Ask HN: Any ideas on solving a flow network?

Problem: In O&G upstream oil produced from well flows from network of pipes and various modalities(Oil, Gas and Water) are measured at different points using meters. The actual production are then back allocated to the actual wells.

These networks can get very complex with thousands of wells in a producing field and many measurements.

An analogy to this problem could be water distribution in a city or traffic flow in a city?

Any libraries or open source frameworks which solves these problems optimally?