Using a mixture of water, sand, and chemicals under high pressure to free tightly held oil and natural gas is known as

Using a mixture of water, sand, and chemicals under high pressure to free tightly held oil and natural gas is known as Hydraulic fracturing. 

This is a process commonly practiced in the United states where millions of gallons of water, sand, and chemicals are pumped underground. This is used to break apart the rock bed and release the gases that are deep in the ground.