This page explains what it takes to run a mobile gas turbine on associated gas, from the wellhead gas to the switchgear, and when it makes sense.
Why associated gas is a fuel and a problem
Associated gas is valuable energy, but it is rarely clean. It can carry heavier hydrocarbons that condense as liquids, water, hydrogen sulphide, carbon dioxide and variable heating value as wells change. Turbines are less forgiving of liquids and contaminants than reciprocating gas engines, so the gas must be treated before it reaches the combustor. The supply also changes over time as production rises and declines, which affects how much power the field can generate.
The gas-to-power chain
- Gas analysis: a full composition, including heavier hydrocarbons, sulphur compounds and water content, sampled more than once.
- Separation and scrubbing: remove free liquids and solids at the inlet.
- Compression: aeroderivative turbines typically need fuel gas at higher pressure than field gas lines deliver, so a compressor package is common.
- Conditioning: dew point control, heating to keep the gas above its dew point, and filtration to the turbine maker’s fuel specification.
- Metering and control: flow, pressure and heating value measured continuously, with shut-off valves and fuel control.
Our page on fuel quality in the field covers the specification side, and fuel skid quick connect covers the hardware.
Why mobile units suit oilfields
Trailer-mounted aeroderivative units such as the GE TM2500 were designed to be moved, set up quickly and run as prime power. On an oilfield that matters, because the gas may last only for the life of a group of wells, and the power may be needed at a different pad later. Mobile units can be redeployed when production shifts, and their compact footprint suits pads and gathering stations. Our TM2500 explainer covers the unit itself.
Some fields need both: mobile turbines for flexibility and speed, and permanent plant once the reserves and demand are proven.
Siting and electrical integration
Place the turbine close to the gas source to keep fuel lines short, but outside hazardous zones around wellheads and process equipment. The units need a level, firm pad, access for heavy haul, and space for the fuel gas skid, control trailer and step-up transformer. Electrically, the plant may run an isolated field network, feeding electric submersible pumps, compressors and camps, so the controls must hold frequency through large motor starts. Battery storage or a few reciprocating engines alongside the turbines can help with load steps.
Emissions and permits
Replacing flaring and diesel with turbine power usually lowers emissions overall, but the turbine still needs an air permit or an exemption under local rules, and some regulators require flare reduction plans that power projects can support. Hydrogen sulphide must be dealt with before combustion, both for the turbine and for exhaust emissions. Our page on mobile GT emissions permitting sets out the process.
Operating on variable gas
Associated gas changes as wells come on line, decline or are worked over. Composition can shift, and so can the volume available. The fuel control and conditioning system should be specified for the range of compositions expected, not just one sample, and the operators should watch heating value and dew point trends as closely as output.
When gas supply falls below what the turbine needs, the plant must either reduce load, switch to a backup fuel where the unit supports it, or shed load in a controlled way. Planning that response in advance avoids trips that stop production. Some projects combine a mobile turbine with gas engines, so smaller units can carry the field as gas declines and the turbine moves on.
Regular gas sampling, filter changes and inspections of the conditioning skid are part of the maintenance plan from day one, alongside the turbine’s own routine.
Making the business case
| Factor | Question to answer |
|---|---|
| Gas volume and decline | How much gas is there, for how long, and how variable is it? |
| Power demand | What loads can switch from diesel to electric supply? |
| Gas treatment | What conditioning and compression does the composition require? |
| Diesel displaced | How much trucked fuel and logistics cost disappears? |
| Regulation | Do flare rules or emissions credits change the economics? |
| Redeployment | Where does the unit go when this field declines? |
We look at the whole chain as an EPC and O&M contractor, from gas treatment to the field network, and our comparison of gas turbines and reciprocating engines helps decide which machine suits the gas and the load.
USP&E for oilfield power
From gas conditioning to the field network, USP&E takes on the whole chain: supply, installation, commissioning and operation of mobile and permanent gas turbine plants. Our project record covers 150+ power projects in 45+ countries, and we have contracted 25,000 MW since 2002.
Offices: Colorado Springs (1755 Telstar Dr, Suite 300), Knoxville (800 S Gay St, Suite 700), London (162-168 Regent Street), Johannesburg (22 Kildoon Rd, Bryanston), Cape Town (31 Brickfield Road, Woodstock) and China (No. 1 Ningzhou Road, Wuxi). Regions: USA | AFRICA | UK | UAE | CHINA. ISO 9001 and ISO 45001 certified.
Associated gas power FAQs
What is associated gas?
It is natural gas produced alongside crude oil from the same wells. Where there is no pipeline or market, it is often flared.
Can a mobile gas turbine run on associated gas?
Yes, once the gas is separated, compressed where needed and conditioned to the turbine maker’s fuel specification, including removal of liquids and sulphur compounds.
Why not use gas engines instead of turbines?
Gas engines tolerate lower-pressure and more variable gas and suit smaller loads. Turbines offer high output in a compact, mobile package. Many fields use the option that best fits their gas and demand, or a mix.
Does turning flare gas into power reduce emissions?
Usually yes, because it can replace both flaring and diesel generation, but the turbine still needs to meet local air permit rules.
What happens to a mobile turbine when the field declines?
It can be moved to another field or site, which is one of the main reasons operators choose mobile units for associated gas projects.
Turn your flare into power
Send us your gas analysis, production forecast and power demand and our engineers will assess the gas treatment, turbine options and project path.
Reach our team on +27 10 822 2324, by email at info@uspeglobal.com, or through the gas turbine team. See available units on our natural gas turbine inventory.
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