The transportation planning of oil products in Brazil's multimodal network is a complex problem that involves various negotiations between decentralized entities in order to agree on which products to transfer, their amounts, and the allocation of shared resources. Due to such complexity, there is a clear need for a decision support tool. This paper presents a model for solving this problem based on a new multi-agent auction protocol. The developed model is used to solve a real scenario of the Brazilian oil supply chain in a multi-level topological approach.