Pipeline leaks and shipping disruptions are doing more to reduce the global oil glut than producers who can’t seem to agree on whether to cap output. Outages from Iraq and Nigeria have disrupted more than 800,000 barrels a day of supply and tightened the Brent market, according to Citigroup Inc. That’s coincided with a 20 percent jump in Brent prices toward $40 a barrel since a proposed production cap from Saudi Arabia and Russia captivated the market and helped turn sentiment bullish. No deal has been struck and Iran has spurned the idea as it seeks to maximize output