--> Abstract: Interaction Between Salt Diapir Growth and Sedimentation: an Example from Côte Blanche Island Field, Louisiana, by R. A. Kolarsky; #90933 (1998).

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Abstract: Interaction Between Salt Diapir Growth and Sedimentation: an Example from Côte Blanche Island Field, Louisiana

Kolarsky, R. A. - Shell Deepwater Development, Inc.

This paper presents a detailed study of the evolution of a salt diapir from the Late Oligocene to Present based on 3D seismic, well logs and biostratigraphy.

There is a notable lack of faulting associated with this diapir. The only observed faults are a large counter-regional normal fault dissecting the diapir, and a few associated synthetic and antithetic faults. This observation is in striking contrast with older interpretations of the field that proposed a large number of radial faults extending outward from the diapir. That was in concert with the thinking of the time that all diapirs actively breached their overburden as they rose to the surface and caused intense faulting. This study, using modern salt-tectonic models of reactive, active and passive diapirism, shows how a diapir can reach the surface without causing extensive faulting at all. This study further suggests that those faults that are observed in the field are related to deep, lateral withdrawal of salt feeding the growing diapir. The faults, albeit partially coeval with diapirism, are not directly caused by salt emplacement, but are, in a broad sense, related to the diapir's growth.

This radical re-interpretation of the field had an immediate economic impact: it changed the reservoir picture and led to an intensive re-development program. Missing section in wells high on structure does not represent faults, but rather unconformities caused by salt movement. Individual reservoirs are not constrained laterally by faulting. Rather, their complexities stem from stratigraphic variations on the sequence and depositional-systems scales.

AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil