Oil
Find a seep, chart it, hold a tap and sell the oil in metal drums.
Oil comes up in only a few places past the wall: seeps, pin-holes into the hydrocarbon world that the Cascade left open deep in the crust. A seep never runs dry, and never gives more than it can pass. The short version is on the Dark Zone page on the site.
The seep
A seep is one chunk. Deep under it, just above the bedrock, lie a few seep blocks that nothing breaks. A Diesel Generators pumpjack draws oil only when its pipe runs straight down onto one of them; over bedrock anywhere else it draws nothing. How many seep blocks a seep has is how many pumpjacks can stand on it at once.
On the surface you know a seep by the eternal flame burning the sour gas over an abandoned oil site — the smoke stands over it from far off — with a sulphur vent and a pool of tar beside it. The site depends on the layer: a derrick with the flame on top, a fenced wellsite, a trestle over the sea, or a burning pit. The air there is sour, so come masked.
Find
A gas detector says how near a seep is and never which way. The survey archive and old maps found in caches say which stretch of ground to search.
Chart
A seep goes on the register only as paper. Hold a survey notebook up while standing in its chunk past the wall, carry the survey report home and use it in the Safe Zone.
The first report filed charts the seep under the name its filer gives it. Every map shows the cell it lies in, and the exact point goes to the filer and everybody in their groups; a later report gives its own filer the point.
Charting a seep does not make it yours: nobody owns a seep past the wall.
Every week the register publishes each charted seep's last week — how much of its cap was drawn, how long it stood dry and how long full — and never who drew it.
Hold
A seep's pressure comes back at its own flow, up to a few hours of it, and holds there: nothing more comes while it stands full. In a week it gives at most its weekly cap, and the week's turn clears only that count, never the pressure. So a seep gives its week to whoever holds it and keeps drawing, and a raider finds at most what stood waiting. An oil scanner says how much pressure stands in a seep now.
How much of the flow a plant takes grows with its pumpjacks, their speed and their arms, and a deep seep asks for a big plant. But each pumpjack is held to its share of the flow, so only a plant with a pumpjack on every seep block takes a seep's whole flow.
Taps
Each seep block with the column over it is a tap, and every tap has its own part of the seep's week. A tap is held by a wellhead set on it, and by somebody coming back to feed its seal lubricant from a grease gun. A pumpjack draws only through the wellhead that holds its tap, and only if the hole on it was set by the wellhead's own side.
A fed seal cannot be broken, blown up or pushed — only cut, with a cutting torch. Each new cut burns a drum of gasoline from the cutter's pockets, and while it runs the wellhead throws smoke and a noise heard a long way off. The cut is lost, fuel and all, if the cutter steps too far off, dies or runs out of time, or if anybody not on the cutter's side feeds the seal: showing up is how a holder answers a cut. A finished cut always works: the tap passes to the cutter's side.
A seal left unfed past its hours goes slack, and a slack wellhead breaks in anybody's hand and drops to them.
One tap of every seep but the Heart's is the wild throat: it takes no wellhead and draws a small share of the seep's week for anybody.
A tap is held from a house built over it: a sealed room a scrubber serves round the taps, a bed inside, spare parts in a chest.
Pumps, pipes and walls past the wall are anybody's to break, and the register records none of it — only a well log of your own, set beside the wellhead, does. Killing the pumper is still a killing: the killer is hunted like any other.
The field lives
Once a week the Heart breathes: on the day its layer is told at the week's turn, a seep's flow is multiplied for a few hours, at an hour nobody is told — and its week's cap does not move, it is only reached sooner. With each new season the throats drift: a layer's flow and cap stay whole, but its seeps share them anew.
And Tlin walks towards noise: while anybody is near a seep drawn to its cap week after week, the dead gather round it, and in the end a warlord. Quiet weeks send them off again.
Sell
Oil past the wall is nothing to the register until it comes home: it is counted where it crosses the line. An oil terminal is set down on this side of the line, and metal drums are handed in to it — by hand or from a train. Every drum goes into your storage (or the terminal owner's, when a train unloaded it), and the hauled oil among them is counted as having crossed; that is the week's figure on the market's Oil tab, and what the week's haulers are named for.
Oil trades on the market in metal drums, and the market's Oil tab follows their prices; a filled canister or oil barrel cannot be listed. It can be sold by contract too: the oil itself with a delivery term, a survey or a share of a seep with the Survey sale and Seep share terms.
The bulk road for oil is the railway: a tank car of Create fluid tanks, or drums riding a train. Past the wall a track is anybody's to break, and the register sees none of it. A pipeline can run all the way home, and a pipeline meter counts what flows through it; anybody can splice into a pipeline.