Definition of terms and explanatory notes. The Official Methods of Analysis was first released in electronic format, as a companion to the print Official Methods of Analysis of AOAC INTERNATIONAL, 18th Edition, in 2005. For new and revised methods approved since 2005, see adoption/revision date for each method. These dates are located in either the header block at the top of the method for major modifications, or in a revision line at the bottom of the method for minor editorial revisions.
They are also known as unconventional because of the novel techniques â like fracking and horizontal drilling â used to extract the gas. Unlike shale gas, coalbed methane extraction doesnât always involve fracking â at least not in the early years of a development.hale gas and coalbed methane are known as 'unconventional' because unlike conventional sources which are found in larger, easier to access reservoirs, the gas is trapped in tiny little pockets in the shale rock or coal seams.
What is Fracking? âFrackingâ is short for hydraulic fracturing, or hydrofracking. It is the process of injecting frack fluid, a mixture of water, sand and chemicals, at high pressure into shale to fracture the rock, thereby releasing trapped natural gas. Marcellus shale is a layer of black rock that lies 3,500-8,000 feet below the surface and is the current target of fracking. Most of West Virginia is underlain with this shale; in West Virginia the vertical depth of the formation itself is approximately 150 feet. The formation also extends into Pennsylvania, New York, Ohio, and Virginia. Fluid recovered from the well after the fracking is completed is called flowback fluid or waste water.