Future Studies

Featured on this page are examples of fracture studies that we find fascinating and that would be worth pursuing. We have numerous other potential studies and welcome your input for projects.

Wild fractures we have known, or studies someone really ought to fund

FractureStudies is currently developing several projects that will be for sale or that can be bought into during the development stages.  These projects include an Atlas of Natural and Induced Fractures in Core, and an Investor Report on Fracture Characteristics of the Niobrara Formation.  These are works in progress, expected completion dates in mid-2011.  The reports can be modified to suit a client needs now or later.

Niobrara Formation: The photographs below illustrate some of the fracture types documented within the Niobrara Formation.

Niobrara core

Niobrara Formation core showing the near parallel strikes of a calcite-mineralized hairline fracture above, and several unmineralized petal fractures, below.   Petal fractures form below the core bit due to the weight on bit, and their strikes record the orientation of the maximum in situ horizontal compressive stress (Lorenz et al., 1991).

Niobrara stylolite

Induced petal fracture (“P”) and its downhole extension centerline fracture (“CL”), that intersect the slab face (the lighter-colored, irregularly shaped plane on the right of the photo) at a small oblique angle.  These induced fractures strike nearly normal, at 80°, to the overall strike of the irregular stylolitized injection that extends vertically along the right side of the core.

Niobrara pavement

Fort Hayes Limestone Member of the Niobrara Formation, fractures on a pavement surface.

niobrara hairline

Two orthogonal natural fracture sets in the Fort Hayes Limestone. Hairline calcite-filled fractures trend top to bottom across the photograph, and a larger-aperture, partially open fracture trends left to right across the photograph.

Fractures in Granite

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Fractures in granite have many localized domains of intersecting and parallel extension fractures (Precambrian Laramie Mountains, Wyoming). Characterization of the fracture domain distributions would afford predictive capabilities for reservoirs in fractured granites.

En Echelon Veins

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En echelon veins in silicified sandstone; Ougarta Arch, Algeria. The orientation of these veins, and their occurrence in conjugate sets, indicates that the now-brittle sandstone was ductile and that the horizontal stress exceeded the vertical stress at the time of fracturing. Quantifying the stress conditions and the mechanical properties that control the formation of extension vs. conjugate fractures would be an important step in predictive capabilities.

Deformation Bands

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An unmineralized bundle of deformation bands in a shear zone forms a resistant ridge and would be a permeability barrier in a reservoir; fluvial Morrison Formation, New Mexico. Characterizing the distribution of such amalgamated shear bands would provide insights into the distribution of reservoir baffles and offer production strategies for overcoming such difficulties.

Dissolution

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Fractures in carbonates that have been preferentially leached out to form slots; Madera Limestone, New Mexico. Much study has been devoted to fracture mineralization. The flip side of the coin, fracture dissolution, is less well studied, but dissolution significantly enhances the effects of fractures on plumbing in many reservoirs.

Fracture Mechanics

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Fracture mechanics in core. Different types of rock deform in different ways: the sandstone accommodated strain with vertical extension fractures whereas the thin shale parting (dark gray/black material above pencil) deformed in a ductile manner and arrested fracture propagation, limiting vertical fracture-related permeability. Pencil for scale. A study of the different types of sedimentary heterogeneities in a reservoir and their effects on fracture distributions would assist in the construction of realistic fractured reservoir models.

Kurdistan

A limestone bedding plane in the Eocene Pila Spi Formation contains two sets of bed-normal stylolites. Stylolite orientations show in this area of Kurdistan there were two phases of compression, with the maximum compressive stress lying in the plane of bedding and trending normal to the stylolites, i.e., about NE-SW and NNE-SSW. This is compatible with the orientations and geometries of the several sets of extension and conjugate shear fractures in the area.

Core showing a strata-bound, calcite-mineralized slot in a thin limestone between calcareous shales. The slot originated as an extension fracture and has been widened by dissolution. Calcite was precipitated on the fracture faces after the slot had been widened by dissolution. The core is from tilted strata cut by a vertical well; for this photo, the core has been positioned to re-orient the fracture to its pre-fold vertical position and bedding to its pre-fold horizontal position.

Assyrian ruins at Khanis. The bas-relief sculptures cut into limestones of the Pila Spi Formation are accompanied by cuneiform inscriptions. The aqueduct that began at this site diverted water from the local river 100 kilometers across the plains to the city of Nineveh, near present-day Mosul.

Many fracture widths in the limestones exposed at the surface in Kurdistan have been enhanced by weathering during the wet winters, and later filled with mud and grass. General fracture strikes can be measured, but little else. Field work in Kurdistan requires an awareness of minefields and various armed political entities.

 

Contact Us

Scott P. Cooper
scott@fracturestudies.com

John C. Lorenz
john@fracturestudies.com

FractureStudies
99 Rainbow Road Suite 4-5 Edgewood, NM 87015