INTRODUCTION TO OFFSHORE

STRUCTURES

An oil platform, also referred to as an offshore platform or oil rig is a large structure facilities to drill well and also to extract oil and natural gas (Hydro carbons).

They may be fixed, complaint and floatable.

Definition

These are fixed structures built with concrete or steel legs anchored on the sea bed.

Gravity platforms Jacket platforms

Fixed Platforms

Gravity platform

These are jacked up above the sea using legs that can be lowered, much like jacks. They are employed only for drilling wells and in shallow waters around 550 feet.

The body structure and legs are connected by RACK and PINION mechanism.

Jack up Drilling Rigs

A semi-submersible is a specialized marine vessel with good stability and seakeeping characteristics. The semi-submersible vessel design is commonly used in a number of specific offshore roles such as for offshore drilling rigs, safety vessels, oil production platforms and heavy lift cranes.

Semi-submersible

These are small in size but operates in deep waters.

Guyed tower TLP’s SPAR Articulate tower These are connected to sea bed allowing

them to move freely to external forces.

COMPLIANT STRUCTURES