The debates surrounding fracking continue to rage after the controversial process was halted by energy firm Cuadrilla at their Balcombe site in West Sussex. Cuadrilla ceased their operations on the advice of police, only two weeks after they first began.
The process of fracking is a technique designed to recover gas and oil from shale rock, but has come under fire from many for a variety of environmental and health reasons. Fracking, industry shorthand for hydraulic fracturing, involves fracturing rocks apart with a high pressure mixture of water, sand and chemicals, allowing the gas to flow out of the channels created.
The drill bores a vertical channel into the ground, and then turns horizontally once submerged below the water table. Drills can extend for up to 10,000 feet having achieved a depth of between 50 – 300 feet vertically. The intense pressure faced by the drill in a subterranean environment in conjunction with the by-product of fracturing fluid leakoff (that is, the loss of fracturing fluid from the fracture channel into the surrounding permeable rock) means that the drill must be precision engineered to withstand incredible forces.
The drill itself must be able to break through rock in a high-pressurised atmosphere, meaning that in its construction, it must be built to withstand extremely intense pressure. Part of this involves the inclusion of high-resistance disc springs, as their conical shape and stackable functionality proves them to be incredibly strong and resilient. Almost invariably made of stainless steel, the use of this material improves the life of the spring, as other materials tend to have greater malleability in extreme temperature conditions, which can ultimately cause a decrease in tensile strength. As fracking drills have to operate underground at incredibly high temperatures (and create more heat in the process of drilling) it is imperative the disc springs are designed to withstand the heat as well as the repeated pressure of the drill motion.
The debate will continue to surround fracking for as long as it is practicable option for energy companies. The abundance of shale gas beneath the earth invariably means that it will be harvested in some fashion, but if fracking remains the only option there may continue to be a defiant stance about it. The environmental concerns include the release of carcinogens into the atmosphere, and destabilisation of the earth has been linked to earthquakes and other terralogical upsets.
It remains to be seen how the process will develop, but until ulterior methods are found, fracking remains the primary means by which shale gas can be extracted.