AAPG Bulletin; August 2007; v. 91; no. 8;
p. 1085-1098; DOI: 10.1306/03060706074
© 2007 American Association of Petroleum Geologists (AAPG)
Toward a quantitative definition of mechanical units: New techniques and results from an outcropping deep-water turbidite succession (Tanqua-Karoo Basin, South Africa)
G. Bertotti1,
N. Hardebol2,
J. K. Taal-van Koppen3 and
S. M. Luthi4
1 Department of Tectonics, Vrije Universiteit, Amsterdam, Netherlands; giovanni.bertotti{at}falw.vu.nl
2 Department of Tectonics, Vrije Universiteit, Amsterdam, Netherlands; present address: Institut Français du Pétrole, Rueil-Malmaison, Paris, France
3 Department of Geotechnology, Delft University of Technology, Delft, Netherlands; present address: Total Exploration and Production Bordewijklaan 18 2591 XR The Hague, Netherlands
4 Department of Geotechnology, Delft University of Technology, Delft, Netherlands
G. Bertotti got his M.S. degree at the University of Pisa (Italy) and his Ph.D. at the Eidgenössische Technische Hochschule (ETH) Zurich (Switzerland). Since moving to the Vrije Universiteit, Amsterdam, he has been involved in structural and tectonics projects at the interface between field data and modeling. He is now leading research programs on fracturing and on young vertical movements and deformations in Morocco and Turkey.
N. J. Hardebol received his M.S. degree in structural geology at the Vrije Universiteit in Amsterdam and is currently working on his Ph.D. at the Institut Français du Petrole. His research includes structural geologic, forward-kinematic, and tectonic modeling, with focus on different petroleum provinces, including the Canadian Foothills. Data mining and processing involving advanced spatial database technology form one of his recent activities.
José Taal received her M.Sc. degree from the Vrije Universiteit, Amsterdam, with a major in structural geology, after which she started a Ph.D. at the Delft University of Technology, focusing on natural fractured reservoirs. Currently, she is working as a geologist with Total E&P in the Netherlands.
Stefan M. Luthi got his Ph.D. in 1978 at the ETH Zurich. He was production geologist with Oil Service Company in Iran and occupied several positions with Schlumberger Oilfield Services in Dubai, the Schlumberger-Doll Research Center in Ridgefield (United States), France, and Angola. Since 1999, he has been professor at the Delft University of Technology and, since 2002, also head of the Department of Geotechnology. Stefan is a senior technical advisor for Schlumberger Limited.
The physical properties of reservoirs are strongly influenced by distributed fracture fields. Outcrop studies are commonly used to determine them but have provided unsatisfactory results because the definition of mechanical units, i.e., (groups of) layers displaying homogeneous fracture patterns, is difficult and typically conducted in a qualitative manner. We have developed a systematic methodology to acquire and process fracture patterns in outcrops and to define their relation with stratigraphy. We dedicate particular attention to the vertical distribution of fractures in a sedimentary succession, commonly composed of layers of different thicknesses and compositions. The method makes full use of geographic information system technologies and allows for direct digital acquisition in the field leading to time-efficient acquisition. Data are processed with a newly developed routine that permits an objective description of the changes of fracture characteristics along the stratigraphy of the outcrop. The operator is then able to define the most suitable fracture stratigraphy. The integration of results from different outcrops is thought to provide a tool for predicting fracture distributions in subsurface target areas.
Copyright © 2009 by American Association of Petroleum Geologists (AAPG)
