Mehdi Varzi, a Non-Executive Director of Gulf Keystone, the AIM-listed oil and gas explorer, has sold a quarter of a million shares.Varzi, who has been on the board since 2008, sold 257,347 shares at 254.17p each for a total of £654,099. Earlier this month the firm reported that the testing programme for the Shaikan-4 appraisal well remains ongoing, with six out of seven planned tests completed to date. So far aggregate flow rates in excess of 14,000 barrels of oil equivalent per day have been achieved. At the Shaikan-5 appraisal well, it became necessary to drill a sidetrack due to a portion of the drill string becoming stuck in the hole. The sidetrack operations were successfully performed and drilling operations have resumed, the firm said. The stock has gained 70%, or 110p, over the past year, despite losing 26% during the past month. The share price rose 5.6% to 268.50p the same day the sale was announced. Top Director BuysRandgold Resources Ltd. (RRS) Director name: Mr R I IsraelAmount purchased: 1,000 @ 5,784.26p Value: £57,843Randgold Resources Ltd. (RRS) Director name: Mr Andrew J QuinnAmount purchased: 600 @ 5,809.56p Value: £34,857Randgold Resources Ltd. (RRS) Director name: Mr R I IsraelAmount purchased: 500 @ 5,577.19p Value: £27,886Medusa Mining Ltd. (DI) (MML) Director name: Mr Andrew Boon San Teo Amount purchased: 5,000 @ 336.87p Value: £16,844Top Director SellsGulf Keystone Petroleum Ltd. (DI) (GKP) Director name: Mr Mehdi VarziAmount sold: 257,347 @ 254.17p Value: £654,099