Natural gas is a versatile form of non-polluting fuel. With just over a dozen nations accounting for 84% of the world-wide production, access to natural gas has become a significant factor in international economics and politics. The major difficulty in the use of natural gas is transportation and storage because of its low density. Despite this, natural gas production has seen tremendous growth over the years. This has been due to large amount of natural gas reserves, the wide variety of uses of natural gas and carbon dioxide emissions from natural gas energy generation are far less.
In the past, the natural gas recovered in the course of producing petroleum could not be profitably sold, and was simply flared. This wasteful practice is now illegal in many countries. The most common method for transporting natural gas was high pressure in underground pipelines. Additionally, countries now recognize that value for the gas may be achieved with LNG, CNG, or other transportation methods to end-users in the future. In many cases the gas is now re-injected back into the formation for later recovery. Transportation is now a very important and key role in the supply chain for natural gas and the big challenge is to transport gas to markets at the lowest cost without too much environmental risks. Now re-gasification at the market is important when selecting the mode of transportation of natural gas.
This paper reviews, analyzes and provide insight to present and future gas transportation methods. These options of transporting gas from oil and gas field to markets include pipelines, liquefied natural gas, compressed natural gas, gas to solids (hydrate), gas to liquids, gas to wire and other gas to commodity methods. The paper provides an overview of the challenges facing present transportation modes, and discussion on possibilities for improvement via new technology or new gas transport options. Another focus of the paper is to compare and highlight some critical factors affecting the different means of transportation of natural gas. These include economics, markets, gas concentrations, environmental risks and re-gasification issues.
The efficient and effective movement of natural gas from producing regions to consumption regions requires an extensive and elaborate transportation system. In many instances, natural gas produced from a particular well will have to travel a great distance to reach its point of use. Transportation of natural gas is closely linked to its storage, as well; should the natural gas being transported not be required at that time, it can be put into storage facilities for when it is needed.
The factors affecting the type of gas transportation used include gas reserves, time frame to monetize the gas, the distances to the markets, investments and infrastructure available and gas processing. Stricter environmental laws' including the prevention of flaring gas has now pushed for ways to monetize associated gas. The possible ways of transporting natural gas to markets are pipelines, liquefied natural gas, compressed natural gas, gas to solids (hydrate), gas to liquids, gas to wire and other gas to commodity methods. Table 1 shows the stages of the different gas transportation methods.
Gas reserves (2005) are in the range of 6500 tcf but what is extremely significant is the 40% or 2500 tcf that is considered stranded gas. These small pockets of gas reserves are found mainly in Russia, Qatar, Australia, Alaska and Trinidad (Fleisch). There is normally a large amount of associated gas that is re-injected or flared however nowadays many countries have banned the flaring of natural gas in large quantities. There is therefore a thrust for economic ways of transported stranded gas.