The South Caucasus Pipeline (SCP) is a pipeline designed to transport gas from the Shah Deniz field in the Azerbaijan sector of the Caspian Sea to the Georgia-Turkey border. In 2016 the existing 42-inch diameter SCP system was expanded – the South Caucasus Pipeline Extention (SCPx) project.  The 42” diameter pipeline had to cross various landscapes including rivers and mountains, to be connected to the Southern Gas Corridor. Contractor Bessac awarded the Bezemer Group the scope of providing a linear winch for two river crossings, that required compact intermittent winches for pulls through micro tunnels.  

Pipeline river crossings using a linear winch 

The SCPx installation comprised two main parts, the first pull was conducted in July 2017, which involved a 1000-meter river crossing micro tunnel in Georgia, while the second pull, carried out in October 2017, encompassed a 600-meter river crossing micro tunnel in Azerbaijan. 

To execute these river crossings, the contractor employed the following work method. Initially, a tunnel was excavated, descending beneath the riverbed. This tunnel extends beneath the river, terminating in a pit. The pit, 20 meters deep, provides sufficient space for the necessary equipment. The linear winch was positioned in the pit, oriented toward the tunnel exit. A messenger wire was laid through the tunnel, facilitating the placement of the heavier 52mm pulling wire. This pulling wire, connected to the pipeline head, enabled the winch to pull the pipeline through the tunnel. 

Pulling a 1000-meter pipeline with a 100-tonnes winch 

Micro tunnels, as utilized in this project, are precisely sized to accommodate the necessary operations. In the case of the SCP, these tunnels were designed to be just large enough to facilitate the pipeline installation process. 

The process of pulling a pipeline through a tunnel inherently generates friction. To minimize the required pull force, the contractor placed the pipeline outside the tunnel on rollers and used rolling collars around the pipeline. This allowed for smooth passage of the pipeline through the tunnel and reduced the maximum required pulling force to 100 mTon.  

 The provided winch spread for the SCPx Project 

To carry out the pulling operation, we used one of our electric-driven winches known as CLI 210. These intermittent winches are engineered to be space-saving and highly efficient, ensuring optimal performance in limited work areas. By employing these specific winches, the pull could be performed in a relatively small shaft, saving costs and time in the worksite preparations. Additionally, the winch has high manoeuvrability allowing streamlined operations. 

Bezemer’s contribution also included providing the 1200-meter, 52-mm and 22-mm non-rotating wire steel wire ropes. Additionally, Bezemer supplied a storage winch capable of storing the steel wire rope, complete with a level winder. To store the wire, Bezemer provided various sheaves, which would guide the wire upwards, out of the tunnel pit, to the storage winch. 

SCPX forms the first link in a chain of pipelines creating a new Southern Gas Corridor (SGC), which brings Caspian gas to Europe Bezemer played a vital role in various parts of the SGC, performing four pulls for the TAP project and a landfall for the TANAP project, which are both part of the development of the Corridor.