Oil extended gains to the highest level in almost a month, with investor focus shifting back to U.S. crude inventories after supply disruptions and optimism over OPEC’s output curbs drove a rally over the past week. Futures added as much as 0.9 percent in New York, rising in six of the past seven days. U.S. crude stockpiles declined by 1.83 million barrels last week, the industry-funded American Petroleum Institute was said to report, while government data due Wednesday is forecast to show they dropped from a record. Production from the Buzzard field, the biggest in the U.K. North Sea, was halted after an unplanned outage , according to a person familiar with the matter. Oil in the U.S. rose above $50 a barrel last week after some members of the Organization of Petroleum Exporting Countries voiced support for an extension to a six-month deal to cut production past June. […]