Petroleum

Petroleum is a mid-game liquid resource used as a fuel, a chemical feedstock and a coolant. It appears naturally on maps that are sufficiently overheated (either through Crude Oil transforming under high temperatures or via Molten Slicksters spawning) and can be produced by refining Crude Oil or by Molten Slicksters. Petroleum’s physical properties—moderately low specific heat, relatively high thermal conductivity and a very large liquid temperature range—make it especially useful where a stable, high-temperature liquid is required.

Petroleum production and transformation follow specific conversions: Molten Slicksters yield Petroleum by consuming Carbon Dioxide (10 kg Petroleum per 20 kg CO2 per cycle). Crude Oil can be converted to Petroleum in an Oil Refinery at 50% efficiency (10 kg/s Crude Oil → 5 kg/s Petroleum + 90 g/s Natural Gas), or Crude Oil can be thermally cracked between about 403 °C and 542 °C for a direct 100% conversion into Petroleum. Heating Petroleum above 541.85 °C converts it to Sour Gas; cooling Sour Gas to about -164.5 °C causes it to condense into a mixture of roughly 66.6% liquid Methane and 33.3% solid Sulfur.

Petroleum’s practical uses are broad and include fuel, manufacturing feedstock and rocket propellant:

• It is consumed in the Petroleum Generator to produce electrical power and in Petroleum Engines / Small Petroleum Engines as rocket fuel; the Petroleum Engine trades some fuel efficiency for higher top speed and range and is constructed from Steel rather than Refined Metal.
• The Polymer Press converts Petroleum into Plastic.
• Several production buildings consume Petroleum: Blastshot Maker (for Blastshot), Exosuit Forge (for Jet Suits) with Jet Suit Docks using Petroleum to refill suit jetpacks, and the Molecular Forge where Petroleum combines with other materials (Isoresin → Visco-Gel Fluid; Fullerene + Gold → Super Coolant).
• Petroleum functions well as a coolant in mid-game systems because of its large liquid temperature range and higher thermal conductivity compared to water, making it suitable for heat exchange and for cooling devices such as Metal Refinery (where liquids absorb refining heat directly).

Practical notes for gameplay:

• Use Petroleum where a liquid must remain stable across wide temperature swings; its high thermal conductivity helps move heat away quickly even though its specific heat is lower than water’s.
• When refining Crude Oil, consider whether you need Natural Gas as a byproduct—Oil Refinery output includes Natural Gas at 50% efficiency.
• Convert Petroleum to Sour Gas (by overheating) if you need Methane and Sulfur downstream after extreme cooling, but account for the wide temperature range required.
• For rockets, prefer the Petroleum Engine when you need greater range or speed and can supply Large Liquid Fuel Tanks; pair with appropriate tank and module layouts to maximize range and utility.
• Liquid Naphtha is an available alternative in some map types: it is more viscous and can be better for liquid valves and certain cooling uses, and it has a slightly better specific heat and liquid temperature range than Petroleum, so evaluate which fluid fits a particular thermal or plumbing design.

Petroleum is a versatile mid-to-late-game resource whose role spans power generation, advanced manufacturing and thermal management; plan production chains and storage with its temperature thresholds and phase-conversion recipes in mind.