Fracture Identification and Analysis Using Seismic Attributes in Carbonate Reservoirs: Cimarrona Formation, Middle Magdalena Valley Basin, Colombia
Blanco, Joan M.; Padrón, Crelia E.; Contreras, Hugo I.
Use of seismic attributes for fault and fracture detection below the resolution of conventional seismic data is one of the major goals of modern seismic interpretation. Key attributes used for fault and fracture mapping include: dip-magnitude, dip-azimuth, coherence, volumetric curvature, and ant tracking. Fracture characterization is a matter of great practical importance in the recovery of hydrocarbons because fractures provide a major control on oil flow within carbonate reservoirs. We use some of these attributes to describe a naturally fractured carbonate reservoir of the Cimarrona Formation in the Middle Magdalena Valley Basin (Colombia). The field is primarily located on the eastern flank of a large north-south trending syncline. Two fault trends have been previously identified: 1) N-S-striking thrust faults; and 2) NW-SE and NE-SW-striking, strike-slip and oblique-slip faults. Attributes enhance these patterns and allow characterization of fracture density, orientation, and type of fluid saturation, using a 3-D post-stack time migrated seismic volume integrated with well data. We use ant tracking performed on discrete frequency cubes in co-blending visualization, spectral decomposition in RGB display, and a tool for automated extraction of faults and fractures, to discover fractured areas at different frequencies. We identify and analyze fracture zones in the discrete frequency ants cubes, then, using diverse diagrams (rose diagram, histogram, cumulative frequency plot) we correlate dipmeter data with the fractures extracted automatically from ant-tracking. This workflow enhances the resolution of faults and fractures, corroborating fracture sets and patterns previously reported. Moreover, t*attenuation and sweetness attributes were also calculated to assist in the fault fluid saturation and sand detection, respectively.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013