Design, Build and Field Trial of Downhole Gas Compressor (DGC)
Problem:
As the gas well matured the pressure in it decreases, therefore, production flow rate reduces and at some point the well stops operating.
Solution:
In 2013 CET completed design and build of the downhole gas compressor (DGC) to operate deployed 2km into a gas well.
The 45kW DGC package consists of 3 compressors, each with a highly efficient mixed flow impeller directly connected to a permanent magnet motor suspended on gas bearings. They are driven by inverters built to operate in the harsh gas well environment. At the wellhead the package has a surface module communicating with the downhole equipment and powering/controlling the individual compressors.
Three variants of DGC were extensively tested in a clean natural gas flow loop in the north of England. Subsequently the DGC for the American customer was tested in a live gas well in Texas.
Results/Benefits:
The performed testing confirmed that implementation of DGC can extend the life of the gas well for another 2-3 years.
| Architecture | 3 stages, permanent magnet motor with gas bearings and downhole inverter driver | 3 stages, permanent magnet motor with gas bearings and downhole inverter driver |
| Process medium | Unfiltered, wet natural gas | Unfiltered, wet natural gas |
| Inlet temperature | 100°C | 70°C |
| Inlet pressure | 5barg | 15barg |
| Pressure Ratio | 2.2 | 1.5 |
| Rated Power | 45kW(Net) | 45kW(Net) |
| Rotational Speed | 52,500rpm | 60,000rpm |
Note: TPG D&T business was dissolved in 2017. Its core Technical Team, who pioneered this project formed C2 Technology, to continue D&T’s business of developing innovative technologies for energy industry.
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