Once the wellbore has been drilled, sometimes as deep as four kilometers below the surface, specialized trucks equipped with high-pressure pumps are brought to the well site for the hydraulic fracturing process. The pumps are used to push the fracturing fluid (water, sand and chemical additives) down the well and into the reservoir at a pressure high enough to create small fractures (i.e. thin cracks) in the rocks. The fractures typically extend a few tens of meters vertically and up to a few hundred meters horizontally. The sand in the fluid holds the hairline cracks open to allow natural gas to flow into the wellbore, and is referred to as proppant.
Through the use of horizontal drilling, multiple wells can be drilled from the same surface location and can develop a large area of the shale gas resource, while using less land at the surface.
These technologies have been in use for decades, but by combining them, Europe has seen a turnaround in its potential to increase domestic gas production. Now, operators can safely produce affordable, reliable quantities of natural gas from previously untapped resources.