What is an offshore 3D seismic survey?

Ever since the advent of three-dimensional (3D) seismic surveys, in the early 1970s, the petroleum industry has undergone a profound transformation. Suffice to say that the chances of successfully locating a commercial oil well increased from about 10%, in the 1970s, to about 50% for contemporary exploration. It is also remarkable that digital high resolution survey techniques offer information which can help identify potential drilling hazards. Such risks include weak geological layers (strata), shallow faults and concealed channels.

The process of offshore or marine seismic surveying commences with the creation of an artificial seismic event (small earthquake). A survey vessel (ship) towing a network of cables usually employs airguns to release compressed air pulses into the seawater which travel to the sea floor. Seismic energy from these events, in the form of sound waves, traverses the water column propagates through the different geologic formations of the earth’s outer surface to be reflected back to the surface of the water where it is recorded by a set of hydrophones. Depending on the composition of the earth’s surface the reflected sound waves convey information about the terrain’s geomorphology and structure. Collected data is then analysed to construct a 3D image of the subsurface. One step further, when the time dimension is factored in the seismic survey four dimensional (4D) or time-lapse seismic surveys can be generated for the purposes of monitoring gas or oil well production changes.

Appreciating the importance of 2D and 3D seismic surveys to the success of offshore hydrocarbon extraction, the Cyprus Energy Service has proceeded to acquire a wealth of seismic data off the coast of Cyprus. The 3D seismic data acquired in 2007 and currently available to interested investors comprise 659 km2 of multi-client seismic data. Findings also help delineate bright spots, flat spots, and amplitude anomalies. Furthermore, a 3D interpretation report commissioned by the Energy Service concentrated on the geological interpretation of the 3D seismic surveys. Hence by gaining access to such valuable data and 2D multi-client seismic survey data, international energy companies can identify promising investment opportunities.

It is also possible that other unmapped areas could harbour large quantities of gas and oil reserves. According the US Geological Survey (USGS) the Levant Basin Province, East Mediterranean, is estimated to hold a mean of 1.7 billion barrels of recoverable oil and a mean of 122 trillion cubic feet of recoverable gas. Another report, again authored by the USGS, projects the technically recoverable reserves of oil and gas in the Nile Delta Province, in the vicinity of Cyprus, to 1.8 billion barrels and 223 trillion cubic feet respectively. Energy companies interested in investing in gas and oil opportunities in the Exclusive Economic Zone (EEZ) of Cyprus can contact Energy Sequel for more information.

Print Friendly
Share and Enjoy:
  • Print
  • Digg
  • StumbleUpon
  • del.icio.us
  • Facebook
  • Yahoo! Buzz
  • Twitter
  • Google Bookmarks
This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>