sadegh fathollahi - petroleum university of tecnology
reza askarinezhad - petroleum university of tecnology
mohammad izady - petroleum university of tecnology

Flow Units or Hydraulic Flow Units are one of the primary and fundamental units in reservoir characterization. They can be defined as the regions in a reservoir with similar properties that affect flow. Different methods can be applied for the determination of the units and their corresponding petrophysical properties.The amount of information required by each method varies depending on the data and tools available.This leads to different flow units interpretation of the same reservoir.The main objective of this study is to compare a number of flow units determination methods in a heterogeneous multilayered fractured reservoir in south Iran.Each clustering method was first applied and then clusters (flow units) were determined using available numerical and mathematical methods of clustering.Simultaneously for the second step the validity of each method was examined by available capillary pressure data, meaning, capillary pressure was predicted by each method as a function of wetting phase saturation, and compared with corresponding measured data.on the third step all the methods were compared in accordance with the quality of classification of the capillary pressure curves (of each core sample) into distinct groups and also in predicting capillary pressure compared with laboratory data. Among these methods first the classic leveret J-Function was applied to the whole data assuming the entire system to be a single cluster (Rock Type). Then with the same assumption the modified J-Function was applied. After that, clustering methods were applied; the basic for each was selection of a property or combination of properties of reservoir that was/were thought to be the main exclusive parameter(s) of causing heterogeneity throughout the reservoir.The parameter combination method was based on Kazney-Carman equation and is known as HFU method; and other three methods are based on threshold pressure, initial wetting phase saturation and lithology. finally regression errors resulted in that the HFU and initial wetting phase saturation clustering methods were the most accurate ones in predicting capillary pressure. Also lithology based and threshold pressure based methods were on the next priorities respectively.

capillary pressure,Hydraulic Flow Units,clustering ,cluster,rockType,leveret J-Function, modified J-Function ,threshold pressure,initial wetting phase saturation,lithology