High Resolution Biostratigraphy of the Phillips Petroleum OCS-P-396-#1 Well, Offshore Santa Maria, California

Abstract

A total of 507cuttings samples, 153-sidewall core and 34 conventional cores were analyzed in the Phillips Petroleum OCS-P-396-#1 Well, Offshore Santa Maria, California, from 760-7738.6 feet using detailed analysis of nannofossils, foraminifers, diatoms and silicoflagellates. The upper unit 760—3010’ is assigned to the early Pleistocene to middle Pliocene, early Hallian to Venturian Facies based on Foraminifera and were deposited in an open marine, upper to middle bathyal environment. Nannofossils suggest a Cn14a, 13b? and CN13a Zones. The middle unit from 3010-7120 feet is assigned to early Pliocene to middle Miocene Luisian Stage. Foraminifera and Nannofossils are barren in this interval. Diatoms present through this interval with first occurrence of Nitzschia reinholdii at 3670-3730 feet and first occurrence of Thalassiosira oestrupii at 3424.0 feet. The interval from 3424.0 feet to 3010 feet is correlated to lower diatomaceous sediments on Harris Grade Road; Capistrano Formation, Newport Beach, California; and the sample near Lompoc, California, CAS 1736 (originally assigned to late Miocene, with contaminated Monterey Shale diatoms). Sediments from 3670-4339 feet are assigned to Delmontian. The interval from 5710-6820 feet is interpreted as Mohnian (undifferentiated) based on Foraminifera deposited in Bathyal environment. Middle Miocene Luisian Foraminifera are present from 6820-6880 feet in this well. The lower unit, 7120-7743 feet, yielded Foraminifera of late Paleocene, Late Ynezian to early Bulitian Age, from 7330-7510 feet.

AAPG Datapages/Search and Discovery Article #90339 ©2019 AAPG Pacific Section Convention 2019, Long Beach, California, April 1-3, 2019