Diagenetic and Rock Physics Depth Trends in the Veracruz Tertiary Basin, Mexico

Abstract

Abstract

The purpose of this project is to identify the relation between diagenesis and elastic properties of sandstones and shales in the Veracruz Tertiary Basin (VTB), eastern Mexico. Porosity-depth trends and rock physics templates were constructed to create the link between geology and elastic response of the rocks. Empirical porosity-depth relations combined with rock physics models were used for the calculation of the velocity trends.

The study area is dominated by mechanical compaction, however chemical compaction is observed in some wells. Additionally, rock physics templates (RPTs) were constructed and displayed as acoustic impedance versus Vp/Vs ratio plots. Brine and hydrocarbons trends were defined for fluid identification. It has been observed that shaly gas sands show similar acoustic impedance as shales.

Seismic interpretation can be uncertain if no geology is related to the elastic response on the subsurface rocks. The rock physics depth trends in the VTB can be applied for porosity, lithology and fluid prediction from seismic data. These tools helped to identify the depth interval where sands and shales can be discriminated by seismic inversion or AVO analysis.

AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016