Views: 157 Author: Venus Publish Time: 2018-05-14 Origin: Google
Hydraulic fracturing, also known as "fracking", is a process by which petroleum fluids can be extracted from deep underground. This is done by pumping large amounts of proppant mixture-typically a slurry of 90% water, 9% proppants, and 1% chemicals-into the drill hole; the hydraulic pressure forms fractures in the rocks.
Once the well has been sufficiently stimulated, the pressure is released, and the proppants in the fluid keep the cracks open by serving as props, without which the closure stress from the weight of the rocks above would quickly close the cracks. The network of cracks creates a large surface area through which petroleum fluids can flow and be extracted to the surface. As a result, fracking has enabled previously non-recoverable resources to be successfully retrieved. The primary beneficiary of this process is the extraction of resources from shale rock formations which, with their high porosity (capacity to hold fluids) and low permeability (ability to let fluids flow through), have historically prevented oil and gas to be extracted at economical volumes.