Rock Typing and Generalization of Permeability- Porosity Relationship for a Carbonate Tight Gas Reservoir

Reservoir characterization methods are very important as they provide a better description of the storage and flow capacities of a hydrocarbon reservoir; moreover it plays crucial role in reservoir simulation models. Carbonate reservoirs show challenges to engineers and geologists to characterize because of their tendency to be tight and generally heterogeneous due to depositional and diagenetic processes. Among the various quantitative rock- typing techniques presented in the literature, the hydraulic flow unit method (RQI/FZI) is more widely used. ‘D’ is a main carbonate formation for one of the giant gas reservoir in Iran. In this study, available routine core data from four wells are assembled to develop mproved generalized permeability porosity relationship for characterize ‘D’ formation by (HFU) concept. For this purpose, three wells are considered to develop HFU transforms for ‘D’ formation. Correlation accuracy of each discrete rock type (DRT) was very good (R2>0.9) for orizontal permeability. Then all data from different wells were combined to determine generalized porosity permeability relationship for ‘D’ formation. This transform was tested for its accuracy on available core data of fourth well which exist in the same formation. Calculated permeability data by HFU technique matched very well with the routine core data which confirm the accuracy of generalized HFU transform. In the same manner, generalized vertical permeability relationship was developed for ‘D’ formation and tested for its accuracy.

Keywords:

Reservoir Characterization , Rock Typing , Hydraulic Flow Unit , Permeability , Carbonate Reservoir