Print this pageRecognition of Secondary Salt Welds, Northwest Gulf of Mexico
THIES, KENNETH J., BRUCE E. BOWEN, DAVID J, HALL and RASHEL N. ROSEN
Secondary salt welds have been recognized and mapped on the western Louisiana shelf and slope using 30,000 km of 80-fold, eight second record length and 2500 km of 60-fold, 15 second record length seismic data, along with well log and biostratigraphic control. Recognition of these welds is based on an integration of seismic reflector geometry, the sedimentary history of associated basins, and biostratigraphic data.
The criteria are: (1) direct association to salt massifs and diapirs; (2) opposing steep dips of seismic reflection away from a vertical plane; (3) symmetrical basins on opposite sides of the weld; (4) thickness variations in strata in these basins; and (5) regional continuity determined by mapping.
The conclusions based on this work are: (1) many of the vertical features previously interpreted as steep faults are remnant salt massifs or vertical welds; (2) these welds fall into two categories: (a) major welds that can be traced vertically down to the primary salt source (Luann -Jurassic) and (b) minor welds that can be traced to origins in younger salt canopies; 3) the linear trend of these welds is generally parallel depositional dip from shelf to slope; and (4) the sedimentary basins separated by these welds have different depositional histories which strongly impact exploration potential.