How the 48-Inch OB3 Gas Pipeline Was Installed Beneath the River Niger

The Obiafu–Obrikom–Oben (OB3) Gas Pipeline is an important part of Nigeria's gas infrastructure, developed to connect the country's eastern gas network with major pipeline systems in the west. The approximately 130-kilometre pipeline is intended to improve the movement of domestic natural gas to power plants, industries and other facilities that depend on a reliable energy supply.

One of the most challenging sections of the OB3 pipeline was its crossing beneath the River Niger, between Ndoni in Rivers State and Aboh in Delta State. This required a 48-inch gas pipeline to be installed along an underground route of approximately 2,000 metres, reaching a depth of 52 metres.

The OB3 River Niger crossing was a critical section of the wider pipeline project, requiring a specialised approach to manage its length, depth and large pipeline diameter. Building on our experience with complex HDD installations, including the AKK River Niger crossing, PCE Nigeria was contracted to execute the crossing using drilling methods and equipment suited to the project's technical requirements.

We carried out the installation using Horizontal Directional Drilling (HDD), with dual-rig intersecting technology, synchronous reaming, high-capacity drilling equipment and a specially developed drilling-fluid system.

We completed the crossing on 28 April 2026. The project provides a practical example of how a large-diameter gas pipeline can be installed beneath a major river and what engineers must consider at each stage of construction.

The OB3 pipeline needed to cross the River Niger without excavating an open trench through the riverbed along the crossing route.

Horizontal Directional Drilling (HDD) provides a way to install pipelines beneath obstacles by creating a controlled underground opening through which the pipeline can be pulled.

For OB3, the method allowed the pipeline to follow a planned route beneath the river while reducing the need for direct disturbance of the riverbed. The crossing was particularly demanding because of its length, depth and pipeline diameter. At 48 inches, the pipeline required a large underground opening, while the 2,000-metre distance placed considerable demands on drilling equipment, guidance systems and fluid circulation.

The route also encountered changing geological conditions, including sand, gravel and rock, which influenced the drilling methodology and the equipment required. These factors had to be considered together when planning the installation.

Equipment selection is important in HDD because the drilling rig must be capable of handling the expected drilling loads and supporting the installation method.

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

These rigs formed part of the dual-rig construction arrangement used for the crossing. The equipment package also included specialist drilling tools, guidance systems and supporting drilling-fluid equipment required for the underground installation.

Rig pulling capacity is an important consideration, but it does not mean the pipeline was necessarily subjected to the rig's maximum rated force. Actual installation loads depend on the borehole geometry, pipeline characteristics, ground conditions and the construction method.

For OB3, the equipment needed to support a long underground crossing and the installation of a large-diameter pipeline.

The first major stage of HDD construction is pilot-hole drilling, which establishes the planned underground route. A pilot hole is a smaller opening drilled along a predetermined alignment. Once completed, it provides the path that will later be enlarged to accommodate the pipeline.

On the OB3 crossing, we used dual-rig intersecting technology, with drilling operations carried out from opposite sides of the River Niger. Each rig drilled towards a planned underground meeting point, while specialist guidance systems helped control the direction of the drilling assemblies.

This arrangement allowed the pilot-hole route to be established through coordinated operations from both sides of the crossing. Accurate guidance was important because the two underground paths needed to meet while maintaining an alignment suitable for subsequent borehole enlargement and pipeline installation.

For a crossing extending approximately two kilometres, maintaining control of the drilling route was an important part of the construction process.

Once the pilot hole was completed, the underground opening needed to be enlarged to accommodate the 48-inch pipeline.

This stage is known as reaming. During reaming, specialist cutting tools remove additional material along the established bore path, gradually creating the opening required for pipeline installation. The final borehole must provide sufficient clearance for the pipeline while accounting for ground conditions, drilling-fluid circulation and the forces involved during pullback.

For OB3, we used dual-rig synchronous reaming, with drilling equipment operating in coordination from opposite sides of the crossing.

This approach formed part of the engineering method selected for the long-distance, large-diameter installation.

Reaming a borehole for a 48-inch pipeline involves removing substantial quantities of excavated material. Effective cuttings transport and fluid circulation are therefore important throughout the enlargement process. The drilling team must also monitor equipment loads and underground conditions as the borehole is prepared for the final installation.

Drilling fluid supports several important functions during HDD construction, particularly when drilling through different geological formations. As the drilling tools excavate soil and rock, the fluid helps transport cuttings towards the surface, cool and lubricate drilling equipment, and maintain suitable borehole conditions.

The OB3 crossing passed through sand, gravel and rock formations, requiring a drilling-fluid system suited to changing underground conditions. We used a specially developed HDD drilling-fluid formulation as part of the project's engineering approach.

The formulation had to support the drilling and reaming operations while accounting for the demands of the long underground route.

Bentonite is commonly used in HDD drilling fluids because it helps develop viscosity and filtration-control properties. Depending on the geology, specialist additives may also be introduced to manage fluid loss, clay-related problems or cuttings transport.

Our Brighter Star drilling-fluid range includes BRSBENT SQ activated Bentonite and other drilling-fluid additives for different construction conditions.

For a project such as OB3, the performance of the fluid system depends on the formulation as well as how the fluid is mixed, circulated, monitored and managed during construction.

While drilling and reaming establish the underground route, the pipeline itself must also be prepared for installation. Large-diameter pipeline preparation generally involves assembling pipe sections, completing welding and inspection requirements, protecting the pipeline coating and arranging suitable handling equipment.

The prepared pipeline must be positioned so that it can enter the borehole along the planned alignment. For a 48-inch pipeline, handling and supporting the pipe string requires careful planning because of its size and weight.

The pipeline preparation and drilling programmes must also be coordinated. The borehole needs to be ready for installation when the pipe string is available, while the equipment and personnel required for pullback must be positioned appropriately. This coordination is particularly important on long-distance crossings where the final installation involves substantial equipment and construction resources.

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 manages pipeline movement and monitors the installation.

Several factors influence the forces acting on the pipeline, including its diameter, weight, borehole geometry, friction and the condition of the underground route. For large-diameter pipelines, engineers must also consider coating protection and the equipment required to support the pipe string as it enters the borehole.

The OB3 installation involved pulling the 48-inch pipeline through the approximately 2,000-metre underground crossing. Our high-capacity HDD equipment formed part of the construction system used to complete this installation.

The operation required coordination between drilling equipment, pipeline handling and field personnel to ensure that the pipeline could be installed along the prepared route.

Several characteristics made the OB3 River Niger crossing a significant HDD engineering project. The first was the pipeline diameter. At 48 inches, the pipeline required a large borehole, increasing the amount of material that had to be removed during reaming.

The second was the crossing distance. Over approximately 2,000 metres, drilling-fluid circulation, cuttings removal and equipment performance had to be maintained along a substantial underground route.

The crossing depth of 52 metres also influenced the bore path and construction requirements. Ground conditions added further complexity, as the drilling route passed through formations with different characteristics.

For these reasons, the project required an approach that considered drilling equipment, guidance, borehole enlargement, drilling-fluid performance and pipeline installation as connected parts of the same operation.

Work on the OB3 River Niger crossing began on 6 October 2025, with PCE Nigeria completing the HDD installation on 28 April 2026.

The completed crossing installed the 48-inch gas pipeline along approximately 2,000 metres beneath the River Niger, connecting the route 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 one of the critical sections affecting the connection of the pipeline network.

Completing the crossing removed a significant obstacle to the wider project's intended purpose of improving gas transportation between Nigeria's eastern and western pipeline systems.

The OB3 River Niger crossing highlights several considerations for future long-distance HDD installations.

Equipment must be selected for the actual crossing requirements. Pipeline diameter and crossing length are important, but engineers must also assess geology, borehole geometry, drilling loads and installation forces.

Drilling and reaming must be planned together. The pilot hole establishes the route, but the borehole must also be enlarged and maintained in suitable condition for pipeline installation.

Drilling-fluid performance matters throughout construction. The fluid system must support cuttings transport, borehole conditions and circulation during different stages of the operation.

Coordination remains essential. Guidance, drilling equipment, pipeline preparation and pullback activities must work together to complete the installation.

These considerations are relevant to other HDD projects involving major rivers, large-diameter pipelines and difficult underground conditions.

What is the OB3 Gas Pipeline?

The Obiafu–Obrikom–Oben (OB3) Gas Pipeline is an approximately 130-kilometre gas transmission project designed to improve connections between Nigeria's eastern and western gas pipeline networks.

How long is the OB3 River Niger crossing?

The HDD crossing extends for approximately 2,000 metres beneath the River Niger, 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 pipeline has a diameter of 48 inches.

What HDD equipment was used for OB3?

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

What drilling method was used on the OB3 crossing?

Our construction approach included dual-rig intersecting pilot-hole technology, dual-rig synchronous reaming and a specially developed drilling-fluid system.

When was the OB3 River Niger crossing completed?

We completed the HDD crossing on 28 April 2026.

The OB3 River Niger crossing demonstrates how specialist HDD methods can be used to install large-diameter pipelines beneath major waterways. Completing the 2,000-metre crossing required an engineering approach that brought together high-capacity drilling equipment, dual-rig technology, drilling-fluid management and coordinated pipeline installation.

For PCE Nigeria, the project adds to our experience in delivering complex HDD crossings and supporting major pipeline infrastructure development in Nigeria.

The lessons from OB3 are relevant to future projects where difficult ground conditions, long underground distances or large pipeline diameters require specialist construction methods.

Planning a large-diameter pipeline crossing or a complex HDD installation?

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

Project enquiries: wanyang@pcenigeria.com