All over the news today, one example - “Panel Seeks More Disclosure on Natural Gas Drilling: Scientific American”
Why do they use several chemicals when ‘‘fracking’’. It would seem to the completely naive that water and perhaps a detergent would be all they need.
It’s probably a matter of solubilities. If you’re trying to cut through a surface of mixed materials with various solvents, you’ll want to be able to remove everything you encounter, perhaps selectively for further sorting and processing.
Molecules have different solubilities. Some things dissolve or mix easily in water, some do not. Some will be soluble in a detergent, but these are often water-based, so many things still won’t go in. Non-polar and/or organic solvents will need to be used, and these have various results depending on what you are trying to put into them. If you intend to get things back out, then certain chemicals may be preferable because of the processing that has to come later. There are many, many chemicals that can be used as solvents.
What they use for fracking really depends on what hydrocarbon they’re drilling for, and the formation(s) they are drilling in, as well as water availability, frac fluid disposal options, and if they are reusing the frac flow back or not.
Generally they use a water based solution as long as there is enough water available. The various chemicals they add are used to stabilize the fluid and fracture the rock - fracturing isn’t always completed via pressure. In addition, some additives are used to hold open the fractures and allow the hydrocarbon to flow. Also, as said, flow back is either treated/diposed of via an injection well, or re-used, and additives are chosen based upon the end use of the frac water as well.
Just to add - I was at a seminar in July regarding fracturing in Shale Gas and in the presentation they showed a poster that lists the ingredients in a typical frac fluid - it can be found here: A Fluid Solution: Typical Solution Used in Hydraulic Fracturing.
Many years ago I worked on software related to fracking… I didn’t know all the additives, but that graph looks about right for the different fluids (acids, lubricants, surfactants, etc.)
IIRC, there was also the option of fracking with diesel instead of water (though that was probably a water-diesel mix of some percentage).
The main component is of course sand, of which I think they had a dozen different types available (thought not all on-site at a time). They had different properties of size and abrasiveness that were important.
Incidentally, a frack site (pic at the top) is freak’n insane to work on. There can be a dozen or more pump trucks set up to provide pressure, each of which is basically a locomotive engine. Takes a bit of co-ordination. 
They are moving away from diesel (and propane) because it’s so dangerous - this was actually mentioned in the report that’s in the news this week.
Nanoda, my husband used to work on a frac crew too, for a company that starts with an S out of Red Deer. Did you work on a crew too?