Investec has raised its target price for Iraq-focused oil explorer Gulf Keystone from 191p to 232p after positive results from its Shaikan-4 deep appraisal well testing programme.Tests of the well, drilled six kilometres west of the Shaikan-1 discovery well in the Kurdistan Region of Iraq, achieved total maximum aggregate flow rates of 24,000 barrels of oil per day. The group's Chief Operating Officer Gulf Keystone John Gerstenlauer said that "Shaikan-4 is our best well drilled to date in the Kurdistan Region of Iraq in terms of the total net pay.""The company is set to move forward with a full development programme and this announcement will provide the government with an assurance that Gulf Keystone is proving up the resource base to achieve this objective," said Investec.The broker has maintained its buy recommendation for the stock.Shares had jumped 9.95% to 232p by 09:54 in London on Monday.BC