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.
2-D Pore Architecture Characterization of a Carbonate Mudrock Reservoir: Insights from the Mid-Continent “Mississippi Lime”
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Published:January 01, 2016
Abstract
This study shows examples of how fundamental relationships between pore shape, porosity, permeability, and acoustic response differ in carbonate mudrocks with micro- to picoporosity (<62 μm diameter) compared to conventional carbonates with primarily macroporosity (256-4 mm diameter). Quantitative data show that some positive correlations exist between porosity and permeability, similar to those observed in conventional carbonates. However, several expected relationships between properties, such as pore shape and laboratory-measured porosity and permeability, are not readily apparent and appear to be complicated by the internal pore architecture coupled with diagenetic alterations and a multiscale fracture network. Additionally, there is a significant shift in measured sonic velocity relative to values calculated from empirically derived equations that are applicable to conventional carbonates. Deviations from expected quantitative data trends can be partially explained through qualitative observations of the pore types and internal pore geometries. Visual observations show how diagenesis can increase the complexity of the internal pore network by nonsystematically subdividing the pores. When correlated to facies, the internal pore geometry partially clarifies deviations to expected relationships between quantitative pore architecture measurements, porosity, and permeability. Although there is an added level of complexity in the pore architecture of carbonate mudrocks, this study shows there are fundamental relationships that exist between the pore architecture, pore shape, porosity, permeability, acoustic response, facies, and sequence stratigraphic framework with variable levels of predictability that, when used as an integrated data set, can be used to enhance the predictability of key petrophysical properties within these types of reservoir systems.
- acoustical methods
- carbonate rocks
- Carboniferous
- classification
- clastic rocks
- cores
- depositional environment
- diagenesis
- electron microscopy data
- geophysical methods
- lithofacies
- Midcontinent
- mineral composition
- Mississippian
- mudstone
- observations
- Oklahoma
- Osage County Oklahoma
- Paleozoic
- permeability
- petroleum
- physical properties
- porosity
- qualitative analysis
- quantitative analysis
- reservoir rocks
- sedimentary rocks
- SEM data
- sequence stratigraphy
- thin sections
- two-dimensional models
- United States
- wackestone
- well logs
- X-ray diffraction data
- north-central Oklahoma
- Mississippi Lime