Sakhalin is a large elongated island stretching over more than 900 km from North to South in the Russian Far East. Sakhalin is known for its seismic hazards with a high probability of occurrence and a high degree of uncertainty. Sakhalin Energy Investment Company Ltd. (Sakhalin Energy)
is the operator of the Sakhalin-II project. Sakhalin Energy has a production sharing agreement with the Russian Federation. Sakhalin-II is the world’s biggest project of integrating oil and gas, consisting of three offshore oil production platforms, 300 km offshore and more than 800 km onshore oil and gas pipelines, an onshore processing facility, an oil export terminal and Russia’s first liquefied natural gas (LNG) plant.
Aiming to be the new energy source for the entire Asia-Pacific area, Sakhalin Energy had to implement an investment strategy regarding the safety due to the seismic activity in the region. Sakhalin Energy therefore sought for comprehensive solutions in relation to the routeing of pipelines, being able to safely deliver the energy source to the identified customer bases. These solutions were not limited to safety measures against direct effects of the seismic hazards but also indirect ones, such as landslides, avalanches, mudflows, subsidence and similar earth movements associated with seismic activity.
The onshore pipeline solution along the Sakhalin Island was impossible to achieve without passing through identified fault locations where extra protection was needed. Special safety measures, in case of an earthquake, were installed in the form of thicker walled pipes, special trench profiles which allow pipe movement plus block valves on either side of most fault crossings. The offshore pipelines do not cross any active geological faults and therefore no special safety measures were required offshore.
In addition to the constructional safety measures, Sakhalin Energy implemented a comprehensive monitoring and management infrastructure called Pipeline Operating Management System (POMS), featuring state-of-the-art monitoring equipment, remote operated block valves, as well as data collection and interpretation components to achieve a rapid and prompt response to any potential damage.
GeoSIG supplied the Seismic Monitoring and Rapid Response System, that, in case of an earthquake, measures the local accelerations, generates a detailed shakemap, compares the accelerations with the design limits of the facilities and triggers alarms accordingly. The supplied instrumentation consists of field stations with borehole accelerometers and intelligent seismic recorders with associated peripheral equipment, designed to work under the harsh environmental conditions. In addition a central cabinet for the system was supplied, featuring hardware and specialised software to facilitate full configuration, operation and interfacing within Sakhalin Energy's local and remote systems. GeoSIG’s Shakemap software application has been extensively customised to meet the specific requirements of Sakhalin Energy, including the addition of an online interactive web-based interface.
Utilising the GeoSIG system, Sakhalin Energy is able to very quickly analyse the effect of an earthquake and determine if it is safe to continue operating or a shut down for inspection has to be initialised. This system is also an enormous help for the company in estimating where to focus the inspection efforts and possible emergency response on. The location of a potential pipeline impairment may be hard to define without the information that is generated with the sensors and shakemap.