A petroleum reservoir production modeling apparatus and method is disclosed which incorporates a complete (from reservoir to wellhead) production systems analysis system for the evaluation of petroleum reservoir production performance, using industry accepted techniques of analysis. A computer generated model facilitates the determination of well and formation properties in a computerized methodology, efficiently, reliably and accurately, thereby facilitating subsequent changes in wellbore properties to maximize well production. The method includes a rigorous analytic reservoir inflow performance model for a variety of well types and reservoir outer boundary conditions and drainage area shapes, and uses industry accepted production analysis techniques. These techniques accepted in the industry include material balance, decline curve analysis, and non-linear minimization procedures. Field-recorded production data is evaluated to obtain estimates of the well or formation properties. Statistical techniques are used to minimize or eliminate the effects of outlier (i.e. noise) points in the data.