Figure 3.1 shows a typical modern gas well, with the wellhead, gas?liquid separator, instrument shed, and condensate tank. Figure 3.2 shows the electronic flow meter, along with the solar collector that powers electronic transmission of the data. The wellhead is in the background. Most companies use electronic metering. However, some wellheads still have circular chart recorders to measure flow rates. The meter is where the gas processor purchases the gas from the producer and the lease royalty owner. Often, the producer and gas processor belong to the same company. If the gas is nonassociated, hydrocarbon liquids knocked out in the separator may be remixed with the gas or stored in a tank and removed by truck. Usually, no compression is applied before the gas is sold.
If the gas is being stripped from oil, separators knock out both oil and water. For high-pressure wells, the oil passes through up to three separators to recover the light ends. Because the last-stage separator is near ambient conditions, the gas may be compressed before it flows into a gathering line to the gas plant.
Frequently, several wells from one lease are tied to one separations unit to reduce the number of separators, compressors, and meters. This practice is especially true in offshore operations because producers need to minimize the number of platforms and platform weight for cost purposes.