ConocoPhillips, a top U.S. oil and gas producer, plans to cut staff as part of a broad restructuring following its acquisition of Marathon Oil. The company has hired Boston Consulting Group to advise on the restructuring and layoff program. Layoffs are expected in the fourth quarter, but the size of the cuts has not been determined. ConocoPhillips has already started restructuring its operations and will follow with reorganizations in corporate and support functions.