Date of Graduation


Document Type


Degree Name

Master of Science in Geology (MS)

Degree Level





Christopher L. Liner

Committee Member

T.A. (Mac) McGilvery

Second Committee Member

David Liner

Third Committee Member

Jamie Woolsey

Fourth Committee Member

Jason Eubanks


Geology, Petroleum Geology, Stratigraphy, Well Log Correlation


The Greta sandstone is an informal lithostratigraphic unit of the upper Frio Formation (Oligocene) that occurs across the Texas Gulf Coastal Plain. The Greta sandstone has been known to geologists since it was first drilled in the 1930’s, yet there has been very little research into this un-depleted and overlooked reservoir. This study provides insights into the lateral distribution and reservoir facies of the Greta sandstone. The unit represents an aggradational to transgressive barrier sandstone package grading up to mud-rich open marine inner shelf deposits. The interval is easily recognizable in well logs based on its strong SP and Gamma-ray responses. The depositional limits of the Greta sandstone within the Greta/Carancahua barrier/strandplain system has been mapped based on correlation of several thousand well logs throughout the south Texas Gulf Coast. This has aided in the understanding of the sequence stratigraphy of the Greta interval and the reservoir bodies that it contains. The Greta sand typically has 30% porosity and 280md permeability, produces heavy oil (~21API), and is commonly the uppermost producer in the Frio section. Cumulative and present day production data of the Greta sandstone has been collected to establish a database for oil production.