LOOFF, KARL M., Geologic Consultant, Lovelady, TX; and KURT M. LOOFF, Sofregaz US Inc., Houston, TX
Abstract: Possible Geologic Influence on Salt Falls Associated with the Storage Caverns at Bryan Mound, Brazoria County, Texas
A frequency distribution map of the number
of salt falls associated with the various storage caverns at the Bryan
Mound facility exhibits a pattern which suggests a geologic influence.
To investigate this possibility, the upper 2500 ft of the undifferentiated
Plio-Pleistocene strata which encloses the salt dome were studied for evidence
of possible differential salt movement. Correlation of well logs in the
area provided the basis for dividing the strata into seven mappable units.
Each unit was isopached and in conjunction with a map of the salt stock
evaluated for evidence of differential salt (spine) movement. The possible
boundary
zones between areas of differential movements were projected into
the salt. In instances where similar trends were observed across the dome,
a projection of the
boundary
zone was made through the salt stock.
A composite of all the boundary
zone projections
was made and overlaid on the salt map. This map suggests that the salt
stock is composed of two separate spine complexes separated by a complex
boundary
zone area. When this map is compared to the frequency distribution
map, caverns with the large number of salt falls commonly are closely associated
with the projected
boundary
zones particularly the zone separating the
main spine complexes. Likewise those caverns which have experienced few
or no salt falls tend to be located within the spine complexes. The isopachs
of the two intervals which overlie the salt stock provide evidence for
the more recent development of a younger spine.
AAPG Search and Discovery Article #90924©1999 GCAGS Annual Meeting Lafayette, Louisiana