Laboratory Investigation of Wettability and Relative Permeability : Case study - A Sudanese sand stone reservoir

Abstract

The Wettability has effects on almost all types of core analyses, hereby wettability changes the remaining oil saturation during enhanced oil recovery processes. The objective of this study was to determine the Wettability of core samples from Sudanese sand stone field by U.S.B.M (U.S. Bureau of Mines) amott wettability method and make quality check by un steady state relative permeability test by using JBN (Johnson, Baossler and Neuman )calculations in modern soft ware from France . The experiments were performed wettability, The oil flood to initial water saturation then Spontaneous imbibition of water ,Forced water imbibitions ,Spontaneous oil imbibition,Forced oil imbibition These combined technique allows the calculation of both Amott indices and the USBM wettability indexThe combined Amott/USBM method has two main advantages when compared to the standard USBM test The resolution of the USBM (U.S. Bureau of Mines) method is improved by accounting for the saturation changes that occur at zero capillary pressure.The Amott indices are also calculated. The Amott-Harvey technique also offers the possibility to measure the end-point effective permeabilities (ko at Swir and kw at Sro), during the same experiment Wettability characteristics could be derived from relative permeability curves: The irreducible water saturation increases as water wetness increase After establishing Swi by oil flood , then starting imbibitions by inject brine into sample and select three values(time,oil production and delta pressure)after that make calculation of three parameter by JBN to gain a relative permeability points (Kro & Krw Vrs Sw ) from these end point easy to know type of rock wettability. From two experiment the result had been in same value indicated to water wet reservoir.