AAPG Bulletin, Vol.83, No.6, 898-924, 1999
Upper Miocene Stevens sandstone, San Joaquin basin, California: Reinterpretation of a petroliferous, sand-rich, deep-sea depositional system
Deep-marine sands of the upper Miocene Stevens sandstone, one of the most important hydrocarbon-producing units in the United States, were deposited by sediment-gravity flows in the Bakersfield arch area of the southern San Joaquin basin. The Stevens sandstone historically has been considered to be a thick turbidite succession shed off the southern Sierra Nevada as four fans in a long-lived submarine fan system fed in large part by several large submarine canyons. Access to previously unavailable proprietary two-dimensional and three-dimensional seismic data sets, carefully calibrated by well-log and core data, permits a more complete understanding of the depositional architecture of this highly petroliferous, deep-marine depositional system. We conclude that these units were deposited in a structurally controlled, sand-rich deep-sea system, which was fed by a delta system that lacked major submarine canyons. The uppermost sand unit, the upper Stevens sandstone, developed as a deep-sea braid plain in the area of the present Bakersfield arch. Within the braid plain, curvilinear features detected on horizon slices through a three-dimensional seismic data cube are interpreted as braided channel-form deposits. Hydrocarbon production established along these linear trends may reflect improved reservoir quality localized by channel sedimentary processes.