Petrophysical Evaluation of Arab Formation using Multimin, Petrography and Petrography Carbonate Methods in one of Iranian Oilfields, Persian Gulf

Abstract

In the present research work, petrophysical parameters of Arab Formation (equal to Surmeh Formation) were evaluated using three methods: petrography, petrography carbonate and multimin. Wirelog data are input in GEOLOG software by probability method in one of southern Iranian oil fields. Arab Formation in this oil field divided into 7 zones. Dolostone and anhydrite with a less value of shale are the main lithological components. Lithological comparing results provided that the calcite variation is not following a sharp trend. Carbonate petrography method is also showing weak correlation to the log in spite of high resolution of limestone presentation than multimin.

The results of petrographic, petrography carbonate, core data and corrected well logs were uploaded in GEOLOG software to construct the basic petrophysical model. To get the high quality and improving the petrophysical evaluation data, the results were compared to core data. The porosity data variation in multimin to petrographic processes, carbonate petrographic and core data revealed that the correlation coefficients are 0.69, 0.71, and 0.91 respectively. This is concluded that the carbonate petrographic procedure in view of the porosity estimation is provided us more suitable results than other methods. Water saturation study is however, provided that the results of the carbonate petrography are scattered and so the petrography method is preferred and matched well with core data. Porosity and permeability variation indicated that they are not correlated well but depend on the reservoir lithological variation. Based on these results, reservoir zones 1 and 3 are indicating the best reservoir quality in view of porosity and water saturation values.