Onshore Pipeline Fault Crossings

Exploration for oil and gas in regions affected by seismic activity is a further example of the challenge and complexity of delivering and operating Sakhalin-2 Phase 2. Seismic activity in Sakhalin is on a par with the Persian Gulf and New Zealand. Therefore, the ability to maintain safe operations in the event of a major earthquake has been embedded in both the design and construction of the Project’s infrastructure. In general, Sakhalin Energy has minimised potential impact by rerouting the pipelines, where possible, away from areas prone to both landslides and seismic hazards.

	Sakhalin Energy has recently completed construction through one of the most challenging aspects of the onshore pipelines construction phase – fault crossings. The onshore pipelines cross 19 active faults at 16 locations. To safeguard the environment the Company developed a unique and specific design for each fault crossing.
	At the fault locations, a combination of thicker-walled pipe and special trench profiles is employed to minimise the forces on the pipelines in the event of an earthquake. The offshore pipelines do not cross any active faults.
	Via its Engineering, Procurement and Construction (EPC) contractor Sakhalin Energy has employed ENI Snamprogetti who have extensive global experience in developing pipeline fault crossing solutions. The design of each fault crossing is based on specially developed models as well as rigorous material testing, optimal pipeline routing and pipeline crossing angles at each fault location.
	The pipeline trench at the fault crossings differs from a standard trench in its shape, size and backfill material. The special configuration allows pipeline movements within the trench during earthquakes and prevents it from becoming damaged.
	Additional block valves are installed from each side of most fault crossings as an extra safety measure. The seismic monitoring system being installed will provide the pipeline operators with immediate detailed information on any seismic event near the pipelines allowing them to swiftly isolate any part or the entire route from north to south.
	Sakhalin Energy is currently developing a seismic monitoring system that will collect data during any earthquake. This data will be recorded in digital format and be available for processing immediately after an earthquake event. To ensure emergency response capability, the processed data will be transmitted to the pipeline control centre for use in operations decision-making. Seismic data from Sakhalin Energy can also be made available to emergency response agencies and various scientific institutes.