Faults, slickenlines
Steven Ogilvie
Slickenlines & Shear Fractures

This blog shows that slickenlines are scratches on the surfaces of shear fractures. The state of stress on a shear fracture can be predicted by Mohr circles.

Slickenlines & Shear Fractures
Fractures, Geothermal
Steven Ogilvie
Wettability & Recovery in Fractured Chalks

This blog addresses why wettability is important in the recovery of oil from fractured chalks.

Wettability & Recovery in Fractured Chalks
Steven Ogilvie
Natural Fracture Types in Fractured Reservoirs

There are 2 basic types of natural fractures that need to be studied when characterising naturally fractured reservoirs - whether it be a geothermal or hydrocarbon reservoir. These are extension and shear fractures.

Natural Fracture Types in Fractured Reservoirs
Faults, Folds
Steven Ogilvie
Thrust systems at different scales

This blog examines some key features of thrust systems with an example from seismic data offshore Namibia and from a hand specimen onshore UK.

Thrust systems at different scales
Fractures, joints
Steven Ogilvie
Deformation band contained Joints

This blog looks at joints contained within zones of deformation bands - how they form and if they are important or not.

Deformation band contained Joints

Is the fracture natural or induced ?

Is the fracture natural or induced ?

When creating a fracture density log, be sure not to include induced fractures (by coring, handling etc). This blog outlines the main criteria I use to differentiate between natural and induced fractures in rock core.

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Classification of Naturally Fractured Reservoirs

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Classification of Naturally Fractured Reservoirs

Fractured reservoirs are often dual porosity systems where the fractures provide an additional porosity to the matrix. Nelson provides a valuable classification of fractured reservoirs based upon relative contribution of matrix and fractures to porosity and permeability.