Currently, most reserves estimates in horizontal wells drilled in unconventional environments are done using modified hyperbolic decline. However, most of the observed production data is recorded when the well is in linear flow, and as such b factors larger than one are frequently observed and terminal decline rates are based on estimations. Attempts at correct for this behavior such as modified power law decline tend to require just as many variables to match curves.
In this paper we will propose a method for decline curve analysis of wells that can be generalized to any well that has linear flow behavior. This equation can be integrated and shown to match curves as well as other methods of decline curve analysis and reserve estimation currently available. Lastly, the method will be shown to be highly robust and effective in a number of difficult to forecast environments.