AAPG Bulletin, V. 84, No. 6 (June 2000), P. 741-764.
Fold-Evolution Matrices and Axial-Surface Analysis of
Fault-Bend Folds: Application to the Medina Anticline, Eastern Cordillera, Colombia1
Mark G. Rowan2 and Roberto Linares3
©Copyright 2000. The American Association of
Petroleum Geologists. All rights reserved.
1Manuscript received April 15, 1998; revised manuscript received July 13, 1999;
final acceptance November 15, 1999.
2Rowan Structural Consulting, 1633 D 4th Street, Boulder, Colorado 80302;
e-mail: [email protected]
3Ecopetrol, Instituto Colombiano del Petroleo, Piedecuesta, Santander,
A.A.4185, Colombia.
We thank Ecopetrol for sponsoring the research and providing the seismic data, originally
acquired by Pennzoil, Exxon, Maxus, and Ecopetrol. CogniSeis Development (now Paradigm
Geophysical) donated the Geosec® restoration and modeling software used to construct the
fold-evolution matrices. The research was done at the Energy and Minerals Applied Research
Center (EMARC) at the University of Colorado, where the first author was funded by an
industrial consortium consisting of Agip, Amerada-Hess, Amoco, Anadarko, BHP, BP,
Burlington, Canadian Oxy, CNG, Conoco, Enterprise, Exxon, Marathon, Maxus, Mobil,
Occidental, Phillips, Shell, Texaco, Union Pacific, Unocal, and Vastar. Finally, we thank
Chuck Kluth, Don Medwedeff, Karl Mueller, Bob Ratliff, Bruce Trudgill, Tomas Villamil, and
Paul Weimer for their comments and contributions, and John Shaw for the invitation to
contribute to this special issue.
ABSTRACT
The Medina anticline is a fault-bend fold located in the hanging wall of the Aguaclara
fault along the southeastern thrust front of the Eastern Cordillera of Colombia, a
petroleum province with giant fields. We employ a modified technique of axial-surface
analysis using fold-evolution matrices, which helps define the subsurface geometry and
thereby provides important constraints on trap geometry, modeling of hydrocarbon migration
pathways, and prediction of reservoir quality.
