Worldwide experience shows that 4D seismic monitoring is now widely used in the development of offshore fields. Its underlying concept is to conduct a baseline seismic survey before development and to arrange an equivalent survey for several years upon operation. The difference in these surveys allows us to determine the yield of hydrocarbon extraction, identify replacement of production with formation water in time and take prompt action to extend the field lifecycle.
At gas and gas condensate production facilities, the most popular 4D survey technique for obtaining a complete wave field on the shelf involves the use of the 4D/4C bottom multi-directional survey system (node-based survey system). A traditional source point towed by a vessel in the water column is used to excite the seismic field, while multi-directional bottom stations, known as nodes, handled by other vessels on the seabed surface are used to record seismic waves. The bottom station is a selfcontained single seismic receiver, containing hydrophone, a three-directional geophone, a seismic data recorder, a high-precision clock, and other necessary items. Bottom stations are deployed using vessels with dynamic positioning systems to provide the necessary accuracy.
While the towed streamer technology has limitations due to the survey system geometry and the lack of full coverage of the surveyed area if any offshore structures are present, the seismic bottom approach makes it possible to safely conduct offshore seismic surveys in the vicinity of drilling platforms and production facilities, covering the entire surveyed area with seismic data.
The article shows the results of the first field season of 4D/4C baseline seismic survey at the Yuzhno-Kirinskoye field (offshore Sakhalin Island) using a Russian navigation and geophysical suite. The positive findings suggest that this approach has prospects for spreading to other deposits on the Russian continental shelf.

V.N. Khoshtaria, PhD in Geology and Mineralogy, Gazprom nedra LLC (Moscow, Russia), v.khoshtariya@nedra.gazprom.ru

N.A. Rybin, Gazprom nedra LLC, n.rybin@nedra.gazprom.ru

D.V. Kozhukhov, Gazprom nedra LLC, d.kozhukhov@nedra.gazprom.ru

A.G. Kazanin, DSc in Economics, JSC Marine Arctic Geological Expedition (Murmansk, Russia), a.kazanin@mage.ru

S.O. Bazilevich, JSC Marine Arctic Geological Expedition, sergey.bazilevich@mage.ru

V.M. Sarkisyan, JSC Marine Arctic Geological Expedition, v.sarkisyan@mage.ru

O.V. Kmet, PJSC Gazprom (Saint Petersburg, Russia), O.Kmet@adm.gazprom.ru

R.V. Shchekalev, DSc in Agriculture, PJSC Gazprom, R.Shchekalev@adm.gazprom.ru