Fossil fuels, including oil and gas, store a part of the energy which the earth has received from the sun during the last several hundred million years. These days, oil and gas account for around 64 % of the total world energy consumption. Despite the efforts in developing new renewable energy sources, oil and gas will continue to play a major role in meeting the world’s ever increasing energy demand for the next few decades. Moreover, oil and gas are expected to remain the most cost effective and the most convenient sources of energy that we have at our disposal.