The Gulf of Mexico sea floor has been mapped with a variety of different methods with varying resolution. Until recently higher resolution 3D seismic surveys have generally been limited to site specific localities. With hydrocarbon exploration advancing and evolving, larger 3D seismic surveys have been acquired and are now available on a regional scale.
Mapping of the sea floor reflector on a regional 3D seismic data set in the Green Knoll/Walker Ridge area has resulted in a higher resolution map than previous data sets. The seismic data has revealed a set of regionally extensive furrows, a previously unknown Gulf of Mexico sea floor feature. Preliminary investigations show that the erosive style of the furrows change in a predictable pattern in conjunction with an increase in current flow velocities. The erosional features of the furrow field indicate the presence of strong ocean bottom currents.
A variety of methods during the past few decades have been used to map the sea floor in the northern part of the Gulf of Mexico. Until recently, the highest resolution data sets with the most extensive coverage have been surface-towed, multibeam, side-scan-sonar (NOAA Seabeam) and long-range sonar (GLORIA). Maps from these data sets, such as those produced by Jia Liu and William Bryant1, have approximately a 30 meter resolution on the sea floor (Fig. 1). However, in deep and ultra-deep water depths the resolution is lower due to the greater travel time from source to receiver.
Other data sources that have been used to generate sea floor maps of the Gulf of Mexico include gravity, magnetics, satellite sensors and 2D seismic surveys. While maps generated from gravity, magnetics and satellite data cover the whole of the northern Gulf of Mexico or over a larger area, they are of much lower resolution than either the NOAA or GLORIA data. 2D seismic data provides a higher resolution of the sea floor, but due to their nature of a lattice of separate lines, they lack the spatial resolution to define subtle features on the sea floor.
As seismic acquisition and processing technology evolved, 3D seismic surveys became available. With the close spacing of data points, 3D surveys provide greater spatial resolution to map the sea floor and illuminate subtle features. However, due to cost and technological limitations, the first surveys were restricted to site specific localities with small areal extents. With the increased spatial resolution these initial surveys provided a more detailed map of the sea floor but only represented a postage stamp look in a regional context of the northern Gulf of Mexico. With the recent advances in technology along with exploration for hydrocarbons advancing to deep and ultra-deep water, larger 3D seismic surveys have been acquired and are now available on a regional scale. With the availability of these regional surveys, sea floor features that were previously unrecognizable have now been identified.
