Classification of Sequence Geometries Near Welds and Salt

Significant hydrocarbon accumulations are found in salt welded traps, which comprise the majority of underexplored targets in the Gulf of Mexico. Most studies on welds focus on weld geometry, their relationships to linked salt, parent salt architecture, kinematics of weld formation, and geophysical imaging. These studies provide constructive and critical information used to describe welds, segregate welds into salt provinces and evaluate weld seal risks. However, the geometries of sequences adjacent to the weld and salt interface are poorly addressed.

We propose that near-weld sequence geometries may provide an important aspect of weld/salt seal criteria. The geometries of sequences that bound welds display a set of common observable characteristics. They are directly related to local and subregional compensation effects, size of weld, and kinematics of minibasin and sedimentary systems. These geometries are found in all mobile salt environments.

We provide a simple classification of two-dimensional sequence geometries near the weld and salt. Five main categories are characterized. They include (1) convergent truncated (2) divergent truncated (3) isopachous truncated (4) isopachous parallel, and (5) convergent parallel.

We examine examples of drilled weld traps from the Gulf of Mexico and establish a basis for a statistical analysis between sequence geometries and weld trap and seal potential

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California