Last year political turmoil in Yemen caused the GCC to step in and broker a deal which called for the president Ali Abdullah Saleh to step down and hand power to his deputy Abdrabbuh Mansour Hadi. Since that time militant groups have led repeated attacks against oil pipelines costing the Middle Eastern nation an estimated $4 billion in revenues.The Safer-Ras Issa pipeline has been the target of the attacks. It is the main pipe for carrying oil from the Marib fields, and has been in operation since February 2011.Yemen is one of the poorest countries…