Walking with Giants - How Rigs Walk to Work

Innovation in Oil and Gas

The oil and gas industry has long been known for its problem solving and innovation. Who can forget Shell’s iconic pictures of the Brent platforms being towed from the construction site in Stavanger, Norway (Bravo and Delta) to their final destination in the North Sea Brent Field. And this was in the early 1970s. Anyone today, not knowing the history, would just assume these were AI generated. For you youngsters out there, these images are real!

Photo credit, Energy Voice available at: https://www.energyvoice.com/promoted/123736/shell-brent-stunning-images-incredible-north-sea-field/

In our industry, we constantly come across problems, and we solve them. From the smallest, simplest jerry-rigged system to mind-boggling complexity such as the Brent platforms. I remember once, while monitoring drilling operations from the comfort of my heated office, realising something was not quite right. When I got to the drill floor, I found the driller had crafted a series of pulleys and ropes. He was operating the rig, that controlled millions in downhole technology, by flicking a foot tied to a loop in the rope while reading a newspaper.

Speaking of innovations, one that never fails to impress me are rigs that walk between wells. These walking rigs are a relatively recent innovation, allowing operators to drill multiple wells from a single pad with unprecedented efficiency.

A Brief History of Drilling Rigs and the Rise of Walking Technology

The story of drilling rigs dates back centuries. Around 200-600 BCE, the Chinese developed percussion drilling methods using bamboo poles and iron bits to access brine and natural gas. These rigs pounded the earth repeatedly to create wells. Fast forward to 19th century US, simple percussion drilling systems (called cable rigs) powered by steam engines, were widely used.

The transition to rotary drilling in the early 20th century was a significant technology leap, enabling much deeper, faster wells, transforming our access to available resources. However, these large drilling units and all their associated equipment remained stationary. These required full disassembly, transport between wells and re-assembly at the new site. This labour-intensive process can take days or weeks depending on the rig. A typical 2,000 HP land rig contains 150-200 different packages and can take 5-7 days to "Rig up" and down at a different well site. This used to be as necessity, even if the rig was moving just a few meters.

Amid the shale boom in 2010, Continental Resources introduced the ECO-Pad rig in North Dakota, a hydraulic walking system that could move 100’s of feet between wells in just a few hours. This had a huge impact on rig moves and significantly reduced operational downtime. This innovation was built on earlier rigs that used rigid fixed beams that allowed “skidding” between wells. This skidding method is also commonly used on large offshore platforms that have fixed drilling units. Unlike skidding, walking uses independent "legs" for versatility on uneven terrain.

Economics

There is no getting around it, one of the key benefits to Operators are the cost savings. Disassembling, transporting and reassembling a rig to a new well site is a significant portion of the cost of a well. And it’s not just cost, time is an extremely important factor. With the introduction of rig walking, Bentek Energy analysis in 2012, showed the averaged time to drill a horizontal well in the Eagle Ford shale formation was reduced by about 17%, from 23 days down to 19 (https://www.eia.gov/todayinenergy/detail.php?id=7910).

Less time per well means more wells brought on stream over a given period, potentially transforming production.

Saving Lives and the Environment

The advantages are not just cost saving, these systems offer huge safety and environmental improvements also. Rigging up and down is labour intensive involving hundreds of heavy lifts and is the source of many tragic accidents.

Modern day multi-pad well-sites concentrate development to a much smaller area. This is crucial in environmentally sensitive areas where wildlife are easily disturbed, such as in Africa. A great example of a government looking to maximise the economic benefit that oil and gas can bring, while minimizing environmental impact is the Tilenga field in Uganda. This field is planned to have 426 wells divided amongst 31 well pad sites. Just imagine the disturbance if this had been 426 different well sites with associated connecting roads! (reference: https://www.pau.go.ug/the-tilenga-project/).

How the Technology Works: Step-by-Step Mechanics

A walking rig uses a hydraulic system to lift, shift, and lower its structure, often weighing millions of pounds, in a controlled, step-like motion. Here's how it operates in practice:

1. Preparation: The rig is aligned toward the next wellhead on the pad. Walking feet (steel plates or skates) are positioned via travel mechanisms, and the rig rests on its substructure or mats.

2. Lifting: Hydraulic jacks or cylinders raise the entire rig off the ground, transferring the load to the feet. This precise lift handles enormous weights without compromising stability.

3. Advancing: Travel cylinders propel the rig forward in increments, typically a few feet per step. Roller chains, skates, or pads enable smooth sliding or rolling, allowing movement in any direction, including 360-degree rotation.

4. Lowering: The rig is lowered back onto the ground, unloading the feet.

5. Resetting: The feet are repositioned forward, and the cycle repeats until the rig is positioned accurately over the new well.

This process occurs at about 30-50 feet per hour, while the rig remains in operational ready state. Modern systems feature remote controls, sensors for precision, and automation to minimise errors.

For more information and some excellent video examples, try search “walking pad rigs” in your favourite search engine or video provider.

The Future

One of the most significant trends shaping the future of rig walking is the integration of automation. Automated systems facilitate more precise movements and scheduling, reducing human error while increasing operational efficiency. This shift towards automation streamlines workflows and reduces human exposure further improving safety.

Another key development is the incorporation of artificial intelligence (AI) within rig walking functionalities. AI can rapidly analyse vast amounts of data to predict potential failures or optimize rig movements in real-time. This level of predictive analytics can significantly reduce downtime and improve maintenance scheduling.

As AI technology continues to mature, its role in Oil and Gas can only expand bringing further technologies we can only imagine today.

Conclusions

From an industry perspective, embracing emerging technology is crucial for Operators to remain competitive in a rapidly evolving energy mix. While we remain reliant on Oil and Gas for the foreseeable future, technological innovation will continue paving the way for a more sustainable and advanced future. As the Oil and Gas industry winds down in my own geographical region (UK), I have no doubt the baton of innovation will be passed along to future locations and generations.