Planning of an Offshore Well Plugging Campaign: A Vehicle Routing Approach

When a petroleum well no longer serves its purpose, the operator is required to plug and abandon (P&A) the well to avoid contamination of reservoir fluids. An increasing number of offshore wells needs to be P&A’d in the near future, and the costs of these operations are substantial. Research on planning methods in order to allocate vessels that are required to perform these operations in a cost-efficient manner is therefore essential. We use an optimization approach and propose a mixed integer linear programming model based on a variant of the uncapacitated vehicle routing problem that includes precedence and non-concurrence constraints to plan a plugging campaign. P&A costs are minimized by creating optimal routes for a set of vessels, such that all operations that are needed to P&A a set of development wells are executed. In a case study, we show that our proposed optimization approach may lead to significant cost savings compared to traditional planning methods and is well suited for P&A planning purposes on a tactical level