Characterization Number (CN): Field Application and Analytical Evaluation for Different Reservoir Characterization Techniques Identifying Hydraulic Flow Units

摘要

Enhanced reservoir characterization is imperative and essential requirement for better and an increasing oil recovery from heterogeneous reservoirs. Several engineering techniques have been developed and used widely worldwide for reservoir characterization identifying hydraulic flow units. These techniques included porositypermeability correlation, J‐function, reservoir quality index (RQI) and characterization number (CN). The challenge in these techniques is that it is frequently assumed they are working properly and capable to identify the flow units but in practice; static rock‐properties are not representative of dynamic flow conditions plus ignoring the fluid properties in the reservoir. In addition, many models ignore and sometimes mixed different reservoir heterogeneity scales. The main objectives of this study are to provide analytical evaluation and investigate the accuracy of field application of the above‐listed techniques. Actual field data from three heterogeneous oil reservoirs from Egypt, Iran and United Arab Emirates (UAE) are analyzed and used to investigate the accuracy and field implementation of these techniques. The results of the three actual oil fields indicated that the porosity‐permeability correlation technique is very local in application and limited to the group of wells used in development of these correlations. In addition, this technique shows always a big scattering degree of data points and consequently is not capable to identify the flow units. The J‐function application shows better performance to achieve the flow unit’s identification but in some other fields is not suitable to delineate different flow units. The reservoir quality index (RQI) has shown better performance than the two‐previously‐mentioned ones but still suffers from high scattering degree. The application of characterization number technique (CN) has proven more accuracy in identification the flow units with minimum scattering degree of data points plus additional advantage of plotting the data on a Cartesian‐scale and not on a log‐log plot, like the reservoir quality index.