At the software development cycle, it is in the requirements analysis phase that most of the problems that can compromise the delivery time and the development and maintenance costs must be identified and resolved. In general, the requirements obtained in this phase have different relationships with each other. Some of these relationships, commonly called negative interactions, make difficult or impossible the progress of some activities of the development process. The detection of interactions between requirements is an important activity that may prevent some of these problems and avoid their propagation throughout the remainder activities. Most of the existent research in this area only focuses on the requirements phase, mainly in the identification of conflict and/or inconsistency interactions. This paper presents a semi-formal event-based approach to model and identify the interactions between requirements, investigating the interactions that influence the other phases of the software development process.