Directional vs Horizontal Drilling

Directional and horizontal directional drilling (HDD) are related but distinct methods used for controlling the trajectory of boreholes. These are both trenchless techniques employed when installing underground utilities whereby a pilot borehole is drilled along a pre-planned route. The bore is then enlarged and the product pipe or casing is pulled through behind this.

Even though directional drilling is a broad term for any drilling method where the bore is intentionally steered in a specific direction rather than going straight down, including horizontally, it’s important to understand the difference when planning your installation project.

The following blog examines the key directional vs horizontal drilling differences. We also examine and emphasise the benefits of using directional drilling, including HDD, to install utility service lines when compared with traditional, open-cut trenching methods.

To find out more about directional vs horizontal drilling read on

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Key Directional vs Horizontal Drilling Differences

Before examining the benefits of using directional or horizontal directional drilling for your utility installation project, here’s a breakdown of the key differences between the two techniques:

Directional Drilling

Directional drilling is a broad term for any drilling method where the borehole is intentionally steered in a specific direction rather than going straight down. As such, the route trajectory can include vertical, slanted, or curved paths. This technique is commonly used in oil, gas and deep well applications, as well as for laying pipe, ducts or cables for utility installations.

Horizontal Directional Drilling (HDD)

HDD is a subset of directional drilling specifically designed for trenchless underground pipeline and utility installation. In particular, due to its ability to avoid obstacles both above and below the surface, this makes it a popular method used to navigate existing infrastructure or environmentally sensitive areas. Indeed, HDD is a popular choice for any installation project where pipework needs to be laid underneath roads, railways, rivers, buildings, conservation areas, or sites of special scientific interest (SSSIs), avoiding the need to reroute the installation.

Unlike directional drilling, where the trajectory is multi-directional (vertical, slanted & horizontal), HDD is mostly horizontal. It starts with a shallow-angle entry into the ground, before it gradually curves to a horizontal path (to avoid any obstacles) and then resurfaces at the exit point.

Comparative Summary: Directional vs Horizontal Drilling

In summary, directional drilling is a broad technique for guiding a borehole in different directions, mostly used in oil and gas applications. HDD, on the other hand, is a specialised trenchless method used for installing utilities with minimal surface disruption.

For the benefits of (horizontal) directional drilling, read on

The Benefits of (Horizontal) Directional Drilling

When it comes to choosing (horizontal) directional drilling over and above traditional open-cut trenching methods, the advantages are numerous. This makes HDD a preferred choice for installing service lines for water, gas, sewers, electricity and telecoms networks.

The key benefits of (horizontal) directional drilling include:

Minimal Surface Disruption: HDD allows for underground installation without extensive excavation, reducing disruption to roads, landscapes, and infrastructure.
Environmentally Friendly: Less soil disturbance minimises erosion and ecosystem damage, where HDD reduces any impact on rivers, wetlands, and other sensitive areas.
Cost-Effective: While the initial setup cost can be higher, horizontal directional drilling reduces costs associated with road closures, traffic control, and land restoration. HDD is also less labour-intensive compared to open-cut trenching.
Faster Installation: HDD can be completed faster than traditional trenching, bypassing obstacles like roads and buildings without the need for removal or reconstruction.
Versatility: unlike traditional trenching, horizontal directional drilling can easily be employed in a variety of soil conditions, including rocky and clay-heavy terrains. This makes HDD ideal for crossing under roads, rivers, railways, and builty-up urban areas.
Increased Durability: Pipes installed using horizontal directional drilling are typically deeper and less exposed to surface elements, reducing the risk of damage and increasing longevity. This equates to additional HDD cost benefits in the long-run.
Safer Operation: horizontal directional drilling reduces the risk of any incidents associated with open trenching, such as worker injuries and public hazards.

Overall, horizontal directional drilling is a more efficient, cost-effective, and environmentally friendly alternative to traditional trenching, especially in urban and sensitive environments.

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The Cost of (Horizontal) Directional Drilling

The cost comparison between (horizontal) directional drilling and traditional trenching depends on several factors, including project size, soil conditions, depth, and required restoration work. At EPS Trenchless Installations, we can provide you with a free, no-obligation (horizontal) directional drilling quote. However, here’s how the two methods generally compare:

1. Upfront Costs

(Horizontal) Directional Drilling: Typically has higher initial costs due to specialised equipment, skilled labour, and drilling fluid requirements.
Traditional Trenching: Generally lower initial costs since it requires standard excavation machinery and basic labour.

2. Labour Costs

(Horizontal) Directional Drilling: Requires fewer workers but skilled operators, making labour costs moderate to high.
Traditional Trenching: Can require more workers for digging, pipe laying, and backfilling, typically increasing overall labour costs.

3. Speed & Efficiency

(Horizontal) Directional Drilling: Faster installation in complex or urban areas, reducing indirect costs like traffic control and business disruption.
Traditional Trenching: Is often much slower, especially in congested areas, leading to higher project costs due to delays.

4. Surface Restoration Costs

(Horizontal) Directional Drilling: Lower restoration costs as it avoids road repaving, landscaping repairs, and environmental remediation.
Traditional Trenching: Higher restoration costs due to roadwork, replanting, and repairing disturbed infrastructure.

5. Suitability for Different Conditions

(Horizontal) Directional Drilling: More cost-effective for crossing roads, rivers, railways, and urban areas where trenching would be expensive or impractical.
Traditional Trenching: More cost-effective for open fields or rural areas where restoration needs are minimal.

6. Long-Term Maintenance & Durability

(Horizontal) Directional Drilling: Pipes are installed at a deeper depth, reducing exposure to external forces and lowering long-term maintenance costs.
Traditional Trenching: Shallower installations may be more prone to weather or other damage, leading to higher maintenance expenses.

In summary, while (horizontal) directional drilling has higher upfront costs, it invariably saves money in the long run by reducing restoration, traffic control, and environmental impact expenses. As industry leaders in trenchless solutions, we also offer other innovative techniques to minimise surface disruption and keep costs low. Our experienced engineers can advise on the most efficient and cost-effective method of completing your underground installation with precision and efficiency, avoiding the mess and disturbance of traditional trenching methods.