Case 2: Optimization of a Multiobjective Natural Gas Production Planning

Barton and Selot [27] formulated a nonconvex MINLP model For the upstream nat­ural gas production system, which has been considered from the wells to the lique­fied natural gas plants (excluding the plants). The upstream production-planning model involves two important components, including the model of actual produc­tion facilities and networks (the infrastructure model) and the customer require­ments (the contractual rule model). In this model, the natural gas network has been presented as a multiproduct network with nonlinear pressure-flow rate relations in the wells and the trunk line network. Moreover, production-sharing contracts (PSCs) and operational rules have been considered. The developed model, which comprises three objective functions, is a relatively large nonconvex MINLP (sev- ^eral hundred continuous variables and tens of binary variables). Maximizing dry B^as production to satisfy contractual demands, maximizing Natural Gas Liquid (NGL) production to increase revenue for the upstream operator, and prioritizing Production from certain fields are the objectives that the model seeks to achieve ^lhem. Because it was not possible to obtain global optimization approaches directly, the model has been reduced through a reduction heuristic and solved by _a global branch-and-cut algorithm.

The result of applying the developed model in a real-world case study i_n Malaysia indicates its efficiency in increasing the secondary products production achieving optimal long-term asset management beside satisfying contractual requirements of gas supply and customers in short term.