Oil explorer Gulf Keystone shares picked up after a bullish update on its Shaikan-3 shallow appraisal well, which tested the Cretaceous intervals in the immediate vicinity its huge Shaikan-1 discovery.As a result of the tests, log evaluations and recovered fluid samples, Gulf Keystone's current P50 (probable) to P10 (possible) estimate of Garagu oil in place volumes is 220m to 2.2bn barrels. The large spread between P50 and P10 volumes is due to the uncertainty with respect to the exact nature of the Cretaceous down dip, on the flanks of the Shaikan structure, Gulf added."The Cretaceous resources evaluated by the Shaikan-3 well are massive by any standard. They represent a significant oil resource for Kurdistan and Iraq. It is a further demonstration of the huge hydrocarbon potential of the area," John Gerstenlauer, Gulf Keystone's chief operating officer commented.