Application of hydraulic flow unit for prediction of flow zone in carbonate reservoir

Abstract

The feasibility of oil production in any reservoir depends on the porosity and the permeability of that reservoir. Particularly, the permeability in the reservoir allows the ease of flow of fluid through it. High permeability is always desirable for the successful production of oil in any reservoir. The porosity and permeability depend on the reservoir rock. In general, the higher value of porosity and permeability makes limestone a suitable reservoir. Therefore, it is very important to characterize the reservoir in terms of porosity and permeability for the feasibility of oil production. In this investigation, reservoir characterization was carried out to determine the porosity and permeability of limestone reservoirs obtained from four different basins of Oilmax Mumbai. A total of 32 core samples of NX size were tested for characterization and determined porosity and permeability values. The variation in porosity and permeability was observed from 0.3 to 20.5% and 0.002 to 1.484 mD at the burial depth from 1618.86 to 1634.14 m, respectively. The normalized porosity and reservoir quality index were determined using the experimentally obtained porosity and permeability values. Normalized porosity values were used to calculate the flow zone indicator (FZI), which varied from 0.071971 to 6.024804. The least-square regression method was used to determine the hydraulic flow units (HFU) for different limestone samples. The porosity range indicates the highly porous reservoir, while the lower permeability was observed due to the non-linearity between porosity and permeability correlations. The results showed the consistent flow regime in five different hydraulic flow units in wellbore A. The consistent fluid regime in the other wellbore is only possible by increasing the reservoir’s permeability. Hence, hydraulic fracturing is highly recommended before the establishment of a production well.