Abstract : In mainstream service orchestration platforms, the orchestration model is executed by a centralized orchestrator through which all interactions are channeled. This architecture is not optimal in terms of communication overhead and has the usual problems of a single point of failure. Moreover, globalization and the increase of competitive pressures created the need for agility in business processes, including the ability to outsource, offshore, or otherwise distribute its once-centralized business processes or parts thereof. An organization that aims for such fragmentation of its business processes needs to be able to separate the process into different parts. Therefore, there is a growing need for the ability to fragment one's business processes in an agile manner, and be able to distribute and wire these fragments together so that their combined execution recreates the function of the original process. This thesis is focused on solving some of the core challenges resulting from the need to restructure enterprise interactions. Restructuring such interactions corresponds to the fragmentation of intra and inter enterprise business process models. This thesis describes how to identify, create, and execute process fragments without loosing the operational semantics of the original process models. It also proposes methods to optimize the fragmentation process in terms of QoS properties and communication overhead. Further, it presents a framework to model web service choreographies in Event Calculus formal language.