ABSTRACT
Reservoir modelling of a fractured reservoir with any dual porosity/permeability simulator requires three basic fracture properties – fracture porosity, permeability, and average fracture spacing – to be provided as part of the reservoir description. Theoretically, any two of these are sufficient to determine the remaining third. In many instances, however, direct measurements on these properties or good pressure test data are missing or unreliable, making it virtually impossible to infer the fracture properties.
In a recently completed study on the Raman reservoir in Turkey, the spatial variations of the fracture system properties were estimated using a method developed for this purpose. The technique utilizes reservoir structure and layer net thickness data, production information, and some qualitative geological input on the nature of the fractures. The generated fracture system description was later used in successfully history matching close to 40 years of reservoir performance with a fractured reservoir simulator.
This paper presents the principles involved and the methodology that was developed to estimate the required fracture description.
Fracture data before and after the history match are compared to show the extent of the modifications that were needed.
The proposed technique is suitable for the Raman reservoir and others like it. Its application to another situation may require appropriate modifications.
