What is Shale
Shale is a sedimentary rock that is essentially fossilized mud, made up of a mixture of clay mineral flakes and microscopic, silt-sized particles of quartz and calcite. Sedimentary rocks such as shale and limestone are formed through the laying down and solidification of mineral sediments over time that have been deposited in a pancaking fashion by rivers, lakes, oceans, glaciers and wind. Fossils are often found embedded within the parallel layers of shale, and these layers, like the pages of a book, are especially effective for interpreting the geological record.Shale Oil Extraction
The extraction of oil from deposits of shale is an industrial process that produces what is known as "unconventional oil" - derived from non-crude and non-natural gas sources that include oil sands, tar sands and shale. The process of shale oil extraction converts kerogen - solid, fossilized organic matter found within sedimentary rocks that consists of immense deposits of carbon - into viable petroleum products via pyrolysis, hydrogenation or thermal dissolution. The resultant product is either a fuel oil or it can later be refined to satisfy feedstock specifications with the introduction of certain additives and the removal of impurities such as sulfur and nitrogen. Shale oil, often referred to as "synthetic crude" can be extracted and heat processed using a variety of aboveground and below ground techniques. The most common extraction process of decomposing shale to become an oil is via pyrolysis, also known as destructive distillation, whereby the shale is heated to produce condensable shale oil vapors and non-condensible oil shale gas. This vapor and gas is then collected and cooled, which causes the oil to condense. A byproduct of oil shale processing is "spent oil shale," a solid, carbonaceous, char residue that can be burned off to produce oil shale ash, which can then be used as additives for the manufacturing of cement and bricks.Shale Energy Development and Economics
Shale energy development has been in existence since the late 1600's, where it was first extracted in Great Britain before becoming widespread all the way up through the 19th century. Shale development later waned in the mid 1900's with the availability of large conventional crude oil reserves, but with the intermittent spikes in petroleum prices during the last 20 years, a renewed interest in shale energy development has emerged. Often tied to a lack of domestically available crude oil resources, Estonia, Brazil and China currently lead the charge in shale oil extractive industries. The economic viability of shale oil and its production is often under question, taking into account the cost of extraction and processing in relation to the price of petroleum. Economists, environmentalists and investors often ponder whether the viable energy ratio of the finished product exceeds the energy used in the extraction and refinement process. Water usage is another economic consideration, especially in areas where it is in short supply.
Shale Oil Environmental Concerns
Economists and environmentalists alike have long been concerned with the extractive processes associated with the production of shale oil. They state that waste disposal, water use, waste water management, and air pollution all contribute to environmental management issues that make shale oil development potentially unsustainable and economically non-viable. Whether through the process of surface or underground mining and with currently available technology, critics state that the introduction of chemicals and metals such as mercury into surface and groundwater, the exposure of previously buried toxic materials, erosion, and air pollution are the main reasons for being averse to further shale energy development. Shale development has been labeled to be more environmentally detrimental than the extraction and refinement of conventional petroleum products, producing higher levels of greenhouse gas emissions and generating a significant volume of waste water.Â