Risks and buffer analysis in critical chain management by system dynamics (Case study: Oil refinery)

In this paper, risks in oil construction projects are identified, analyzed and considered for buffers in system dynamics modeling. To do so, all important and effective variables and risks within an oil construction project are determined, including internal and external variables and then, conceptual model is developed using system thinking approach. Based on the conceptual model, state and flow model is obtained and the relations between variables are established. In order to show efficiency and effectiveness of the proposed method, a real case study is considered and solved. Moreover, sensitivity analysis is provided, by using real data and this model. The primary goal of this research is to investigate the impact of different risks that exist in oil construction risks on key variables; these key variables include human resources, facilities and materials. The results demonstrate that the initial plan of each resource is not consistent with the actual need of them. In other words, based on the existing risks in the model, the proposed approach determines what level the actual resources requirement would be placed at and given existing risks, which buffer should be considered for each resource. Furthermore, the impact of risks in performing activities is forecasted and the model shows what impact the risks have on the delay in initial progress of the project as time passes. Finally, it is studied how changes in key and input variables affect the all project.