Across the world, vast quantities of natural gas sit trapped in the ground — discovered, but effectively unusable. These “stranded” reserves represent both an environmental liability and a missed economic opportunity. Thanks to advances in cryogenic gas recovery technology, however, many of these once-worthless gas wells can now be converted into a source of clean fuel, electricity, or exportable liquefied natural gas (LNG).
What Is a Stranded Gas Well?
A stranded gas well is one where natural gas has been discovered but cannot be used or sold, either for physical or economic reasons. Gas found alongside oil during drilling — known as “associated gas” — has historically simply been flared off, wasting a valuable resource and releasing greenhouse gases into the atmosphere.
Gas becomes economically stranded for one of two main reasons:
- Remoteness — the well is too far from a natural gas market to justify the cost of pipeline construction.
- Market saturation — the well sits in a region where local gas demand is already met, and exporting beyond that region is too costly.
These wells are often the first candidates to be redeveloped once existing, more accessible reserves begin to deplete.
Why This Matters Now
Global demand for LNG is rising quickly, as gas-consuming nations diversify their supply sources for energy security and seek to reach markets that pipelines simply cannot serve. This has fuelled growing demand for small-to-medium-scale LNG plants capable of developing gas from associated reserves and remote locations for local distribution and vehicle fuel use.
At the same time, environmental pressure to end routine flaring is intensifying. Regulators and resource owners increasingly view flaring as an unacceptable waste of value — and in many newly developed, remote fields, flaring is no longer even a permitted option.
Advances in process technology, standardised designs, and manufacturing efficiencies have significantly reduced the cost of small-to-medium-scale plants, making previously uneconomic reserves commercially viable.
Just How Small Can a Stranded Gas Project Be?
One of the most striking aspects of modern cryogenic recovery technology is how little gas is needed to make a project worthwhile.
A typical installation may produce as little as 20 to 40 tonnes of methane per day and still be commercially viable — with 20 tonnes per day capable of generating approximately 4.5 MW of electricity.
This means that even modest, remote reserves — previously dismissed as too small to develop — can now be turned into a functioning energy asset.
Understanding the Composition of Stranded Gas
Stranded gas is a combustible mixture of hydrocarbons, primarily methane, but often including ethane, propane, butane, and pentane, along with a variable mix of impurities. Because composition varies so widely from well to well, a detailed gas analysis is essential before any clean-up or liquefaction system can be designed.
| Component | Typical Range |
|---|---|
| Methane | 70–90% |
| Ethane / Propane / Butane (combined) | 0–20% |
| Carbon dioxide | 0–13% |
| Oxygen | 0–0.2% |
| Nitrogen | 0–16% |
| Hydrogen sulphide | 0–5% |
| Rare gases | Trace |
In cryogenic conversion to liquid methane, the ethane, propane, and butane fractions can often be separated and sold separately, adding additional revenue streams. Carbon dioxide, nitrogen, and oxygen must be removed prior to liquefaction — with all but carbon dioxide typically simply released after separation.
Choosing the Right Technology: CNG, LNG, or Power Generation?
There is no single “correct” way to exploit stranded gas. The best route depends heavily on how far the gas needs to travel to reach a usable market:
- Grid connection nearby — if the economics work, on-site power generation is often the simplest solution, since methane is relatively straightforward to use as a power-generation fuel.
- Distances under roughly 100 km — compressing the gas into Compressed Natural Gas (CNG) for road transport can be viable.
- Longer distances — converting the gas to a liquid via cryogenic Gas-to-Liquid (GTL) processing becomes the most practical option, since liquefaction dramatically increases storage density and reduces transport costs.
Cryogenic processing offers a particular advantage: it not only produces liquid methane, but also allows separation of the gas into its constituent hydrocarbon fractions — each of which may have its own commercial market.
How the Cryogenic Recovery Process Works
A cryogenic liquefaction facility for stranded gas is generally built around several key process components:
- Cold Box(es) — containing brazed aluminium heat exchangers, separator vessels, cryogenic piping, instrumentation, and valves. Propane pre-cooled systems may also include core-in-kettle heat exchangers.
- Mixed Refrigerant Compressor — driven by either an electric motor or a gas turbine, depending on site-specific requirements.
- Refrigerant System Vessels — installed on the compressor suction and discharge sides.
- Aerial Inter-Coolers and Condensers — to remove waste heat generated by the process.
- Cryogenic Liquid Collection and Vaporiser System — converting the stranded gas into a liquid suitable for off-site transport.
- Heavies Removal Column — included where the feed gas composition requires it.
The process cycle itself is typically either a single-mixed refrigerant process or a propane pre-cooled single-mixed refrigerant process, with the choice driven by a detailed comparison of capital and operating costs for each site.
Why Small-Scale Liquefaction Makes Sense
Small-scale LNG plants offer several practical advantages over large centralised facilities:
- Their compact footprint allows LNG production close to the point of use, cutting transport and product costs.
- They enable localised “peak-shaving,” balancing gas availability during periods of high and low demand.
- They allow communities without pipeline access to build local distribution systems supplied by stored LNG.
Interestingly, the industry’s cost trajectory hasn’t been a simple story of continuous improvement. As recently as 2003 it was assumed that a “learning curve” effect would continue driving liquefaction costs down indefinitely. Instead, construction costs for green-field LNG projects began climbing from 2004 onward, driven by limited availability of EPC contractors (amid a boom in global petroleum projects), rising raw material prices such as various steel grades, and a shortage of skilled technical operators. Since then, technology maturation and the spread of cryogenic know-how into developing nations have helped moderate prices again, making small-scale applications commercially attractive once more.
Safety Considerations
Natural gas is combustible, and LNG facilities are designed, built, and operated according to strict safety standards. Importantly, LNG itself, in its liquid state, is not explosive and cannot burn — it must first vaporise and mix with air within a flammable range of 5% to 15% before ignition is even possible.
LNG tankers have sailed over 100 million miles without a shipboard death or major accident — a testament to the maturity and rigor of industry safety standards.
Facilities operating under this datasheet’s framework are built to ISO 9001 standards, ensuring safety is embedded throughout design, construction, and operation.
Environmental Benefits
Natural gas is widely regarded as the cleanest of the fossil fuels. Using recovered stranded gas — rather than flaring it — reduces the release of harmful pollutants and greenhouse gases, and supports the wider shift toward cleaner transport fuels such as Compressed Natural Gas (CNG) for vehicles, which is already helping to reduce urban air pollution in many cities worldwide.
Transporting Liquid Methane
Once liquefied, methane is typically transported at approximately -160°C, at pressures of up to 20 atmospheres, using either trailer-mounted road vessels or ISO frames of standard international dimensions for combined road, rail, and sea transport.
Liquefaction dramatically improves transport economics: the energy density of LNG is 2.4 times that of CNG, and around 60% that of diesel fuel — making it cost-efficient to move over long distances where no pipeline exists. Because the liquid is stored at such extreme low temperatures, full insulation is essential; well-designed vessels can limit heat-ingress losses to as little as 0.5% per day.
The Project Route: From Discovery to Operation
Developing a stranded gas resource follows a structured, phased approach:
- Identification of a possible stranded gas resource
- Desk study to evaluate available geological data
- Estimation of methane quantities
- Field study to determine factors affecting viability
- Final system specification and design
- Procurement of component parts
- Construction and commissioning
- Ongoing operation and maintenance
This process typically begins with confirmation that an operating concession or extraction licence can be obtained, followed by analysis of borehole logs and local geology to estimate reservoir size. From there, a full financial model can be built covering installation costs, operating expenses, and expected project revenue — providing the factual basis needed to test long-term project viability before construction begins.
Key Takeaways
- Stranded gas wells — often uneconomic due to remoteness or market saturation — can now be developed commercially thanks to modern cryogenic recovery technology.
- Installations producing as little as 20–40 tonnes of methane per day can be commercially viable, with 20 tonnes/day capable of generating ~4.5 MW of electricity.
- The right technology pathway (power generation, CNG, or LNG) depends primarily on distance to market.
- Cryogenic processing enables separation of valuable hydrocarbon by-products (ethane, propane, butane) alongside methane liquefaction.
- Robust safety and environmental standards, including ISO 9001 compliance, underpin the design and operation of these facilities.
- A full turnkey route — from geological assessment through design, construction, and operation — is required to bring a stranded gas project to life.
Get in Touch
Turning a stranded or flared gas resource into a commercially viable asset requires specialist technical expertise, careful financial modelling, and a proven project delivery process. If you have a stranded gas well or associated gas resource you’d like to explore, contact our team today to discuss a feasibility study and find out how cryogenic gas recovery could work for your site.