When we fill up our cars to go to work, turn up the heat to stay warm in the winter, or board a plane for a much-anticipated vacation, one of the last thoughts on our minds is the process behind how the fuel we use gets to us. We’ve talked about how pipelines are the safest, most environmentally friendly, and most reliable option to deliver the oil and natural gas that fuels our lives. However, many people for a number of reasons still have misconceptions around how they’re built and the science that goes into constructing them. That’s why we’re going to dive into understanding horizontal directional drilling or HDD, a safe, precise, and environmentally conscious method of constructing pipelines that will be used on the upcoming Bluewater project.
The process above shows the distinct processes of Horizontal Directional Drilling.
What is it?
Horizontal directional drilling (HDD), is a construction method used to install pipes underground without disturbing the ground surface. HDD has become a preferred alternative to conventional pipe-laying methods like vertical drilling that require digging and excavation along the entire pipeline route. It’s also ideal for areas where trenching – ground that is generally deeper than it is wide and more narrow compared with its length – is too sensitive and needs to be avoided. This occurs under a railroad, an embankment, a highway, and beneath lakes and rivers.
How Does it Work?
Imagine you’re wearing a hoodie and when you go to adjust the drawstring, you notice that it’s stuck inside the hole that it was threaded through. To get it back out, you’ll have to carefully pull it back through that hole. If that scenario sounds familiar then you already have a general concept of how HDD works.
With that example in mind, we’ll break down the three main stages HDD consists of pilot boring, reaming, and pipe installation.
In this picture, a drill is boring into the ground on a job site.
Pilot Boring: Think of this stage as that hole in your hoodie that your drawstring will go through. For pipelines, boring involves drilling a deep and narrow hole in the ground (the pilot hole) along a designated path. An example of this at home would be drilling a hole in a piece of wood or reaming a lime for juice in your favorite cocktail. In pilot boring for pipelines, the drilling continues until it reaches the final length of its destination. Bluewater’s pilot boring process will extend for 24 miles where it’s out of sight and far away from coastlines, beaches, and tourism activities like fishing and sailing.
Fun fact: pilot holes normally range from 1 to 5 inches in diameter which is equivalent to roughly the size of a quarter to the size of a softball.
Reaming is a process that involves making a boring hole wider. Pipeliners use the same process that those in carpentry use.
Reaming: This is where the original pilot hole is enlarged to accommodate the pipeline. Depending on the size of the required hole, the reaming process may undergo several attempts to effectively and precisely enlarge the pilot hole.
Pipe Installation: We have the hole in our hoodie (pilot boring) and the expertly sized destination for the drawstring (reaming). Now all that’s left is to thread the drawstring from one hole to the other. Our hoodie is ready for the pipe installation process.
Pipelines are pulled through the initial boring hole until they reach their desired destination – like a fuel terminal, a platform, or a production area that supplies or stores the energy running through the pipe. Once the pipeline is put in place, it’s checked, surveyed, and tested with rigorous engineering and safety standards. The final step in the process is clearing the worksite of all equipment and restoring the environment to its preexisting condition. Now the energy or fuel source is ready for use at businesses and consumers that rely on it.
What are the Benefits?
HDD is a minimum impact process that – aside from the entry and exit point of the drill – takes place underground and out of sight. Because the pipeline is placed underground with precision-based equipment, it avoids and reduces threats to environmentally sensitive areas like wetlands, estuaries, rivers, and lakes. Using horizontal drilling is also faster compared to trenching, avoids significant surface excavation work, and allows the environment and worksite to be restored in a fraction of the time. Further, HDD technology allows project developers to minimize disruptions to existing modes of transportation at ports and other congested thoroughfares to keep commerce moving while developing new environmentally responsible energy infrastructure.
