The Stanford Project on Deep-water Depositional Systems (SPODDS) is a research program in the Department of Geological and Environmental Sciences at Stanford University focused on the study of ancient and modern deep-water deposits and depositional systems around the world. Affiliate members of this industrial consortium include numerous international energy companies that seek greater understanding of deep-water deposits as reservoirs for oil and gas.
Recent to modern submarine fan systems offer unique insights into the processes of sandy deep-water sedimentation. Analysis of modern systems provides turbidite researchers a glimpse of sea-floor morphology as well as timing and distribution of sediment gravity flow deposits. Factors that influence deep-water sedimentation, such as (1) basin setting, (2) source-to-basin sediment dispersal, (3) source area composition, (4) structural/tectonic activity, (5) sea level stands, and (6) climatic fluctuations, are relatively well-known for Holocene systems (last 11,000 years) and, thus, provide a contextual framework for understanding controls on deep-water sedimentation...
Lisa Stright worked with data form the Puchkirchen Field in the Molasse Basin of Upper Austria. She has developed a novel calibration between well log and inverted seismic attributes for sub-seismic facies prediction. The goal of this research was to generate and apply a new methodology for predicting sub-seismic scale facies (or rock types) from a calibration between core, well logs and inverted seismic attributes. The product of the calibration is a prediction of the contributions (in proportions) of each facies, defined at the log scale, which contribute to the coarse-scale seismic response...
Salinas Basin California
Classical deep-water outcrops of California have been a focus of SPODDS since its inception in the early 90's. The sedimentary and stratigraphic architecture of channel, canyon fill and submarine fan deposits have been an important focus, as has the process sedimentological analysis of various types of sediment gravity-flow deposits. SPODDS supported dissertations focused at least partially on ancient gravity-flow deposits in California.
South China Sea
Mangzheng Zhu (2007) used seismic reflect data sets along the east coast of China in the South China Sea to explore migrating submarine canyons and mass transport deposits.
Offshore West Africa
Near-surface, high-resolution 3-D seismic datasets in the region of the Niger Delta, West Africa, provide an excellent means to assess and refine models of deep-water depositional systems due to their unparalleled resolution of deposits over large areas (Adedayo Adeogba, 2003). The application of Adedayo's work in near-surface seismic data interpretation is in gaining a better understanding of the distribution of reservoir facies in other, complex slope depositional settings. SPODDS research has also included a 3D seismic reflection-based study of the avulsion histories and evolution of channel systems on the sea floor and shallow subsurface of the Niger Delta continental slope (Dominic Armitage, 2009) and studies of the types and evolution of Cenozoic to modern submarine canyons off Equatorial Guinea (Zane Jobe, 2010).
The northern Gulf of Mexico (GoM) basin is an ocean basin that formed as a
result of sea-floor spreading associated with the break-up of Pangea between
the early to mid-Jurassic. Following the formation of the basin, the deposition
of the widespread “Louann Salt” took place during Callovian due to aridity and
restriction of connection to other oceans. Another remarkable time in the geologic
history of the GoM is the episodes of high sedimentation during the Miocene
related to the formation of uplands by the Laramide Orogeny which shed sediments
into the Mississippi river. The episodes of high sedimentation resulted in
rapid salt tectonism due to mobilization by sediments load. This resulted on a
complex structural framework reshaped by dynamic interplay between
sedimentation and salt movement.
The Midyan peninsula is located at the junction of the northern Red Sea and the Gulf of Aqaba in NW Saudi Arabia. It contains uplifted syn-rift sediments from the Lower Miocene, including a deep-water unit, known as the Burqan Formation.
Cody Trigg (PhD 2018) is working on the facies relationships and overall sedimentary mechanics in this proximal, coarse-grained system.
In fine-grained sedimentary rocks, the most complete
understanding of a rock’s history is accessed through a combined
sedimentological and geochemical approach. In this endeavor, geologists know
that ‘the present is the key to the past.’ Unfortunately for the development of
geochemical proxies useful in deep-water shale systems, most geochemists have
not had access to much of the ‘present.’ This is mainly due to the simple fact
that geologists and oceanographers inhabit different academic worlds and
different departments. Thus a ‘dirty secret’ is that many geochemical proxies
in common use throughout industry and academia were often calibrated decades
ago on a relatively small number of samples, sometimes with incomplete
environmental data. Many proxies also rely on a single threshold value rather
than more appropriate confidence intervals. Through links to many oceanographic
institutions—including SPODDS long-standing association with MBARI—we are
fortunate to have access to a large library of modern sediment samples that are
directly associated with high-quality in-situ oceanographic data. Many of these
samples are from modern upwelling margins (Oxygen Minimum Zones) or other
hypoxic/anoxic areas—modern analogues of the sediments that form source rocks
and unconventional targets. We are currently analyzing this sediment library
using a variety of methods to better refine interpretations from existing
proxies and to develop new proxies. By analyzing these data with machine learning
algorithms we expect this project to provide the new standard in geochemical
proxies and ultimately a richer understanding of ancient deep-water systems.
It has long been known that black shales (i.e., the targets in unconventional systems) were deposited under dysoxic to anoxic conditions. In the modern ocean, essentially all anoxic environments are characterized by the presence of free sulfide (euxinia), and this model has been explicitly or implicitly applied to most ancient shales. Recently, it has been recognized that many black shales were deposited under ferruginous (free ferrous iron) conditions. This fundamental feature of depositional redox state likely influences many parameters in the rock that are ultimately important for production, but these links have yet to be elucidated. The Sperling research group is conducting detailed case studies of selected unconventional targets to provide the most nuanced view possible of the depositional environments of these units. These studies comprise an integrated analysis of sedimentology, stratigraphy, and multi-proxy geochemistry (iron speciation chemistry, trace metals, organic carbon contents and isotopes, and pyrite sulfur isotopes). Studies are currently ongoing in the Exshaw/Patry, Horn River Group, Montney Formation, Wolfcamp Formation, Cline Shale, Barnett Shale, Eagle Ford Shale, Bakken Formation, Marcellus Shale, and Utica Shale.
Moving forward from these detailed studies of individual cores, we are working to understand how environmental conditions changed across shale basins in time and space, and the oceanographic factors controlling such changes. We are also utilizing trace metal isotopes (specifically molybdenum and uranium) as tracers of the ancient global redox landscape. When these metal isotopic data are integrated into our modeling framework, we are able to predict intervals of Earth history when anoxia or euxinia—the conditions necessary for world-class unconventional targets—will be more widespread. Ultimately this will help identify under-explored areas of the geological column. Finally, we will undertake studies designed to mechanistically relate depositional conditions to parameters important for production.