Marine gravity and magnetic data can be acquired either onboard seismic vessels or vessels dedicated to gravity and magnetic surveys (stand-alone marine gravity and magnetics). Marine gravity and magnetic data have also been acquired on hydrographic and multi-beam bathymetry vessels. EDCON-PRJ has completed over 30 stand-alone marine gravity and magnetic surveys and hundreds of gravity surveys on board seismic vessels. In the Gulf of Mexico, EDCON-PRJ has acquired over 115,000 line-km of stand-alone surface-ship gravity and magnetic data. EDCON-PRJ has also completed stand-alone marine gravity and magnetic surveys in many other parts of the world, including:
- Western Australia
Advantages of stand-alone surveys include:
1. Survey Design: The survey layout is specifically created to optimize survey results. The density of primary survey lines is chosen to match the geologic goals of the program with sufficient tie-lines to allow effective data leveling during processing. The line orientation is chosen with a view to both geologic goals and efficient data acquisition.
2. Quality: Stand-alone gravity and magnetic survey data quality is excellent because the survey line layout and vessel operation (speed and heading) are selected to yield optimum gravity and magnetic results, considering sea direction and weather conditions.
3. Rapid Results: The speed of data collection on a stand-alone survey is generally much greater when the vessel speed is not limited by requirements of other survey methods. Gravity and/or magnetic stand-alone surveys are typically acquired at vessel speeds of 8-10 knots with rapid line changes. In comparison, seismic operations are generally limited to 5-knot or slower vessel speeds with long line-change times.
4. On-the-fly Data Evaluation: On our stand-alone surveys, preliminary processing (both on the vessel and at the EDCON-PRJ office) identifies line segments that are of sub-standard quality (generally due to heavy sea conditions) so that the lines may be re-acquired efficiently.
5. Follow-up: Stand-alone survey results are available quickly to aid in follow-up survey design and planning.
EDCON-PRJ has the ability and unrivaled experience to provide the highest quality marine gravity and magnetic services to its customers on stand-alone surveys as well as on client vessels.
EDCON-PRJ has developed specifications for the acquisition and processing of marine gravity and magnetic data which have been adopted by many client companies world-wide.