Complexly-Faulted Salt Wall Terminations in the Paradox Basin: Implications for Salt Evolution, Reservoir Compartmentalization and Exploration for Natural Resources

Abstract

The Paradox Basin represents a geologically unique and economically significant petroleum system in the western United States, characterized by the presence and dynamic nature of the halite-rich Pennsylvanian Paradox Formation. Decades of research have revealed a great deal about the behavior of the Paradox salt throughout the tectonic history of this basin, which provides valuable insight into other basins around the globe that are similarly dominated by salt tectonics (e.g., the Central North Sea, the Gulf of Mexico). Within the Paradox Basin, evacuation and diapirism of the Paradox Formation has substantially influenced sedimentation and stratigraphy, which has implications for the presence, location, and geometry of petroleum and potash deposits. Many previous studies have focused on the overall structural setting of the Paradox Basin as well as northwest-southeast-striking pre-salt structures that may have influenced the formation of the Paradox salt walls. However, a detailed study of several complex three-dimensional systems at the termination of some salt walls has not been entirely accomplished to date. In an idealized setting, one might expect the linear salt walls to laterally taper out gradually, as salt supply toward the basin margins thins and/or the effect of tectonism wanes. Yet some of the salt walls deviate considerably from this model, displaying in places abrupt terminations (e.g., Castle Valley) or significant changes in strike over relatively small distances (e.g., Salt Valley-Fisher Valley, Gypsum Valley). An in-depth evaluation incorporating field and subsurface data (i.e., well, gravity, and seismic data where available) of these anomalous structures will support or dispel hypotheses that suggest preexisting structural features are the major controlling factor in the development of these terminations. Therefore, a thorough investigation of these complexly-faulted salt wall terminations is essential to better understand the trapping mechanisms for petroleum deposits and the distribution of potash systems throughout the basin. Furthermore, these collected data will provide further insight into the evolution of salt structures in similar basins around the world.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015