Publications

Information of residual oil saturation of reservoir is important to estimate remaining hydrocarbon resources of Brown field. Residual oil saturation is commonly measured from core by Water/Oil Relative Permeability (Kr) Unsteady State. This measurement is costly and time consuming, and further coring is more the exception then the rule. Therefore, an alternative technique of residual oil saturation computation by using log data is required since log data are generally available covering most of the pay zones. Residual oil saturation was computed by comparing computed water saturation in well with virgin oil zone, water rise zone, and virgin water zone. The result shows good matching between the residual oil saturation computed from resistivity and residual oil saturation data from relative permeability measurement. Residual oil saturation computed from resistivity result by using dual water equation can be used to estimate displacement sweep efficiency of the reservoir with no core data. Displacement sweep efficiency can be estimated using the Welge procedure from fractional flow curve analysis by inputting water saturation in waterise zone and water saturation in virgin oil zone. The result is reasonably acceptable compared with microscopic recovery factor from core data and megascopic recovery factor from simulation by considering reservoir heterogeneity. The details of methodology and examples in Brown field from the Mahakam PSC, East Kalimantan, Indonesia will be explained in this paper.