Preliminary estimates suggested that Iraq’s Eridu oil field holds between 7-10 billion barrels of reserves. Senior Russian oil industry sources spoken to exclusively by OilPrice.com last week said the true figure may well be 50 percent more than the higher figure of that band. In either event, the Eridu field - part of Iraq’s Block 10 exploration and development region – is the biggest oil find in Iraq in the last 20 years, and Russia wants to control all of it, alongside its chief geopolitical ally, China. This is in…