Imaging Unconventional Reservoir Pore Systems

This Memoir covers recent advances in the acquisition and application of high-resolution image data to unconventional reservoirs. The value of integrating multiple techniques is a common theme. Chapters address imaging methods, recognition of artifacts, and case studies that explore nanopore systems within particular depositional settings. The importance of mineralogy, organic matter content, and fabric to reservoir quality issues such as wettability, porosity, and formation damage are addressed. This volume will prove useful to anyone interested in the methods for observing and quantifying the pore systems that control hydrocarbon storage and flow in unconventional reservoirs. Unconventional reservoirs studied include Bakken, Barnett, Bossier, Eagle Ford, Geneseo, Green River, Horn River, Marcellus, Mississippi Lime, Monterey, Niobrara, Wolfcamp, and Woodford formations.
The Influence of Primary and Secondary Sedimentary Features on Reservoir Quality: Examples from the Geneseo Formation of New York, U.S.A.
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Published:January 01, 2016
Abstract
The Middle Devonian Geneseo Formation and its lateral equivalents in the Northern Appalachian Basin are regarded as crucial secondary targets to the extensively explored Marcellus subgroup. High-resolution sedimentology, stratigraphy, and petrography have yielded differentiation of genetically related packages, comprised of distinct lithofacies with characteristic physical, biological, and chemical attributes. In addition, argon ion milling and nanoscale scanning electron microscopy of shale sections has shown that the pore structure of the Geneseo derives from pores defined by phyllosilicate frameworks, carbonate dissolution, and within organic matter. Intervals of silt-rich mudstones and muddy siltstones occur in multiple facies types and “interrupt” facies, reflecting background sedimentation. These deposits and their sedimentary features are interpreted as products of high-density fluvial discharge events.
Pore morphology and distribution correlates with distinct mudstone lithofacies as a result of small-scale compositional and textural characteristics. Phyllosilicate framework pores are small triangular openings (100-1500 nm wide) and are the dominant pore type observed in hyperpycnites. Organic matter porosity is common (10-500 nm pore size) and dominates the organic-rich facies that represents “background” sedimentation with high organic content. Carbonate dissolution pores (50-500 nm wide) are observed in calcareous intervals and reflect partial dissolution of carbonate grains during catagenetic formation of carboxylic/phenolic acids.
- Appalachian Basin
- carboxylic acids
- catagenesis
- Cayuga Lake
- chronostratigraphy
- clastic rocks
- cores
- Devonian
- electron microscopy data
- Finger Lakes
- high-resolution methods
- lithofacies
- Marcellus Shale
- microstructure
- Middle Devonian
- mudstone
- New York
- North America
- organic acids
- organic compounds
- Paleozoic
- petroleum
- porosity
- reservoir properties
- sedimentary rocks
- SEM data
- shale oil
- sheet silicates
- silicates
- siltstone
- solution
- textures
- Tompkins County New York
- United States
- phenolic acids
- Geneseo Formation
- Lansing New York