Production decline prediction modelling and application in shale gas reservoir

Shale gas reservoir is usually developed by multi-fractured horizontal well, and stimulated reservoir volume dominates the gas rate as the main factor. For the heterogeneity of formation, both size and distribution of each fracturing area are not uniform. To investigate effect of heterogeneous fracturing on rate decline of multiple fractured horizontal well in shale gas reservoir, by introducing the parameters of different stimulated area’s size and location in equations, a mathematical model based on horizontal well flow equations is established. Analytical solution and rate decline curve for model are presented then. The flow regimes are divided in gas rate dechlin curve, and curves characters of different un-uniform fracturing types are analyzed. The result shows that heterogeneity of fracturing affects production rate and linear flow stage. With more heterogenous of fracturing, the gas rate becomes fewer and duration of linear flow period is longer. Example analysis shows that the model can be used for production prediction of multiple fractured horizontal wells. This approach provides a theoretical basis on production flow decline prediction.