Horizontal Drilling Services

Deltek provides horizontal drilling (horizontal directional drilling / HDD) across every region of Türkiye from its Istanbul and Izmir offices: trenchless crossings from 2 to 2000 mm for natural gas, water, sewer, power and fibre-optic lines under rivers, motorways, railways and city streets. The feasibility study and site survey are free of charge; instead of a flat rate per metre we prepare a project-specific quotation.

Request a quote · What determines the cost

Horizontal Drilling

In the modern understanding of urban planning, horizontal drilling technology has become one of the most important innovations in the infrastructure sector. Thanks to this special method, underground utility lines are installed with minimum interference in the daily life of the city. What is horizontal drilling, how is it applied and what advantages does it offer? In this article you will find all the technical and practical details of horizontal drilling technology.

Fundamentals of Horizontal Drilling Technology

Horizontal drilling is the controlled driving of a tunnel underground. The technology is preferred especially in dense residential areas, on heavily trafficked streets and in environmentally sensitive areas. Using a steerable drill head, the target point is reached with millimetre precision. With growing infrastructure investment in Türkiye in recent years, demand for horizontal drilling grows every year.

Although the working principle of the system is quite complex, its basic logic is simple. A specially designed horizontal drilling rig cuts through the ground with a combination of rotation and forward thrust. A locating system (walk-over or wireline) keeps the route under continuous control, and the operator can clearly see the position of the drill head at every stage.

How Is HDD Carried Out? Pilot Bore, Reaming and Pullback

Horizontal directional drilling is carried out in three stages:

Pilot bore: After the entry and exit points are prepared, the drill head is advanced along the designed profile. A transmitter inside the head lets position, depth and pitch be read from the surface at every rod; steering is done by pushing the bevelled (asymmetric) head without rotation.

Reaming: The pilot bore is enlarged in stages with reamers attached on the exit side. The final bore diameter is usually planned at 1.2 to 1.5 times the pipe diameter.

Pullback: The prefabricated pipe string is pulled from the exit point towards the rig and installed underground; pull force and friction calculations govern this stage.

A step-by-step account of the stages with site photographs is on the HDD Construction Method page; the definition and history of the method are on What Is HDD?.

Anatomy of a Horizontal Drilling Rig

Engine and Power Unit

The heart of a horizontal drilling rig is its high-performance engine. These engines are usually diesel and come in a range of power options: from 75 hp in compact models up to 500 hp for large projects. Choosing the right power unit directly affects the efficiency of the horizontal drilling project.

Most modern horizontal drilling rigs have environmentally friendly emission control systems, and sound insulation means they cause no disturbance in urban applications. Fuel-injection technology optimises consumption and provides economic efficiency on long drilling operations.

Steering and Control System

The most critical part of a horizontal drilling rig is its precision steering system, which combines a transmitter in the drill head, electromagnetic receivers at the surface and sensors reading depth, pitch and roll. Real-time position data is read from the screens in the operator cabin and the bore path is kept under constant control.

The angle, depth and direction of the drill head are monitored continuously. Obstacles are detected immediately and the route adjusted. In this way the target point is reached without deviation, and the risk of damaging existing underground lines is minimised.

Fields of Application for Horizontal Drilling

Telecommunications Infrastructure

Horizontal drilling has become indispensable for fibre-optic cable installation, and is frequently used in building 5G network infrastructure. It offers internet service providers a fast and reliable solution; cable lines reach their destination without damaging the surface or closing roads.

Fibre-to-the-building projects in city centres suffer minimal loss thanks to horizontal drilling. It offers important advantages in customer satisfaction and project time, especially where uninterrupted service in busy business districts matters.

Water and Wastewater Systems

Horizontal drilling is frequently preferred in municipal infrastructure projects. It is the ideal solution for potable water distribution mains, wastewater collection systems and stormwater drainage.

The method is especially valuable in renewal work where existing infrastructure is present. The surface is not damaged while old lines are replaced, and roads, pavements and landscaping are preserved thanks to horizontal drilling.

Power Transmission Lines

Electricity distribution companies use horizontal drilling widely. It offers important safety and aesthetic advantages in underground cable installation; in tourist areas visual pollution is prevented and the urban aesthetic preserved.

In natural gas distribution lines, horizontal drilling is preferred for both safety and cost. Maximum efficiency is achieved with minimum risk in sensitive underground work.

Planning Process in Horizontal Drilling Projects

Preliminary Investigation and Mapping

Every horizontal drilling project starts with detailed preliminary investigation. Existing infrastructure maps are examined and the positions of underground utility lines determined. Geological analysis calculates soil type and degree of compaction.

3D modelling is used at this stage. The route is simulated on computer and possible problems are identified in advance. Risk analysis evaluates alternative horizontal drilling routes and the most suitable route is chosen.

Permits and Coordination

Horizontal drilling projects require permits from various institutions. Coordination is established with the municipality, the water and sewerage authority and the electricity distribution company.

Traffic management is planned at this stage. Working hours, safety measures and emergency plans are prepared. Risk assessment is completed with occupational safety specialists before drilling starts.

Selection of Technical Equipment

The appropriate horizontal drilling rig is chosen according to the size and difficulty of the project. Soil type, bore length and diameter requirements are evaluated and the equipment configuration determined.

Spare-part supply, maintenance planning and operator training are completed at this stage. Quality control systems are commissioned and measuring instruments calibrated ready for the drilling operation.

Strengths of Horizontal Drilling Technology

Environmental Protection

Thanks to horizontal drilling, trees, landscaping and green areas are preserved. Interference with natural habitats is kept to a minimum. Soil erosion and habitat damage are prevented, which makes horizontal drilling the only viable option in environmentally sensitive areas.

It also offers important advantages for air quality: far less dust and noise are produced than with conventional excavation, and the negative effect on city life is minimal.

Economic Efficiency

Cost optimisation in horizontal drilling projects is striking. Road repair costs, traffic management expenses and labour costs are substantially reduced.

Because the project is short, indirect costs fall too. Commercial losses, transport problems and public inconvenience stay at a minimum, which makes horizontal drilling one of the most economical infrastructure solutions in the long run.

Technical Precision

Modern horizontal drilling rigs work with millimetre precision. The success rate of reaching the target point is high — a precision that matters greatly on critical infrastructure projects.

Quality control systems provide continuous monitoring. Any deviation is detected immediately and corrective action taken to keep the horizontal drilling line from leaving its route.

Challenges in Horizontal Drilling Applications

Geological Obstacles

Horizontal drilling in rocky terrain involves technical difficulty. Special drill heads and powerful engines may be needed. Project cost may rise in such cases, but it still remains more economical than conventional methods.

In areas with a high water table, water control becomes important. Drainage systems and water pumps may be needed. The intervention of experienced crews is critical to a successful horizontal drilling operation in such difficult ground.

Density of Existing Infrastructure

The density of existing cables and pipes in city centres can affect the horizontal drilling route, requiring detailed planning and precise application.

Electromagnetic detection systems are used to locate existing lines. Work is carried out while maintaining safety distances, and potential damage is avoided.

DELTEK’s Horizontal Drilling Experience

One of the pioneering companies in the sector, DELTEK has more than 20 years of broad experience in horizontal drilling. With our modern rigs and expert team we provide quality service at every scale.

We deliver horizontal drilling services across the country from our Istanbul and Izmir offices. With a customer-focused approach we develop solutions specific to different ground conditions and project sizes.

Quality Assurance and Standards

International quality standards are applied in horizontal drilling projects. Processes are managed within the ISO 9001 quality management system.

For occupational safety, the relevant OHS standards are met. Drilling work is carried out under ISO 14001 environmental management certification.

Other Trenchless Methods and Choosing the Right One

HDD is not the answer to every crossing. When the diameter approaches 2000 mm, when a gravity line needs millimetre gradient control or when the ground is full of cobbles, the pipe pushing, auger boring and microtunnelling methods described under three headings on the pipe jacking page take over; where an old line is to be replaced without excavation, trenchless pipe bursting is used.

The choice is made by ground formation, pipe diameter, line length, groundwater level, density of existing utilities and environmental constraints together: horizontal directional drilling stands out for long routes and flexible profiles, auger boring for medium and large diameter short crossings, and microtunnelling for precise gradient control and ground below the water table. If you are not sure which method fits, contact us with your geotechnical report; our tender states not only the price but why we chose that method.

Frequently asked questions

What diameters can be installed by horizontal drilling? Deltek installs pipes and cables from 2 mm up to 2000 mm by HDD; above 2000 mm, pipe jacking or microtunnelling is considered.

Which ground conditions are suitable? Clay, sand, gravel and rock; rock drilling uses a separate tooling set with a mud motor and dedicated bits. Ground type is the single factor that changes duration and price the most.

Where do you work? From our Istanbul and Izmir offices to every region of Türkiye: river, highway, railway and urban crossings.

When should HDD be preferred over open-cut? Whenever there is a road that cannot be closed, a surface that cannot be disturbed or a watercourse to cross above the alignment. We compare the two methods in a separate article.

What information do you need for a quotation? Crossing length, pipe diameter and material, geotechnical report, the structure to be crossed and the location. Site survey and feasibility are free of charge; see what determines the cost.

Conclusion and Recommendations

Horizontal drilling technology has become an indispensable part of modern infrastructure projects. Thanks to this environmentally friendly, economical and effective method, the infrastructure of our cities is being strengthened.

If you are looking for a reliable horizontal drilling partner in the sector, DELTEK is the right choice. With our experienced team, quality rigs and customer-focused service approach, we guarantee success in your projects.

Contact us for your horizontal drilling projects. Let us develop the most suitable solution together.