Jawaharlal Nehru Technological University Hyderabad B.Tech III DRILLING TECHNOLOGY Previous Question Paper (March - 2021 - R15)

The drilling rig is the primary integrated system of machinery used to penetrate the earth's crust to access subsurface resources. Its importance lies in its ability to provide the necessary mechanical power, structural support, and fluid circulation required to create a borehole safely and efficiently.

Key functions include:

• Hoisting: Supporting the weight of the drill string and casing using the derrick and drawworks.
• Rotating: Providing the torque necessary to turn the drill bit via the rotary table or top drive.
• Circulating: Managing the drilling fluid system to remove cuttings, cool the bit, and maintain hydrostatic pressure to prevent blowouts.
• Pressure Control: Utilizing the Blowout Preventer (BOP) stack to seal the wellbore and manage formation pressures.

Drilling rigs are classified based on their mobility, power source, and the environment in which they operate. The main types include:

• Land Rigs: These are mobile units mounted on trucks or trailers (for shallow depths) or modular structures (for deep drilling) that can be disassembled and transported across land.
• Jack-up Rigs: Used in shallow offshore waters, these rigs have movable legs that can be lowered to the seabed, allowing the hull to be elevated above the water surface.
• Semi-submersible Rigs: Designed for deeper waters, these float on large pontoons and are anchored or kept in position using dynamic positioning systems.
• Drillships: Self-propelled vessels equipped with drilling equipment, ideal for deep-water exploration due to their high mobility and large storage capacity.
• Platform Rigs: Fixed structures permanently installed on the seabed for long-term production drilling in offshore fields.