Measurement is the contract
Crude oil is bought and sold by volume corrected for temperature, gravity, and impurities. At a lease tank, the volume is read from a gauge and a strapping table, the temperature is read from the tank, and the quality is defined by a sample. The run ticket that comes out of that process is the legal record of what changed hands. If the ticket is wrong, the barrel count is wrong, no matter how good the truck is.
The industry's measurement practices are documented in the API Manual of Petroleum Measurement Standards, and the field habit that matters is simpler: measure every time, sample every time, and write the ticket at the tank, not later from memory.
The chain from tank to ticket
An open gauge gives a level, and the strapping table converts level to volume. That volume is gross, at tank temperature. The net volume for the ticket applies temperature correction and the API gravity correction to move the barrel count to standard conditions. The BSW sample determines how much of the volume is water and sediment, which the buyer deducts.
Every step is an error opportunity. A gauge read at the wrong hatch, a strapping table from a previous tank modification, a temperature taken at the wrong depth, a sample from the top of the tank instead of the middle, a gravity number from last month. Each one is small. Together they decide the barrel count.
The run ticket as evidence
The run ticket records the load: lease, tank, gauge, temperature, gravity, BSW, volume, time, and the signatures of the pumper and the driver. A ticket missing a signature, missing a time, or filled from memory is a dispute waiting for an operator's back office to find it.
Disputes over barrels are expensive because they are argued weeks after the fact, when nobody remembers the tank level and the only evidence is the paper. The operator holds the leverage, and the hauler holds a ticket that may not survive scrutiny.
Where the losses hide
Shrinkage between the lease and the buyer is normal and expected to a point: temperature change, vapor loss, and handling loss are physical realities. The losses that hurt are the controllable ones. A leaky valve on the truck, a driver taking a sample after the load has settled instead of before, a pumper guessing the gauge on a tank too dangerous to climb.
Loss control in crude hauling is mostly process control: consistent gauging, consistent sampling, sealed compartments, and tickets written at the tank with the numbers actually read.
The ops tie
The run ticket is the first document in the billing chain, the same chain that stretches to 14 days or more when it runs on paper. A digital ticket captured at the tank, with the gauge and the sample photo attached, turns a disputed barrel count into a closed record.
If run tickets are still paper and the tank numbers live only in a logbook, an operations audit will show what the measurement chain is costing.