A study of the subsurface conditions prevailing in the Newhall-Potrero oil field

• Main Author: Edmundson, James Wiliam
• Format: Others
• Published: 1947
• Online Access: https://thesis.library.caltech.edu/5743/6/Edmundson_jw_1947.pdf; https://thesis.library.caltech.edu/5743/2/Edmundson_jw_1947_plate.PDF; Edmundson, James Wiliam (1947) A study of the subsurface conditions prevailing in the Newhall-Potrero oil field. Master's thesis, California Institute of Technology. doi:10.7907/M479-4913. https://resolver.caltech.edu/CaltechTHESIS:04272010-094146381 <https://resolver.caltech.edu/CaltechTHESIS:04272010-094146381>

The Newhall-Potrero Oil Field is a long, narrow, asymmetrical anti line whose longitudinal axis trends northwest-southeast. From a critical examination of many of the electric logs of the field, it is apparent that lensing of sands thickening and thinning of both sands and shales, and rapid facies changes are prevalent throughout the field. Several of the oil sands in the Miocene either lens out or die out due to facies changes toward the southeast. Two faults of major displacement are well shown in the logs of four wells, with other faulting probably occurring. A stratigraphic correlation chart is presented to illustrate the rapid lithologic changes which prevail in the field. The Newhall-Potrero anticline is exposed on the surface in the hills north of the Potrero, but seams to die out to the southeast. The rocks encountered at depth in the wells of the Newhall-Potrero field outcrop to the south, but no ecru ate correlations between the surface exposures and the well logs were possible.