The assessment of the success of a stimulation job often has a lot of uncertainties caused by the different viewpoints assumed by engineers. This paper presents a methodology to evaluate the success of workovers jobs, using common production data and well known equations. For wells in pseudo-steady state flow, assuming that the oil rate can be extrapolated using decline curve analysis, the effectiveness of the stimulation job is quantified in terms of additional oil reserves, changes in productivity index, removed skin and profits. A MatlabTM software application was built to calculate the declining parameters and two examples in the Brisas field (an oilfield located at the Southwest of Colombia) are used to illustrate the methodology.