Characterisation of 3-D Fracture Networks Using Quantitative Outcrop Analogues Analysed with Lidar and Shallow Geophysics

Jones, Richard R.¹; Vsemirnova, Ekaterina A.¹; Bubeck, Alodie A.¹; Pearce, Mark A.¹; Watson, Francesca E.¹; Daniels, Susan E.¹; Carle, Joël A.¹
(1) Geospatial Research Ltd, University of Durham, United Kingdom.

Improving our understanding of flow of hydrocarbons and CO₂ in fractured reservoirs requires detailed characterisation of three-dimensional fracture networks at seismic and sub-seismic scales. Terrestrial laser scanning (ground-based lidar) is a very rapid method to record the three-dimensional surface of outcrops, at centimetre resolution, with high spatial precision. Geological processing of the resultant lidar outcrop allows a virtual fracture network to be constructed. This can then be analysed semi-automatically in order to derive robust bulk fracture statistics for the outcrop. These typically include: fracture orientations; fracture size analysis; fracture spacing; fracture clustering; fracture connectivity; fracture orientations relative to fold geometries and dip of bedding in the host outcrop; variation of fracture geometry relative to stratigraphy; and spatial heterogeneity in fracture orientations. Lidar is essentially non-penetrative, however shallow geophysical methods, including Ground Penetrating Radar (GPR), can be combined with lidar data to derive fully three-dimensional models of the near sub-surface. To date we have analysed more than 25,000 fractures from over 45 sites globally, in a wide range of lithologies (including carbonates, sandstones, shales, mixed carbonate/clastic sequences, crystalline rocks) and tectonic settings (extensional, compression, strike-slip, and oblique).

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.