By Nichola Groom LOS ANGELES, Oct 4 (Reuters) - Pump prices in California have soared this week and are poised to break a record set in the summer of 2008 due to low inventories and disruptions at key Golden State refineries. The state average for a gallon of regular gasoline jumped to $4.315 on Thursday, 18.2 cents higher than last week and 49 cents higher than a year ago, according to AAA data. In recent weeks, California refineries have dropped production in anticipation of switching over to a "winter blend" of gasoline next month. At the same time, a power outage at Exxon Mobil Corp's Torrance, California refinery on Monday and a shutdown of the crude distillation unit at Chevron Corp's Richmond, California refinery contributed to the tight supplies. Chevron also said a pipeline that carries 85,000 barrels per day of crude oil from the state's Central Valley to refineries in the San Francisco Bay area has been closed since mid-September due to the presence of elevated organic chloride levels in the crude stream. "It's a series of unfortunate events," said Tom Kloza, chief oil analyst for Oil Price Information Service, which compiles the price data for AAA. "This is not something that is going to last for months. This is something that is going to last for days or weeks." Still, Kloza said it was likely that the record California average gasoline price of $4.61 a gallon, set in June of 2008, would be broken. "We are looking at the highest California prices ever," he said in an interview. At a Chevron station in the Brentwood section of Los Angeles, the price for regular gasoline went up 20 cents a gallon overnight. "My car is a gas guzzler, it's sucking me dry," realtor Marty Halfon said as he filled up his 1992 Mercedes. "I'm in real estate, I live in my car. I'm held hostage. LA doesn't have public transportation and the problem is you have to drive everywhere you go. So what do you do? Stay home?" Prices in the Los Angeles spot market for October-delivery gasoline reached a record $1.75 a gallon on Thursday over NYMEX RBOB gasoline. Valero Energy Corp on Thursday said it was temporarily withdrawing from the Los Angeles spot refined products market to assure supplies to its branded and unbranded retail stations the company supplies.