Modeling Controls on Fluvial Architecture from Outcrop

Alexandre Turner

Fluvial Architecture: The three dimensional geometry, proportion, and spatial distribution of the various types of alluvial deposits in sedimentary basins. (Allen, 1978)

Allen, 1965

Why study fluvial architecture?

Why build outcrop-based 3-D ‘truth models’ of fluvial deposits?

• Driven by Economics- Reduce Risk through more complete predictive models

- Maximize Efficiency by understanding static and dynamic components

• Because fluvial packages in the subsurface are often prolific hydrocarbon producing reservoirs

- North Sea

- Frontier Formation (Wyoming)

- Williams Fork Formation (Colorado) Reservoirs are complicated!!

What is known about the topic?• Short answer….A Lot!

The Geology of Fluvial Deposits (A.D. Miall 1996)

Dec. 8, 2011: Connectivity in Fluvial Systems – An AAPG E-Symposium

Ongoing: Fluvial Stratigraphy – An AAPG E-Symposium

Early 90s: John Bridge – Studying fluvial sandstone body dimensions

Current: Matthew Pranter (CU Boulder) – Training image based modeling

Current: M.J. Pyrcz (Chevron) – Has pioneered ‘rule-based’ modeling

What are the deficiencies in existing knowledge? How can I contribute?

Fluvial Architecture is influenced by tectonics, climate, base levels, and channel types

*How do these factors influence connectivity and can we quantify them?*

For Example: The A/S ratio

Benefits of Outcrop• The study of three-dimensional fluvial architecture can be enhanced by examining extensive exposures (outcrops)• New/Emerging technologies and the availability of these technologies can greatly enhance outcrop studies

- LiDAR- Gigapans- Software (Petrel, GOCAD)

What are the main elements of this study? What is the significance of this study?

Qualitative Sedimentology/Stratigraphy and Building a Quantitative Model1. Build a ‘Truth Model’ for the Rock House Cove area

- interpretation of outcrop faces- interpretation between: document uncertainty

2. *Quantitative Description*- predictive model

3. Connectivity Analysis…maybe- static component- streamline and fluid flow simulations

Significance: Can we draw conclusion about how depositional processes impact fluvial connectivity and can we use this to build better and more complete predictive models.

-Given sparse subsurface data (1-D) can this study give us some clues as to what is happening in 3-D connectivity.