Compressed natural gas can be stored in horizontal wells

The underground is home to many empty wells. A research team has published a study aiming to use obsolete oil and gas wells to store compressed natural gas. The researchers say that reusing wells as a low-cost energy storage solution will offer significant advantages.

Compressed natural gas storage in horizontal wells

US Department of Energy National Renewable Energy Laboratory (NREL) researchers aim to use horizontal gas and oil wells to store renewable energy through compressed natural gas.

Horizontal wells are widely used in the industry with the advantages they offer, but they tend to lose their active status quickly. The team thought that these uncapped horizontal wells could be a storage solution for compressed natural gas, and by running a lot of computer simulations, they observed that it was feasible in both the long and short term.

The researchers initially considered injecting compressed air into old wells but abandoned the idea because adding air to a natural gas well risked causing an explosion. Thereupon, the team began to lean on current thinking.

Their calculations showed that, depending on the temperature and pressure in the well, using compressed natural gas to generate electricity could produce hundreds of kilowatts to almost one megawatt.

The researchers note that inactive horizontal wells that could be used need to be identified. While the number of active horizontal wells in the USA was around 9 thousand in 2000, this number exceeded a quarter million in 2017.