Petrophysical Challenges and Impact of Bitumen Quantification in Reservoir Rocks

Abstract Conventional reservoirs with bitumen pose a challenge to accurately quantify its presence and impact on reservoir producibility. Due to the presence of bitumen in the reservoir, which can be in the form of pore lining, pore fill and/or pore throat blocking, reservoir connected porosity and permeability is impaired. If volume of bitumen is not correctly quantified then hydrocarbon in place, completion decisions, reservoir producibility and ultimate recovery is impacted. Basic logs often do not have sufficient contrast to differentiate bitumen from hydrocarbon in the reservoir, hence, advanced logs viz. NMR and spectroscopy logs are required to identify bitumen and its quantification. An in-house simultaneous multi-sensor inversion algorithm is developed to quantity lithology and fluid volumes which are then calibrated with available conventional core data. This paper outlines a workflow to accurately quantity bitumen in the reservoir with the integration of logs and core. Detailed thin sections, core sedimentology, digital rock and petrography work has been integrated with logs to quantify bitumen and assessing its impact on reservoir properties. Moreover, impact of bitumen presence on reservoir producibility is assessed with production data and PLT acquired across the reservoirs of interest. Reservoir properties modelling workflow to build static model is also discussed to generate static model with bitumen variation and thereby assessing its impact on hydrocarbon in place and ultimate recovery.