Abstract: Distribution of production data tends to be sparse in low permeability gas reservoirs. The traditional production decline analyses, no matter Arps or modified attenuation decline analysis, are all poor in forecast effect. This paper analyzes the standard deviation of the sample space set up by differences between the predicted and actual production data, finding out that in view of actual data of multi-section weak step distribution in low permeability gas reservoir, multi-section decline analysis results are far better than overall decline analysis, which is easy to attain in Excel, so being accurate and efficient. For low permeability and super-low permeability oil-gas reservoirs with sparse distribution of production data, this method is recommended for production decline dynamic analysis.

Key words: low permeability reservoir, decline, section, standard deviation