ABSTRACT

The economic significance of the Camerina and Cibicides hazzardi zones and the numerous unanswered questions relative to possible areas of reservoir sand occurence, areas of maximum and minimum deposition and sand percentages and sand percentages, and downdip lithofacies developments prompted the preparation of electric log correlation section and lithofacies study of the intervals.

Three west-east (strike) and five north-south (dip) electric log correlation sections are presented. These section show the correlation points used, depths at which various zones occur, and the relationship between the lithologic and paleontological markers. The correlations are extended as deep as possible and include the tops of the Hackberry, Nonion struma and Nodosaria blanpiedi.

Isopachous maps of the Camerina and Cibicides hazzardi intervals, isopachous maps of the net effective porous and permeable sand found in each interval, and sand percentage maps were constructed. In addition to providing lithofacies data, these maps add a third dimension to the correlation sections. The primary purpose of the study was to develop data and make them available for individual interpretation. For this reason, only general observations relative to the findings are recorded in the text.

Sedimentation within the Cibicides hazzardi interval was influenced markedly by regional growth faults. Pronounced thickening and net sand increase occur on the downthrown sides of these faults. Sedimentation within this interval has also been affected locally by the older Hackberry negative area and by Nodosaria blanpiedi growth faults. Cibicides hazzardi sediments are best developed along northeast-southwest trending axes; they exhibit thickening and a decrease in net sand and sand percentage Gulfward. The downdip limit of Cibicides hazzardi sand development exist in the southeast part of the area studied.

The Camerina zone is characterized by the existence of large positive areas north of regional growth faults and tremendous thickening and net sand increases on the downthrown sides of these fault. Camerina sands show good development as far south as the study was extended.