CONCEPT – SHALE GAS, FRACKING AND RISKS

Excellent study material for all civil services aspirants - begin learning - Kar ke dikhayenge!

CONCEPT – SHALE GAS, FRACKING AND RISKS

---

Read more on - Polity | Economy | Schemes | S&T | Environment

---

• What is groundwater? Groundwater is part of the water cycle and consists of water that has filtered into the ground from rainfall, snowmelt and rivers. In India, a large part of groundwater taken is used for public water supply, with the remainder being used for agricultural, industrial and other purposes. Groundwater is relatively higher in quality compared to surface water, and requires less treatment prior to use. Groundwater also provides flow to many rivers and wetlands and so sustains a wide range of ecosystems.
• What is shale gas? Shale gas is natural gas trapped in shales and clays, which are fine-grained, sedimentary rocks predominantly comprised of consolidated clay sized particles that were originally deposited as muds.

1. It is the decay of organic matter, in the form of algae, plant and animal derived organic debris that was deposited along with the very fine-grained sediments, that is the source of the shale gas.
2. The gas is produced from the breakdown of organic material as the muddy sediments are buried, pressurised and heated and turned into shale rocks.
3. The formation of the gas typically requires burial of shales to depths of a kilometre or more and many potential shale gas source rocks are found at those depths.
4. The shale is both the source and the reservoir for the natural gas, which is predominantly methane (approximately 90 %) but may also contain other hydrocarbons, carbon dioxide, nitrogen, hydrogen sulphide and rare gases.
5. The gas is held in natural fractures and pore spaces or adsorbed onto the organic material and minerals in the shale.

• How is shale gas extracted? It is challenging to obtain shale gas because it is bound to rocks at great depth. Unlike conventional drilling for hydrocarbons, drilling for shale gas combines horizontal drilling with hydraulic fracturing ("fracking").
1. Horizontal drilling, sometimes to more than 1500 m away from the vertical wellbore, greatly increases the length of contact between the shale gas formation and the wellbore relative to a conventional vertical well, and hydraulic fracturing releases shale gas to enable it to be retrieved in commercially viable quantities.
2. Hydraulic fracturing fluids can contain a variety of toxic chemicals such as diesel fuel, acids, and acetone.
3. Though industry proponents of the practice assert that only a small fraction of the fluid volume used in any fracturing operation consists of chemicals, because of the large volume of fluids needed for each “frack job”—sometimes millions of gallons—the chemical components of fracturing fluid can amount to tens of thousands of gallons.
4. Hundreds of different types of chemicals are used in fracturing operations, many of which can cause serious health problems — some are also known carcinogens. After hydraulic fracturing takes place, both the waste fluid that is brought back to the surface as “flowback” as well as the fluids that remain underground can contain toxic substances that may come back.

Read more on - Polity | Economy | Schemes | S&T | Environment

---

---

---

---

---

---

---

---

---

---

---

---

---

Join UPSC Self Prep course | Online Course (PT Gurukul)  | Covid Special Course | Join PT courses

* Content sourced from free internet sources (publications, PIB site, international sites, etc.). Take your own subscriptions. Copyrights acknowledged.