StatoilHydro's need for robust long-term solutions for repeated seismic data acquisition led in 2004 to a collaboration project between StatoilHydro R&D and Optoplan AS to develop a fibre-optic based ocean bottom seismic technology suitable for FSM. The Snorre field pilot made information on vessel and source positioning available in real time, while broadband transfer of the recorded seismic data via a fibre optic communications network to the dedicated operations centre in Trondheim permitted quality control and seismic imaging in “near time” – within a minute or so of acquisition.

The project investigated the benefit of frequent monitoring of the reservoir in areas with large remaining reserves where a high number of advanced and expensive wells are to be drilled, as well as the feasibility of optimising production/injection and increasing the understanding of the drainage pattern. In 2006, Snorre initiated a focused seismic monitoring (FSM) project. The field's future economy relies on an effective IOR strategy. Snorre is a thick, heavily faulted, eroded and heterogeneous fluvial reservoir with a complex production history and with a large IOR potential. The Snorre field (see Box) is a major North Sea oil field that is expected to benefit from frequent surveys with accurate survey repetition. The consequent improved reservoir understanding allows (1) early reaction to unexpected well or injection program failure, (2) search for bypassed zones, and better placement of future wells, (3) confident development of reservoir production plan, (4) validation of the dynamic model, and updating of the reservoir simulation model, and (5) monitoring of fluid migration, injection paths, and well performance. Courtesy: StatoilHydroįrequent time-lapse observations with high survey repetition accuracy hold the potential to provide a wealth of information related to production and injection responses. The first seismic section measured with light! The blank area in the middle is caused by the gap between the two cables as laid out on Snorre. In fields with more than 10 years of production left, and with a significant number of wells to be drilled, or those where difficult reservoir conditions imply that it would be advantageous to carry out frequent surveys, typically at intervals of about one year or less, permanently installed ocean bottom seismic (OBS) cable systems is the cost-effective alternative to conventional streamer surveys. The choice of which seismic reservoir monitoring technique to use depends on a number of factors.

Wag seismac