Evaluation of LNG, CNG, GTL, and NGHs for Monetization of Stranded Gas
Authors: Bybee Karen 
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper IPTC 14083, ’Evaluation of LNG, CNG, GTL and NGH for Monetization of Stranded Associated Gas With the Incentive of Carbon Credit,’ by R. Khalilpour, SPE, and I.A. Karimi, Department of Chemical and Biomolecular Engineering, National University of Singapore, originally prepared for the 2009 International Petroleum Technology Conference, Doha, Qatar, 7-9 December.
Associated gas is estimated to account for 17% of global gas reserves. However, the majority of associated-gas resources are small or located offshore, which has made their use uneconomical. Operators thus have preferred either flaring or reinjecting the gas rather than use. There are a number of gas technologies that have the potential to make the development of stranded gas resources economically viable. The full-length paper details a study that investigated each of these processes on the basis of different variables.
Introduction
Associated gas is natural gas found in association with crude oil. According to the latest data from the Energy Information Administration, the total world gas reserves are approximately 6,200 Tcf. Some studies have estimated that global associated-gas reserves without commercial value exceed 1,000 Tcf.
The National Geographic Data Center through collaboration with the World Bank’s Global Gas Flaring Reduction (GGFR) partnership is carrying out a project to develop a method to estimate global gas-flaring volumes on the basis of satellite-sensor observations. The center has reported the global volume at approximately 4.9 to 6.1 Tcf/yr within the period of 1994–2008, with a maximum amount of 6.1 Tcf in year 2005 and minimum of 4.9 Tcf in 2008. This amount of gas accounts for approximately 5 to 6% of total world natural-gas consumption.
A significant issue with associated-gas flaring is its contribution to global warming. The World Bank has reported that flaring of associated gas emits approximately 300 million tons/yr of carbon dioxide (CO2) equivalent. The impact on global warming becomes more serious when associated gas is vented because methane is 21 times more powerful as a greenhouse gas (GHG) than CO2. Therefore, with current carbon-tax legislations, the oil and gas industry seems to have reached the stage where new field developments will not be possible unless the associated-gas problem is solved.
Carbon Credit
The United Nations Framework Convention on Climate Change (UNFCCC) is an international environmental treaty produced in 1992. The original treaty was legally non-binding and contained no mandatory limits on GHG emissions for individual nations and had no enforcement provisions. It entered into effect from 1994 when more than 50 countries had signed the UNFCCC. The parties then established an annual meeting called Conference of the Parties (COP) to assess progress in dealing with climate change. In 1997, in the third COP in Kyoto, Japan, a protocol with legal binding was developed that later became famous as the Kyoto Protocol. In February 2005, the protocol entered into effect by obligating industrialized countries, addressed as “Annex I” countries, to reduce their GHG emission by 5.2% from the 1990 level.