When a well is completed, it must be cleared of sand before it’s production can be lined up to the collection laterals. This is accomplished by “flowing-back”, or “flaring”, the well. For a typical gas well, this requires venting the tubing to the atmosphere for 3 or 4 days at a typical rate of 5… Read More »
Figure 2—2 shows how high pressure gas from the tubing side of dual completion can be employed to compress the low pressure casing gas. An ejector, an apparatus in common use in process plants, acts as a compressor without moving parts. The installed cost of the apparatus pictured in figure 2-2, is less than $10,000,… Read More »
By perforating the casing both below and above the packer, as shown in figure 2-1, a lease operator can produce natural gas from two different zones simultaneously. Thus, a dual completion can double the intiial gas flow from a well. If, as often happens, the formation being drained by the tubing is depleted first, a… Read More »
“Mendoza, this meter is broken”, I complained. “Every time we increase the compressors speed to pull-down the wellhead pressure, the recorded gas flow drops. I just raised the rpm from 375 to 425, and the wellhead pressure fell from 220 PSIG to 15 PSIG. But the metered flow decreased from 180 MSCFD to 150 MSCFD.… Read More »
One of the more puzzling phenomenon I have observed in gas field production happened during my tenure as an operator of wellhead compressors. One would intuitively assume that the faster the wellhead compressor ran, the more gas would be delivered through the sales meter. Normally, as the compressor speed was increased by manually screwing open… Read More »
Rapidly opening the wellhead valves on a high pressure well flowing into a low pressure collection system is a good way to ruin a well when the following two criteria are met: • The wellhead choke is large. • The well has been shut-in for a while. The surge of gas flow resulting from following… Read More »
Equation 5 implies that the lower the density of the liquid accumulating in the tubing, the lower the entrainment velocity. This means that less gas flow is required to keep a well unloaded of liquids, when the liquid density is reduced. Addition of soap sticks to a well is a simple method to reduce the… Read More »
The valve trim on the intermitter should be at least twice the diameter of the choke. When the intermitter valve opens it should not restrict gas flow from the well. Unfortunately, if the wellhead pressure builds to an excessive level, the sudden surge in gas flow when the intermitter opens may have two detrimental effects:… Read More »
Mr. Howlaway eyed my equations suspiciously, “I can see that you have developed a method to predict the combination of the gas production rate and wellhead pressure necessary to keep my wells from loading -up with liquid. But suppose the production rate that the reservoir can support is too low, or the wellhead pressure is… Read More »
When I first started troubleshooting partially depleted natural gas wells, I often wondered why so many of the hundred odd wells I visited were averaging 200-300 MSCFD. I had expected a more linear distribution between the minimum gas production per well (20 MSCFD). Actually, 30 to 40% of the wells I observed clustered around an… Read More »