Abstract: A gas reservoir reserve determination is affected by the production data, reservoir pressure and property parameters of reservoir rock and fluid. The rock compressibility is mostly determined by lab measurement and Hall empirical equation that can be obtained from core analysis data. However, the Hall curve shows a wrong logic relation and prov ides abnormally high values of rock compressibility. With the new curve proposed by LI Chuan-liang, the rock compressibility usually appears low values in the porosity range of gas reservoir. This study indicated that the original gas in-place value calculated with the rock compressibility given by Hall curve or lab analysis will be underesti-mated obviously.

Key words: gas reservoir, reserve, rock, compressibility