? When you drill, you make a well, and create a casing around it as you go through various mantel layers and especially through underground aquifers; essentially you need to lay pipe as you dig down to the target region. If that target is hydrocarbons under pressure, they will just rush to the surface once tapped. Without the casing, then they mix with the ground water as they come to the surface. That's not what you want when you are tapping into oil, so the casing makes a passage way for the oil to flow to the surface without mixing, and while maintaining full underground pressure to push it to the surface. Fracking just means to release the oil/gas, you dig the well through the various layers to your target layer, and they inject water into that layer to break up the shale and flush it out, so to speak. This was no big deal until horizontal drilling was invented. Now we have the ability to drill down and then sideways to maximize the effectiveness of the water injection. Problems are that drills going horizontal cross surface boundaries of mineral rights. Plus, the effectiveness has prompted 100x more wells being drilled, so the odds of ground water contamination of failing well casings increases, versus previous methods of fracking without horizontal drilling technology. It's about odds. Is it safe: As safe as any wells. Is it needed: As much as any wells. Does it use an enormous amount of water that cannot be reclaimed...pretty much Does it contaminate ground water: not if done safely any more than other injection wells (for waste water/sewage, etc). But the shear increase of fracking wells and their continued use, increases the probability of failure occurring around any given water aquifer.
