Texas Wilcox Regional Study and Rock Catalog

Gulf of Mexico Onshore

REGIONAL GEOLOGICAL, PETROPHYSICAL, AND ENGINEERING STUDY OF THE "DOWNDIP" WILCOX GROUP IN SOUTH TEXAS AND ROCK CATALOG - Available in RAPID

Formation evaluation, recognition of pay versus non pay and completion challenges are inherent to this prolific south Texas formation. This project was to designed to address these issues and aid participating companies in their exploration and exploitation activities in the trend. A full spectrum of geological and petrophysical analyses have been performed on the 171 wells with drill cuttings and conventional cores. The major objectives of this study are as follows:

• Describe, document, and interpret Wilcox sandstone lithology, vertical sequences, and the character of various lithofacies present within conventional cores
• Define, document, and evaluate sandstone mineral, textural, and pore space properties for Wilcox pay and potential pay zones
• Measure and evaluate various rock logging and fluid-flow parameters for selected Wilcox sandstone samples and zones representative of the spectrum of reservoir-quality rock types

The above geological, petrophysical and engineering data are compiled and evaluated to provide a regional synthesis and summary of Wilcox rock properties significant to current exploration and exploitation activities.

Individual well reports for each well are provided. The final report combines, correlates, and evaluates all of this information on a regional basis and contains information and conclusions regarding:

• Regional setting and stratigraphy
• Depositional environments and models, log response, sand body geometry, and vertical/lateral relationships
• Sandstone mineralogy, texture, and pore types
• Quantification of Wilcox rock types
• Petrophysical evaluation of Wilcox sandstones
• Detailed drilling and completion evaluations and recommendations

The Texas Wilcox Rock Catalog focuses on well completion and proper stimulation techniques for representative Wilcox rock types. It was designed to develop drilling and completion procedures compatible with the reservoir rock types defined in the regional study. Results of various geological and engineering analyses are included in catalog format for quick reference to a particular rock type. Rock type criteria include porosity, cement/clay content, and texture, along with permeability as the primary criteria used to differentiate Wilcox rock types in this study.

• 171 wells
• Conventional core, percussion sidewall cores and cuttings
• Regional rock catalog