The goal of any pumping operation is obviously to sell oil. Once the fluid produced from the well has been separated, and the crude oil has had enough sediment and water removed to meet the buyer’s standard, it’s ready to be sold. The sales system is everything after the stock tank, all of the lines that bring the oil to the transport system.
Obviously, this is an important part of the operation, and of the tank battery. This is particularly true as the sales system has to meet standards set by specific regulations. It’s where the interests of the pumper, the owner of the mineral rights, and the buyer of the oil all meet, and so the regulations are very strict to protect all concerned.
Common Requirements For The Sales System
The valves on the sales system are usually required to be sealed when not in use. Seals can be flat, locking the valve, or use wire and a lead seal. They’ll usually have some information on them, including the name of the purchasing company and a serial number. All these seals have to be accounted for, and if you remove one for any reason, you should hang on to it. You’ll almost certainly be required to return it and explain why it was removed.
The tank openings for the sales lines are usually about 12 inches from the bottom of the tank, allowing room for emulsion to collect there. Sales lines are usually 4-inch diameter pipe.
Figure 1. Diagram of a tank battery. The sales system is labeled with an S.
Transporting By Truck
Trucks are common when a pipeline isn’t economical, or can’t be run for some other reason. The truck will connect to the sales system using flexible hoses, and while there can be some loss it’s usually quite small. There should be a grounding post near the sales opening for the driver to connect to, which will help to prevent sparks.
Figure 2. A sales system set up to sell by truck transportation.
In Figure 2, you can see the sales lines for a tank battery, as well as the tank for holding sales oil and a water tank. This operation is also set up to dispose of water through truck transportation, and so there are lines to the water tank as well. These lines are at the standard 12 inch height. The sales oil tank is sealed, as is required. There’s also a riser, which you can see to the left of the sales oil line valve. That allows the valve to be controlled from the ground, so you don’t have to spend as much time near the thief hatch. Fumes there, particularly when there’s hydrogen sulfide, can be dangerous.
Figure 3. A mailbox near openings to allow truck transport. This allows you to exchange receipts and other paperwork.
You’ll usually need to be there when the truck driver is hooking up the sales tank. However, that’s not usually the case when water is being trucked out. A mailbox is shown in Figure 3, so that the you and the lease pumper can communicate and leave paperwork.
Transporting By Pipeline
The sales system will often lead directly to a pipeline owned by the purchasing company. With this setup, using a Lease Automatic Custody Transfer (LACT) Unit allows oil to automatically sent through the sales system and sold. The stock tanks that feed into the sales system essentially act as surge tanks, then, with crude oil flowing into the stock tanks until enough oil of sufficient quality has been collected. The LACT Unit will activate and sell oil through the pipeline. When the level of oil eventually falls low enough, the LACT Unit will shut in the tank. There’s usually two switches inside the tank to activate the LACT Unit, one about 2 feet off the bottom, and a second one or two feet higher. This setup prevents gas from being sucked into the sales line, and is generally pretty reliable.
Figure 4. An LACT Unit from two angles.
Is your appetite for oil & gas operating knowledge insatiable like ours? 😀 If so, check out these related articles below – they’ll be sure to pump you up!!!
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