Shale is the most common type of sedimentary rock on Earth. They are the parent rocks of hydrocarbons that migrate further into permeable reservoir rocks and serve as covers, forming oil and gas traps in the underlying sedimentary rocks. Until recently, specialists in the oil and gas industry, as a rule, considered these rocks to be nothing more than obstacles that they have to put up with when drilling wells for targeted productive sandstones and limestones.
Hydrocarbon production from shale deposits is not new, and began long before the advent of the modern oil and gas industry. In 1821, a few decades before the first oil well was drilled, an industrial shale gas well was drilled in the United States in the town of Fredonia, New York.
Currently, shale gas production has become a more frequent case and involves horizontal drilling and hydraulic fracturing. The whole point of this method is that a horizontal well is laid through a layer of gas shale. Then, tens of thousands of cubic meters of water, sand and chemicals are pumped into the well under pressure. For each drilling, up to 26 thousand cubic meters of special solution are needed.
As a result of the fracture, gas flows through the cracks into the well and then already enters the surface. This technology carries enormous environmental damage. Independent environmentalists have estimated that a special drilling fluid contains more than 596 chemicals, which also include: corrosion inhibitors, thickeners, acids, biocides, inhibitors for shale control, gelling agents.
The main difference between shale gas production and natural gas is the need to drill several wells and the presence of hydraulic fracturing is necessary, which can lead to tectonic movements of the earth's crust. I would also like to note that the resources of the shale well are running out after a year of use.
About 200 tons of sand and 4,000 tons of water, which subsequently cannot be used anywhere else, are required for shale gas production, just as a well drilled in shale rocks cannot be mothballed.
The cost of shale gas production is two times higher than natural. Shale gas is of average quality, so it needs additional processing;
Groundwater and soil receive huge damage from shale gas production as a result of the penetration of the explosion mixture into the rock mass. Water contaminated with chemicals, which after the explosion and gas production is again pumped into the devastated formations, can lead to an earthquake of small capacity, but of great environmental disaster;
Also modern for people living near places of gas production, the occurrence of diseases of the respiratory tract and skin.
Currently, oil shale is used as fuel and energy-chemical raw materials. From shale ore receive:
Phenols, adhesives, plasticizers, chemicals to combat soil erosion and weeds.
Refined shale gas has the same physical properties as traditional natural gas and is used as fuel.
Oil from shale can be used directly as fuel or refined at an oil refinery. In the process of processing, sulfur and nitrogen impurities are removed, and hydrogen is added to hydrocarbons. Processing products are:
Gasoline, diesel and fuel oil. Use these products in the same way as from ordinary oil.
To date, shale gas is produced: the USA, Iran, Canada, Norway, China, the Netherlands, but the United States is the largest producing country;
Shale gas is one of the types of resources that can replace natural gas, but for successful replacement, you must first create an environmentally friendly technology for its production.