Abstract
Wettability indices were derived using centrifuge capillary pressure tests on two sets of core samples of carbonate reservoir of Mumbai High, an Indian offshore field. One set of samples were aged in crude and then displaced with Isopar mineral oil so that the test sequence could be conducted at ambient temperature. Another set of samples were aged in crude and the subsequent testing conducted using crude oil at elevated temperature. The wettability indices indicated intermediate wettability character with slightly water wet to slightly oil wet and the field is expected to yield higher oil recovery. Moreover, similar wettability indices derived from both sets of tests indicated that displacing crude with Isopar left the samples in a reservoir representative wetting condition. Hence subsequent testing using Isopar at ambient temperature would yield valid results at much lower cost, and in a much faster time frame, than conducting tests at reservoir temperature and pressure with crude oil.
