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Modelling Deformation and Stress to Assess Reservoir Potential in Fractured Carbonates: Cesar Rancheria Basin, Colombia
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 5
Abstract
Fractured carbonate reservoirs form a sizeable proportion of hydrocarbon reserves. In this study, fracture distributions are characterised in carbonate units in the Cesar Rancheria Basin to assist in future well planning. To achieve this the analysis focused on relating measured fractures in wells to specific deformation mechanisms. Most of the observed fractures are interpreted to have formed due to regional stresses in a strike-slip faulting regime. However, two additional fault-related fracture forming mechanisms are proposed for the reservoir: near-fault and fault bend folding fractures. The orientations and relative intensities of these fractures have been assessed through kinematic and geomechanical modelling. To ensure realistic fracture intensities, an approach was developed that included assessing the likelihood of failure under an assumed regional stress field. A DFN was then created by combining these predicted fracture distributions with the results of statistical analysis performed on the observed fractures. Fracture apertures within this DFN were then scaled according to their proximity to shear and tensile failure under the present-day stress field. The resulting DFN suggests high fracture intensities in the hanging wall of the main faults; however, these are likely to have low apertures under the present-day stress field, resulting in low secondary porosity.