With the growing use of user-oriented perspectives at requirements engineering, transforming requirements models into executable models is considered to be significant. One of the key elements in this perspective is the notion of scenarios; scenarios are used to describe specific behaviors of the application through a flow of events based on user-perspective. Since scenarios are often stated in natural languages, they have the advantage to be easy to adopt, but the requirements can then hardly be processed for further purposes like analysis or test generation; partly because interactions among scenarios are rarely represented explicitly. In this work, we propose a transformation method that takes textual description of scenarios as input and generates an equivalent Petri-Net model as output. The resulting Petri-Net model can be further processed and analyzed using Petri-Net tools to verify model properties, to identify concurrency problems and to optimize the input and output models. Demonstration of the feasibility of the proposed method is based on two examples using a supporting tool.