OB3 Gas Pipeline: How PCE Completed the River Niger HDD Crossing

The Obiafu–Obrikom–Oben (OB3) Gas Pipeline is a major part of Nigeria's gas infrastructure, designed to connect the country's eastern gas network with major transmission systems in the west. The approximately 130-kilometre pipeline is intended to improve domestic natural gas transportation and support supply to power plants, industries and other facilities.

One of the most challenging sections of the OB3 Gas Pipeline was its crossing beneath the River Niger, between Ndoni in Rivers State and Aboh in Delta State.

The project required a 48-inch gas pipeline to be installed along a 2,000-metre underground route, reaching a depth of 52 metres. Sand, gravel and rock formations added to the engineering requirements, making the crossing an important part of the wider pipeline construction programme.

Following our work on the AKK River Niger crossing, PCE Nigeria was contracted by Nigerian Gas Infrastructure Company (NGIC) to execute the specialist OB3 crossing package. We used Horizontal Directional Drilling (HDD), combining dual-rig intersecting technology, synchronous reaming, high-capacity drilling equipment and a specially developed drilling-fluid formulation.

We completed the OB3 River Niger crossing on 28 April 2026, completing an important underground connection within the wider gas pipeline project.

Horizontal Directional Drilling (HDD) is a trenchless construction method used to install pipelines beneath obstacles without excavating an open trench across the entire crossing route.

For the OB3 Gas Pipeline, HDD provided a method for installing the 48-inch pipeline beneath the River Niger while reducing direct disturbance to the riverbed.

The scale of the crossing created significant technical requirements. At approximately two kilometres, the underground route required drilling equipment capable of operating over a substantial distance, while the 48-inch pipeline needed a sufficiently large borehole for installation.

The geological conditions introduced further complexity. The route passed through sand, gravel and rock formations, each presenting different challenges during drilling. Loose sand and gravel can affect borehole stability, while rock formations require suitable cutting tools and effective removal of excavated material. These conditions influenced the drilling method, equipment selection, borehole enlargement and drilling-fluid requirements.

For our team at PCE Nigeria, completing the crossing required an approach that considered each stage of construction, from pilot-hole drilling through to the final pipeline pullback.

Equipment selection is particularly important for long-distance, large-diameter HDD projects. The drilling rigs must provide suitable torque and pulling capacity while supporting the planned construction method.

For the OB3 River Niger crossing, we deployed two high-capacity HDD rigs:

These rigs formed part of the dual-rig construction arrangement, supported by specialist drilling tools, guidance systems, drilling-fluid equipment and coordinated field operations. Rig pulling capacity is an important equipment specification, but it should not be confused with the actual force applied to the pipeline during installation.

The required pulling force depends on pipeline weight, borehole geometry, friction, geological conditions and the installation method. For OB3, equipment selection had to account for the crossing's length, depth and the requirements of installing a 48-inch gas pipeline.

The first major stage of HDD construction is pilot-hole drilling. A pilot hole is a smaller underground opening drilled along a planned alignment, establishing the route that will later be enlarged to accommodate the pipeline.

For the OB3 crossing, we used dual-rig intersecting technology, which involves drilling from opposite sides of the crossing, with the pilot holes guided towards a planned underground intersection.

Specialist guidance systems help drilling teams monitor the direction and position of the drilling assemblies as they advance. For OB3, accurate guidance was essential because the two pilot holes needed to connect underground while maintaining an alignment suitable for reaming and pipeline installation.

The approximately 2,000-metre crossing also required close coordination between drilling teams working from opposite sides of the River Niger. Changes in geological conditions or drilling resistance could influence operations, making monitoring and communication important throughout pilot-hole construction.

The completed pilot hole established the underground route required for the subsequent stages.

After completing the pilot hole, the underground opening needed to be enlarged sufficiently to accommodate the 48-inch pipeline.

This process is known as reaming, which involves using specialist cutting tools to remove additional soil and rock along the established underground alignment. For a large-diameter pipeline, borehole enlargement can be demanding because substantial quantities of excavated material must be removed while maintaining suitable underground conditions.

We used dual-rig synchronous reaming for the OB3 crossing, coordinating drilling equipment from opposite sides of the River Niger during borehole enlargement.

The reaming process required careful attention to geological conditions, cutting resistance, borehole diameter, pipeline clearance, drilling-fluid circulation, equipment loads and borehole stability.

Sand and gravel formations required attention to borehole stability, while rock formations introduced different cutting and material-removal requirements. The coordinated reaming operation formed part of our approach to preparing the underground route for installation of the 48-inch pipeline.

Drilling fluid plays an important role in HDD construction, particularly when drilling through mixed geological formations over long distances. As drilling tools excavate soil and rock, the fluid helps transport cuttings towards the surface, cool and lubricate drilling equipment, and maintain suitable borehole conditions.

For the OB3 River Niger crossing, the drilling route passed through sand, gravel and rock, creating different requirements for fluid circulation and performance. We used a specially developed drilling-fluid formulation suited to the project's underground conditions.

Bentonite is commonly used in HDD drilling fluids because it helps develop viscosity and filtration-control properties. Depending on geological conditions, specialist additives may also be required to manage fluid loss, cuttings transport and other drilling challenges.

Our Brighter Star drilling-fluid product range includes BRSBENT SQ activated bentonite and specialist additives for different HDD applications.

Selecting suitable materials is only one part of drilling-fluid engineering. Fluid preparation, circulation, monitoring and solids management must also be coordinated with drilling and reaming activities. For a crossing extending approximately two kilometres, maintaining effective cuttings transport and suitable borehole conditions was an important part of the construction process.

While pilot-hole drilling and reaming establish the underground route, the pipeline must also be prepared for installation. For a large-diameter HDD crossing, pipeline preparation generally involves assembling pipe sections, completing welding and inspection requirements, protecting the pipeline coating and arranging suitable handling equipment.

The prepared pipe string must be positioned so that it can enter the borehole along the planned alignment. For a 48-inch pipeline, its size and weight create additional handling and installation requirements.

Engineers must consider pipeline support, bending limitations, available working space and the equipment needed during pullback. Pipeline preparation must also be coordinated with the drilling programme.

The borehole, prepared pipeline, drilling equipment and construction teams must all be ready for the final installation operation. This coordination is especially important for long-distance HDD projects, where delays during pullback preparation can affect the wider construction schedule.

Pipeline pullback is the stage when the prepared pipe string is drawn through the enlarged underground opening. During this operation, the drilling equipment applies controlled pulling force while the construction team monitors pipeline movement and installation conditions.

Several factors influence the pulling forces involved, including pipeline diameter, weight, friction, borehole geometry and the condition of the underground route. Coating protection and pipeline handling are also important because the pipeline must pass through the borehole without exceeding its allowable installation limits.

For the OB3 River Niger crossing, we used high-capacity HDD equipment and coordinated field operations to install the 48-inch pipeline along the approximately 2,000-metre route. The completed pullback established the underground pipeline connection beneath the River Niger.

Explore the OB3 River Niger crossing project for more information.

Several factors made the OB3 River Niger crossing technically demanding.

Pipeline diameter: The 48-inch pipeline required a large underground opening, increasing the demands on borehole enlargement and cuttings removal.

Crossing distance: The approximately 2,000-metre route required effective drilling guidance, equipment performance and fluid circulation across a substantial underground distance.

Crossing depth: The depth of 52 metres influenced bore path design and the requirements for drilling and pipeline installation.

Geological conditions: Sand, gravel and rock formations created different challenges for cutting tools, borehole stability and drilling-fluid management.

Construction coordination: Dual-rig operations required guidance, drilling equipment, fluid systems and field personnel to work together throughout construction.

These conditions explain why complex HDD crossings require more than drilling capacity. The construction method must account for the geology, equipment requirements and the different activities involved in preparing the borehole and installing the pipeline.

We commenced work on the OB3 River Niger crossing on 6 October 2025 and completed the HDD installation on 28 April 2026. The completed crossing installed the 48-inch gas pipeline along the approximately 2,000-metre route beneath the River Niger, connecting the crossing section between Ndoni in Rivers State and Aboh in Delta State.

For the wider OB3 Gas Pipeline, this was an important construction milestone because the River Niger crossing was a critical section required to connect the pipeline route.

Completing the installation removed a major physical obstacle affecting the connection and commissioning of the wider pipeline project. Full commissioning and commercial operation of the entire transmission system involve additional project and operational requirements beyond the river crossing.

For PCE Nigeria, the completed crossing adds to our experience in specialist HDD engineering for large-diameter, long-distance pipeline installations in Nigeria.

The OB3 River Niger crossing offers several practical considerations for pipeline developers, engineers and EPC contractors planning complex underground installations.

Equipment Must Match the Crossing Requirements

Large-diameter and long-distance crossings require equipment selected around expected drilling loads, pipeline dimensions, geological conditions and installation forces. Rig capacity must be considered alongside the wider construction method and the equipment needed for drilling, reaming and pipeline pullback.

Drilling Methods Must Respond to Geological Conditions

Sand, gravel and rock formations create different challenges during HDD construction. Specialist drilling methods and suitable cutting tools must be selected according to the expected underground conditions, while drilling teams need to monitor performance as the formation changes.

Drilling-Fluid Engineering Must Be Integrated Into Construction

Fluid formulation, circulation and solids management influence borehole stability, cuttings transport and drilling performance. These systems must be considered alongside drilling and reaming equipment so that excavated material can be removed effectively throughout construction.

Pipeline Preparation and Drilling Must Be Coordinated

The completed borehole and prepared pipeline must be ready for the same pullback operation. Fabrication, inspection, handling equipment and installation planning all contribute to the construction process, particularly on large-diameter installations.

Specialist Crossings Can Influence Wider Project Delivery

A single river crossing may represent only a small portion of a major pipeline's total length, but it can still affect when adjoining sections can be connected and tested. The OB3 crossing illustrates the importance of coordinating specialist underground construction with the wider pipeline programme.

What is the OB3 Gas Pipeline?

The Obiafu–Obrikom–Oben (OB3) Gas Pipeline is an approximately 130-kilometre gas transmission project developed to connect Nigeria's eastern gas network with major transmission infrastructure in western Nigeria.

How long is the OB3 River Niger HDD crossing?

The OB3 River Niger crossing extends approximately 2,000 metres between Ndoni in Rivers State and Aboh in Delta State.

What is the diameter of the OB3 pipeline at the River Niger crossing?

The installed gas pipeline has a diameter of 48 inches.

How deep is the OB3 River Niger crossing?

The crossing reaches a depth of approximately 52 metres beneath the River Niger.

What HDD equipment did PCE Nigeria use for OB3?

We deployed the GS-12000L and GD-5000L HDD rigs, supported by specialist guidance systems, drilling tools and drilling-fluid equipment.

What drilling technology was used for the OB3 crossing?

The project used dual-rig intersecting technology for pilot-hole drilling, dual-rig synchronous reaming and a specially developed drilling-fluid formulation.

When did PCE Nigeria complete the OB3 River Niger crossing?

We completed the specialist HDD crossing on 28 April 2026, following commencement of work on 6 October 2025.

The OB3 River Niger crossing provides an example of how specialist Horizontal Directional Drilling technology can support large-diameter pipeline installation beneath major waterways.

Completing the underground crossing required an engineering approach that brought together high-capacity drilling equipment, dual-rig technology, suitable drilling-fluid systems and coordinated pipeline installation.

By installing the 48-inch pipeline beneath the River Niger, we completed a critical construction section of the wider OB3 project. The experience provides useful considerations for future HDD installations involving long crossing distances, complex geological conditions and large pipeline diameters.

At PCE Nigeria, our services include specialist HDD engineering and construction, pipeline EPC, drilling equipment and technical support for infrastructure projects.

Planning a major HDD river crossing or large-diameter pipeline installation?

Explore our HDD capabilities or contact our technical team to discuss your project's engineering requirements.

Project enquiries: wanyang@pcenigeria.com