Systems and methods for determining operating settings of a fluid production system with a gathering network and a plurality of reservoirs, at least some of which include a method that includes lumping common pseudo-components into reservoir pseudo-components associated with each of the reservoirs. Each common pseudo-component is associated with the gathering network and maps to one reservoir pseudo-component of each of the reservoirs. The method further includes performing at least part of a fully-coupled simulation of the gathering network and the reservoirs using the common pseudo-components to obtain one or more operating settings that meet one or more constraints of the production system, and presenting to a user the operating settings.