Business transactions are governed by legally established contracts. Contractual obligations are to be fulfilled by executing business processes of the involved parties. To enable this, contract terms and conditions need to be semantically mapped to process concepts and then analyzed for compliance with existing process models. To solve the problem, we propose a methodology that, using a layered contract ontology, deduces contract requirements into a high-level process description named Contract Workflow Model (CWM). By applying a set of transformation rules, the CWM is then compared for compliance with existing, executable process models. By the use of its concepts, the methodology enables comprehensive identification and evolution of requirements for interoperability of processes of the contracting parties.