Semi-submersible rigs are floating platforms used in offshore drilling for oil and gas. They are designed with large buoyant columns that keep the rig stable and above water, even in rough sea conditions. This stability allows for safe drilling operations in deep waters. These rigs are anchored to the seabed with mooring lines, which helps them maintain their position. Semi-submersible rigs can operate in various water depths and are often used in areas where traditional drilling platforms are not feasible, making them essential for the oil and gas industry.