A Norwegian company has successfully pilot-tested in Canada a new technology that will permanently plug oil wells and ensure that no greenhouse methane gas escapes.
Currently, the most-widely used technique to plug wells in Alberta is to place a cast-iron-and-rubber seal inside the steel casing and pour cement on top of it. Industry experts and plug and abandonment (P&A) specialists concur that the cement plug is not the ideal solution, because it deteriorates over time and the plug sometimes has to be tweaked and resealed again, which adds to the P&A costs.
Norwegian company Interwell has developed a possible solution that uses thermite—a metal-chemical powder that has very stable components and causes a non-violent reaction that can be controlled. The thermite burns at around 3,000 degrees Celsius (5,432 degrees Fahrenheit) and melts the wellbore components with the surrounding rock, by creating “artificial magma,” like in volcanoes.
Thermite is considered safe to handle and store because it requires significant heat to start a reaction. Thermite is used in the welding of railway tracks, for example, and the thermite reaction and thermite welding technology was first discovered and developed in the 19th century in Germany.
“The reaction lasts for maybe two or three minutes and then it acts like magma that’s erupting from a volcano. A small man-made volcano. Very controllable,” Michael Skjold, the innovation and business development manager at Interwell, told The Canadian Press in an interview in Calgary.
“Actually, we’ve used the volcano as inspiration because ... we are creating something very similar to igneous rock and basalt formations,” Skjold said.
Skjold came up with the idea to recreate a controllable magma-creating reaction eight years ago. Since then, the technology has advanced from lab and backyard tests to a commercial test program.
Interwell has obtained patents for its technology in Norway, Europe, Eurasia, China, and the United States.
In Canada, the company has tested the technology on five wells over the past year and a half, and is planning to perform tests on 8 to 10 more wells this year, Skjold told The Canadian Press, adding that the next tests would be on “problem wells” where the standard P&A solutions have failed.
Interwell initially thought of testing its technology in Norway’s offshore wells. But the well leaking problem is more visible in onshore Alberta than deep in the North Sea, and Alberta has much higher well inventory for plugging than Norway. This convinced Interwell to shift its efforts and focus on Canada, Skjold said.
In Alberta, up to 100,000 wells are inactive, meaning they are no longer producing oil, but not yet permanently plugged, Will Butler, lead, regulatory efficiency for the oil and gas operations group at the Alberta Energy Regulator (AER), told The Canadian Press.
According to Butler, between 10 and 12 percent of those wells are probably leaking at least some volume of natural gas.
“We know there are many, many hundreds if not thousands of wells that the industry doesn’t realize are leaking,” Butler said.
“They’ve been abandoned previously in the past, maybe decades ago, but not to the standards of today and they may be leaking again ... Industry is of the mindset this is no longer their issue. But it is,” he concluded.
Interwell’s technology also looks promising because it doesn’t involve rigs to place cement plugs like conventional P&A operations do, according to a recent presentation by Spirit Energy—a company created in 2017 following the combination of Centrica’s Exploration & Production business and Bayerngas Norge AS. Spirit Energy, 69-percent-owned by Centrica, has collaborated with Interwell on two field tests in Canada, but noted the technique needs to be recognized as acceptable for its future success.
Interwell’s Skjold himself admits that the technology is maybe too expensive to compete with the simple well plugging, but could be competitive with the methods used to re-plug a well if leaks occur outside the casing.
The technology would need more field tests in more challenging conditions to prove it could permanently solve the gas-leaking problem. Then it would need acceptance and regulatory approvals. But with increasingly rigid methane emission rules and goals to cut greenhouse gases in Canada and around the world, it could be a possible solution to safely sealing oil wells.
By Tsvetana Paraskova for Oilprice.com
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