Drilling rigs come in multiple designs, each engineered for a specific environment and operational challenge.

Whether operating on land, in shallow coastal waters, or in ultra-deepwater fields, every rig type is selected based on technical requirements, target depth, and local conditions.

These rigs form the backbone of safe, efficient oil and gas exploration and production.

Below is an overview of the major categories of drilling rigs used to drill oil and gas wells.

1. Land-Based Rigs

Land rigs operate on solid ground and can be moved between drilling locations.

They are commonly used for shallow, intermediate, and deep onshore wells.

Conventional Drilling Rigs

These rigs feature a fixed mast or derrick and are built for long-term, heavy-duty drilling.

They support large-diameter, deep wells and offer strong operational stability.

After finishing a well, the rig is dismantled, transported to the next location, and reassembled.

Mobile Rigs

Mobile rigs place most of the drilling equipment on a truck, trailer, or skid.

They move quickly between well sites and reduce relocation time.

While more portable and cost-effective than conventional rigs, they have lower drilling capacity.

Larger components like mud tanks and power systems are transported separately and connected at the site.

2. Mobile Offshore Drilling Units (MODU)

MODUs are designed for offshore drilling and can relocate from one offshore well to another.

The type of MODU used depends largely on water depth.

Barge Rigs

Barge rigs operate in very shallow waters such as swamps, marshes, rivers, and inland lakes.

They are floated or towed to the site and then partially submerged for stability.

Many can rest directly on the seafloor.

With their extremely shallow draft, they typically operate in water depths of 10–15 feet.

Jack-Up Rigs

Jack-up rigs are used in shallow offshore waters.

They stand on long legs that penetrate the seabed, lifting the working deck above the waves for stability.

These rigs are common for exploration and development drilling in water depths up to about 500 feet.

Because they cannot self-propel, they require a separate vessel for towing.

Semi-Submersible Rigs

Semi-submersibles float on large hollow pontoons and remain partially submerged, offering strong stability in rough seas.

Some are self-propelled, while others must be towed.

They rely on sophisticated anchoring or computerized station-keeping systems to maintain position.

Semi-submersibles typically operate in water depths from 1,000 to 3,500 feet and offer a steadier platform than drillships.

Drillships

Drillships resemble oceangoing vessels and are fully self-propelled.

They are equipped to drill in ultra-deepwater, often between 1,000 and 10,000 feet.

Dynamic positioning systems allow them to maintain exact location over the well without anchors.

Their mobility makes them ideal for remote offshore fields.

3. Platform Rigs

Platform rigs are installed on long-term offshore structures built above productive reservoirs. They support both production and drilling operations.

• Fixed Platforms: Permanent structures anchored directly to the seabed, suitable for shallow to moderate water depths.

• Tension-Leg Platforms (TLPs): Floating platforms held in place by tensioned vertical tendons, allowing installation in deeper waters while maintaining stability.

4. Slimhole Rigs

Slimhole rigs drill smaller-diameter wells and are often used during early-stage exploration.

They consume less energy, require smaller drilling fluid volumes, and reduce overall drilling costs.

This makes them a practical choice for evaluating formations before committing to full-scale development.