TDW Offshore Completes Double-Block Onshore Pipeline in Austria

TDW Offshore has successfully completed an onshore pipeline isolation operation for OMV Gas GmbH. The operation was carried for OMV Gas GmbH in Austria in conjunction with the company's Trans Austria Gas pipeline (TAG) expansion program.

One of the key developments of the expansion program is the newly constructed compressor station in Eggendorf, Austria. OMV Gas GmbH needed to safely re-route the existing pipelines to this new station. To achieve this, TDW was retained to carry out pipeline isolation services on the 38-inch import pipeline that stretches approximately 70km from Baumgarten to Eggendorf, and on the export pipeline that runs approximately 70km from Eggendorf to Grafendorf.

Double-block Isolation Enhances Pipeline Modification Efficiency

TDW isolated these pipelines by using its remote-controlled 38-inch SmartPlug® trains to create double-block isolations against the gas pressure. Both SmartPlug trains were launched and pigged with production gas into excavated sections of the pipelines, travelling approximately 100 meters from launcher to the work position.

Using wireless, through the wall communication system, TDW manoeuvred each plug train into place, and set them horizontally in the excavated area of the pipeline. While the plug trains were in place and isolated pipeline sections, OMV Gas GmbH carried out the necessary modifications and re-routed the two pipelines to the new compressor station in Eggendorf. Once this was completed, TDW released the SmartPlug trains and pigged them back to the launcher and receiver using gas pressure from the pipelines. The pipeline pressures for both pipelines were 50 bar during the isolation operations. While each SmartPlug train isolated the pipeline sections for three days, the entire isolation operation took just 10 days from TDW's arrival onsite in Austria through to demobilization.

Custom Tension Belts Speed Isolation Process

In order to help the two pipeline sections cope more effectively with the additional internal pressure exerted by the SmartPlug trains, TDW developed eight custom-made tension belts specifically for the OMV Gas GmbH operation. Although traditional belts can be cumbersome and time-consuming to attach to the pipelines during onshore isolation operations, TDW designed the tension belts in such a way that they are quickly and easily mounted. As a result, TDW was able to reduce the time and effort required to attach the belts and progress more rapidly to isolating the pipeline sections in order that the modifications could be made, and the pipelines safely re-routed.

Throughout the operation, the SmartPlug trains were continuously monitored by TDW as they travelled along the pigging route using TDW's SmartTrack system that interacts with the transceiver systems that are featured as standard in all SmartPlug trains.

"As a result of our ability to effectively isolate the pressure in the two pipelines so efficiently, OMV Gas GmbH was able to initiate modifications to the system sooner than anticipated, which was highly beneficial, reducing the overall pipeline re-routing programme schedule," said Rune Haddeland, General Manager TDW Offshore Services. "Coupled with the fact that the pipelines were isolated with minimal venting of product into the atmosphere in accordance with OMV Gas GmbH environmental policy, we consider it a real testament to the dedication and innovative spirit of the TDW team," he added.

TDW Offshore Services has carried out more than 120 successful pressure isolation projects around the world. The recent pipeline isolation operation for OMV Gas GmbH on the TAG pipeline system in Austria illustrates how SmartPlug technology can facilitate necessary pipeline intervention activities onshore, saving time and money.