Hydraulic fracturing is the process of creating, and then reproducing a series of fractures within a well. Millions of gallons of fracturing fluids are then mixed with a proppant material, and pumped into the well. Hydraulic fracturing produces a highly permeable drain that can increase the exchange of fluids between a well and a reservoir of water, as well as the production of various hydrocarbons.
The first hydraulic fracking job was conducted on limestone deposits in July of 1947. Since that time, thousands of fracking operations have been done around the world, and it’s only been in the last decade or so that fracturing technology has improved greatly. Fracking has recently become more sophisticated in regards to design and fluid modeling, as well as newly developed technology involving the use of metrology.
Domestic natural gas production in America was in decline during the 1970s and 1980s. The gas industry and the Federal Power Commission worked together to develop new methods of drilling and extracting natural gas; the most extensive of which was to drill for natural gas from shale deposits. This process sparked the modern gas boom.
Prior to the modern gas boom, fracking had mostly been performed on relatively soft minerals, like limestone. In order to tap a harder substance like shale, new innovations needed to be made. These included the utilization of diamond-studded drill bits, microseismic imaging, and horizontal drilling.
In the use of hydraulic fracking, a proppant is necessary to ensure that the process is carried out successfully. A proppant is a material that keeps fractures open, and is used either during or after a fracking treatment.
Fluids used for hydraulic fracturing consist primarily of water, but include various other additives as well. The amount of chemical additives used in fracking depends mostly on the specific well being treated.
There are three types of fracking fluids; gel, foam, and slickwater-based. Slickwater fluids are made up of generally 99% water, and sometimes even more than that. A common additive in hydraulic fracturing fluid is hydrochloric acid. This is chosen due to its chemical properties. Hydrochloric acid has a low pH, and can therefore dissolve and etch certain rocks, such as limestone. Other additives include friction reducers and guar gum. Radioactive tracer isotopes are occasionally placed into the hydraulic fracturing fluid in order to determine the injection profile and location of fractures.