When it comes to the world’s petroleum reserves, there is a lot of collective worry over when exactly mankind will have tapped them all. What the general public may not know is that for every well drilled a significant portion of crude is left behind.

“In a conventional reservoir, you might get 40%, and leave 60%,” Montana Tech Professor and Petroleum Engineering Department Head Todd Hoffman notes. “Most reservoirs we are leaving some petroleum behind.”

Areas with specific types of geological formations extraction can yield even less petroleum. They are called unconventional reserves. Montana’s Bakken region is a prime example.

“We are only getting a small fraction of the oil out,” Hoffman notes. “90-95% of the oil remains in the reservoir.”

For 15 years, around half of Hoffman’s focus has been figuring out how to extract this untapped petroleum. Hoffman presented a new paper, "Improved Oil Recovery Injection Pilot Projects in the Permian,” at the Society of Petroleum Canadian Energy Technology Conference in March 2023. The paper details how Texas petroleum producers use new methods to extract more from unconventional reserves.

Hoffman uses modeling technology housed in the Montana Tech Petroleum Engineering Department to compare the results of the new extraction techniques in the Permian Basin, near Midland, Texas, to his models. He then adjusts the models based on data from the field to better predict how techniques might work.

The methods he’s testing involve injecting gas into the well, which boosts the amounts of retrievable petroleum. Many of these wells can retrieve 1.5 times the amount of petroleum as  expected without using the new method.

“It’s a hot topic,” Hoffman said. “They have tried it in a handful of wells, and we are definitely seeing more wells trying these techniques.”