In which of the following regions of India are shale gas resources found?

Answer: (d) 1, 2 and 3

Shale gas sits in the same sedimentary basins that hold conventional oil and gas, so all three qualify.

Statement by statement

1. ✓ YES Gujarat’s Cambay basin — India’s oldest onshore oil basin — is one of the six identified for shale gas.

2. ✓ YES Tamil Nadu’s Cauvery basin holds both conventional oil/gas and shale prospects.

3. ✓ YES The KG basin, famous for offshore gas, also has shale layers onshore.

The idea

Shale gas remains trapped in very fine-grained rock rather than collecting in an easily flowing reservoir. A sedimentary basin can contain both shale and conventional reservoirs. Geological potential does not mean that commercial extraction has begun.

Organic matter settles with fine sediment → Burial adds heat and pressure → Gas forms within shale → Low permeability limits its movement → Horizontal drilling reaches more rock → Fractures provide paths towards the well

Why the others are wrong

(a) Drops KG — thinking of it only as a deep-sea conventional gas field. It has onshore shale too.

(b) Keeps only KG, the famous gas basin. Shale is not tied to one basin — it sits in all the old sedimentary ones.

(c) Drops Cambay — India’s oldest onshore oil basin is also on the shale list.

The trap

KG and Cauvery are known for conventional oil and gas, so people think shale must be somewhere else. The same sedimentary basins hold both.

Also know

Coal-bed methane is held within coal seams; shale gas is held in shale, and gas hydrates trap methane in ice-like solids. The Damodar region is associated with coal-bed methane as well as shale prospects. Drilling and fracturing need water, so resource assessment must also consider local water stress.