Engineers at Louisiana State University are testing what they claim to be a highly efficient, carbon-neutral process to extract remaining reserves from abandoned oil wells. If proven, the LSU process could be one solution to the looming nationwide problem of "orphan" wells, which could number in the millions, according to some estimates.

Dandina N. Rao, a professor in the university's petroleum engineering department, is leading a team taking a two-prong approach to the problem of reducing harmful gases from the wells.

“With the oil industry possibly venturing toward renewable energy, the question is can we continue to use fossil fuels but in an environmentally sustainable manner, and that’s exactly what our invention does,” say Rao.

The method that the LSU team has created—called gas-assisted gravity drainage—sequesters CO2, or flue gas while enabling recovery of about 85% of the total reserve. By comparison, says Rao, conventional recovery methods, such as conventional gas injection, only yield about 15% of a well's remaining oil reserves.

The process works by placing a horizontal pipe near the bottom of the orphaned well and injecting gas through existing vertical wells, allowing remaining gas to rise and creating a gas zone. Then oil and water flow down to the horizontal pipe, ending the process and creating significantly fewer gas emissions. 

A pilot project received LSU’s LIFT² (Leveraging Innovation for Technology Transfer) program grant, allowing Rao to move the idea from the concept stage to reality and closer to commercialization. Rao says the pilot would initially convert a small number of wells into carbon-neutral production wells through the new process, adding that LSU holds the patents. The team’s model could be a “needed boost” to investors’ and operators’ confidence in harnessing the depleted fields still holding millions of barrels of stranded oil. 

The process could have a positive impact, says A.W. Szur, the managing member of TADC Oilfield Restoration LLC, a company specializing in abandoned wells reclamation. It provides "an opportunity for going into orphan or marginal wells and providing significant barrels of oil that, under current conditions, cannot be attained,” he adds. 

More than half of U.S. states have abandoned wells within their borders. According to Rao's data, Louisiana has more than 4,600 abandoned wells, while Oklahoma has more than 17,000, and Texas has nearly 7,500. 

Across the U.S., officials have documented roughly 131,000 orphan oil wells.  However, the U.S. Dept. of Interior estimates there could be as many as 3.5 million. 

The process, Rao says, would help Louisiana revive its declining oil industry. From 1980 to 2020, oil production in Louisiana dipped from 200 million barrels/year to 40 million barrels/year.

“We want to help the state spur oil production in an environmentally sensitive manner so we will have a booming energy and petrochemical industry for several decades into the future, [creating] jobs and prosperity,” he says. “There is a need for oil, not only as a source of energy but also as a raw material for the enormous petrochemicals industry worldwide, which neither solar nor wind energy can fulfill.”

“The success of this project would have far-reaching consequences to Louisiana’s oil industry and economy,” Rao adds.