Advanced oil processing turns 100 crude oil into 25 heavy oil, 45 light oil, and 55 petroleum gas [1] — and that exact split is why a badly-planned refinery locks up. Heavy oil accumulates faster than most new setups can crack it, the storage tank behind it hits its ceiling, and the whole refinery backpressures to a stop mid-cycle. The fix isn’t more storage tanks. It’s building cracking capacity at the ratio the recipe actually demands — 20 advanced oil processing refineries for every 5 heavy oil cracking and 17 light oil cracking plants [1] — before you ever turn the valve on.
This guide covers the path from your first pumpjack to a cracking loop that doesn’t jam, plus what changes the moment you leave Nauvis for a planet with no crude oil at all. If you haven’t left the ground yet, our Space Age beginner’s guide covers the milestones that come before this one.
Quick Start
- Place one pumpjack per crude oil field — only one can ever work a given field, so more pumpjacks on the same patch does nothing [2].
- Run Basic Oil Processing first: 2-4 refineries turning 100 crude oil into 45 petroleum gas each, no water required [1].
- Spend that petroleum gas on plastic and sulfur before touching heavy or light oil — basic processing alone covers most early blue-science needs.
- Switch to Advanced Oil Processing once ready to manage three outputs at once; it needs 50 water per 100 crude oil but pushes total petroleum output toward roughly 19.5/s once cracking is running, against 9/s from a lone basic refinery [1].
- Build heavy-oil and light-oil cracking chemical plants the same session you flip that switch — an advanced refinery with no cracking attached is the fastest way to deadlock a factory [1][6].
- Target the 20:5:17 build ratio (advanced oil processing : heavy oil cracking : light oil cracking), or the close-enough 8:2:7 version for a small base [1].
- Drop a storage tank after heavy oil and after light oil before it’s needed — treat them as active buffers against demand spikes, not just overflow catchers [5].
Basic vs. Advanced Processing: When to Make the Switch
Basic Oil Processing is the entire early-game answer: 100 crude oil in, 45 petroleum gas out, five-second cycle, no water, no byproducts to manage [1]. It covers plastic, sulfur, and the first blue science packs, and there’s no reason to complicate a base still running on two or three refineries. The cue to switch to Advanced Oil Processing is petroleum gas demand alone no longer justifying more refineries — advanced trades a flat 45 petroleum gas for a mixed 25 heavy oil, 45 light oil, and 55 petroleum gas per cycle [1].
That mix is why advanced processing intimidates new players — one output becomes three, and two of them need dedicated destinations or they pile up and stop the chain. Don’t flip the switch until the cracking plants go in during the same sitting; advanced processing with no cracking attached guarantees a heavy oil backup within minutes.
The 20:5:17 Ratio That Actually Balances
Advanced Oil Processing runs on a five-second cycle: 100 crude oil plus 50 water in, 25 heavy oil, 45 light oil, and 55 petroleum gas out [1]. Heavy oil cracking takes 40 heavy oil and 30 water and returns 30 light oil over 2 seconds; light oil cracking takes 30 light oil and 30 water and returns 20 petroleum gas, also over 2 seconds [1]. Run those as throughput per second rather than per cycle, and the balanced building ratio comes out to 20 advanced oil processing refineries for every 5 heavy oil cracking and 17 light oil cracking chemical plants — 20:5:17. Below mega-base scale, the simplified 8:2:7 ratio gets close enough that the rounding error disappears into the storage tank buffers [1].
Build at that ratio and heavy oil production matches consumption, light oil production (direct output plus cracked-in heavy oil) matches consumption, and petroleum gas comes out the other end without any tank creeping toward full. One advanced refinery paired with one heavy cracking plant and one light cracking plant — the 1:1:1-scale version most new bases actually build — nets roughly 19.5 petroleum gas per second once everything is cracked down, more than double a lone basic refinery’s 9/s [1].
Why Refineries Deadlock (And Why It’s Never the Refinery’s Fault)
A refinery doesn’t stall because it’s broken — it stalls because everything downstream of it is full. Petroleum gas is usually the first tank to top out, since it has the most competing uses (plastic, sulfuric acid, whatever else the factory is drawing on it for) and is the easiest to under-provision. Once that tank hits its ceiling, light oil cracking has nowhere to send its output and stops. Light oil backs up with nowhere to drain. Heavy oil cracking then has nowhere to send its light oil, so it stops too — and heavy oil, with nowhere left to go, backs all the way into the refinery itself, which stalls on its own output pipe [6].
This is also why lubricant is the first casualty of a deadlock: it draws from the same heavy oil now backed up solid. Players chasing a stalled base commonly find the real bottleneck sitting two steps downstream — a sulfuric acid or plastic consumer that quietly stopped running — rather than anything wrong with the oil setup itself [6].
The Circuit-Controlled Fix
The 20:5:17 ratio prevents the slow version of this problem: production matching consumption under steady load. It doesn’t protect against a temporary demand spike or a downstream consumer dropping out, filling a tank faster than a fixed ratio can respond to. That’s what circuit control is for. Wire a storage tank’s fluid level to the chemical plants cracking it, and gate cracking to run only with a comfortable reserve. A common community pattern: crack heavy oil only once its tank sits above roughly 20% full, and stop cracking light oil once its tank crosses roughly 80% full, so light oil never gets flooded by heavy oil cracking right as it’s already backing up [6]. It’s a heuristic, not an official value, but the mechanism holds — gating cracking on tank level turns a fixed-ratio system into one that reacts to what the factory is actually doing right now.
Storage Tanks Are Buffers, Not Just Overflow Catchers
A storage tank holds 25,000 fluid units and fills to the same percentage as whatever pipe segment it’s attached to [5] — so the moment a tank starts creeping upward on the map, the pipe network behind it is already under pressure, not just “getting full.” Placing one tank each after heavy oil, light oil, and petroleum gas before the buffer is actually needed gives headroom to survive a demand spike, plus a visible fill level to wire a circuit condition to. A base with no storage tanks on its oil outputs has no early warning system — the first sign of a deadlock is the refinery itself going idle, by which point every stage behind it is already backed up.
Off Nauvis: Fulgora and Gleba Don’t Have Crude Oil At All
Everything above assumes a Nauvis base, where crude oil comes from pumpjacks working a depleting field. That model breaks the moment you leave. Fulgora has no crude oil whatsoever — an offshore pump on the shore of its oil oceans pulls heavy oil directly, in infinite, non-diminishing quantities, no pumpjack required [3]. On a Fulgora base, the depletion math above doesn’t apply — the constraint is what to do with unlimited heavy oil, not how to avoid running out of it.
Gleba goes further: crude oil isn’t available at all, and there’s no coal liquefaction workaround unless coal is shipped in from another planet [4]. Plastic, sulfur, lubricant, and rocket fuel come from biological chains instead — bioplastic, biosulfur, biolubricant, and jelly [4]. More importantly, Gleba’s spoilage system means the storage-tank buffer strategy that keeps a Nauvis base alive works against you there: biological products spoil on a timer, so a large buffered stockpile doesn’t protect against a demand spike — it just guarantees lost product to spoilage before it’s used [4]. Anyone heading to Gleba next should treat throughput, not buffering, as the priority.
Squeezing More From a Depleting Field
Every crude oil field loses 1% of its yield per 300 pumpjack cycles, down to a floor of 20% of starting yield or 2 oil per second, whichever is larger [2]. A pumpjack on a fresh 100%-yield field pumps 10 oil per second; the same pumpjack depleted can be producing a fraction of that. Productivity modules scale their bonus with current yield percentage, so they’re strongest on a fresh field and progressively weaker as it runs down. Speed modules add a flat oil-per-second gain that doesn’t care about yield percentage, making them the better pick once a field drops toward roughly 60% yield and below, per community testing on the module math [7]. The practical version: productivity modules on fields just tapped, speed modules on the oldest, most depleted patches.
Priorities By Player Type
| Player Type | Priority |
|---|---|
| New player | Stay on Basic Oil Processing until petroleum gas demand outpaces two to three refineries. Don’t add cracking plants until ready to manage all three outputs at once. |
| Casual player | Build the simplified 8:2:7 ratio instead of memorizing 20:5:17 — the rounding error disappears into a couple of storage tanks and it’s far easier to lay out. |
| Hardcore / optimiser | Build the exact 20:5:17 ratio, wire circuit-gated cracking on every tank rather than trusting the fixed ratio alone, and track which pumpjacks have dropped below ~60% yield to know when to swap productivity modules for speed. |
| Completionist | Plan oil strategy per planet — Nauvis’s pumpjack-and-cracking loop, Fulgora’s infinite offshore heavy oil, and Gleba’s zero-oil bioprocessing chain are three separate systems, not local variations of one. |
When Not to Build Advanced Oil Processing Yet
Skip Advanced Oil Processing without reliable petroleum gas demand beyond plastic and sulfur. It adds two more products to manage for a benefit that won’t get used, and an idle heavy oil tank is a deadlock waiting to happen the moment a consumer arrives without cracking capacity to match. The signal to upgrade is running short on petroleum gas with the current refinery count — not a tech unlock.
FAQ
Why does my heavy oil tank fill up even though I have cracking plants?
Almost always because the tank downstream — light oil, or petroleum gas beyond that — is the one that’s actually full, and the backup has propagated upstream to heavy oil [6]. Check petroleum gas consumption first; adding more heavy oil cracking to a base where petroleum gas is the real bottleneck just moves the full tank one step over.
Should I build the exact 20:5:17 ratio or just eyeball it?
Eyeball it with storage tank buffers on a small base — the buffers absorb the rounding error from 8:2:7. Chase the exact ratio only once a base is large enough that a few percent of wasted throughput actually matters.
Do I need cracking plants if I’m only running Basic Oil Processing?
No. Basic Oil Processing never produces heavy or light oil, so there’s nothing to crack. Cracking only matters once Advanced Oil Processing is running.
Is coal liquefaction worth building instead of pumpjacks?
Only when crude oil is running low relative to coal supply, or on a planet like Gleba where crude oil isn’t available and coal is already being imported anyway [1][4]. On Nauvis with an intact field, pumpjacks are simpler.
Sources
- Official Factorio Wiki, “Oil processing”
- Official Factorio Wiki, “Pumpjack”
- Official Factorio Wiki, “Fulgora”
- Official Factorio Wiki, “Gleba”
- Official Factorio Wiki, “Storage tank”
- Factorio Forums, “How to avoid an oil deadlock”
- Factorio Forums, “Modules in Pumpjacks”
Verified against the current live Factorio 2.0 / Space Age recipes and mechanics as of August 2026. Recipe ratios and yield-decay values are stable across patches but worth a quick check against the in-game tooltip after a major update.
I've been playing video games for over 20 years, spanning everything from early PC titles to modern open-world games. I started Switchblade Gaming to publish the kind of accurate, well-researched guides I always wanted to find — built on primary sources, tested in-game, and kept up to date after patches. I currently focus on Minecraft and Pokémon GO.