Publications

Fractured basement reservoirs are amongst the most difficult and expensive types of reservoir to evaluate. Yet, of all reservoirs, they are the most important to evaluate early in the field lifecycle to minimise the costs of drilling unnecessary wells. It is essential to acquire important fracture characterization data early to optimise future well locations and paths, to predict field production rates and recovery, and to deplete the field economically. There are a number of crucial fracture parameters that must be quantified (or at least semi-quantified) before developing an effective static/dynamic fracture model and deciding if the discovery is an economic field. These parameters include: Fracture identification: e.g. how to differentiate between natural, stress-enhanced natural and drilling-induced fractures. Fracture geometry: orientation, height, length, density and clustering. Is the fracture open or closed? (i.e. cemented, non-cemented or partially cemented). Fracture aperture - can we really measure aperture from image logs? The importance of understanding the in-situ stress regime to determine which of the many fractures really matter. (critically stressed and permeable fractures). This paper presents a critical assessment of common datasets and methodologies. Each parameter is discussed and the associated traps and pitfalls are highlighted using examples from Vietnam, Indonesia, Australia, Yemen and the USA.