Upper Campanian and lower Maestrichtian depositional systems and gas production, southern Sacramento basin, California
- Applied Earth Technology, Inc., Redwood City, CA (USA)
Upper Campanian and lower Maestrichtian strata of the southern Sacramento basin include four west- and southwest-prograding submarine-fan/slope/delta systems. The Winters, Lathrop, Tracy, and Blewett formations consist of submarine-fan and related slope/basin-plain deposits that were fed by various deltaic complexes of the Starkey Formation. Four major basinwide transgressive shale units (Sacramento Shale, Sawtooth Shale, Ragged Valley Shale, and H and T Shale) help intrasystem correlations. The Winters, Tracy, and Blewett fans are small, radial, coalescing sand-rich systems that contain the following principal facies: (1) sandstone-filled inner fan channel deposits, (2) mudstone-dominated inner fan interchannel deposits, (3) middle-fan amalgamated suprafan-type sandstone-rich channel deposits, and (4) mudstone-dominated outer fan deposits. The Lathrop fans are larger, elongate, mixed-sediment systems that contain basin-plain, outer fan lobe, middle fan-channel, levee, interchannel, and inner fan channel facies. The Sierran-derived fluvio-deltaic Starkey Formation can be divided into six sand-rich deltaic cycles that can be subdivided on the basis of log signaturres and spatial distribution into prodelta, delta-front, lower delta-plain, and upper delta-plain/fluvial facies. More than 50 gas fields produce from these systems. Stratigraphic traps include updip pinchouts of submarine canyon/gullies and inner fan channels into slope shale, especially in the many overlapping and coalescing sand-rich systems. Lateral pinchouts of outer fan lobes and middle-fan suprafan-type bodies are also productive. Structural traps generally characterize production from deltaic deposits because of the more continuous nature of these bodies.
- OSTI ID:
- 6663649
- Report Number(s):
- CONF-900605-; CODEN: AABUD
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (USA), Vol. 74:5; Conference: Annual convention and exposition of the American Association of Petroleum Geologists, San Francisco, CA (USA), 3-6 Jun 1990; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
58 GEOSCIENCES
CALIFORNIA
NATURAL GAS DEPOSITS
RESERVOIR ROCK
ALLUVIAL DEPOSITS
CONGLOMERATES
GEOLOGIC FORMATIONS
GEOLOGIC TRAPS
SANDSTONES
SEDIMENTARY BASINS
SILTSTONES
FEDERAL REGION IX
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
MINERAL RESOURCES
NORTH AMERICA
RESOURCES
ROCKS
SEDIMENTARY ROCKS
USA
030200* - Natural Gas- Reserves
Geology
& Exploration
580000 - Geosciences