Fault property database 

Subsurface faults and fractures are difficult to predict and characterise because seismic resolution only permits major features to be detected.

At the same time, well data are best suited to identifying and mapping the smallest-scale features (faults and fractures on the centimetre-decimetre scale). 

Large-scale fault zone with a 200-metre displacement, juxtaposing Jurassic sandstones (reddish rocks to the right) against Cretaceous siltstones, sandstones and conglomerates (left). Waterfall Canyon in the Moab Desert of Utah, USA.

One way of plugging this gap is to collect and standardise data from various analogues – oil and gas fields and similar rocks cropping out at the Earth’s surface. 

StatoilHydro has therefore developed a highly organised, user-friendly computer database aimed at capturing various empirical fault property datasets. These have been assembled from 22 fields and outcrop studies in Iran, Egypt, and Greece. 
 
The database contains a variety of fault properties, ranging from geometrical descriptions of fault zone thicknesses, throws and fracture frequencies to petrophysical properties and simple mathematical expressions aimed at predicting sealing capacity.

More general information about geological context and history is also included to provide guidance when assigning properties to fault models designed for different geological settings.
 

Mixed (heterogeneous) rock unit displaying a high frequency of deformation bands (small faults) and joints. Such features may act as conduits or flow barriers, depending on their origin and the governing geological conditions. The deformation bands occur in the less cemented parts of the sandstones, whereas the joints are concentrated in the highly cemented bluish horizons. Waterfall Canyon in the Moab Desert of Utah.

The database is divided into two interactive modules: one for fault properties and the other covering case studies. These facilitate efficient accessing, visualising and comparing both types of information. 

The database accordingly provides an important tool for improved understanding of fault properties in general, and a unique opportunity for comparing the flow properties of faults in different fields.