The pickup and delivery problem with time windows in the oil industry: model and Branch-and-cut methods

Abstract

This paper addresses the routing and scheduling problem of vessels that collect crude oil from offshore platforms (located in the ocean) and transport it to terminals on the coast. This problem is motivated by a case study carried out in an oil company that operates in Brazil. Based on this study, we propose a mixed integer programming model that extends the classical pickup and delivery problem with time windows. This problem belongs to the NP-hard class and its solution is very challenging in practice. To model specific features of the addressed case, we include new constraints in the classical formulation, which makes it even more challenging for general purpose optimization solvers. To overcome this, we propose two Branch-and-cut methods that use valid inequalities especially developed for the oil company case. Computational results performed with a real data set provided by the company show that the proposed Branch-and-cut methods are effective and able to solve more instances than a state of the art general purpose optimization solver.

Keywords:
Pickup and delivery problem; Ship routing and scheduling; Oil industry; Branch-and-cut method