Unconventional gas is the collective term used to describe tight gas, shale gas and/or coal bed methane (CBM). While conventional gas resources can be developed and produced without any special well completions, most unconventional gas production requires the rock to be fractured (“fracked”) or stimulated to allow gas to escape from the tight rock and flow through the wellbore to the surface. These special well completions made drilling for unconventional gas uneconomical for many years.
Toward the end of the 20th century, the combination of two existing technologies – horizontal drilling and hydraulic fracturing – shifted unconventional gas production into the main stream. Learn more about how unconventional gas is extracted with our interactive animation.
The potential of shale gas, tight gas and CBM has been known for centuries, with the first shale gas wells drilled in the 1820s. However, it is only with recent technological improvements that extracting the resources has become an economically viable option.
Currently, natural gas has approximately 60 years of proven reserves at current demand levels, but according to the International Energy Agency (IEA), this rises to more than 250 years if the unconventional gas potential is added. Clearly, unconventional gas may play a large part in ensuring the security of global energy supply for years to come.
Compared to conventional gas, unconventional gas reservoirs extend over much broader areas (hundreds or even thousands of square kilometres). However, finding the “sweet spots” in these large areas where the gas can be produced commercially is often difficult. Despite this fact, unconventional gas resources are being found across the world. In Europe, the largest endowments of tight gas resources are thought to be in the Ukraine and Hungary; shale gas in Germany, Poland, Romania, Sweden, Denmark, the UK and France; and CBM in the Ukraine and Germany. However, as exploration and extraction are still at an early stage, more work needs to be done to determine if commercial deposits are present, and if so, where exactly the key sites are.
In Europe, projects are currently underway to precisely map out unconventional gas resources. The Shale Gas Research Initiative, known as GASH, is a European interdisciplinary research project with the aim of developing a black shale database. In Germany, the Ministry for Education and Research has funded the GeoEn Project to strengthen shale gas research. Germany is one of the few countries in Europe where exploratory projects are already underway.