What ‘shale gas’ in the east of Ukraine was Energy Minister Boiko talking about?
Over the past 20 years, which have been described as a period of globalization and market fundamentalism, the natural gas industry has changed drastically. The world has quickly assessed the economic and environmental benefits of this «blue fuel.» Thanks to this, producers have begun rapidly to increase its production, improving production technology and delivery. The swift gas price increase in 1995-2008 made many new extraction technologies cost effective. They made it possible to develop not only conventional deposits of natural gas located mainly in turbulent regions of the globe but also produce unconventional gas, reserves of which have been found in practically every country on the face of the Earth.
In order to understand the subject matter, you have to understand a bit of terminology.
Natural gas – a mixture of methane and other gaseous hydrocarbons (ethane, propane, butane, etc.), which was formed in the bowels of the earth due to the decomposition of organic substances without access of oxygen. Natural gas can be:
- in a gaseous state – in the form of individual clusters (gas deposits), or a gas cap over oil and gas fields (conventional non-associated gas);
- dissolved in oil or water – in the form of associated gas (conventional associated gas);
- in the solid crystalline state – in the form of natural gas hydrates (gas clathrates, gas hydrates).
Non-traditional (unconventional gas) is natural gas originating from:
- clay shale rocks (shales rich in organic substances; gas-rich shale, shale gas);
- coal seams (coalbed methane);
- tight reservoirs (central basins, tight sandstones; tight gas sands).
There are also deep natural gas and gas from geopressurized zones.
Since 2010 the U.S. Department of Energy has been using term «low-permeability gas reservoirs» to define gas from unconventional sources. It is believed that some regions, particularly China, India, Australia and Europe have large resources of unconventional gas in the vicinity of the main centers of consumption. However, their development is associated with the following difficulties:
- insufficient prospecting of deposits in terms of geological and economic characteristics;
- limited access to the resources due to their dispersion and usually great depth;
- environmental restrictions related with the need to involve vast areas in production, with large and intense damage of the integrity of mineral resources, and the lack of large volumes of water needed for drilling wells;
- the remoteness of the resources from existing infrastructure.
However, there is great difference in assessments of non-traditional gas resources (whose amount is determined on the basis of geological assumptions and theoretical patterns) and reserves (determined as a result of geological and geophysical prospecting). As a result, there is great uncertainty over actual stocks of unconventional gas. While the IAEA believes that the stocks of this fuel around the globe are five times more than those of traditional gas, Cedigaz considers that non-traditional gas accounts for a mere 4% of the world’s proved stocks…
You can read full article in journal «Terminal: Oil Review» №5 (591) 6 Feb 2012
