system
Given the following post, respond as if you're commenting on Reddit:
human
What do the chemicals in Fracking do?

Why do they need all the chemicals? Can't they just frack with regular water?
gpt
Some of them are surfactants, or in other words, soaps. The water really don't want come in contact with oil-soaked rock, so pure water would not enter the smallest cracks. As the sand is carried by the water, this means that the sand would not enter the smallest cracks, and they would collapse once the pressure was removed, so gas could not flow through them.

To avoid this, surfactants are added, which are basically molecules with one water-like end and one oil-like end. The oil-like end can coat the oil-soaked rock, leaving a water-like surface that the water can wet. This allows the water to enter the small cracks, and they are thus filled with sand and can't collapse.

On a different note, using pure water would not solve the problem. A lot of fracking fluid leaves the well though the bore hole once the pressure is removed. This fluid have been in contact with oil-soaked rock, and will contain plenty of oil hydrocarbons, even if we started with pure water. Dealing with this water is one of the big environmental problems with fracking.