key words: remaining gas, reservoir, low-permeability gas reservoir, dry gas reservoir, produced degree of recoverable gas reserve