Carbon capture tech makes oilfield go greener

In order to construct the carbon storage facility, employees from Liaohe Oilfield collaborated with dozens of experts and professors from several universities, including Dalian University of Technology.

"Compared to overcoming high-temperature and high-pressure technology, overcoming the corrosion of the wellbore is the most critical issue," Luan said. Once the injected carbon dioxide encounters water in the formation, it will generate acidic liquid, and the acidity is directly proportional to the mineralization of the water.

The mineralization level of the formation water in the Liaohe region is very high. And if not controlled, it can corrode the wellbore into fragments within a year.

Hence, researchers coated the surface of the wellbore with a protective film to isolate the acidic liquid from the wellbore. Based on the composition of the acidic liquid and the material of the wellbore, they developed a chemical agent, quaternary ammonium salt, to slow the corrosion rate of the wellbore by over 99 percent.

In addition to technological breakthroughs, independently developed equipment for the CCUS project at Liaohe Oilfield has significantly reduced costs.

Wang explained that the cyclic injection station includes important components such as the hydrocarbon removal unit, carbon dioxide pressure swing adsorption unit, and pressurized dehydration unit. The price of a single set of domestically produced equipment can be reduced to less than one-tenth of the price of imported equipment from the 1990s.

Currently, three carbon capture facilities and one cyclic injection facility have been completed and put into operation at the CCUS cyclic injection station, with a maximum daily processing capacity of 240,000 cubic meters, possessing an annual carbon capture capacity of 137,000 tons and an injection capacity of 208,200 tons.