Gulf Keystone's shares soared Wednesday after the company said it believes it has 'yet another potential world class oil source' on its hands in the Kurdistan region of Iraq. The preliminary resource estimates for its Sheikh Adi block indicated a significant range of between 1 bn and 3 bn barrels of gross oil-in-place volumes calculated on the proven-to-possible reserves scale (also known as P90 to P10), with probable reserves (P50) estimated at 1.9 bn barrels. Gulf Keystone has completed drilling of the first well to be drilled at Sheikh Adi (Sheikh Adi-1 well) and a series of flow tests will now be carried out in the surrounding zone. John Gerstenlauer, Gulf Keystone's Chief Operating Officer commented: "This independent report demonstrates the potential of the Sheikh Adi block." "We plan to further evaluate the Sheikh Adi structure and define and assess this complicated geological structure. The Sheikh Adi oil-in-place numbers are all the more significant due to our 80 percent interest in the block," Gerstenlauer added. The share price was up 14.32% to 129.75p at 14:04. NR