A flow line curves above the horizon on the western North Slope. (Elizabeth Harball/Alaska’s Energy Desk)A Papua New Guinea company says a North Slope oil field may be a lot bigger than it first estimated.Listen nowOil Search told investors this week that the Pikka development could hold 750 million barrels of oil, increasing its original estimate by 50 percent. The company aims to drill two wells this winter to help confirm the field’s size.The company also said another area just south of Pikka, called Horseshoe, could hold more than 300 million barrels of oil. Another oil company with a stake in the project said last year that the entire area could hold upwards of a billion barrels of oil.Pikka is west of Prudhoe Bay, on land owned by the state and Kuukpik Corporation.Oil Search is relatively new to Alaska. Its other major projects are in Papua New Guinea. The company bought up a significant stake of the Alaska oil field last year from the Denver-based Armstrong Energy.Oil Search managing director Peter Botten told investors he’s feeling optimistic about the company’s North Slope venture.“We’re acutely aware we need to walk before we can run in Alaska, and we need to get it right and not drop the ball, but things are really going well there,” Botten said.Botten added that Oil Search plans to double its Anchorage staff to 100 by the end of the year.Oil Search’s increased estimate for Pikka was first reported by the Anchorage Daily News.