72 Km High Pressure Natural Gas Pipeline - From Stefani to Public Power Corporation's Plant at Aliveri
72 Km High Pressure Natural Gas Pipeline - From Stefani to Public Power Corporation's Plant at Aliveri
Client:
HELLENIC GAS TRANSMISSION SYSTEM OPERATOR S.A. (DESFA S.A.)
Business Area:
Natural Gas
Solution/Service:
Project Management Services,Technical Consulting
Category:
High & Medium Pressure Pipelines
Technical Data
High Pressure Pipeline: STEFANI - VARNAVAS - ALIVERI, (ALIVERI BRANCH - THREE ONSHORE SECTIONS)
- Diameter 20” underground, cathodically protected steel pipeline
- Total length: 72 km (ONSHORE)
- Design pressure: 70 barg
- Two Metering Stations, one at the area of Aliveri town and the other at the Power Plant of Public Power Company (PPC)
- Five Line Valve stations in the areas of Stefani, Markopoulo-Oropos, Varnavas, Aliveri and Power Generating Plant (PPC)
- Two 20” Scrapper Stations located one in the area of Stefani and the other in Aliveri
Our Services
The scope of ASPROFOS work included the Basic design, Environmental Impacts Assessment Study, Safety Study, Investigation-Licensing, Geoseismic-Geotechnical Studies and Detailed Survey Engineering Studies. In detail:
- Basic Engineering: pipeline routing design and developing of the background for the process and instrumentation issues according to which, the detail engineering is based. The Basic design includes the final routing of the pipeline, contact(s) with public authorities, pipe and mechanical material selection and take off, technical specifications, design of the basic electrical and cathodic protection systems, design of instruments for communication and gas flow control, project cost estimation and management of the project technical documentation / archiving.
- Environmental Impacts Assessment Study (EIA): preparation of scientifically substantiated environmental study investigating the impacts to the environmental systems of the regions which the pipeline is passing through, from the construction up to the operation phase of the project. In addition to the EIA the legal constraints, contacts with the authorities, investigation of the environmental systems and finally, environmental management plan of the project was also included.
- Safety Study: preparation of a scientifically substantiated study investigating the safety levels related with the gas pipeline to be commissioned and analyzing the potential risks and their consequences during the stage(s) of the project implementation / operation.
- Authorities Investigation / Permits Acquisition: investigation of the routing, in collaboration with the public authorities, for obtaining the pipeline routing licensing, as well as acquisition of all the legally required permits for the project implementation (i.e. Installation Act).
- Geological / Geolechnical / Geoelectrical / Seismic Studies: The Basic design of the project requires the execution of Geological / Geotechnical and Seismic studies along the pipeline route. The coordination and preparation of an integrated geophysical study aiming to evaluate and verify of the technical efficiency of the pipeline routing were included in the scope of ASPROFOS services. The objectives of this specific study, are the following:
- Seismo-tectonic analysis and evaluation of the seismic hazardousness along the pipeline route
- Study of the correlation of the active and potentially active tectonic faults
- Study of evaluation of the gas pipeline wall thickness
- Mapping and evaluation of the geological / geotechnical conditions and formations
- Geotechnical investigation comprising literature review and laboratory tests (cross holes, trial pits, SPT, CPT, soil chemical analysis, examination of the soil / subsoil mechanical properties)
- Study of the geoelectrical conditions
- Detailed topographical studies: execution of field geodetic measurements for recording of the right of way (ROW) zone along the pipeline route, preparation of the detailed surveys / cadastral drawings and the corresponding cadastral registers, in which the physical /technical characteristics of the ground are depicted, as well as the corresponding topographical map of the land ownership that is to be encroached and compensated because of the ROW preparation.
The scope of ASPROFOS services also included the Construction supervision of the project namely
- Administration and review of the detailed engineering design prepared by the Contractor
- On site supervision of the construction works and mechanical tests
- Review of Contractor’s payment certificates
- Technical support to the framework of third party inspection
- Administration of issues related with the construction safety and quality management / control
- Support to the Client by monitoring of the construction time schedules and reviewing of the Contractor’s variation order requests / claims
- Checking of the ‘’As-Built’’ documentation
- Certification of the project completion and issuance of the provisional and final acceptance certificates of the pipeline construction phase.
Description
This project of Hellenic Gas Transmission Operator (DESFA) concerned the merging of two independent but sequential sections of a pipeline, one onshore and one offshore, to transport high pressure natural gas from the prefecture of Attica to the Power Plant of PPC at Aliveri. ASPROFOS was involved only with the design and studies associated with the onshore pipeline section.
