MOSCOW, July 17. KAZINFORM - Russian energy giant Gazprom [RTS: GAZP] said Monday it had signed a deal with Sweden's Lundin Petroleum AB to acquire a call option for 50% plus one share in a Caspian oil and gas field. The cost of the planned deal, under which Gazprom will buy the shares in the Lundin-owned company that holds the deposit's license, has not been disclosed. The Lagansky block is located in the Russian sector of the Caspian Sea and has estimated reserves of more than 800 million barrels of oil equivalent. Sweden's Lundin Petroleum AB is an oil and gas exploration and production company with operations in Europe, Africa and Asia. The company is involved in five oil and gas projects in Russia. As of January 1, the company had existing proven and probable reserves of 176.4 million barrels of oil equivalent, Kazinform quotes RIA Novosti.