Historically much of the geological knowledge of the Paradox Basin has been based on petrologic studies conducted in the late 1940's and 50's. Major advances in the understanding of continental tectonism during Paleozoic times have aided in deciphering the buried structural history of the Paradox Basin. Although advances in recent years in both carbonate and evaporite sedimentology have been made, many operators in the Paradox Basin have been employing sedimentological concepts developed over thirty (30) years ago.
This Study has explained many of the geological ambiguities of the basin by placing the Paradox Basin in an accurate global and regional tectonic and glacioeustatic setting, whereby specific diagenetic events and subtle depositional environmental changes have been defined and placed in a predictive model.
This Study has analyzed and interpreted Paradox Formation lithology, depositional environments and geological, petrophysical, and engineering properties gathered from conventional core analysis of fifty-six (56) wells. These wells contain approximately 4,800 feet of cored interval. Detailed facies characterization of productive and non-productive intervals are provided utilizing thin section petrology, scanning electron microscopy, X-ray diffraction, and cathodoluminescence analytical techniques. Particular attention has been directed toward diagenetic variations in relation to well productivity within specific lithofacies, including their associated log signatures. In addition, new stratigraphic terminology is introduced in this Study which clarifies depositional environments and their relationship to associated structure.
The regional stratigraphy of the Paradox Formation, including the Desert Creek and Ismay stages, has been evaluated in this study through the correlation of over 1,500 wildcat and development wells drilled to the Paradox or deeper zones. Various stratigraphic correlations and relationships are incorporated into numerous structure maps, isopachs/lithofacies maps, and cross-sections. Facies zonation, which was established from detailed core studies, has been tied to well logs and correlated within the various cross-sections and maps, providing a basin-wide distribution of facies.
The geological and engineering data generated and the interpretations presented in this study represent the crux of information necessary for a well integrated exploration/development play in the Paradox Basin. Particular emphasis has been placed on the uppermost carbonate cycles (Desert Creek, Lower Ismay and Upper Ismay stages) of the Paradox Formation because of their known economic importance as major oil and gas reservoirs in the Four Corners area.