NEWSROOM

Proud to announce the successful completion of the final 3 HDD crossings for Teréga’s 23km network extension in the Tarn-et-Garonne region of southwestern France. From feasibility studies to construction, OPTIMUM engineers have accompanied project owner Teréga at every step of the way since 2019.

Teréga continues to reinforce its gas transport network in south-eastern France and OPTIMUM trenchless engineers continue to accompany the project owner at every step. The latest project, near Montauban (Tarn-et-Garonne), will add some 23km to the network, so crossing under key infrastructure and natural obstacles was both inevitable and critical to success. Three of the HDD (horizontal directional drilling) crossings, design engineered and supervised by OPTIMUM, are now complete :

Great to have assisted Teréga for its pipeline deviation under the Adour River, which was successfully completed in southern France last week. The project will increase pipeline durability and allow the river to be restored back to its natural state, as the existing fish passes can now be removed. The 500-metre long DN 600 HDD crossing, which replaces a surface laid pipe, passes through marl formations, drilling down 23 metres under the riverbed. Gravelly surface conditions called for a DN1200 steel casing at the entry point as well as an 8-metre excavation at the exit.

Alongside SUBTERRA recently for the successful completion of 3 parallel 360-metre-long HDD crossings under the Gave de Pau river in southern France: a DN250 for Teréga, a DN80 and a DN50 for Arkema. Up until now, the network crossed the river via a dedicated pipe bridge. Placing it underground will ensure optimal security given the river hydrology and the geology of the site.

Beautiful blue skies in southern France on Friday for SUBTERRA’s successful installation of a DN300 HDD gas pipeline under the Garonne River, the second of 2 parallel 364-metre-long crossings. Crossing the Garonne was another important step in Teréga’s network renewal programme, which followed the 607-metre-long DN150 / DN300 parallel crossing under the Ariège River a few weeks ago. With a 60-metre height difference between the entry and exit points on the Ariège crossing, the job was far from straightforward. The complex geology of both sites, with significant gravel layers and in flood risk areas, required careful monitoring and casing to enhance pipe stability. OPTIMUM trenchless specialists accompanied SUBTERRA during the engineering design phase and throughout the drilling works of both crossings, determining casing characteristics and analysing drilling parameters.

Great to have accompanied Teréga for another HDD project successfully completed this week in Sauternes. The 350-metre-long DN200 pipe passed under a protected natural area and through fractured limestone crags in the heart of the region’s vineyards. OPTIMUM engineers worked with Teréga from design and feasibility (G1 PGC, G2 PRO) and throughout the 3-week drilling operations (G4), to ensure breakouts were avoided and the agricultural land preserved.

Sunny skies last week on the Côte d’Azur for the successful HDD installation of GRTgaz’s DN100 gas pipeline under the Marseille to Ventimiglia railway line in La Ciotat. Finding the right drill path was the key challenge for this project, since the crossing is in a residential area with narrow streets, an already congested underground environment and goes through tough grey and yellow sandstone.

Despite the grey skies, OPTIMUM was delighted to accompany GRT Gaz last week during the successful installation of its 575m-long DN100 pipeline in Lozanne, near Lyon. The HDD crossing, which drilled through basalt rock and across fault lines, passed underneath housing, an equestrian centre, a road as well as a river, which will be restored to its original state. Engineered by OPTIMUM from the outset, the project would have been impossible to complete using conventional trenched techniques.

OPTIMUM continues to grow its portfolio of international clients in the oil and gas industry with a new contract in Peru. Acutely aware of the importance of a thorough site visit from the outset, OPTIMUM flew a trenchless specialist to Lima this week to see the context and constraints for himself.

A beautiful sunny afternoon yesterday in the Basque country: OPTIMUM was proud to see TEREGA’s DN650 gas pipeline be successfully installed under the river Saison, near Trois-Villes. OPTIMUM accompanied TEREGA throughout the drilling works in complex geological conditions, which called for several technical modifications and dedication in abundance.

OPTIMUM continues to expand its international reach with its latest mission in Romania. The 1500m long horizontal curve landfall project, which used an anchored lay barge during pull-back, will connect two natural gas fields 120kms out in the Black Sea to the inland gas treatment plant. OPTIMUM’s engineers were present in Romania for over 6 weeks and supervised HDD operations onsite 24/7 given the geotechnical complexities of the project, now one of the longest landfalls ever drilled in soft soils (sand, silt and clay).

The dual gas pipeline crossing of the Dordogne at Cubzac is complete. By reworking the project engineering and assisting technical operations on a daily basis, OPTIMUM managed to halve both the drilling costs and the project timeframe.