TULSA, Oklahoma - Gas prices are going up across Green Country, and some are saying they will continue that way over the next week.

This is the time of year when many refineries shut down for maintenance. The maintenance began right about the same time there was an unusual spike in demand and the price of oil rose. 

Price-tracking website GasBuddy shows the average price per gallon in Tulsa is up five cents since Tuesday and up 13 cents from a week ago. Many stations are now selling regular gas for 2.29 per gallon.

Patrick DeHaan, senior petroleum analyst for GasBuddy.com, wrote that refineries in the Midwest are using about 10-percent less of their capacity than they were a month ago.

"Statistics from the Energy Information Administration (EIA) show that Midwest refiners used just 87.0% of their capacity in the most recent week, down over 10% from early September, when they utilized 98.3% of their capacity," he wrote. "Twelve refiners in the region are currently undergoing work: three in Illinois and Ohio, two in Minnesota, and one in Indiana, Kansas, Oklahoma and Kentucky. The work varies in scope at each refinery and may last several weeks or longer."

"A gain in crude oil prices to this week is adding insult to injury and a combination of higher oil prices and reduced gasoline output due to the aforementioned issues will lead retail gasoline prices to rise as much as 10-30 cents per gallon over the next week in a handful of states: North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Minnesota, Iowa, Missouri, Wisconsin, Illinois, Michigan, Indiana, Ohio and Kentucky," he continued.

A spokesperson from AAA Oklahoma says he hopes this price increase is temporary.