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Borehole Geophysics Research Laboratory (BGRL), a specialised institute under the Ministry of Earth Sciences is mandated to execute India’s sole Scientific Deep Drilling (SDD) programme.
- SDD is the enterprise of strategically digging boreholes to observe and analyse deeper parts of the Earth’s crust.
About Scientific Drilling at Koyna
- Objective: Strategically drill the Earth’s crust to a depth of 7 km and conduct scientific observations.
- Reason for choosing Koyna
- Recurrent earthquakes since the impounding of Koyna Dam (Shivaji Sagar Lake) in 1962.
- Most outstanding example of Reservoir Triggered Seismicity (RTS) located close to India’s west coast.
- Technique used at Koyna: Hybrid of mud rotary drilling and percussion drilling (air hammering).
- Rotary drilling: It uses a steel rod to cut rocks which generates heat. Cooling liquid or drilling mud cools the tools and removes debris from the borehole.
- Air hammering: It pushes highly compressed air through the drilling rod to deepen the borehole and flush the cuttings out.
Associated Challenges
- Labour and Capital-Intensive and requires meticulous planning and drilling acumen.
- Load on hook keeps increasing as the borehole gets deeper.
- Nature of Earth’s Interior (hot, dark, high-pressure region) hinders long and continuous operations.
Significance of Scientific Drilling at Koyna
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