Abstract

Basement is unconventional in the context of reservoir nature and complex to characterize. Hydrocarbon accumulations in Basement are generally seen in the fault zones and associated interconnected networks of fractures which account for the porosity and permeability. Identification of Fractures in the Basement sections using primarily the resistivity image logs and anisotropy from advanced sonic logs. A case study from Mumbai offshore is presented where fewer wells have shown hydrocarbon potential in the basement section. However, it is a well-known fact that the production from fractured basement is directly related to the occurrence of critically stressed fractures (CSF). In basement reservoirs, critically stressed fractures refer to natural fractures that are oriented favourably to shear failure under the prevailing in-situ stress conditions, potentially acting as primary pathways for fluid production. Thus, the identification of CSF’s becomes more important to forecast a sustained production from the basement and the direction of these fractures may give further lead while placement of future wells (Javier Franquet etal, 2008). This paper illustrates the methodology for basement characterization and to identify critically stressed fractures (CSF), in naturally fractured reservoirs