Dr. ir. René Peters
- Offshore Energy
Current alternative energy technologies are not yet sufficiently well developed to replace fossil fuels. Until we are able to switch completely to renewable alternatives we will remain dependant on oil, coal and gas. Of these three, gas is the cleanest. It can also be used flexibly to meet peak load demand. In the short term, gas can also replace oil and coal, thereby reducing CO2 emissions. This is also addressed in the European Commission’s Energy Roadmap 2050.
Europe’s growing population and economic prosperity is fuelling demand at a time when the continent’s gas reserves are in decline. As a result, Europe is now becoming increasingly dependent on gas imports from countries such as Russia, as well as states in the Middle East and North Africa. Europe sees the security of its energy supplies as a major item on the agenda. By supplementing European gas reserves, gas from unconventional sources (such as shale gas) could play an important part in this regard.
Shale gas is natural gas that is “locked up" in shale layers in the subsurface. Research has shown that the European subsurfacel potentially contains vast reserves of shale gas. It is more difficult to extract gas from this source than from conventional fields, whose reservoirs consist of sandstone, for example. This is because shale has a much more compact structure.
The technique used to extract shale gas is referred to as “fracking” or fracturing. This technique involves fracturing the rock in which the gas is trapped, by pumping a water/sand mixture into the shale layer under high pressure. This can also involve the use of chemical additives, whose uses include keeping the sand suspended in the water during transport, keeping the well open, and preventing corrosion of the well. The sand is used as a proppant, to keep the newly created fractures open. Each producer decides whether or not it is necessary to add chemicals and, if so, which ones to use.
In the United States, companies have been drilling for shale gas for many years now. Shale gas currently accounts for 20% of domestic gas production in the US. This requires a lot of wells. While this is not an issue in the US, Europe has much less available space (due to its higher population density) and a subsurfacel that is used extensively for other purposes. As a result, it is neither possible or desirable to drill so many wells. If the search for shale gas is successful, then it may be possible to produce shale gas in Europe. This is already happening in the United Kingdom. Shale gas exploration and production requires specialized knowledge and advanced technology. These make it possible, for example, to drill multiple wells from a single location, and target frackable layers that contain high gas volumes more effectively by understanding the shale’s heterogeneity.
TNO is committed to achieving a robust transition to renewable energy supplies. Accordingly, TNO is investing in environmentally friendly alternatives, while working to achieve the most efficient and cleanest possible use of fossil fuels in the transition to renewable solutions. TNO is using its extensive knowledge of the Dutch subsurface to investigate potential shale gas reserves. We are also searching for methods and technologies that could be important in the production of shale gas. These include minimizing the space used, techniques for simulating, monitoring and controlling the newly opened fractures in the subsurface, alternative fracking methods, monitoring well integrity, and responsible treatment of production water.