--> ABSTRACT: The Monterey Formation of California: New Research Directions, by Behl, Richard J.; #90142 (2012)

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The Monterey Formation of California: New Research Directions

Behl, Richard J.*1
(1) Geological Sciences, Calif State University, Long Beach, CA.

The Miocene Monterey Formation is an exceedingly heterogeneous, biogenic-rich (siliceous, calcareous and carbonaceous) deposit and only a minor fraction of its volume would be considered a true “shale”. It is California’s primary petroleum source rock and an important “conventional” reservoir in many areas, primarily exploiting naturally fractured rocks. Recently, due to its great thickness, broad areal extent and organic-richness, the Monterey was recently estimated to hold more than half of all the recoverable shale oil resources in the lower 48 states. This significance raises the following fundamental and applied research questions: How much of the Monterey’s varied lithostratigraphy reflects global vs. local environmental conditions? How do facies in the formation vary laterally? How does porosity and permeability vary with diagenetic setting and timing - not just silica phase and composition? How does diagenesis and deformation vary with depositional environment, primary composition and structural setting?

As part of the CSU Long Beach Monterey and Related Sedimentary rocks (MARS) Project, we are investigating stratigraphic, geochemical, diagenetic, and structural aspects of this important formation with the following goals: Refine the chronostratigraphy lithostratigraphy for the Monterey Formation of the San Joaquin Basin, applying chemostratigraphic, cyclostratigraphic and tephrochonologic methods. Investigate compositional variability in facies of the "Nodular Shale" or "Black Shale" of the Los Angeles Basin. Characterize Monterey lithologies and microfacies petrographically, including unusually porous diagenetic siliceous rocks. Investigate variability in genus-level composition of diatomite related to depositional environments and the influence of diatom assemblage on physical properties and diagenetic potential. Study mechanical stratigraphy in different lithologies and stratal architectures and their influence on fracture development in the Monterey Formation. Develop a genetic model of lithologic composition and cyclicity that can be predictive of mechanical stratigraphy and fracturability in different lithofacies. Hopefully, wih success in these endeavors, the Monterey Formation, with its varied composition and stratigraphic character, can serve as a valuable analog for other “shale” and non-conventional resource plays.

 

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California